Merge branches 'arm/rockchip', 'arm/exynos', 'arm/smmu', 'x86/vt-d', 'x86/amd', ...
[sfrench/cifs-2.6.git] / drivers / target / target_core_user.c
1 /*
2  * Copyright (C) 2013 Shaohua Li <shli@kernel.org>
3  * Copyright (C) 2014 Red Hat, Inc.
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms and conditions of the GNU General Public License,
7  * version 2, as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  *
14  * You should have received a copy of the GNU General Public License along with
15  * this program; if not, write to the Free Software Foundation, Inc.,
16  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
17  */
18
19 #include <linux/spinlock.h>
20 #include <linux/module.h>
21 #include <linux/idr.h>
22 #include <linux/timer.h>
23 #include <linux/parser.h>
24 #include <scsi/scsi.h>
25 #include <scsi/scsi_host.h>
26 #include <linux/uio_driver.h>
27 #include <net/genetlink.h>
28 #include <target/target_core_base.h>
29 #include <target/target_core_fabric.h>
30 #include <target/target_core_backend.h>
31 #include <target/target_core_backend_configfs.h>
32
33 #include <linux/target_core_user.h>
34
35 /*
36  * Define a shared-memory interface for LIO to pass SCSI commands and
37  * data to userspace for processing. This is to allow backends that
38  * are too complex for in-kernel support to be possible.
39  *
40  * It uses the UIO framework to do a lot of the device-creation and
41  * introspection work for us.
42  *
43  * See the .h file for how the ring is laid out. Note that while the
44  * command ring is defined, the particulars of the data area are
45  * not. Offset values in the command entry point to other locations
46  * internal to the mmap()ed area. There is separate space outside the
47  * command ring for data buffers. This leaves maximum flexibility for
48  * moving buffer allocations, or even page flipping or other
49  * allocation techniques, without altering the command ring layout.
50  *
51  * SECURITY:
52  * The user process must be assumed to be malicious. There's no way to
53  * prevent it breaking the command ring protocol if it wants, but in
54  * order to prevent other issues we must only ever read *data* from
55  * the shared memory area, not offsets or sizes. This applies to
56  * command ring entries as well as the mailbox. Extra code needed for
57  * this may have a 'UAM' comment.
58  */
59
60
61 #define TCMU_TIME_OUT (30 * MSEC_PER_SEC)
62
63 #define CMDR_SIZE (16 * 4096)
64 #define DATA_SIZE (257 * 4096)
65
66 #define TCMU_RING_SIZE (CMDR_SIZE + DATA_SIZE)
67
68 static struct device *tcmu_root_device;
69
70 struct tcmu_hba {
71         u32 host_id;
72 };
73
74 #define TCMU_CONFIG_LEN 256
75
76 struct tcmu_dev {
77         struct se_device se_dev;
78
79         char *name;
80         struct se_hba *hba;
81
82 #define TCMU_DEV_BIT_OPEN 0
83 #define TCMU_DEV_BIT_BROKEN 1
84         unsigned long flags;
85
86         struct uio_info uio_info;
87
88         struct tcmu_mailbox *mb_addr;
89         size_t dev_size;
90         u32 cmdr_size;
91         u32 cmdr_last_cleaned;
92         /* Offset of data ring from start of mb */
93         size_t data_off;
94         size_t data_size;
95         /* Ring head + tail values. */
96         /* Must add data_off and mb_addr to get the address */
97         size_t data_head;
98         size_t data_tail;
99
100         wait_queue_head_t wait_cmdr;
101         /* TODO should this be a mutex? */
102         spinlock_t cmdr_lock;
103
104         struct idr commands;
105         spinlock_t commands_lock;
106
107         struct timer_list timeout;
108
109         char dev_config[TCMU_CONFIG_LEN];
110 };
111
112 #define TCMU_DEV(_se_dev) container_of(_se_dev, struct tcmu_dev, se_dev)
113
114 #define CMDR_OFF sizeof(struct tcmu_mailbox)
115
116 struct tcmu_cmd {
117         struct se_cmd *se_cmd;
118         struct tcmu_dev *tcmu_dev;
119
120         uint16_t cmd_id;
121
