drivers/target/target_core_user.c

   1 /*
   2  * Copyright (C) 2013 Shaohua Li <shli@kernel.org>
   3  * Copyright (C) 2014 Red Hat, Inc.
   4  * Copyright (C) 2015 Arrikto, Inc.
   5  * Copyright (C) 2017 Chinamobile, Inc.
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms and conditions of the GNU General Public License,
   9  * version 2, as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20
  21 #include <linux/spinlock.h>
  22 #include <linux/module.h>
  23 #include <linux/idr.h>
  24 #include <linux/kernel.h>
  25 #include <linux/timer.h>
  26 #include <linux/parser.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/uio_driver.h>
  29 #include <linux/radix-tree.h>
  30 #include <linux/stringify.h>
  31 #include <linux/bitops.h>
  32 #include <linux/highmem.h>
  33 #include <linux/configfs.h>
  34 #include <linux/mutex.h>
  35 #include <linux/workqueue.h>
  36 #include <net/genetlink.h>
  37 #include <scsi/scsi_common.h>
  38 #include <scsi/scsi_proto.h>
  39 #include <target/target_core_base.h>
  40 #include <target/target_core_fabric.h>
  41 #include <target/target_core_backend.h>
  42
  43 #include <linux/target_core_user.h>
  44
  45 /**
  46  * DOC: Userspace I/O
  47  * Userspace I/O
  48  * -------------
  49  *
  50  * Define a shared-memory interface for LIO to pass SCSI commands and
  51  * data to userspace for processing. This is to allow backends that
  52  * are too complex for in-kernel support to be possible.
  53  *
  54  * It uses the UIO framework to do a lot of the device-creation and
  55  * introspection work for us.
  56  *
  57  * See the .h file for how the ring is laid out. Note that while the
  58  * command ring is defined, the particulars of the data area are
  59  * not. Offset values in the command entry point to other locations
  60  * internal to the mmap-ed area. There is separate space outside the
  61  * command ring for data buffers. This leaves maximum flexibility for
  62  * moving buffer allocations, or even page flipping or other
  63  * allocation techniques, without altering the command ring layout.
  64  *
  65  * SECURITY:
  66  * The user process must be assumed to be malicious. There's no way to
  67  * prevent it breaking the command ring protocol if it wants, but in
  68  * order to prevent other issues we must only ever read *data* from
  69  * the shared memory area, not offsets or sizes. This applies to
  70  * command ring entries as well as the mailbox. Extra code needed for
  71  * this may have a 'UAM' comment.
  72  */
  73
  74 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
  75
  76 /* For cmd area, the size is fixed 8MB */
  77 #define CMDR_SIZE (8 * 1024 * 1024)
  78
  79 /*
  80  * For data area, the block size is PAGE_SIZE and
  81  * the total size is 256K * PAGE_SIZE.
  82  */
  83 #define DATA_BLOCK_SIZE PAGE_SIZE
  84 #define DATA_BLOCK_SHIFT PAGE_SHIFT
  85 #define DATA_BLOCK_BITS_DEF (256 * 1024)
  86
  87 #define TCMU_MBS_TO_BLOCKS(_mbs) (_mbs << (20 - DATA_BLOCK_SHIFT))
  88 #define TCMU_BLOCKS_TO_MBS(_blocks) (_blocks >> (20 - DATA_BLOCK_SHIFT))
  89
  90 /*
  91  * Default number of global data blocks(512K * PAGE_SIZE)
  92  * when the unmap thread will be started.
  93  */
  94 #define TCMU_GLOBAL_MAX_BLOCKS_DEF (512 * 1024)
  95
  96 static u8 tcmu_kern_cmd_reply_supported;
  97 static u8 tcmu_netlink_blocked;
  98
  99 static struct device *tcmu_root_device;
 100
 101 struct tcmu_hba {
 102         u32 host_id;
 103 };
 104
 105 #define TCMU_CONFIG_LEN 256
 106
 107 static DEFINE_MUTEX(tcmu_nl_cmd_mutex);
 108 static LIST_HEAD(tcmu_nl_cmd_list);
 109
 110 struct tcmu_dev;
 111
 112 struct tcmu_nl_cmd {
 113         /* wake up thread waiting for reply */
 114         struct completion complete;
 115         struct list_head nl_list;
 116         struct tcmu_dev *udev;
 117         int cmd;
 118         int status;
 119 };
 120
 121 struct tcmu_dev {
 122         struct list_head node;
 123         struct kref kref;
 124
 125         struct se_device se_dev;
 126
 127         char *name;
 128         struct se_hba *hba;
 129
 130 #define TCMU_DEV_BIT_OPEN 0
 131 #define TCMU_DEV_BIT_BROKEN 1
 132 #define TCMU_DEV_BIT_BLOCKED 2
 133         unsigned long flags;
 134
 135         struct uio_info uio_info;
 136
 137         struct inode *inode;
 138
 139         struct tcmu_mailbox *mb_addr;
 140         uint64_t dev_size;
 141         u32 cmdr_size;
 142         u32 cmdr_last_cleaned;
 143         /* Offset of data area from start of mb */
 144         /* Must add data_off and mb_addr to get the address */
 145         size_t data_off;
 146         size_t data_size;
 147         uint32_t max_blocks;
 148         size_t ring_size;
 149
 150         struct mutex cmdr_lock;
 151         struct list_head qfull_queue;
 152
 153         uint32_t dbi_max;
 154         uint32_t dbi_thresh;
 155         unsigned long *data_bitmap;
 156         struct radix_tree_root data_blocks;
 157
 158         struct idr commands;
 159
 160         struct timer_list cmd_timer;
 161         unsigned int cmd_time_out;
 162         struct list_head inflight_queue;
 163
 164         struct timer_list qfull_timer;
 165         int qfull_time_out;
 166
 167         struct list_head timedout_entry;
 168
 169         struct tcmu_nl_cmd curr_nl_cmd;
 170
 171         char dev_config[TCMU_CONFIG_LEN];
 172
 173         int nl_reply_supported;
 174 };
 175
 176 #define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
 177
 178 #define CMDR_OFF sizeof(struct tcmu_mailbox)
 179
 180 struct tcmu_cmd {
 181         struct se_cmd *se_cmd;
 182         struct tcmu_dev *tcmu_dev;
 183         struct list_head queue_entry;
 184
 185         uint16_t cmd_id;
 186
 187         /* Can't use se_cmd when cleaning up expired cmds, because if
 188            cmd has been completed then accessing se_cmd is off limits */
 189         uint32_t dbi_cnt;
 190         uint32_t dbi_cur;
 191         uint32_t *dbi;
 192
 193         unsigned long deadline;
 194
 195 #define TCMU_CMD_BIT_EXPIRED 0
 196 #define TCMU_CMD_BIT_INFLIGHT 1
 197         unsigned long flags;
 198 };
 199 /*
 200  * To avoid dead lock the mutex lock order should always be:
 201  *
 202  * mutex_lock(&root_udev_mutex);
 203  * ...
 204  * mutex_lock(&tcmu_dev->cmdr_lock);
 205  * mutex_unlock(&tcmu_dev->cmdr_lock);
 206  * ...
 207  * mutex_unlock(&root_udev_mutex);
 208  */
 209 static DEFINE_MUTEX(root_udev_mutex);
 210 static LIST_HEAD(root_udev);
 211
 212 static DEFINE_SPINLOCK(timed_out_udevs_lock);
 213 static LIST_HEAD(timed_out_udevs);
 214
 215 static struct kmem_cache *tcmu_cmd_cache;
 216
 217 static atomic_t global_db_count = ATOMIC_INIT(0);
 218 static struct delayed_work tcmu_unmap_work;
 219 static int tcmu_global_max_blocks = TCMU_GLOBAL_MAX_BLOCKS_DEF;
 220
 221 static int tcmu_set_global_max_data_area(const char *str,
 222                                          const struct kernel_param *kp)
 223 {
 224         int ret, max_area_mb;
 225
 226         ret = kstrtoint(str, 10, &max_area_mb);
 227         if (ret)
 228                 return -EINVAL;
 229
 230         if (max_area_mb <= 0) {
 231                 pr_err("global_max_data_area must be larger than 0.\n");
 232                 return -EINVAL;
 233         }
 234
 235         tcmu_global_max_blocks = TCMU_MBS_TO_BLOCKS(max_area_mb);
 236         if (atomic_read(&global_db_count) > tcmu_global_max_blocks)
 237                 schedule_delayed_work(&tcmu_unmap_work, 0);
 238         else
 239                 cancel_delayed_work_sync(&tcmu_unmap_work);
 240
 241         return 0;
 242 }
 243
 244 static int tcmu_get_global_max_data_area(char *buffer,
 245                                          const struct kernel_param *kp)
 246 {
 247         return sprintf(buffer, "%d", TCMU_BLOCKS_TO_MBS(tcmu_global_max_blocks));
 248 }
 249
 250 static const struct kernel_param_ops tcmu_global_max_data_area_op = {
 251         .set = tcmu_set_global_max_data_area,
 252         .get = tcmu_get_global_max_data_area,
 253 };
 254
 255 module_param_cb(global_max_data_area_mb, &tcmu_global_max_data_area_op, NULL,
 256                 S_IWUSR | S_IRUGO);
 257 MODULE_PARM_DESC(global_max_data_area_mb,
 258                  "Max MBs allowed to be allocated to all the tcmu device's "
 259                  "data areas.");
 260
 261 static int tcmu_get_block_netlink(char *buffer,
 262                                   const struct kernel_param *kp)
 263 {
 264         return sprintf(buffer, "%s\n", tcmu_netlink_blocked ?