122         /* Can't use se_cmd->data_length when cleaning up expired cmds, because if
123            cmd has been completed then accessing se_cmd is off limits */
124         size_t data_length;
125
126         unsigned long deadline;
127
128 #define TCMU_CMD_BIT_EXPIRED 0
129         unsigned long flags;
130 };
131
132 static struct kmem_cache *tcmu_cmd_cache;
133
134 /* multicast group */
135 enum tcmu_multicast_groups {
136         TCMU_MCGRP_CONFIG,
137 };
138
139 static const struct genl_multicast_group tcmu_mcgrps[] = {
140         [TCMU_MCGRP_CONFIG] = { .name = "config", },
141 };
142
143 /* Our generic netlink family */
144 static struct genl_family tcmu_genl_family = {
145         .id = GENL_ID_GENERATE,
146         .hdrsize = 0,
147         .name = "TCM-USER",
148         .version = 1,
149         .maxattr = TCMU_ATTR_MAX,
150         .mcgrps = tcmu_mcgrps,
151         .n_mcgrps = ARRAY_SIZE(tcmu_mcgrps),
152 };
153
154 static struct tcmu_cmd *tcmu_alloc_cmd(struct se_cmd *se_cmd)
155 {
156         struct se_device *se_dev = se_cmd->se_dev;
157         struct tcmu_dev *udev = TCMU_DEV(se_dev);
158         struct tcmu_cmd *tcmu_cmd;
159         int cmd_id;
160
161         tcmu_cmd = kmem_cache_zalloc(tcmu_cmd_cache, GFP_KERNEL);
162         if (!tcmu_cmd)
163                 return NULL;
164
165         tcmu_cmd->se_cmd = se_cmd;
166         tcmu_cmd->tcmu_dev = udev;
167         tcmu_cmd->data_length = se_cmd->data_length;
168
169         tcmu_cmd->deadline = jiffies + msecs_to_jiffies(TCMU_TIME_OUT);
170
171         idr_preload(GFP_KERNEL);
172         spin_lock_irq(&udev->commands_lock);
173         cmd_id = idr_alloc(&udev->commands, tcmu_cmd, 0,
174                 USHRT_MAX, GFP_NOWAIT);
175         spin_unlock_irq(&udev->commands_lock);
176         idr_preload_end();
177
178         if (cmd_id < 0) {
179                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
180                 return NULL;
181         }
182         tcmu_cmd->cmd_id = cmd_id;
183
184         return tcmu_cmd;
185 }
186
187 static inline void tcmu_flush_dcache_range(void *vaddr, size_t size)
188 {
189         unsigned long offset = (unsigned long) vaddr & ~PAGE_MASK;
190
191         size = round_up(size+offset, PAGE_SIZE);
192         vaddr -= offset;
193
194         while (size) {
195                 flush_dcache_page(virt_to_page(vaddr));
196                 size -= PAGE_SIZE;
197         }
198 }
199
200 /*
201  * Some ring helper functions. We don't assume size is a power of 2 so
202  * we can't use circ_buf.h.
203  */
204 static inline size_t spc_used(size_t head, size_t tail, size_t size)
205 {
206         int diff = head - tail;
207
208         if (diff >= 0)
209                 return diff;
210         else
211                 return size + diff;
212 }
213
214 static inline size_t spc_free(size_t head, size_t tail, size_t size)
215 {
216         /* Keep 1 byte unused or we can't tell full from empty */
217         return (size - spc_used(head, tail, size) - 1);
218 }
219
220 static inline size_t head_to_end(size_t head, size_t size)
221 {
222         return size - head;
223 }
224
225 #define UPDATE_HEAD(head, used, size) smp_store_release(&head, ((head % size) + used) % size)
226
227 /*
228  * We can't queue a command until we have space available on the cmd ring *and* space
229  * space avail on the data ring.
230  *
231  * Called with ring lock held.
232  */
233 static bool is_ring_space_avail(struct tcmu_dev *udev, size_t cmd_size, size_t data_needed)
234 {
235         struct tcmu_mailbox *mb = udev->mb_addr;
236         size_t space;
237         u32 cmd_head;
238         size_t cmd_needed;
239
240         tcmu_flush_dcache_range(mb, sizeof(*mb));
241
242         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
243
244         /*
245          * If cmd end-of-ring space is too small then we need space for a NOP plus
246          * original cmd - cmds are internally contiguous.