 265                        "blocked" : "unblocked");
 266 }
 267
 268 static int tcmu_set_block_netlink(const char *str,
 269                                   const struct kernel_param *kp)
 270 {
 271         int ret;
 272         u8 val;
 273
 274         ret = kstrtou8(str, 0, &val);
 275         if (ret < 0)
 276                 return ret;
 277
 278         if (val > 1) {
 279                 pr_err("Invalid block netlink value %u\n", val);
 280                 return -EINVAL;
 281         }
 282
 283         tcmu_netlink_blocked = val;
 284         return 0;
 285 }
 286
 287 static const struct kernel_param_ops tcmu_block_netlink_op = {
 288         .set = tcmu_set_block_netlink,
 289         .get = tcmu_get_block_netlink,
 290 };
 291
 292 module_param_cb(block_netlink, &tcmu_block_netlink_op, NULL, S_IWUSR | S_IRUGO);
 293 MODULE_PARM_DESC(block_netlink, "Block new netlink commands.");
 294
 295 static int tcmu_fail_netlink_cmd(struct tcmu_nl_cmd *nl_cmd)
 296 {
 297         struct tcmu_dev *udev = nl_cmd->udev;
 298
 299         if (!tcmu_netlink_blocked) {
 300                 pr_err("Could not reset device's netlink interface. Netlink is not blocked.\n");
 301                 return -EBUSY;
 302         }
 303
 304         if (nl_cmd->cmd != TCMU_CMD_UNSPEC) {
 305                 pr_debug("Aborting nl cmd %d on %s\n", nl_cmd->cmd, udev->name);
 306                 nl_cmd->status = -EINTR;
 307                 list_del(&nl_cmd->nl_list);
 308                 complete(&nl_cmd->complete);
 309         }
 310         return 0;
 311 }
 312
 313 static int tcmu_set_reset_netlink(const char *str,
 314                                   const struct kernel_param *kp)
 315 {
 316         struct tcmu_nl_cmd *nl_cmd, *tmp_cmd;
 317         int ret;
 318         u8 val;
 319
 320         ret = kstrtou8(str, 0, &val);
 321         if (ret < 0)
 322                 return ret;
 323
 324         if (val != 1) {
 325                 pr_err("Invalid reset netlink value %u\n", val);
 326                 return -EINVAL;
 327         }
 328
 329         mutex_lock(&tcmu_nl_cmd_mutex);
 330         list_for_each_entry_safe(nl_cmd, tmp_cmd, &tcmu_nl_cmd_list, nl_list) {
 331                 ret = tcmu_fail_netlink_cmd(nl_cmd);
 332                 if (ret)
 333                         break;
 334         }
 335         mutex_unlock(&tcmu_nl_cmd_mutex);
 336
 337         return ret;
 338 }
 339
 340 static const struct kernel_param_ops tcmu_reset_netlink_op = {
 341         .set = tcmu_set_reset_netlink,
 342 };
 343
 344 module_param_cb(reset_netlink, &tcmu_reset_netlink_op, NULL, S_IWUSR);
 345 MODULE_PARM_DESC(reset_netlink, "Reset netlink commands.");
 346
 347 /* multicast group */
 348 enum tcmu_multicast_groups {
 349         TCMU_MCGRP_CONFIG,
 350 };
 351
 352 static const struct genl_multicast_group tcmu_mcgrps[] = {
 353         [TCMU_MCGRP_CONFIG] = { .name = "config", },
 354 };
 355
 356 static struct nla_policy tcmu_attr_policy[TCMU_ATTR_MAX+1] = {
 357         [TCMU_ATTR_DEVICE]      = { .type = NLA_STRING },
 358         [TCMU_ATTR_MINOR]       = { .type = NLA_U32 },
 359         [TCMU_ATTR_CMD_STATUS]  = { .type = NLA_S32 },
 360         [TCMU_ATTR_DEVICE_ID]   = { .type = NLA_U32 },
 361         [TCMU_ATTR_SUPP_KERN_CMD_REPLY] = { .type = NLA_U8 },
 362 };
 363
 364 static int tcmu_genl_cmd_done(struct genl_info *info, int completed_cmd)
 365 {
 366         struct tcmu_dev *udev = NULL;
 367         struct tcmu_nl_cmd *nl_cmd;
 368         int dev_id, rc, ret = 0;
 369
 370         if (!info->attrs[TCMU_ATTR_CMD_STATUS] ||
 371             !info->attrs[TCMU_ATTR_DEVICE_ID]) {
 372                 printk(KERN_ERR "TCMU_ATTR_CMD_STATUS or TCMU_ATTR_DEVICE_ID not set, doing nothing\n");
 373                 return -EINVAL;
 374         }
 375
 376         dev_id = nla_get_u32(info->attrs[TCMU_ATTR_DEVICE_ID]);
 377         rc = nla_get_s32(info->attrs[TCMU_ATTR_CMD_STATUS]);
 378
 379         mutex_lock(&tcmu_nl_cmd_mutex);
 380         list_for_each_entry(nl_cmd, &tcmu_nl_cmd_list, nl_list) {
 381                 if (nl_cmd->udev->se_dev.dev_index == dev_id) {
 382                         udev = nl_cmd->udev;
 383                         break;
 384                 }
 385         }
 386
 387         if (!udev) {
 388                 pr_err("tcmu nl cmd %u/%d completion could not find device with dev id %u.\n",
 389                        completed_cmd, rc, dev_id);
 390                 ret = -ENODEV;
 391                 goto unlock;
 392         }
 393         list_del(&nl_cmd->nl_list);
 394
 395         pr_debug("%s genl cmd done got id %d curr %d done %d rc %d stat %d\n",
 396                  udev->name, dev_id, nl_cmd->cmd, completed_cmd, rc,
 397                  nl_cmd->status);
 398
 399         if (nl_cmd->cmd != completed_cmd) {
 400                 pr_err("Mismatched commands on %s (Expecting reply for %d. Current %d).\n",
 401                        udev->name, completed_cmd, nl_cmd->cmd);
 402                 ret = -EINVAL;
 403                 goto unlock;
 404         }
 405
 406         nl_cmd->status = rc;
 407         complete(&nl_cmd->complete);
 408 unlock:
 409         mutex_unlock(&tcmu_nl_cmd_mutex);
 410         return ret;
 411 }
 412
 413 static int tcmu_genl_rm_dev_done(struct sk_buff *skb, struct genl_info *info)
 414 {
 415         return tcmu_genl_cmd_done(info, TCMU_CMD_REMOVED_DEVICE);
 416 }
 417
 418 static int tcmu_genl_add_dev_done(struct sk_buff *skb, struct genl_info *info)
 419 {
 420         return tcmu_genl_cmd_done(info, TCMU_CMD_ADDED_DEVICE);
 421 }
 422
 423 static int tcmu_genl_reconfig_dev_done(struct sk_buff *skb,
 424                                        struct genl_info *info)
 425 {
 426         return tcmu_genl_cmd_done(info, TCMU_CMD_RECONFIG_DEVICE);
 427 }
 428
 429 static int tcmu_genl_set_features(struct sk_buff *skb, struct genl_info *info)
 430 {
 431         if (info->attrs[TCMU_ATTR_SUPP_KERN_CMD_REPLY]) {
 432                 tcmu_kern_cmd_reply_supported  =
 433                         nla_get_u8(info->attrs[TCMU_ATTR_SUPP_KERN_CMD_REPLY]);
 434                 printk(KERN_INFO "tcmu daemon: command reply support %u.\n",
 435                        tcmu_kern_cmd_reply_supported);
 436         }
 437
 438         return 0;
 439 }
 440
 441 static const struct genl_ops tcmu_genl_ops[] = {
 442         {
 443                 .cmd    = TCMU_CMD_SET_FEATURES,
 444                 .flags  = GENL_ADMIN_PERM,
 445                 .policy = tcmu_attr_policy,
 446                 .doit   = tcmu_genl_set_features,
 447         },
 448         {
 449                 .cmd    = TCMU_CMD_ADDED_DEVICE_DONE,
 450                 .flags  = GENL_ADMIN_PERM,
 451                 .policy = tcmu_attr_policy,
 452                 .doit   = tcmu_genl_add_dev_done,
 453         },
 454         {
 455                 .cmd    = TCMU_CMD_REMOVED_DEVICE_DONE,
 456                 .flags  = GENL_ADMIN_PERM,
 457                 .policy = tcmu_attr_policy,
 458                 .doit   = tcmu_genl_rm_dev_done,
 459         },
 460         {
 461                 .cmd    = TCMU_CMD_RECONFIG_DEVICE_DONE,
 462                 .flags  = GENL_ADMIN_PERM,
 463                 .policy = tcmu_attr_policy,
 464                 .doit   = tcmu_genl_reconfig_dev_done,
 465         },
 466 };
 467
 468 /* Our generic netlink family */
 469 static struct genl_family tcmu_genl_family __ro_after_init = {
 470         .module = THIS_MODULE,
 471         .hdrsize = 0,
 472         .name = "TCM-USER",
 473         .version = 2,
 474         .maxattr = TCMU_ATTR_MAX,
 475         .mcgrps = tcmu_mcgrps,
 476         .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
 477         .netnsok = true,
 478         .ops = tcmu_genl_ops,
 479         .n_ops = ARRAY_SIZE(tcmu_genl_ops),
 480 };
 481
 482 #define tcmu_cmd_set_dbi_cur(cmd, index) ((cmd)->dbi_cur = (index))
 483 #define tcmu_cmd_reset_dbi_cur(cmd) tcmu_cmd_set_dbi_cur(cmd, 0)
 484 #define tcmu_cmd_set_dbi(cmd, index) ((cmd)->dbi[(cmd)->dbi_cur++] = (index))
 485 #define tcmu_cmd_get_dbi(cmd) ((cmd)->dbi[(cmd)->dbi_cur++])
 486
 487 static void tcmu_cmd_free_data(struct tcmu_cmd *tcmu_cmd, uint32_t len)
 488 {
 489         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
 490         uint32_t i;
 491
 492         for (i = 0; i < len; i++)
 493                 clear_bit(tcmu_cmd->dbi[i], udev->data_bitmap);
 494 }
 495
 496 static inline bool tcmu_get_empty_block(struct tcmu_dev *udev,
 497                                         struct tcmu_cmd *tcmu_cmd)
 498 {
 499         struct page *page;
 500         int ret, dbi;
 501
 502         dbi = find_first_zero_bit(udev->data_bitmap, udev->dbi_thresh);
 503         if (dbi == udev->dbi_thresh)
 504                 return false;
 505
 506         page = radix_tree_lookup(&udev->data_blocks, dbi);
 507         if (!page) {
 508                 if (atomic_add_return(1, &global_db_count) >
 509                                       tcmu_global_max_blocks)
 510                         schedule_delayed_work(&tcmu_unmap_work, 0);
 511
 512                 /* try to get new page from the mm */
 513                 page = alloc_page(GFP_KERNEL);
 514                 if (!page)
 515                         goto err_alloc;
 516
 517                 ret = radix_tree_insert(&udev->data_blocks, dbi, page);
 518                 if (ret)
 519                         goto err_insert;
 520         }
 521
 522         if (dbi > udev->dbi_max)
 523                 udev->dbi_max = dbi;
 524
 525         set_bit(dbi, udev->data_bitmap);
 526         tcmu_cmd_set_dbi(tcmu_cmd, dbi);
 527
 528         return true;
 529 err_insert:
 530         __free_page(page);
 531 err_alloc:
 532         atomic_dec(&global_db_count);
 533         return false;
 534 }
 535
 536 static bool tcmu_get_empty_blocks(struct tcmu_dev *udev,
 537                                   struct tcmu_cmd *tcmu_cmd)
 538 {
 539         int i;
 540
 541         for (i = tcmu_cmd->dbi_cur; i < tcmu_cmd->dbi_cnt; i++) {
 542                 if (!tcmu_get_empty_block(udev, tcmu_cmd))
 543                         return false;
 544         }
 545         return true;
 546 }
 547
 548 static inline struct page *
 549 tcmu_get_block_page(struct tcmu_dev *udev, uint32_t dbi)
 550 {
 551         return radix_tree_lookup(&udev->data_blocks, dbi);
 552 }
 553
 554 static inline void tcmu_free_cmd(struct tcmu_cmd *tcmu_cmd)
 555 {
 556         kfree(tcmu_cmd->dbi);
 557         kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 558 }
 559
 560 static inline size_t tcmu_cmd_get_data_length(struct tcmu_cmd *tcmu_cmd)
 561 {
 562         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
 563         size_t data_length = round_up(se_cmd->data_length, DATA_BLOCK_SIZE);
 564
 565         if (se_cmd->se_cmd_flags & SCF_BIDI) {
 566                 BUG_ON(!(se_cmd->t_bidi_data_sg && se_cmd->t_bidi_data_nents));
 567                 data_length += round_up(se_cmd->t_bidi_data_sg->length,
 568                                 DATA_BLOCK_SIZE);
 569         }
 570
 571         return data_length;
 572 }
 573
 574 static inline uint32_t tcmu_cmd_get_block_cnt(struct tcmu_cmd *tcmu_cmd)
 575 {
 576         size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
 577
 578         return data_length / DATA_BLOCK_SIZE;
 579 }
 580
 581 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
 582 {
 583         struct se_device *se_dev = se_cmd->se_dev;
 584         struct tcmu_dev *udev = TCMU_DEV(se_dev);
 585         struct tcmu_cmd *tcmu_cmd;
 586
 587         tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL);
 588         if (!tcmu_cmd)
 589                 return NULL;
 590
 591         INIT_LIST_HEAD(&tcmu_cmd->queue_entry);
 592         tcmu_cmd->se_cmd = se_cmd;
 593         tcmu_cmd->tcmu_dev = udev;
 594
 595         tcmu_cmd_reset_dbi_cur(tcmu_cmd);
 596         tcmu_cmd->dbi_cnt = tcmu_cmd_get_block_cnt(tcmu_cmd);
 597         tcmu_cmd->dbi = kcalloc(tcmu_cmd->dbi_cnt, sizeof(uint32_t),
 598                                 GFP_KERNEL);
 599         if (!tcmu_cmd->dbi) {
 600                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
 601                 return NULL;
 602         }
 603
 604         return tcmu_cmd;
 605 }
 606
 607 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
 608 {
 609         unsigned long offset = offset_in_page(vaddr);
 610         void *start = vaddr - offset;
 611
 612         size = round_up(size+offset, PAGE_SIZE);
 613
 614         while (size) {
 615                 flush_dcache_page(virt_to_page(start));
 616                 start += PAGE_SIZE;
 617                 size -= PAGE_SIZE;
 618         }
 619 }
 620
 621 /*
 622  * Some ring helper functions. We don't assume size is a power of 2 so
 623  * we can't use circ_buf.h.
 624  */
 625 static inline size_t spc_used(size_t head, size_t tail, size_t size)
 626 {
 627         int diff = head - tail;
 628
 629         if (diff >= 0)
 630                 return diff;
 631         else
 632                 return size + diff;
 633 }
 634
 635 static inline size_t spc_free(size_t head, size_t tail, size_t size)
 636 {
 637         /* Keep 1 byte unused or we can't tell full from empty */
 638         return (size - spc_used(head, tail, size) - 1);
 639 }
 640
 641 static inline size_t head_to_end(size_t head, size_t size)
 642 {
 643         return size - head;
 644 }
 645
 646 static inline void new_iov(struct iovec **iov, int *iov_cnt)
 647 {
 648         struct iovec *iovec;
 649
 650         if (*iov_cnt != 0)
 651                 (*iov)++;
 652         (*iov_cnt)++;
 653
 654         iovec = *iov;
 655         memset(iovec, 0, sizeof(struct iovec));
 656 }
 657
 658 #define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
 659
 660 /* offset is relative to mb_addr */
 661 static inline size_t get_block_offset_user(struct tcmu_dev *dev,
 662                 int dbi, int remaining)
 663 {
 664         return dev->data_off + dbi * DATA_BLOCK_SIZE +
 665                 DATA_BLOCK_SIZE - remaining;
 666 }
 667
 668 static inline size_t iov_tail(struct iovec *iov)
 669 {
 670         return (size_t)iov->iov_base + iov->iov_len;
 671 }
 672
 673 static void scatter_data_area(struct tcmu_dev *udev,
 674         struct tcmu_cmd *tcmu_cmd, struct scatterlist *data_sg,
 675         unsigned int data_nents, struct iovec **iov,
 676         int *iov_cnt, bool copy_data)
 677 {
 678         int i, dbi;
 679         int block_remaining = 0;
 680         void *from, *to = NULL;
 681         size_t copy_bytes, to_offset, offset;
 682         struct scatterlist *sg;
 683         struct page *page;
 684
 685         for_each_sg(data_sg, sg, data_nents, i) {
 686                 int sg_remaining = sg->length;
 687                 from = kmap_atomic(sg_page(sg)) + sg->offset;
 688                 while (sg_remaining > 0) {
 689                         if (block_remaining == 0) {
 690                                 if (to)
 691                                         kunmap_atomic(to);
 692
 693                                 block_remaining = DATA_BLOCK_SIZE;
 694                                 dbi = tcmu_cmd_get_dbi(tcmu_cmd);
 695                                 page = tcmu_get_block_page(udev, dbi);
 696                                 to = kmap_atomic(page);
 697                         }
 698
 699                         /*
 700                          * Covert to virtual offset of the ring data area.
 701                          */
 702                         to_offset = get_block_offset_user(udev, dbi,
 703                                         block_remaining);
 704
 705                         /*
 706                          * The following code will gather and map the blocks
 707                          * to the same iovec when the blocks are all next to
 708                          * each other.
 709                          */
 710                         copy_bytes = min_t(size_t, sg_remaining,
 711                                         block_remaining);
 712                         if (*iov_cnt != 0 &&
 713                             to_offset == iov_tail(*iov)) {
 714                                 /*
 715                                  * Will append to the current iovec, because
 716                                  * the current block page is next to the
 717                                  * previous one.
 718                                  */
 719                                 (*iov)->iov_len += copy_bytes;
 720                         } else {
 721                                 /*
 722                                  * Will allocate a new iovec because we are
 723                                  * first time here or the current block page
 724                                  * is not next to the previous one.
 725                                  */
 726                                 new_iov(iov, iov_cnt);
 727                                 (*iov)->iov_base = (void __user *)to_offset;
 728                                 (*iov)->iov_len = copy_bytes;
 729                         }
 730
 731                         if (copy_data) {
 732                                 offset = DATA_BLOCK_SIZE - block_remaining;
 733                                 memcpy(to + offset,
 734                                        from + sg->length - sg_remaining,
 735                                        copy_bytes);
 736                                 tcmu_flush_dcache_range(to, copy_bytes);
 737                         }
 738
 739                         sg_remaining -= copy_bytes;
 740                         block_remaining -= copy_bytes;
 741                 }
 742                 kunmap_atomic(from - sg->offset);
 743         }
 744
 745         if (to)
 746                 kunmap_atomic(to);
 747 }
 748
 749 static void gather_data_area(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
 750                              bool bidi, uint32_t read_len)
 751 {
 752         struct se_cmd *se_cmd = cmd->se_cmd;
 753         int i, dbi;
 754         int block_remaining = 0;
 755         void *from = NULL, *to;
 756         size_t copy_bytes, offset;
 757         struct scatterlist *sg, *data_sg;
 758         struct page *page;
 759         unsigned int data_nents;
 760         uint32_t count = 0;
 761
 762         if (!bidi) {
 763                 data_sg = se_cmd->t_data_sg;
 764                 data_nents = se_cmd->t_data_nents;
 765         } else {
 766
 767                 /*
 768                  * For bidi case, the first count blocks are for Data-Out
 769                  * buffer blocks, and before gathering the Data-In buffer
 770                  * the Data-Out buffer blocks should be discarded.
 771                  */
 772                 count = DIV_ROUND_UP(se_cmd->data_length, DATA_BLOCK_SIZE);
 773
 774                 data_sg = se_cmd->t_bidi_data_sg;
 775                 data_nents = se_cmd->t_bidi_data_nents;
 776         }
 777
 778         tcmu_cmd_set_dbi_cur(cmd, count);
 779
 780         for_each_sg(data_sg, sg, data_nents, i) {
 781                 int sg_remaining = sg->length;
 782                 to = kmap_atomic(sg_page(sg)) + sg->offset;
 783                 while (sg_remaining > 0 && read_len > 0) {
 784                         if (block_remaining == 0) {
 785                                 if (from)
 786                                         kunmap_atomic(from);
 787
 788                                 block_remaining = DATA_BLOCK_SIZE;
 789                                 dbi = tcmu_cmd_get_dbi(cmd);
 790                                 page = tcmu_get_block_page(udev, dbi);
 791                                 from = kmap_atomic(page);
 792                         }
 793                         copy_bytes = min_t(size_t, sg_remaining,
 794                                         block_remaining);
 795                         if (read_len < copy_bytes)
 796                                 copy_bytes = read_len;
 797                         offset = DATA_BLOCK_SIZE - block_remaining;
 798                         tcmu_flush_dcache_range(from, copy_bytes);
 799                         memcpy(to + sg->length - sg_remaining, from + offset,
 800                                         copy_bytes);
 801
 802                         sg_remaining -= copy_bytes;
 803                         block_remaining -= copy_bytes;
 804                         read_len -= copy_bytes;
 805                 }
 806                 kunmap_atomic(to - sg->offset);
 807                 if (read_len == 0)
 808                         break;
 809         }
 810         if (from)
 811                 kunmap_atomic(from);
 812 }
 813
 814 static inline size_t spc_bitmap_free(unsigned long *bitmap, uint32_t thresh)
 815 {
 816         return thresh - bitmap_weight(bitmap, thresh);
 817 }
 818
 819 /*
 820  * We can't queue a command until we have space available on the cmd ring *and*
 821  * space available on the data area.
 822  *
 823  * Called with ring lock held.
 824  */
 825 static bool is_ring_space_avail(struct tcmu_dev *udev, struct tcmu_cmd *cmd,
 826                 size_t cmd_size, size_t data_needed)
 827 {
 828         struct tcmu_mailbox *mb = udev->mb_addr;
 829         uint32_t blocks_needed = (data_needed + DATA_BLOCK_SIZE - 1)
 830                                 / DATA_BLOCK_SIZE;
 831         size_t space, cmd_needed;
 832         u32 cmd_head;
 833
 834         tcmu_flush_dcache_range(mb, sizeof(*mb));
 835
 836         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
 837
 838         /*
 839          * If cmd end-of-ring space is too small then we need space for a NOP plus
 840          * original cmd - cmds are internally contiguous.
 841          */
 842         if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
 843                 cmd_needed = cmd_size;
 844         else
 845                 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
 846
 847         space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
 848         if (space < cmd_needed) {
 849                 pr_debug("no cmd space: %u %u %u\n", cmd_head,
 850                        udev->cmdr_last_cleaned, udev->cmdr_size);
 851                 return false;
 852         }
 853
 854         /* try to check and get the data blocks as needed */
 855         space = spc_bitmap_free(udev->data_bitmap, udev->dbi_thresh);
 856         if ((space * DATA_BLOCK_SIZE) < data_needed) {
 857                 unsigned long blocks_left =
 858                                 (udev->max_blocks - udev->dbi_thresh) + space;
 859
 860                 if (blocks_left < blocks_needed) {
 861                         pr_debug("no data space: only %lu available, but ask for %zu\n",
 862                                         blocks_left * DATA_BLOCK_SIZE,
 863                                         data_needed);
 864                         return false;
 865                 }
 866
 867                 udev->dbi_thresh += blocks_needed;
 868                 if (udev->dbi_thresh > udev->max_blocks)
 869                         udev->dbi_thresh = udev->max_blocks;
 870         }
 871
 872         return tcmu_get_empty_blocks(udev, cmd);
 873 }
 874
 875 static inline size_t tcmu_cmd_get_base_cmd_size(size_t iov_cnt)
 876 {
 877         return max(offsetof(struct tcmu_cmd_entry, req.iov[iov_cnt]),
 878                         sizeof(struct tcmu_cmd_entry));
 879 }
 880
 881 static inline size_t tcmu_cmd_get_cmd_size(struct tcmu_cmd *tcmu_cmd,
 882                                            size_t base_command_size)
 883 {
 884         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
 885         size_t command_size;
 886
 887         command_size = base_command_size +
 888                 round_up(scsi_command_size(se_cmd->t_task_cdb),
 889                                 TCMU_OP_ALIGN_SIZE);
 890
 891         WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
 892
 893         return command_size;
 894 }
 895
 896 static int tcmu_setup_cmd_timer(struct tcmu_cmd *tcmu_cmd, unsigned int tmo,
 897                                 struct timer_list *timer)
 898 {
 899         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
 900         int cmd_id;
 901
 902         if (tcmu_cmd->cmd_id)
 903                 goto setup_timer;
 904
 905         cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 1, USHRT_MAX, GFP_NOWAIT);
 906         if (cmd_id < 0) {
 907                 pr_err("tcmu: Could not allocate cmd id.\n");
 908                 return cmd_id;
 909         }
 910         tcmu_cmd->cmd_id = cmd_id;
 911
 912         pr_debug("allocated cmd %u for dev %s tmo %lu\n", tcmu_cmd->cmd_id,
 913                  udev->name, tmo / MSEC_PER_SEC);
 914
 915 setup_timer:
 916         if (!tmo)
 917                 return 0;
 918
 919         tcmu_cmd->deadline = round_jiffies_up(jiffies + msecs_to_jiffies(tmo));
 920         if (!timer_pending(timer))
 921                 mod_timer(timer, tcmu_cmd->deadline);
 922
 923         return 0;
 924 }
 925
 926 static int add_to_qfull_queue(struct tcmu_cmd *tcmu_cmd)
 927 {
 928         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
 929         unsigned int tmo;
 930         int ret;
 931
 932         /*
 933          * For backwards compat if qfull_time_out is not set use
 934          * cmd_time_out and if that's not set use the default time out.
 935          */
 936         if (!udev->qfull_time_out)
 937                 return -ETIMEDOUT;
 938         else if (udev->qfull_time_out > 0)
 939                 tmo = udev->qfull_time_out;
 940         else if (udev->cmd_time_out)
 941                 tmo = udev->cmd_time_out;
 942         else
 943                 tmo = TCMU_TIME_OUT;
 944
 945         ret = tcmu_setup_cmd_timer(tcmu_cmd, tmo, &udev->qfull_timer);
 946         if (ret)
 947                 return ret;
 948
 949         list_add_tail(&tcmu_cmd->queue_entry, &udev->qfull_queue);
 950         pr_debug("adding cmd %u on dev %s to ring space wait queue\n",
 951                  tcmu_cmd->cmd_id, udev->name);
 952         return 0;
 953 }
 954
 955 /**
 956  * queue_cmd_ring - queue cmd to ring or internally
 957  * @tcmu_cmd: cmd to queue
 958  * @scsi_err: TCM error code if failure (-1) returned.
 959  *
 960  * Returns:
 961  * -1 we cannot queue internally or to the ring.
 962  *  0 success
 963  *  1 internally queued to wait for ring memory to free.
 964  */
 965 static int queue_cmd_ring(struct tcmu_cmd *tcmu_cmd, sense_reason_t *scsi_err)
 966 {
 967         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
 968         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
 969         size_t base_command_size, command_size;
 970         struct tcmu_mailbox *mb;
 971         struct tcmu_cmd_entry *entry;
 972         struct iovec *iov;
 973         int iov_cnt, ret;
 974         uint32_t cmd_head;
 975         uint64_t cdb_off;
 976         bool copy_to_data_area;
 977         size_t data_length = tcmu_cmd_get_data_length(tcmu_cmd);
 978
 979         *scsi_err = TCM_NO_SENSE;
 980
 981         if (test_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags)) {
 982                 *scsi_err = TCM_LUN_BUSY;
 983                 return -1;
 984         }
 985
 986         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
 987                 *scsi_err = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 988                 return -1;
 989         }
 990
 991         /*
 992          * Must be a certain minimum size for response sense info, but
 993          * also may be larger if the iov array is large.
 994          *
 995          * We prepare as many iovs as possbile for potential uses here,
 996          * because it's expensive to tell how many regions are freed in
 997          * the bitmap & global data pool, as the size calculated here
 998          * will only be used to do the checks.
 999          *
1000          * The size will be recalculated later as actually needed to save
1001          * cmd area memories.
1002          */
1003         base_command_size = tcmu_cmd_get_base_cmd_size(tcmu_cmd->dbi_cnt);
1004         command_size = tcmu_cmd_get_cmd_size(tcmu_cmd, base_command_size);
1005
1006         if (!list_empty(&udev->qfull_queue))
1007                 goto queue;
1008
1009         mb = udev->mb_addr;
1010         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
1011         if ((command_size > (udev->cmdr_size / 2)) ||
1012             data_length > udev->data_size) {
1013                 pr_warn("TCMU: Request of size %zu/%zu is too big for %u/%zu "
1014                         "cmd ring/data area\n", command_size, data_length,
1015                         udev->cmdr_size, udev->data_size);
1016                 *scsi_err = TCM_INVALID_CDB_FIELD;
1017                 return -1;
1018         }
1019
1020         if (!is_ring_space_avail(udev, tcmu_cmd, command_size, data_length)) {
1021                 /*
1022                  * Don't leave commands partially setup because the unmap
1023                  * thread might need the blocks to make forward progress.