247          */
248         if (head_to_end(cmd_head, udev->cmdr_size) >= cmd_size)
249                 cmd_needed = cmd_size;
250         else
251                 cmd_needed = cmd_size + head_to_end(cmd_head, udev->cmdr_size);
252
253         space = spc_free(cmd_head, udev->cmdr_last_cleaned, udev->cmdr_size);
254         if (space < cmd_needed) {
255                 pr_debug("no cmd space: %u %u %u\n", cmd_head,
256                        udev->cmdr_last_cleaned, udev->cmdr_size);
257                 return false;
258         }
259
260         space = spc_free(udev->data_head, udev->data_tail, udev->data_size);
261         if (space < data_needed) {
262                 pr_debug("no data space: %zu %zu %zu\n", udev->data_head,
263                        udev->data_tail, udev->data_size);
264                 return false;
265         }
266
267         return true;
268 }
269
270 static int tcmu_queue_cmd_ring(struct tcmu_cmd *tcmu_cmd)
271 {
272         struct tcmu_dev *udev = tcmu_cmd->tcmu_dev;
273         struct se_cmd *se_cmd = tcmu_cmd->se_cmd;
274         size_t base_command_size, command_size;
275         struct tcmu_mailbox *mb;
276         struct tcmu_cmd_entry *entry;
277         int i;
278         struct scatterlist *sg;
279         struct iovec *iov;
280         int iov_cnt = 0;
281         uint32_t cmd_head;
282         uint64_t cdb_off;
283
284         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags))
285                 return -EINVAL;
286
287         /*
288          * Must be a certain minimum size for response sense info, but
289          * also may be larger if the iov array is large.
290          *
291          * iovs = sgl_nents+1, for end-of-ring case, plus another 1
292          * b/c size == offsetof one-past-element.
293         */
294         base_command_size = max(offsetof(struct tcmu_cmd_entry,
295                                          req.iov[se_cmd->t_data_nents + 2]),
296                                 sizeof(struct tcmu_cmd_entry));
297         command_size = base_command_size
298                 + round_up(scsi_command_size(se_cmd->t_task_cdb), TCMU_OP_ALIGN_SIZE);
299
300         WARN_ON(command_size & (TCMU_OP_ALIGN_SIZE-1));
301
302         spin_lock_irq(&udev->cmdr_lock);
303
304         mb = udev->mb_addr;
305         cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
306         if ((command_size > (udev->cmdr_size / 2))
307             || tcmu_cmd->data_length > (udev->data_size - 1))
308                 pr_warn("TCMU: Request of size %zu/%zu may be too big for %u/%zu "
309                         "cmd/data ring buffers\n", command_size, tcmu_cmd->data_length,
310                         udev->cmdr_size, udev->data_size);
311
312         while (!is_ring_space_avail(udev, command_size, tcmu_cmd->data_length)) {
313                 int ret;
314                 DEFINE_WAIT(__wait);
315
316                 prepare_to_wait(&udev->wait_cmdr, &__wait, TASK_INTERRUPTIBLE);
317
318                 pr_debug("sleeping for ring space\n");
319                 spin_unlock_irq(&udev->cmdr_lock);
320                 ret = schedule_timeout(msecs_to_jiffies(TCMU_TIME_OUT));
321                 finish_wait(&udev->wait_cmdr, &__wait);
322                 if (!ret) {
323                         pr_warn("tcmu: command timed out\n");
324                         return -ETIMEDOUT;
325                 }
326
327                 spin_lock_irq(&udev->cmdr_lock);
328
329                 /* We dropped cmdr_lock, cmd_head is stale */
330                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
331         }
332
333         /* Insert a PAD if end-of-ring space is too small */
334         if (head_to_end(cmd_head, udev->cmdr_size) < command_size) {
335                 size_t pad_size = head_to_end(cmd_head, udev->cmdr_size);
336
337                 entry = (void *) mb + CMDR_OFF + cmd_head;
338                 tcmu_flush_dcache_range(entry, sizeof(*entry));
339                 tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_PAD);
340                 tcmu_hdr_set_len(&entry->hdr.len_op, pad_size);
341                 entry->hdr.cmd_id = 0; /* not used for PAD */
342                 entry->hdr.kflags = 0;
343                 entry->hdr.uflags = 0;
344
345                 UPDATE_HEAD(mb->cmd_head, pad_size, udev->cmdr_size);
346
347                 cmd_head = mb->cmd_head % udev->cmdr_size; /* UAM */
348                 WARN_ON(cmd_head != 0);
349         }
350
351         entry = (void *) mb + CMDR_OFF + cmd_head;
352         tcmu_flush_dcache_range(entry, sizeof(*entry));
353         tcmu_hdr_set_op(&entry->hdr.len_op, TCMU_OP_CMD);
354         tcmu_hdr_set_len(&entry->hdr.len_op, command_size);
355         entry->hdr.cmd_id = tcmu_cmd->cmd_id;
356         entry->hdr.kflags = 0;
357         entry->hdr.uflags = 0;
358
359         /*
360          * Fix up iovecs, and handle if allocation in data ring wrapped.