1024                  */
1025                 tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cur);
1026                 tcmu_cmd_reset_dbi_cur(tcmu_cmd);
1027                 goto queue;
1028         }
1029
1030         /* Insert a PAD if end-of-ring space is too small */
1031         if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
1032                 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
1033
1034                 entry = (void *) mb + CMDR_OFF + cmd_head;
1035                 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
1036                 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
1037                 entry->hdr.cmd_id = 0; /* not used for PAD */
1038                 entry->hdr.kflags = 0;
1039                 entry->hdr.uflags = 0;
1040                 tcmu_flush_dcache_range(entry, sizeof(*entry));
1041
1042                 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
1043                 tcmu_flush_dcache_range(mb, sizeof(*mb));
1044
1045                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
1046                 WARN_ON(cmd_head != 0);
1047         }
1048
1049         entry = (void *) mb + CMDR_OFF + cmd_head;
1050         memset(entry, 0, command_size);
1051         tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
1052
1053         /* Handle allocating space from the data area */
1054         tcmu_cmd_reset_dbi_cur(tcmu_cmd);
1055         iov = &entry->req.iov[0];
1056         iov_cnt = 0;
1057         copy_to_data_area = (se_cmd->data_direction == DMA_TO_DEVICE
1058                 || se_cmd->se_cmd_flags & SCF_BIDI);
1059         scatter_data_area(udev, tcmu_cmd, se_cmd->t_data_sg,
1060                           se_cmd->t_data_nents, &iov, &iov_cnt,
1061                           copy_to_data_area);
1062         entry->req.iov_cnt = iov_cnt;
1063
1064         /* Handle BIDI commands */
1065         iov_cnt = 0;
1066         if (se_cmd->se_cmd_flags & SCF_BIDI) {
1067                 iov++;
1068                 scatter_data_area(udev, tcmu_cmd, se_cmd->t_bidi_data_sg,
1069                                   se_cmd->t_bidi_data_nents, &iov, &iov_cnt,
1070                                   false);
1071         }
1072         entry->req.iov_bidi_cnt = iov_cnt;
1073
1074         ret = tcmu_setup_cmd_timer(tcmu_cmd, udev->cmd_time_out,
1075                                    &udev->cmd_timer);
1076         if (ret) {
1077                 tcmu_cmd_free_data(tcmu_cmd, tcmu_cmd->dbi_cnt);
1078
1079                 *scsi_err = TCM_OUT_OF_RESOURCES;
1080                 return -1;
1081         }
1082         entry->hdr.cmd_id = tcmu_cmd->cmd_id;
1083
1084         /*
1085          * Recalaulate the command's base size and size according
1086          * to the actual needs
1087          */
1088         base_command_size = tcmu_cmd_get_base_cmd_size(entry->req.iov_cnt +
1089                                                        entry->req.iov_bidi_cnt);
1090         command_size = tcmu_cmd_get_cmd_size(tcmu_cmd, base_command_size);
1091
1092         tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
1093
1094         /* All offsets relative to mb_addr, not start of entry! */
1095         cdb_off = CMDR_OFF + cmd_head + base_command_size;
1096         memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
1097         entry->req.cdb_off = cdb_off;
1098         tcmu_flush_dcache_range(entry, sizeof(*entry));
1099
1100         UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
1101         tcmu_flush_dcache_range(mb, sizeof(*mb));
1102
1103         list_add_tail(&tcmu_cmd->queue_entry, &udev->inflight_queue);
1104         set_bit(TCMU_CMD_BIT_INFLIGHT, &tcmu_cmd->flags);
1105
1106         /* TODO: only if FLUSH and FUA? */
1107         uio_event_notify(&udev->uio_info);
1108
1109         return 0;
1110
1111 queue:
1112         if (add_to_qfull_queue(tcmu_cmd)) {
1113                 *scsi_err = TCM_OUT_OF_RESOURCES;
1114                 return -1;
1115         }
1116
1117         return 1;
1118 }
1119
1120 static sense_reason_t
1121 tcmu_queue_cmd(struct se_cmd *se_cmd)
1122 {
1123         struct se_device *se_dev = se_cmd->se_dev;
1124         struct tcmu_dev *udev = TCMU_DEV(se_dev);
1125         struct tcmu_cmd *tcmu_cmd;
1126         sense_reason_t scsi_ret;
1127         int ret;
1128
1129         tcmu_cmd = tcmu_alloc_cmd(se_cmd);
1130         if (!tcmu_cmd)
1131                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1132
1133         mutex_lock(&udev->cmdr_lock);
1134         ret = queue_cmd_ring(tcmu_cmd, &scsi_ret);
1135         mutex_unlock(&udev->cmdr_lock);
1136         if (ret < 0)
1137                 tcmu_free_cmd(tcmu_cmd);
1138         return scsi_ret;
1139 }
1140
1141 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
1142 {
1143         struct se_cmd *se_cmd = cmd->se_cmd;
1144         struct tcmu_dev *udev = cmd->tcmu_dev;
1145         bool read_len_valid = false;
1146         uint32_t read_len = se_cmd->data_length;
1147
1148         /*
1149          * cmd has been completed already from timeout, just reclaim
1150          * data area space and free cmd
1151          */
1152         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
1153                 goto out;
1154
1155         list_del_init(&cmd->queue_entry);
1156
1157         tcmu_cmd_reset_dbi_cur(cmd);
1158
1159         if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
1160                 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
1161                         cmd->se_cmd);
1162                 entry->rsp.scsi_status = SAM_STAT_CHECK_CONDITION;
1163                 goto done;
1164         }
1165
1166         if (se_cmd->data_direction == DMA_FROM_DEVICE &&
1167             (entry->hdr.uflags & TCMU_UFLAG_READ_LEN) && entry->rsp.read_len) {
1168                 read_len_valid = true;
1169                 if (entry->rsp.read_len < read_len)
1170                         read_len = entry->rsp.read_len;
1171         }
1172
1173         if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
1174                 transport_copy_sense_to_cmd(se_cmd, entry->rsp.sense_buffer);
1175                 if (!read_len_valid )
1176                         goto done;
1177                 else
1178                         se_cmd->se_cmd_flags |= SCF_TREAT_READ_AS_NORMAL;
1179         }
1180         if (se_cmd->se_cmd_flags & SCF_BIDI) {
1181                 /* Get Data-In buffer before clean up */
1182                 gather_data_area(udev, cmd, true, read_len);
1183         } else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
1184                 gather_data_area(udev, cmd, false, read_len);
1185         } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
1186                 /* TODO: */
1187         } else if (se_cmd->data_direction != DMA_NONE) {
1188                 pr_warn("TCMU: data direction was %d!\n",
1189                         se_cmd->data_direction);
1190         }
1191
1192 done:
1193         if (read_len_valid) {
1194                 pr_debug("read_len = %d\n", read_len);
1195                 target_complete_cmd_with_length(cmd->se_cmd,
1196                                         entry->rsp.scsi_status, read_len);
1197         } else
1198                 target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
1199
1200 out:
1201         cmd->se_cmd = NULL;
1202         tcmu_cmd_free_data(cmd, cmd->dbi_cnt);
1203         tcmu_free_cmd(cmd);
1204 }
1205
1206 static void tcmu_set_next_deadline(struct list_head *queue,
1207                                    struct timer_list *timer)
1208 {
1209         struct tcmu_cmd *tcmu_cmd, *tmp_cmd;
1210         unsigned long deadline = 0;
1211
1212         list_for_each_entry_safe(tcmu_cmd, tmp_cmd, queue, queue_entry) {
1213                 if (!time_after(jiffies, tcmu_cmd->deadline)) {
1214                         deadline = tcmu_cmd->deadline;
1215                         break;
1216                 }
1217         }
1218
1219         if (deadline)
1220                 mod_timer(timer, deadline);
1221         else
1222                 del_timer(timer);
1223 }
1224
1225 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
1226 {
1227         struct tcmu_mailbox *mb;
1228         struct tcmu_cmd *cmd;
1229         int handled = 0;
1230
1231         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
1232                 pr_err("ring broken, not handling completions\n");
1233                 return 0;
1234         }
1235
1236         mb = udev->mb_addr;
1237         tcmu_flush_dcache_range(mb, sizeof(*mb));
1238
1239         while (udev->cmdr_last_cleaned != READ_ONCE(mb->cmd_tail)) {
1240
1241                 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
1242
1243                 tcmu_flush_dcache_range(entry, sizeof(*entry));
1244
1245                 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
1246                         UPDATE_HEAD(udev->cmdr_last_cleaned,
1247                                     tcmu_hdr_get_len(entry->hdr.len_op),
1248                                     udev->cmdr_size);
1249                         continue;
1250                 }
1251                 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
1252
1253                 cmd = idr_remove(&udev->commands, entry->hdr.cmd_id);
1254                 if (!cmd) {
1255                         pr_err("cmd_id %u not found, ring is broken\n",
1256                                entry->hdr.cmd_id);
1257                         set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
1258                         break;
1259                 }
1260
1261                 tcmu_handle_completion(cmd, entry);
1262
1263                 UPDATE_HEAD(udev->cmdr_last_cleaned,
1264                             tcmu_hdr_get_len(entry->hdr.len_op),
1265                             udev->cmdr_size);
1266
1267                 handled++;
1268         }
1269
1270         if (mb->cmd_tail == mb->cmd_head) {
1271                 /* no more pending commands */
1272                 del_timer(&udev->cmd_timer);
1273
1274                 if (list_empty(&udev->qfull_queue)) {
1275                         /*
1276                          * no more pending or waiting commands so try to
1277                          * reclaim blocks if needed.
1278                          */
1279                         if (atomic_read(&global_db_count) >
1280                             tcmu_global_max_blocks)
1281                                 schedule_delayed_work(&tcmu_unmap_work, 0);
1282                 }
1283         } else if (udev->cmd_time_out) {
1284                 tcmu_set_next_deadline(&udev->inflight_queue, &udev->cmd_timer);
1285         }
1286
1287         return handled;
1288 }
1289
1290 static int tcmu_check_expired_cmd(int id, void *p, void *data)
1291 {
1292         struct tcmu_cmd *cmd = p;
1293         struct tcmu_dev *udev = cmd->tcmu_dev;
1294         u8 scsi_status;
1295         struct se_cmd *se_cmd;
1296         bool is_running;
1297
1298         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
1299                 return 0;
1300
1301         if (!time_after(jiffies, cmd->deadline))
1302                 return 0;
1303
1304         is_running = test_bit(TCMU_CMD_BIT_INFLIGHT, &cmd->flags);
1305         se_cmd = cmd->se_cmd;
1306
1307         if (is_running) {
1308                 /*
1309                  * If cmd_time_out is disabled but qfull is set deadline
1310                  * will only reflect the qfull timeout. Ignore it.
1311                  */
1312                 if (!udev->cmd_time_out)
1313                         return 0;
1314
1315                 set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
1316                 /*
1317                  * target_complete_cmd will translate this to LUN COMM FAILURE
1318                  */
1319                 scsi_status = SAM_STAT_CHECK_CONDITION;
1320                 list_del_init(&cmd->queue_entry);
1321         } else {
1322                 list_del_init(&cmd->queue_entry);
1323                 idr_remove(&udev->commands, id);
1324                 tcmu_free_cmd(cmd);
1325                 scsi_status = SAM_STAT_TASK_SET_FULL;
1326         }
1327
1328         pr_debug("Timing out cmd %u on dev %s that is %s.\n",
1329                  id, udev->name, is_running ? "inflight" : "queued");
1330
1331         target_complete_cmd(se_cmd, scsi_status);
1332         return 0;
1333 }
1334
1335 static void tcmu_device_timedout(struct tcmu_dev *udev)
1336 {
1337         spin_lock(&timed_out_udevs_lock);
1338         if (list_empty(&udev->timedout_entry))
1339                 list_add_tail(&udev->timedout_entry, &timed_out_udevs);
1340         spin_unlock(&timed_out_udevs_lock);
1341
1342         schedule_delayed_work(&tcmu_unmap_work, 0);
1343 }
1344
1345 static void tcmu_cmd_timedout(struct timer_list *t)
1346 {
1347         struct tcmu_dev *udev = from_timer(udev, t, cmd_timer);
1348
1349         pr_debug("%s cmd timeout has expired\n", udev->name);
1350         tcmu_device_timedout(udev);
1351 }
1352
1353 static void tcmu_qfull_timedout(struct timer_list *t)
1354 {
1355         struct tcmu_dev *udev = from_timer(udev, t, qfull_timer);
1356
1357         pr_debug("%s qfull timeout has expired\n", udev->name);
1358         tcmu_device_timedout(udev);
1359 }
1360
1361 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
1362 {
1363         struct tcmu_hba *tcmu_hba;
1364
1365         tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
1366         if (!tcmu_hba)
1367                 return -ENOMEM;
1368
1369         tcmu_hba->host_id = host_id;
1370         hba->hba_ptr = tcmu_hba;
1371
1372         return 0;
1373 }
1374
1375 static void tcmu_detach_hba(struct se_hba *hba)
1376 {
1377         kfree(hba->hba_ptr);
1378         hba->hba_ptr = NULL;
1379 }
1380
1381 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
1382 {
1383         struct tcmu_dev *udev;
1384
1385         udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
1386         if (!udev)
1387                 return NULL;
1388         kref_init(&udev->kref);
1389
1390         udev->name = kstrdup(name, GFP_KERNEL);
1391         if (!udev->name) {
1392                 kfree(udev);
1393                 return NULL;
1394         }
1395
1396         udev->hba = hba;
1397         udev->cmd_time_out = TCMU_TIME_OUT;
1398         udev->qfull_time_out = -1;
1399
1400         udev->max_blocks = DATA_BLOCK_BITS_DEF;
1401         mutex_init(&udev->cmdr_lock);
1402
1403         INIT_LIST_HEAD(&udev->node);
1404         INIT_LIST_HEAD(&udev->timedout_entry);
1405         INIT_LIST_HEAD(&udev->qfull_queue);
1406         INIT_LIST_HEAD(&udev->inflight_queue);
1407         idr_init(&udev->commands);
1408
1409         timer_setup(&udev->qfull_timer, tcmu_qfull_timedout, 0);
1410         timer_setup(&udev->cmd_timer, tcmu_cmd_timedout, 0);
1411
1412         INIT_RADIX_TREE(&udev->data_blocks, GFP_KERNEL);
1413
1414         return &udev->se_dev;
1415 }
1416
1417 static bool run_qfull_queue(struct tcmu_dev *udev, bool fail)
1418 {
1419         struct tcmu_cmd *tcmu_cmd, *tmp_cmd;
1420         LIST_HEAD(cmds);
1421         bool drained = true;
1422         sense_reason_t scsi_ret;
1423         int ret;
1424
1425         if (list_empty(&udev->qfull_queue))
1426                 return true;
1427
1428         pr_debug("running %s's cmdr queue forcefail %d\n", udev->name, fail);
1429
1430         list_splice_init(&udev->qfull_queue, &cmds);
1431
1432         list_for_each_entry_safe(tcmu_cmd, tmp_cmd, &cmds, queue_entry) {
1433                 list_del_init(&tcmu_cmd->queue_entry);
1434
1435                 pr_debug("removing cmd %u on dev %s from queue\n",
1436                          tcmu_cmd->cmd_id, udev->name);
1437
1438                 if (fail) {
1439                         idr_remove(&udev->commands, tcmu_cmd->cmd_id);
1440                         /*
1441                          * We were not able to even start the command, so
1442                          * fail with busy to allow a retry in case runner
1443                          * was only temporarily down. If the device is being
1444                          * removed then LIO core will do the right thing and
1445                          * fail the retry.
1446                          */
1447                         target_complete_cmd(tcmu_cmd->se_cmd, SAM_STAT_BUSY);
1448                         tcmu_free_cmd(tcmu_cmd);
1449                         continue;
1450                 }
1451
1452                 ret = queue_cmd_ring(tcmu_cmd, &scsi_ret);
1453                 if (ret < 0) {
1454                         pr_debug("cmd %u on dev %s failed with %u\n",
1455                                  tcmu_cmd->cmd_id, udev->name, scsi_ret);
1456
1457                         idr_remove(&udev->commands, tcmu_cmd->cmd_id);
1458                         /*
1459                          * Ignore scsi_ret for now. target_complete_cmd
1460                          * drops it.
1461                          */
1462                         target_complete_cmd(tcmu_cmd->se_cmd,
1463                                             SAM_STAT_CHECK_CONDITION);
1464                         tcmu_free_cmd(tcmu_cmd);
1465                 } else if (ret > 0) {
1466                         pr_debug("ran out of space during cmdr queue run\n");
1467                         /*
1468                          * cmd was requeued, so just put all cmds back in
1469                          * the queue
1470                          */
1471                         list_splice_tail(&cmds, &udev->qfull_queue);
1472                         drained = false;
1473                         break;
1474                 }
1475         }
1476
1477         tcmu_set_next_deadline(&udev->qfull_queue, &udev->qfull_timer);
1478         return drained;
1479 }
1480
1481 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
1482 {
1483         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1484
1485         mutex_lock(&udev->cmdr_lock);
1486         tcmu_handle_completions(udev);
1487         run_qfull_queue(udev, false);
1488         mutex_unlock(&udev->cmdr_lock);
1489
1490         return 0;
1491 }
1492
1493 /*
1494  * mmap code from uio.c. Copied here because we want to hook mmap()
1495  * and this stuff must come along.
1496  */
1497 static int tcmu_find_mem_index(struct vm_area_struct *vma)
1498 {
1499         struct tcmu_dev *udev = vma->vm_private_data;
1500         struct uio_info *info = &udev->uio_info;
1501
1502         if (vma->vm_pgoff < MAX_UIO_MAPS) {
1503                 if (info->mem[vma->vm_pgoff].size == 0)
1504                         return -1;
1505                 return (int)vma->vm_pgoff;
1506         }
1507         return -1;
1508 }
1509
1510 static struct page *tcmu_try_get_block_page(struct tcmu_dev *udev, uint32_t dbi)
1511 {
1512         struct page *page;
1513
1514         mutex_lock(&udev->cmdr_lock);
1515         page = tcmu_get_block_page(udev, dbi);
1516         if (likely(page)) {
1517                 mutex_unlock(&udev->cmdr_lock);
1518                 return page;
1519         }
1520
1521         /*
1522          * Userspace messed up and passed in a address not in the
1523          * data iov passed to it.
1524          */
1525         pr_err("Invalid addr to data block mapping  (dbi %u) on device %s\n",
1526                dbi, udev->name);
1527         page = NULL;
1528         mutex_unlock(&udev->cmdr_lock);
1529
1530         return page;
1531 }
1532
1533 static vm_fault_t tcmu_vma_fault(struct vm_fault *vmf)
1534 {
1535         struct tcmu_dev *udev = vmf->vma->vm_private_data;
1536         struct uio_info *info = &udev->uio_info;
1537         struct page *page;
1538         unsigned long offset;
1539         void *addr;
1540
1541         int mi = tcmu_find_mem_index(vmf->vma);
1542         if (mi < 0)
1543                 return VM_FAULT_SIGBUS;
1544
1545         /*
1546          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
1547          * to use mem[N].
1548          */
1549         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
1550
1551         if (offset < udev->data_off) {
1552                 /* For the vmalloc()ed cmd area pages */
1553                 addr = (void *)(unsigned long)info->mem[mi].addr + offset;
1554                 page = vmalloc_to_page(addr);
1555         } else {
1556                 uint32_t dbi;
1557
1558                 /* For the dynamically growing data area pages */
1559                 dbi = (offset - udev->data_off) / DATA_BLOCK_SIZE;
1560                 page = tcmu_try_get_block_page(udev, dbi);
1561                 if (!page)
1562                         return VM_FAULT_SIGBUS;
1563         }
1564
1565         get_page(page);
1566         vmf->page = page;
1567         return 0;
1568 }
1569
1570 static const struct vm_operations_struct tcmu_vm_ops = {
1571         .fault = tcmu_vma_fault,
1572 };
1573
1574 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
1575 {
1576         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1577
1578         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
1579         vma->vm_ops = &tcmu_vm_ops;
1580
1581         vma->vm_private_data = udev;
1582
1583         /* Ensure the mmap is exactly the right size */
1584         if (vma_pages(vma) != (udev->ring_size >> PAGE_SHIFT))
1585                 return -EINVAL;
1586
1587         return 0;
1588 }
1589
1590 static int tcmu_open(struct uio_info *info, struct inode *inode)
1591 {
1592         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1593
1594         /* O_EXCL not supported for char devs, so fake it? */
1595         if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
1596                 return -EBUSY;
1597
1598         udev->inode = inode;
1599         kref_get(&udev->kref);
1600
1601         pr_debug("open\n");
1602
1603         return 0;
1604 }
1605
1606 static void tcmu_dev_call_rcu(struct rcu_head *p)
1607 {
1608         struct se_device *dev = container_of(p, struct se_device, rcu_head);
1609         struct tcmu_dev *udev = TCMU_DEV(dev);
1610
1611         kfree(udev->uio_info.name);
1612         kfree(udev->name);
1613         kfree(udev);
1614 }
1615
1616 static int tcmu_check_and_free_pending_cmd(struct tcmu_cmd *cmd)
1617 {
1618         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
1619                 kmem_cache_free(tcmu_cmd_cache, cmd);
1620                 return 0;
1621         }
1622         return -EINVAL;
1623 }
1624
1625 static void tcmu_blocks_release(struct radix_tree_root *blocks,
1626                                 int start, int end)
1627 {
1628         int i;
1629         struct page *page;
1630
1631         for (i = start; i < end; i++) {
1632                 page = radix_tree_delete(blocks, i);
1633                 if (page) {
1634                         __free_page(page);
1635                         atomic_dec(&global_db_count);
1636                 }
1637         }
1638 }
1639
1640 static void tcmu_dev_kref_release(struct kref *kref)
1641 {
1642         struct tcmu_dev *udev = container_of(kref, struct tcmu_dev, kref);
1643         struct se_device *dev = &udev->se_dev;
1644         struct tcmu_cmd *cmd;
1645         bool all_expired = true;
1646         int i;
1647
1648         vfree(udev->mb_addr);
1649         udev->mb_addr = NULL;
1650
1651         spin_lock_bh(&timed_out_udevs_lock);
1652         if (!list_empty(&udev->timedout_entry))
1653                 list_del(&udev->timedout_entry);
1654         spin_unlock_bh(&timed_out_udevs_lock);
1655
1656         /* Upper layer should drain all requests before calling this */
1657         mutex_lock(&udev->cmdr_lock);
1658         idr_for_each_entry(&udev->commands, cmd, i) {
1659                 if (tcmu_check_and_free_pending_cmd(cmd) != 0)
1660                         all_expired = false;
1661         }
1662         idr_destroy(&udev->commands);
1663         WARN_ON(!all_expired);
1664
1665         tcmu_blocks_release(&udev->data_blocks, 0, udev->dbi_max + 1);
1666         kfree(udev->data_bitmap);
1667         mutex_unlock(&udev->cmdr_lock);
1668
1669         call_rcu(&dev->rcu_head, tcmu_dev_call_rcu);
1670 }
1671
1672 static int tcmu_release(struct uio_info *info, struct inode *inode)
1673 {
1674         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
1675
1676         clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
1677
1678         pr_debug("close\n");
1679         /* release ref from open */
1680         kref_put(&udev->kref, tcmu_dev_kref_release);
1681         return 0;
1682 }
1683
1684 static int tcmu_init_genl_cmd_reply(struct tcmu_dev *udev, int cmd)
1685 {
1686         struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
1687
1688         if (!tcmu_kern_cmd_reply_supported)
1689                 return 0;
1690
1691         if (udev->nl_reply_supported <= 0)
1692                 return 0;
1693
1694         mutex_lock(&tcmu_nl_cmd_mutex);
1695
1696         if (tcmu_netlink_blocked) {
1697                 mutex_unlock(&tcmu_nl_cmd_mutex);
1698                 pr_warn("Failing nl cmd %d on %s. Interface is blocked.\n", cmd,
1699                         udev->name);
1700                 return -EAGAIN;
1701         }
1702
1703         if (nl_cmd->cmd != TCMU_CMD_UNSPEC) {
1704                 mutex_unlock(&tcmu_nl_cmd_mutex);
1705                 pr_warn("netlink cmd %d already executing on %s\n",
1706                          nl_cmd->cmd, udev->name);
1707                 return -EBUSY;
1708         }
1709
1710         memset(nl_cmd, 0, sizeof(*nl_cmd));
1711         nl_cmd->cmd = cmd;
1712         nl_cmd->udev = udev;
1713         init_completion(&nl_cmd->complete);
1714         INIT_LIST_HEAD(&nl_cmd->nl_list);
1715
1716         list_add_tail(&nl_cmd->nl_list, &tcmu_nl_cmd_list);
1717
1718         mutex_unlock(&tcmu_nl_cmd_mutex);
1719         return 0;
1720 }
1721
1722 static int tcmu_wait_genl_cmd_reply(struct tcmu_dev *udev)
1723 {
1724         struct tcmu_nl_cmd *nl_cmd = &udev->curr_nl_cmd;
1725         int ret;
1726
1727         if (!tcmu_kern_cmd_reply_supported)
1728                 return 0;
1729
1730         if (udev->nl_reply_supported <= 0)
1731                 return 0;
1732
1733         pr_debug("sleeping for nl reply\n");
1734         wait_for_completion(&nl_cmd->complete);
1735
1736         mutex_lock(&tcmu_nl_cmd_mutex);
1737         nl_cmd->cmd = TCMU_CMD_UNSPEC;
1738         ret = nl_cmd->status;
1739         mutex_unlock(&tcmu_nl_cmd_mutex);
1740
1741         return ret;
1742 }
1743
1744 static int tcmu_netlink_event_init(struct tcmu_dev *udev,
1745                                    enum tcmu_genl_cmd cmd,
1746                                    struct sk_buff **buf, void **hdr)
1747 {
1748         struct sk_buff *skb;