361          */
362         iov = &entry->req.iov[0];
363         for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) {
364                 size_t copy_bytes = min((size_t)sg->length,
365                                      head_to_end(udev->data_head, udev->data_size));
366                 void *from = kmap_atomic(sg_page(sg)) + sg->offset;
367                 void *to = (void *) mb + udev->data_off + udev->data_head;
368
369                 if (tcmu_cmd->se_cmd->data_direction == DMA_TO_DEVICE) {
370                         memcpy(to, from, copy_bytes);
371                         tcmu_flush_dcache_range(to, copy_bytes);
372                 }
373
374                 /* Even iov_base is relative to mb_addr */
375                 iov->iov_len = copy_bytes;
376                 iov->iov_base = (void __user *) udev->data_off +
377                                                 udev->data_head;
378                 iov_cnt++;
379                 iov++;
380
381                 UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
382
383                 /* Uh oh, we wrapped the buffer. Must split sg across 2 iovs. */
384                 if (sg->length != copy_bytes) {
385                         from += copy_bytes;
386                         copy_bytes = sg->length - copy_bytes;
387
388                         iov->iov_len = copy_bytes;
389                         iov->iov_base = (void __user *) udev->data_off +
390                                                         udev->data_head;
391
392                         if (se_cmd->data_direction == DMA_TO_DEVICE) {
393                                 to = (void *) mb + udev->data_off + udev->data_head;
394                                 memcpy(to, from, copy_bytes);
395                                 tcmu_flush_dcache_range(to, copy_bytes);
396                         }
397
398                         iov_cnt++;
399                         iov++;
400
401                         UPDATE_HEAD(udev->data_head, copy_bytes, udev->data_size);
402                 }
403
404                 kunmap_atomic(from);
405         }
406         entry->req.iov_cnt = iov_cnt;
407         entry->req.iov_bidi_cnt = 0;
408         entry->req.iov_dif_cnt = 0;
409
410         /* All offsets relative to mb_addr, not start of entry! */
411         cdb_off = CMDR_OFF + cmd_head + base_command_size;
412         memcpy((void *) mb + cdb_off, se_cmd->t_task_cdb, scsi_command_size(se_cmd->t_task_cdb));
413         entry->req.cdb_off = cdb_off;
414         tcmu_flush_dcache_range(entry, sizeof(*entry));
415
416         UPDATE_HEAD(mb->cmd_head, command_size, udev->cmdr_size);
417         tcmu_flush_dcache_range(mb, sizeof(*mb));
418
419         spin_unlock_irq(&udev->cmdr_lock);
420
421         /* TODO: only if FLUSH and FUA? */
422         uio_event_notify(&udev->uio_info);
423
424         mod_timer(&udev->timeout,
425                 round_jiffies_up(jiffies + msecs_to_jiffies(TCMU_TIME_OUT)));
426
427         return 0;
428 }
429
430 static int tcmu_queue_cmd(struct se_cmd *se_cmd)
431 {
432         struct se_device *se_dev = se_cmd->se_dev;
433         struct tcmu_dev *udev = TCMU_DEV(se_dev);
434         struct tcmu_cmd *tcmu_cmd;
435         int ret;
436
437         tcmu_cmd = tcmu_alloc_cmd(se_cmd);
438         if (!tcmu_cmd)
439                 return -ENOMEM;
440
441         ret = tcmu_queue_cmd_ring(tcmu_cmd);
442         if (ret < 0) {
443                 pr_err("TCMU: Could not queue command\n");
444                 spin_lock_irq(&udev->commands_lock);
445                 idr_remove(&udev->commands, tcmu_cmd->cmd_id);
446                 spin_unlock_irq(&udev->commands_lock);
447
448                 kmem_cache_free(tcmu_cmd_cache, tcmu_cmd);
449         }
450
451         return ret;
452 }
453
454 static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *entry)
455 {
456         struct se_cmd *se_cmd = cmd->se_cmd;
457         struct tcmu_dev *udev = cmd->tcmu_dev;
458
459         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags)) {
460                 /* cmd has been completed already from timeout, just reclaim data
461                    ring space */
462                 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
463                 return;
464         }
465
466         if (entry->hdr.uflags & TCMU_UFLAG_UNKNOWN_OP) {
467                 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
468                 pr_warn("TCMU: Userspace set UNKNOWN_OP flag on se_cmd %p\n",
469                         cmd->se_cmd);
470                 transport_generic_request_failure(cmd->se_cmd,
471                         TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
472                 cmd->se_cmd = NULL;
473                 kmem_cache_free(tcmu_cmd_cache, cmd);
474                 return;
475         }