1749         void *msg_header;
1750         int ret = -ENOMEM;
1751
1752         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
1753         if (!skb)
1754                 return ret;
1755
1756         msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
1757         if (!msg_header)
1758                 goto free_skb;
1759
1760         ret = nla_put_string(skb, TCMU_ATTR_DEVICE, udev->uio_info.name);
1761         if (ret < 0)
1762                 goto free_skb;
1763
1764         ret = nla_put_u32(skb, TCMU_ATTR_MINOR, udev->uio_info.uio_dev->minor);
1765         if (ret < 0)
1766                 goto free_skb;
1767
1768         ret = nla_put_u32(skb, TCMU_ATTR_DEVICE_ID, udev->se_dev.dev_index);
1769         if (ret < 0)
1770                 goto free_skb;
1771
1772         *buf = skb;
1773         *hdr = msg_header;
1774         return ret;
1775
1776 free_skb:
1777         nlmsg_free(skb);
1778         return ret;
1779 }
1780
1781 static int tcmu_netlink_event_send(struct tcmu_dev *udev,
1782                                    enum tcmu_genl_cmd cmd,
1783                                    struct sk_buff *skb, void *msg_header)
1784 {
1785         int ret;
1786
1787         genlmsg_end(skb, msg_header);
1788
1789         ret = tcmu_init_genl_cmd_reply(udev, cmd);
1790         if (ret) {
1791                 nlmsg_free(skb);
1792                 return ret;
1793         }
1794
1795         ret = genlmsg_multicast_allns(&tcmu_genl_family, skb, 0,
1796                                       TCMU_MCGRP_CONFIG, GFP_KERNEL);
1797         /* We don't care if no one is listening */
1798         if (ret == -ESRCH)
1799                 ret = 0;
1800         if (!ret)
1801                 ret = tcmu_wait_genl_cmd_reply(udev);
1802         return ret;
1803 }
1804
1805 static int tcmu_send_dev_add_event(struct tcmu_dev *udev)
1806 {
1807         struct sk_buff *skb = NULL;
1808         void *msg_header = NULL;
1809         int ret = 0;
1810
1811         ret = tcmu_netlink_event_init(udev, TCMU_CMD_ADDED_DEVICE, &skb,
1812                                       &msg_header);
1813         if (ret < 0)
1814                 return ret;
1815         return tcmu_netlink_event_send(udev, TCMU_CMD_ADDED_DEVICE, skb,
1816                                        msg_header);
1817 }
1818
1819 static int tcmu_send_dev_remove_event(struct tcmu_dev *udev)
1820 {
1821         struct sk_buff *skb = NULL;
1822         void *msg_header = NULL;
1823         int ret = 0;
1824
1825         ret = tcmu_netlink_event_init(udev, TCMU_CMD_REMOVED_DEVICE,
1826                                       &skb, &msg_header);
1827         if (ret < 0)
1828                 return ret;
1829         return tcmu_netlink_event_send(udev, TCMU_CMD_REMOVED_DEVICE,
1830                                        skb, msg_header);
1831 }
1832
1833 static int tcmu_update_uio_info(struct tcmu_dev *udev)
1834 {
1835         struct tcmu_hba *hba = udev->hba->hba_ptr;
1836         struct uio_info *info;
1837         size_t size, used;
1838         char *str;
1839
1840         info = &udev->uio_info;
1841         size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
1842                         udev->dev_config);
1843         size += 1; /* for \0 */
1844         str = kmalloc(size, GFP_KERNEL);
1845         if (!str)
1846                 return -ENOMEM;
1847
1848         used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
1849         if (udev->dev_config[0])
1850                 snprintf(str + used, size - used, "/%s", udev->dev_config);
1851
1852         /* If the old string exists, free it */
1853         kfree(info->name);
1854         info->name = str;
1855
1856         return 0;
1857 }
1858
1859 static int tcmu_configure_device(struct se_device *dev)
1860 {
1861         struct tcmu_dev *udev = TCMU_DEV(dev);
1862         struct uio_info *info;
1863         struct tcmu_mailbox *mb;
1864         int ret = 0;
1865
1866         ret = tcmu_update_uio_info(udev);
1867         if (ret)
1868                 return ret;
1869
1870         info = &udev->uio_info;
1871
1872         mutex_lock(&udev->cmdr_lock);
1873         udev->data_bitmap = kcalloc(BITS_TO_LONGS(udev->max_blocks),
1874                                     sizeof(unsigned long),
1875                                     GFP_KERNEL);
1876         mutex_unlock(&udev->cmdr_lock);
1877         if (!udev->data_bitmap) {
1878                 ret = -ENOMEM;
1879                 goto err_bitmap_alloc;
1880         }
1881
1882         udev->mb_addr = vzalloc(CMDR_SIZE);
1883         if (!udev->mb_addr) {
1884                 ret = -ENOMEM;
1885                 goto err_vzalloc;
1886         }
1887
1888         /* mailbox fits in first part of CMDR space */
1889         udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
1890         udev->data_off = CMDR_SIZE;
1891         udev->data_size = udev->max_blocks * DATA_BLOCK_SIZE;
1892         udev->dbi_thresh = 0; /* Default in Idle state */
1893
1894         /* Initialise the mailbox of the ring buffer */
1895         mb = udev->mb_addr;
1896         mb->version = TCMU_MAILBOX_VERSION;
1897         mb->flags = TCMU_MAILBOX_FLAG_CAP_OOOC | TCMU_MAILBOX_FLAG_CAP_READ_LEN;
1898         mb->cmdr_off = CMDR_OFF;
1899         mb->cmdr_size = udev->cmdr_size;
1900
1901         WARN_ON(!PAGE_ALIGNED(udev->data_off));
1902         WARN_ON(udev->data_size % PAGE_SIZE);
1903         WARN_ON(udev->data_size % DATA_BLOCK_SIZE);
1904
1905         info->version = __stringify(TCMU_MAILBOX_VERSION);
1906
1907         info->mem[0].name = "tcm-user command & data buffer";
1908         info->mem[0].addr = (phys_addr_t)(uintptr_t)udev->mb_addr;
1909         info->mem[0].size = udev->ring_size = udev->data_size + CMDR_SIZE;
1910         info->mem[0].memtype = UIO_MEM_NONE;
1911
1912         info->irqcontrol = tcmu_irqcontrol;
1913         info->irq = UIO_IRQ_CUSTOM;
1914
1915         info->mmap = tcmu_mmap;
1916         info->open = tcmu_open;
1917         info->release = tcmu_release;
1918
1919         ret = uio_register_device(tcmu_root_device, info);
1920         if (ret)
1921                 goto err_register;
1922
1923         /* User can set hw_block_size before enable the device */
1924         if (dev->dev_attrib.hw_block_size == 0)
1925                 dev->dev_attrib.hw_block_size = 512;
1926         /* Other attributes can be configured in userspace */
1927         if (!dev->dev_attrib.hw_max_sectors)
1928                 dev->dev_attrib.hw_max_sectors = 128;
1929         if (!dev->dev_attrib.emulate_write_cache)
1930                 dev->dev_attrib.emulate_write_cache = 0;
1931         dev->dev_attrib.hw_queue_depth = 128;
1932
1933         /* If user didn't explicitly disable netlink reply support, use
1934          * module scope setting.
1935          */
1936         if (udev->nl_reply_supported >= 0)
1937                 udev->nl_reply_supported = tcmu_kern_cmd_reply_supported;
1938
1939         /*
1940          * Get a ref incase userspace does a close on the uio device before
1941          * LIO has initiated tcmu_free_device.
1942          */
1943         kref_get(&udev->kref);
1944
1945         ret = tcmu_send_dev_add_event(udev);
1946         if (ret)
1947                 goto err_netlink;
1948
1949         mutex_lock(&root_udev_mutex);
1950         list_add(&udev->node, &root_udev);
1951         mutex_unlock(&root_udev_mutex);
1952
1953         return 0;
1954
1955 err_netlink:
1956         kref_put(&udev->kref, tcmu_dev_kref_release);
1957         uio_unregister_device(&udev->uio_info);
1958 err_register:
1959         vfree(udev->mb_addr);
1960         udev->mb_addr = NULL;
1961 err_vzalloc:
1962         kfree(udev->data_bitmap);
1963         udev->data_bitmap = NULL;
1964 err_bitmap_alloc:
1965         kfree(info->name);
1966         info->name = NULL;
1967
1968         return ret;
1969 }
1970
1971 static void tcmu_free_device(struct se_device *dev)
1972 {
1973         struct tcmu_dev *udev = TCMU_DEV(dev);
1974
1975         /* release ref from init */
1976         kref_put(&udev->kref, tcmu_dev_kref_release);
1977 }
1978
1979 static void tcmu_destroy_device(struct se_device *dev)
1980 {
1981         struct tcmu_dev *udev = TCMU_DEV(dev);
1982
1983         del_timer_sync(&udev->cmd_timer);
1984         del_timer_sync(&udev->qfull_timer);
1985
1986         mutex_lock(&root_udev_mutex);
1987         list_del(&udev->node);
1988         mutex_unlock(&root_udev_mutex);
1989
1990         tcmu_send_dev_remove_event(udev);
1991
1992         uio_unregister_device(&udev->uio_info);
1993
1994         /* release ref from configure */
1995         kref_put(&udev->kref, tcmu_dev_kref_release);
1996 }
1997
1998 static void tcmu_unblock_dev(struct tcmu_dev *udev)
1999 {
2000         mutex_lock(&udev->cmdr_lock);
2001         clear_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags);
2002         mutex_unlock(&udev->cmdr_lock);
2003 }
2004
2005 static void tcmu_block_dev(struct tcmu_dev *udev)
2006 {
2007         mutex_lock(&udev->cmdr_lock);
2008
2009         if (test_and_set_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags))
2010                 goto unlock;
2011
2012         /* complete IO that has executed successfully */
2013         tcmu_handle_completions(udev);
2014         /* fail IO waiting to be queued */
2015         run_qfull_queue(udev, true);
2016
2017 unlock:
2018         mutex_unlock(&udev->cmdr_lock);
2019 }
2020
2021 static void tcmu_reset_ring(struct tcmu_dev *udev, u8 err_level)
2022 {
2023         struct tcmu_mailbox *mb;
2024         struct tcmu_cmd *cmd;
2025         int i;
2026
2027         mutex_lock(&udev->cmdr_lock);
2028
2029         idr_for_each_entry(&udev->commands, cmd, i) {
2030                 if (!test_bit(TCMU_CMD_BIT_INFLIGHT, &cmd->flags))
2031                         continue;
2032
2033                 pr_debug("removing cmd %u on dev %s from ring (is expired %d)\n",
2034                           cmd->cmd_id, udev->name,
2035                           test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags));
2036
2037                 idr_remove(&udev->commands, i);
2038                 if (!test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
2039                         list_del_init(&cmd->queue_entry);
2040                         if (err_level == 1) {
2041                                 /*
2042                                  * Userspace was not able to start the
2043                                  * command or it is retryable.
2044                                  */
2045                                 target_complete_cmd(cmd->se_cmd, SAM_STAT_BUSY);
2046                         } else {
2047                                 /* hard failure */
2048                                 target_complete_cmd(cmd->se_cmd,
2049                                                     SAM_STAT_CHECK_CONDITION);
2050                         }
2051                 }
2052                 tcmu_cmd_free_data(cmd, cmd->dbi_cnt);
2053                 tcmu_free_cmd(cmd);
2054         }
2055
2056         mb = udev->mb_addr;
2057         tcmu_flush_dcache_range(mb, sizeof(*mb));
2058         pr_debug("mb last %u head %u tail %u\n", udev->cmdr_last_cleaned,
2059                  mb->cmd_tail, mb->cmd_head);
2060
2061         udev->cmdr_last_cleaned = 0;
2062         mb->cmd_tail = 0;
2063         mb->cmd_head = 0;
2064         tcmu_flush_dcache_range(mb, sizeof(*mb));
2065
2066         del_timer(&udev->cmd_timer);
2067
2068         mutex_unlock(&udev->cmdr_lock);
2069 }
2070
2071 enum {
2072         Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_hw_max_sectors,
2073         Opt_nl_reply_supported, Opt_max_data_area_mb, Opt_err,
2074 };
2075
2076 static match_table_t tokens = {
2077         {Opt_dev_config, "dev_config=%s"},
2078         {Opt_dev_size, "dev_size=%s"},
2079         {Opt_hw_block_size, "hw_block_size=%d"},
2080         {Opt_hw_max_sectors, "hw_max_sectors=%d"},
2081         {Opt_nl_reply_supported, "nl_reply_supported=%d"},
2082         {Opt_max_data_area_mb, "max_data_area_mb=%d"},
2083         {Opt_err, NULL}
2084 };
2085
2086 static int tcmu_set_dev_attrib(substring_t *arg, u32 *dev_attrib)
2087 {
2088         int val, ret;
2089
2090         ret = match_int(arg, &val);
2091         if (ret < 0) {
2092                 pr_err("match_int() failed for dev attrib. Error %d.\n",
2093                        ret);
2094                 return ret;
2095         }
2096
2097         if (val <= 0) {
2098                 pr_err("Invalid dev attrib value %d. Must be greater than zero.\n",
2099                        val);
2100                 return -EINVAL;
2101         }
2102         *dev_attrib = val;
2103         return 0;
2104 }
2105
2106 static int tcmu_set_max_blocks_param(struct tcmu_dev *udev, substring_t *arg)
2107 {
2108         int val, ret;
2109
2110         ret = match_int(arg, &val);
2111         if (ret < 0) {
2112                 pr_err("match_int() failed for max_data_area_mb=. Error %d.\n",
2113                        ret);
2114                 return ret;
2115         }
2116
2117         if (val <= 0) {
2118                 pr_err("Invalid max_data_area %d.\n", val);
2119                 return -EINVAL;
2120         }
2121
2122         mutex_lock(&udev->cmdr_lock);
2123         if (udev->data_bitmap) {
2124                 pr_err("Cannot set max_data_area_mb after it has been enabled.\n");
2125                 ret = -EINVAL;
2126                 goto unlock;
2127         }
2128
2129         udev->max_blocks = TCMU_MBS_TO_BLOCKS(val);
2130         if (udev->max_blocks > tcmu_global_max_blocks) {
2131                 pr_err("%d is too large. Adjusting max_data_area_mb to global limit of %u\n",
2132                        val, TCMU_BLOCKS_TO_MBS(tcmu_global_max_blocks));
2133                 udev->max_blocks = tcmu_global_max_blocks;
2134         }
2135
2136 unlock:
2137         mutex_unlock(&udev->cmdr_lock);
2138         return ret;
2139 }
2140
2141 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
2142                 const char *page, ssize_t count)
2143 {
2144         struct tcmu_dev *udev = TCMU_DEV(dev);
2145         char *orig, *ptr, *opts;
2146         substring_t args[MAX_OPT_ARGS];
2147         int ret = 0, token;
2148
2149         opts = kstrdup(page, GFP_KERNEL);
2150         if (!opts)
2151                 return -ENOMEM;
2152
2153         orig = opts;
2154
2155         while ((ptr = strsep(&opts, ",\n")) != NULL) {
2156                 if (!*ptr)
2157                         continue;
2158
2159                 token = match_token(ptr, tokens, args);
2160                 switch (token) {
2161                 case Opt_dev_config:
2162                         if (match_strlcpy(udev->dev_config, &args[0],
2163                                           TCMU_CONFIG_LEN) == 0) {
2164                                 ret = -EINVAL;
2165                                 break;
2166                         }
2167                         pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
2168                         break;
2169                 case Opt_dev_size:
2170                         ret = match_u64(&args[0], &udev->dev_size);
2171                         if (ret < 0)
2172                                 pr_err("match_u64() failed for dev_size=. Error %d.\n",
2173                                        ret);
2174                         break;
2175                 case Opt_hw_block_size:
2176                         ret = tcmu_set_dev_attrib(&args[0],
2177                                         &(dev->dev_attrib.hw_block_size));
2178                         break;
2179                 case Opt_hw_max_sectors:
2180                         ret = tcmu_set_dev_attrib(&args[0],
2181                                         &(dev->dev_attrib.hw_max_sectors));
2182                         break;
2183                 case Opt_nl_reply_supported:
2184                         ret = match_int(&args[0], &udev->nl_reply_supported);
2185                         if (ret < 0)
2186                                 pr_err("match_int() failed for nl_reply_supported=. Error %d.\n",
2187                                        ret);
2188                         break;
2189                 case Opt_max_data_area_mb:
2190                         ret = tcmu_set_max_blocks_param(udev, &args[0]);
2191                         break;
2192                 default:
2193                         break;
2194                 }
2195
2196                 if (ret)
2197                         break;
2198         }
2199
2200         kfree(orig);
2201         return (!ret) ? count : ret;
2202 }
2203
2204 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
2205 {
2206         struct tcmu_dev *udev = TCMU_DEV(dev);
2207         ssize_t bl = 0;
2208
2209         bl = sprintf(b + bl, "Config: %s ",
2210                      udev->dev_config[0] ? udev->dev_config : "NULL");
2211         bl += sprintf(b + bl, "Size: %llu ", udev->dev_size);
2212         bl += sprintf(b + bl, "MaxDataAreaMB: %u\n",
2213                       TCMU_BLOCKS_TO_MBS(udev->max_blocks));
2214
2215         return bl;
2216 }
2217
2218 static sector_t tcmu_get_blocks(struct se_device *dev)
2219 {
2220         struct tcmu_dev *udev = TCMU_DEV(dev);
2221
2222         return div_u64(udev->dev_size - dev->dev_attrib.block_size,
2223                        dev->dev_attrib.block_size);
2224 }
2225
2226 static sense_reason_t
2227 tcmu_parse_cdb(struct se_cmd *cmd)
2228 {
2229         return passthrough_parse_cdb(cmd, tcmu_queue_cmd);
2230 }
2231
2232 static ssize_t tcmu_cmd_time_out_show(struct config_item *item, char *page)
2233 {
2234         struct se_dev_attrib *da = container_of(to_config_group(item),
2235                                         struct se_dev_attrib, da_group);
2236         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2237
2238         return snprintf(page, PAGE_SIZE, "%lu\n", udev->cmd_time_out / MSEC_PER_SEC);
2239 }
2240
2241 static ssize_t tcmu_cmd_time_out_store(struct config_item *item, const char *page,
2242                                        size_t count)
2243 {
2244         struct se_dev_attrib *da = container_of(to_config_group(item),
2245                                         struct se_dev_attrib, da_group);
2246         struct tcmu_dev *udev = container_of(da->da_dev,
2247                                         struct tcmu_dev, se_dev);
2248         u32 val;
2249         int ret;
2250
2251         if (da->da_dev->export_count) {
2252                 pr_err("Unable to set tcmu cmd_time_out while exports exist\n");
2253                 return -EINVAL;
2254         }
2255
2256         ret = kstrtou32(page, 0, &val);
2257         if (ret < 0)
2258                 return ret;
2259
2260         udev->cmd_time_out = val * MSEC_PER_SEC;
2261         return count;
2262 }
2263 CONFIGFS_ATTR(tcmu_, cmd_time_out);
2264
2265 static ssize_t tcmu_qfull_time_out_show(struct config_item *item, char *page)
2266 {
2267         struct se_dev_attrib *da = container_of(to_config_group(item),
2268                                                 struct se_dev_attrib, da_group);
2269         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2270
2271         return snprintf(page, PAGE_SIZE, "%ld\n", udev->qfull_time_out <= 0 ?
2272                         udev->qfull_time_out :
2273                         udev->qfull_time_out / MSEC_PER_SEC);
2274 }
2275
2276 static ssize_t tcmu_qfull_time_out_store(struct config_item *item,
2277                                          const char *page, size_t count)
2278 {
2279         struct se_dev_attrib *da = container_of(to_config_group(item),
2280                                         struct se_dev_attrib, da_group);
2281         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2282         s32 val;
2283         int ret;
2284
2285         ret = kstrtos32(page, 0, &val);
2286         if (ret < 0)
2287                 return ret;
2288
2289         if (val >= 0) {
2290                 udev->qfull_time_out = val * MSEC_PER_SEC;
2291         } else if (val == -1) {
2292                 udev->qfull_time_out = val;
2293         } else {
2294                 printk(KERN_ERR "Invalid qfull timeout value %d\n", val);
2295                 return -EINVAL;
2296         }
2297         return count;
2298 }
2299 CONFIGFS_ATTR(tcmu_, qfull_time_out);
2300
2301 static ssize_t tcmu_max_data_area_mb_show(struct config_item *item, char *page)
2302 {
2303         struct se_dev_attrib *da = container_of(to_config_group(item),
2304                                                 struct se_dev_attrib, da_group);
2305         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2306
2307         return snprintf(page, PAGE_SIZE, "%u\n",
2308                         TCMU_BLOCKS_TO_MBS(udev->max_blocks));
2309 }
2310 CONFIGFS_ATTR_RO(tcmu_, max_data_area_mb);
2311
2312 static ssize_t tcmu_dev_config_show(struct config_item *item, char *page)
2313 {
2314         struct se_dev_attrib *da = container_of(to_config_group(item),
2315                                                 struct se_dev_attrib, da_group);
2316         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2317
2318         return snprintf(page, PAGE_SIZE, "%s\n", udev->dev_config);
2319 }
2320
2321 static int tcmu_send_dev_config_event(struct tcmu_dev *udev,
2322                                       const char *reconfig_data)
2323 {
2324         struct sk_buff *skb = NULL;
2325         void *msg_header = NULL;
2326         int ret = 0;
2327
2328         ret = tcmu_netlink_event_init(udev, TCMU_CMD_RECONFIG_DEVICE,
2329                                       &skb, &msg_header);
2330         if (ret < 0)
2331                 return ret;
2332         ret = nla_put_string(skb, TCMU_ATTR_DEV_CFG, reconfig_data);
2333         if (ret < 0) {
2334                 nlmsg_free(skb);
2335                 return ret;
2336         }
2337         return tcmu_netlink_event_send(udev, TCMU_CMD_RECONFIG_DEVICE,
2338                                        skb, msg_header);
2339 }
2340
2341
2342 static ssize_t tcmu_dev_config_store(struct config_item *item, const char *page,
2343                                      size_t count)
2344 {
2345         struct se_dev_attrib *da = container_of(to_config_group(item),
2346                                                 struct se_dev_attrib, da_group);
2347         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2348         int ret, len;
2349
2350         len = strlen(page);
2351         if (!len || len > TCMU_CONFIG_LEN - 1)
2352                 return -EINVAL;
2353
2354         /* Check if device has been configured before */
2355         if (target_dev_configured(&udev->se_dev)) {
2356                 ret = tcmu_send_dev_config_event(udev, page);
2357                 if (ret) {
2358                         pr_err("Unable to reconfigure device\n");
2359                         return ret;
2360                 }
2361                 strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);
2362
2363                 ret = tcmu_update_uio_info(udev);
2364                 if (ret)
2365                         return ret;
2366                 return count;
2367         }
2368         strlcpy(udev->dev_config, page, TCMU_CONFIG_LEN);
2369
2370         return count;
2371 }
2372 CONFIGFS_ATTR(tcmu_, dev_config);
2373
2374 static ssize_t tcmu_dev_size_show(struct config_item *item, char *page)
2375 {
2376         struct se_dev_attrib *da = container_of(to_config_group(item),
2377                                                 struct se_dev_attrib, da_group);
2378         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2379
2380         return snprintf(page, PAGE_SIZE, "%llu\n", udev->dev_size);
2381 }
2382
2383 static int tcmu_send_dev_size_event(struct tcmu_dev *udev, u64 size)
2384 {
2385         struct sk_buff *skb = NULL;
2386         void *msg_header = NULL;
2387         int ret = 0;
2388
2389         ret = tcmu_netlink_event_init(udev, TCMU_CMD_RECONFIG_DEVICE,
2390                                       &skb, &msg_header);
2391         if (ret < 0)
2392                 return ret;
2393         ret = nla_put_u64_64bit(skb, TCMU_ATTR_DEV_SIZE,
2394                                 size, TCMU_ATTR_PAD);
2395         if (ret < 0) {
2396                 nlmsg_free(skb);
2397                 return ret;
2398         }
2399         return tcmu_netlink_event_send(udev, TCMU_CMD_RECONFIG_DEVICE,
2400                                        skb, msg_header);
2401 }
2402
2403 static ssize_t tcmu_dev_size_store(struct config_item *item, const char *page,
2404                                    size_t count)
2405 {
2406         struct se_dev_attrib *da = container_of(to_config_group(item),
2407                                                 struct se_dev_attrib, da_group);
2408         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2409         u64 val;
2410         int ret;
2411
2412         ret = kstrtou64(page, 0, &val);
2413         if (ret < 0)
2414                 return ret;
2415
2416         /* Check if device has been configured before */
2417         if (target_dev_configured(&udev->se_dev)) {
2418                 ret = tcmu_send_dev_size_event(udev, val);
2419                 if (ret) {
2420                         pr_err("Unable to reconfigure device\n");
2421                         return ret;
2422                 }
2423         }
2424         udev->dev_size = val;
2425         return count;
2426 }
2427 CONFIGFS_ATTR(tcmu_, dev_size);
2428
2429 static ssize_t tcmu_nl_reply_supported_show(struct config_item *item,
2430                 char *page)
2431 {
2432         struct se_dev_attrib *da = container_of(to_config_group(item),
2433                                                 struct se_dev_attrib, da_group);
2434         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2435
2436         return snprintf(page, PAGE_SIZE, "%d\n", udev->nl_reply_supported);
2437 }
2438
2439 static ssize_t tcmu_nl_reply_supported_store(struct config_item *item,
2440                 const char *page, size_t count)
2441 {
2442         struct se_dev_attrib *da = container_of(to_config_group(item),
2443                                                 struct se_dev_attrib, da_group);
2444         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2445         s8 val;
2446         int ret;
2447
2448         ret = kstrtos8(page, 0, &val);
2449         if (ret < 0)
2450                 return ret;
2451
2452         udev->nl_reply_supported = val;
2453         return count;
2454 }
2455 CONFIGFS_ATTR(tcmu_, nl_reply_supported);
2456
2457 static ssize_t tcmu_emulate_write_cache_show(struct config_item *item,
2458                                              char *page)
2459 {
2460         struct se_dev_attrib *da = container_of(to_config_group(item),
2461                                         struct se_dev_attrib, da_group);
2462
2463         return snprintf(page, PAGE_SIZE, "%i\n", da->emulate_write_cache);
2464 }
2465
2466 static int tcmu_send_emulate_write_cache(struct tcmu_dev *udev, u8 val)
2467 {
2468         struct sk_buff *skb = NULL;
2469         void *msg_header = NULL;
2470         int ret = 0;
2471
2472         ret = tcmu_netlink_event_init(udev, TCMU_CMD_RECONFIG_DEVICE,
2473                                       &skb, &msg_header);
2474         if (ret < 0)
2475                 return ret;
2476         ret = nla_put_u8(skb, TCMU_ATTR_WRITECACHE, val);
2477         if (ret < 0) {
2478                 nlmsg_free(skb);
2479                 return ret;
2480         }
2481         return tcmu_netlink_event_send(udev, TCMU_CMD_RECONFIG_DEVICE,
2482                                        skb, msg_header);
2483 }
2484
2485 static ssize_t tcmu_emulate_write_cache_store(struct config_item *item,
2486                                               const char *page, size_t count)
2487 {
2488         struct se_dev_attrib *da = container_of(to_config_group(item),
2489                                         struct se_dev_attrib, da_group);
2490         struct tcmu_dev *udev = TCMU_DEV(da->da_dev);
2491         u8 val;
2492         int ret;
2493
2494         ret = kstrtou8(page, 0, &val);
2495         if (ret < 0)
2496                 return ret;
2497
2498         /* Check if device has been configured before */
2499         if (target_dev_configured(&udev->se_dev)) {
2500                 ret = tcmu_send_emulate_write_cache(udev, val);
2501                 if (ret) {
2502                         pr_err("Unable to reconfigure device\n");
2503                         return ret;
2504                 }
2505         }
2506
2507         da->emulate_write_cache = val;
2508         return count;
2509 }
2510 CONFIGFS_ATTR(tcmu_, emulate_write_cache);
2511
2512 static ssize_t tcmu_block_dev_show(struct config_item *item, char *page)
2513 {
2514         struct se_device *se_dev = container_of(to_config_group(item),
2515                                                 struct se_device,
2516                                                 dev_action_group);
2517         struct tcmu_dev *udev = TCMU_DEV(se_dev);
2518
2519         if (test_bit(TCMU_DEV_BIT_BLOCKED, &udev->flags))
2520                 return snprintf(page, PAGE_SIZE, "%s\n", "blocked");
2521         else
2522                 return snprintf(page, PAGE_SIZE, "%s\n", "unblocked");
2523 }
2524
2525 static ssize_t tcmu_block_dev_store(struct config_item *item, const char *page,
2526                                     size_t count)
2527 {
2528         struct se_device *se_dev = container_of(to_config_group(item),
2529                                                 struct se_device,
2530                                                 dev_action_group);
2531         struct tcmu_dev *udev = TCMU_DEV(se_dev);
2532         u8 val;
2533         int ret;
2534
2535         if (!target_dev_configured(&udev->se_dev)) {
2536                 pr_err("Device is not configured.\n");
2537                 return -EINVAL;
2538         }
2539
2540         ret = kstrtou8(page, 0, &val);
2541         if (ret < 0)
2542                 return ret;
2543
2544         if (val > 1) {
2545                 pr_err("Invalid block value %d\n", val);
2546                 return -EINVAL;
2547         }
2548
2549         if (!val)
2550                 tcmu_unblock_dev(udev);
2551         else
2552                 tcmu_block_dev(udev);
2553         return count;
2554 }
2555 CONFIGFS_ATTR(tcmu_, block_dev);
2556
2557 static ssize_t tcmu_reset_ring_store(struct config_item *item, const char *page,
2558                                      size_t count)
2559 {
2560         struct se_device *se_dev = container_of(to_config_group(item),
2561                                                 struct se_device,
2562                                                 dev_action_group);
2563         struct tcmu_dev *udev = TCMU_DEV(se_dev);
2564         u8 val;
2565         int ret;
2566
2567         if (!target_dev_configured(&udev->se_dev)) {
2568                 pr_err("Device is not configured.\n");
2569                 return -EINVAL;
2570         }
2571
2572         ret = kstrtou8(page, 0, &val);
2573         if (ret < 0)
2574                 return ret;
2575
2576         if (val != 1 && val != 2) {
2577                 pr_err("Invalid reset ring value %d\n", val);
2578                 return -EINVAL;
2579         }
2580
2581         tcmu_reset_ring(udev, val);
2582         return count;
2583 }
2584 CONFIGFS_ATTR_WO(tcmu_, reset_ring);
2585
2586 static struct configfs_attribute *tcmu_attrib_attrs[] = {
2587         &tcmu_attr_cmd_time_out,
2588         &tcmu_attr_qfull_time_out,
2589         &tcmu_attr_max_data_area_mb,
2590         &tcmu_attr_dev_config,
2591         &tcmu_attr_dev_size,
2592         &tcmu_attr_emulate_write_cache,
2593         &tcmu_attr_nl_reply_supported,
2594         NULL,
2595 };
2596
2597 static struct configfs_attribute **tcmu_attrs;
2598
2599 static struct configfs_attribute *tcmu_action_attrs[] = {
2600         &tcmu_attr_block_dev,
2601         &tcmu_attr_reset_ring,
2602         NULL,
2603 };
2604
2605 static struct target_backend_ops tcmu_ops = {
2606         .name                   = "user",
2607         .owner                  = THIS_MODULE,
2608         .transport_flags        = TRANSPORT_FLAG_PASSTHROUGH,
2609         .attach_hba             = tcmu_attach_hba,
2610         .detach_hba             = tcmu_detach_hba,
2611         .alloc_device           = tcmu_alloc_device,
2612         .configure_device       = tcmu_configure_device,
2613         .destroy_device         = tcmu_destroy_device,
2614         .free_device            = tcmu_free_device,
2615         .parse_cdb              = tcmu_parse_cdb,
2616         .set_configfs_dev_params = tcmu_set_configfs_dev_params,
2617         .show_configfs_dev_params = tcmu_show_configfs_dev_params,
2618         .get_device_type        = sbc_get_device_type,
2619         .get_blocks             = tcmu_get_blocks,
2620         .tb_dev_action_attrs    = tcmu_action_attrs,
2621 };
2622
2623 static void find_free_blocks(void)
2624 {
2625         struct tcmu_dev *udev;
2626         loff_t off;
2627         u32 start, end, block, total_freed = 0;
2628
2629         if (atomic_read(&global_db_count) <= tcmu_global_max_blocks)
2630                 return;
2631
2632         mutex_lock(&root_udev_mutex);
2633         list_for_each_entry(udev, &root_udev, node) {
2634                 mutex_lock(&udev->cmdr_lock);
2635
2636                 if (!target_dev_configured(&udev->se_dev)) {
2637                         mutex_unlock(&udev->cmdr_lock);
2638                         continue;
2639                 }
2640
2641                 /* Try to complete the finished commands first */
2642                 tcmu_handle_completions(udev);
2643
2644                 /* Skip the udevs in idle */
2645                 if (!udev->dbi_thresh) {
2646                         mutex_unlock(&udev->cmdr_lock);
2647                         continue;
2648                 }
2649
2650                 end = udev->dbi_max + 1;
2651                 block = find_last_bit(udev->data_bitmap, end);
2652                 if (block == udev->dbi_max) {
2653                         /*
2654                          * The last bit is dbi_max, so it is not possible
2655                          * reclaim any blocks.
2656                          */
2657                         mutex_unlock(&udev->cmdr_lock);
2658                         continue;
2659                 } else if (block == end) {
2660                         /* The current udev will goto idle state */
2661                         udev->dbi_thresh = start = 0;
2662                         udev->dbi_max = 0;
2663                 } else {
2664                         udev->dbi_thresh = start = block + 1;
2665                         udev->dbi_max = block;
2666                 }
2667
2668                 /* Here will truncate the data area from off */
2669                 off = udev->data_off + start * DATA_BLOCK_SIZE;
2670                 unmap_mapping_range(udev->inode->i_mapping, off, 0, 1);
2671
2672                 /* Release the block pages */
2673                 tcmu_blocks_release(&udev->data_blocks, start, end);
2674                 mutex_unlock(&udev->cmdr_lock);
2675
2676                 total_freed += end - start;
2677                 pr_debug("Freed %u blocks (total %u) from %s.\n", end - start,
2678                          total_freed, udev->name);
2679         }
2680         mutex_unlock(&root_udev_mutex);
2681
2682         if (atomic_read(&global_db_count) > tcmu_global_max_blocks)
2683                 schedule_delayed_work(&tcmu_unmap_work, msecs_to_jiffies(5000));
2684 }
2685
2686 static void check_timedout_devices(void)
2687 {
2688         struct tcmu_dev *udev, *tmp_dev;
2689         LIST_HEAD(devs);
2690
2691         spin_lock_bh(&timed_out_udevs_lock);
2692         list_splice_init(&timed_out_udevs, &devs);
2693
2694         list_for_each_entry_safe(udev, tmp_dev, &devs, timedout_entry) {
2695                 list_del_init(&udev->timedout_entry);
2696                 spin_unlock_bh(&timed_out_udevs_lock);
2697
2698                 mutex_lock(&udev->cmdr_lock);
2699                 idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
2700
2701                 tcmu_set_next_deadline(&udev->inflight_queue, &udev->cmd_timer);
2702                 tcmu_set_next_deadline(&udev->qfull_queue, &udev->qfull_timer);
2703
2704                 mutex_unlock(&udev->cmdr_lock);
2705
2706                 spin_lock_bh(&timed_out_udevs_lock);
2707         }
2708
2709         spin_unlock_bh(&timed_out_udevs_lock);
2710 }
2711
2712 static void tcmu_unmap_work_fn(struct work_struct *work)
2713 {
2714         check_timedout_devices();
2715         find_free_blocks();
2716 }
2717
2718 static int __init tcmu_module_init(void)
2719 {
2720         int ret, i, k, len = 0;
2721
2722         BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
2723
2724         INIT_DELAYED_WORK(&tcmu_unmap_work, tcmu_unmap_work_fn);
2725
2726         tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
2727                                 sizeof(struct tcmu_cmd),
2728                                 __alignof__(struct tcmu_cmd),
2729                                 0, NULL);
2730         if (!tcmu_cmd_cache)
2731                 return -ENOMEM;
2732
2733         tcmu_root_device = root_device_register("tcm_user");
2734         if (IS_ERR(tcmu_root_device)) {
2735                 ret = PTR_ERR(tcmu_root_device);
2736                 goto out_free_cache;
2737         }
2738
2739         ret = genl_register_family(&tcmu_genl_family);
2740         if (ret < 0) {
2741                 goto out_unreg_device;
2742         }
2743
2744         for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
2745                 len += sizeof(struct configfs_attribute *);
2746         }
2747         for (i = 0; tcmu_attrib_attrs[i] != NULL; i++) {
2748                 len += sizeof(struct configfs_attribute *);
2749         }
2750         len += sizeof(struct configfs_attribute *);
2751
2752         tcmu_attrs = kzalloc(len, GFP_KERNEL);
2753         if (!tcmu_attrs) {
2754                 ret = -ENOMEM;
2755                 goto out_unreg_genl;
2756         }
2757
2758         for (i = 0; passthrough_attrib_attrs[i] != NULL; i++) {
2759                 tcmu_attrs[i] = passthrough_attrib_attrs[i];
2760         }
2761         for (k = 0; tcmu_attrib_attrs[k] != NULL; k++) {
2762                 tcmu_attrs[i] = tcmu_attrib_attrs[k];
2763                 i++;
2764         }
2765         tcmu_ops.tb_dev_attrib_attrs = tcmu_attrs;
2766
2767         ret = transport_backend_register(&tcmu_ops);
2768         if (ret)
2769                 goto out_attrs;
2770
2771         return 0;
2772
2773 out_attrs:
2774         kfree(tcmu_attrs);
2775 out_unreg_genl:
2776         genl_unregister_family(&tcmu_genl_family);
2777 out_unreg_device:
2778         root_device_unregister(tcmu_root_device);
2779 out_free_cache:
2780         kmem_cache_destroy(tcmu_cmd_cache);
2781
2782         return ret;
2783 }
2784
2785 static void __exit tcmu_module_exit(void)
2786 {
2787         cancel_delayed_work_sync(&tcmu_unmap_work);
2788         target_backend_unregister(&tcmu_ops);
2789         kfree(tcmu_attrs);
2790         genl_unregister_family(&tcmu_genl_family);
2791         root_device_unregister(tcmu_root_device);
2792         kmem_cache_destroy(tcmu_cmd_cache);
2793 }
2794
2795 MODULE_DESCRIPTION("TCM USER subsystem plugin");
2796 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
2797 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
2798 MODULE_LICENSE("GPL");
2799
2800 module_init(tcmu_module_init);
2801 module_exit(tcmu_module_exit);