476
477         if (entry->rsp.scsi_status == SAM_STAT_CHECK_CONDITION) {
478                 memcpy(se_cmd->sense_buffer, entry->rsp.sense_buffer,
479                                se_cmd->scsi_sense_length);
480
481                 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
482         }
483         else if (se_cmd->data_direction == DMA_FROM_DEVICE) {
484                 struct scatterlist *sg;
485                 int i;
486
487                 /* It'd be easier to look at entry's iovec again, but UAM */
488                 for_each_sg(se_cmd->t_data_sg, sg, se_cmd->t_data_nents, i) {
489                         size_t copy_bytes;
490                         void *to;
491                         void *from;
492
493                         copy_bytes = min((size_t)sg->length,
494                                          head_to_end(udev->data_tail, udev->data_size));
495
496                         to = kmap_atomic(sg_page(sg)) + sg->offset;
497                         WARN_ON(sg->length + sg->offset > PAGE_SIZE);
498                         from = (void *) udev->mb_addr + udev->data_off + udev->data_tail;
499                         tcmu_flush_dcache_range(from, copy_bytes);
500                         memcpy(to, from, copy_bytes);
501
502                         UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size);
503
504                         /* Uh oh, wrapped the data buffer for this sg's data */
505                         if (sg->length != copy_bytes) {
506                                 from = (void *) udev->mb_addr + udev->data_off + udev->data_tail;
507                                 WARN_ON(udev->data_tail);
508                                 to += copy_bytes;
509                                 copy_bytes = sg->length - copy_bytes;
510                                 tcmu_flush_dcache_range(from, copy_bytes);
511                                 memcpy(to, from, copy_bytes);
512
513                                 UPDATE_HEAD(udev->data_tail, copy_bytes, udev->data_size);
514                         }
515
516                         kunmap_atomic(to);
517                 }
518
519         } else if (se_cmd->data_direction == DMA_TO_DEVICE) {
520                 UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
521         } else {
522                 pr_warn("TCMU: data direction was %d!\n", se_cmd->data_direction);
523         }
524
525         target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);
526         cmd->se_cmd = NULL;
527
528         kmem_cache_free(tcmu_cmd_cache, cmd);
529 }
530
531 static unsigned int tcmu_handle_completions(struct tcmu_dev *udev)
532 {
533         struct tcmu_mailbox *mb;
534         LIST_HEAD(cpl_cmds);
535         unsigned long flags;
536         int handled = 0;
537
538         if (test_bit(TCMU_DEV_BIT_BROKEN, &udev->flags)) {
539                 pr_err("ring broken, not handling completions\n");
540                 return 0;
541         }
542
543         spin_lock_irqsave(&udev->cmdr_lock, flags);
544
545         mb = udev->mb_addr;
546         tcmu_flush_dcache_range(mb, sizeof(*mb));
547
548         while (udev->cmdr_last_cleaned != ACCESS_ONCE(mb->cmd_tail)) {
549
550                 struct tcmu_cmd_entry *entry = (void *) mb + CMDR_OFF + udev->cmdr_last_cleaned;
551                 struct tcmu_cmd *cmd;
552
553                 tcmu_flush_dcache_range(entry, sizeof(*entry));
554
555                 if (tcmu_hdr_get_op(entry->hdr.len_op) == TCMU_OP_PAD) {
556                         UPDATE_HEAD(udev->cmdr_last_cleaned,
557                                     tcmu_hdr_get_len(entry->hdr.len_op),
558                                     udev->cmdr_size);
559                         continue;
560                 }
561                 WARN_ON(tcmu_hdr_get_op(entry->hdr.len_op) != TCMU_OP_CMD);
562
563                 spin_lock(&udev->commands_lock);
564                 cmd = idr_find(&udev->commands, entry->hdr.cmd_id);
565                 if (cmd)
566                         idr_remove(&udev->commands, cmd->cmd_id);
567                 spin_unlock(&udev->commands_lock);
568
569                 if (!cmd) {
570                         pr_err("cmd_id not found, ring is broken\n");
571                         set_bit(TCMU_DEV_BIT_BROKEN, &udev->flags);
572                         break;
573                 }
574
575                 tcmu_handle_completion(cmd, entry);
576
577                 UPDATE_HEAD(udev->cmdr_last_cleaned,
578                             tcmu_hdr_get_len(entry->hdr.len_op),
579                             udev->cmdr_size);
580
581                 handled++;
582         }
583
584         if (mb->cmd_tail == mb->cmd_head)
585                 del_timer(&udev->timeout); /* no more pending cmds */
586
587         spin_unlock_irqrestore(&udev->cmdr_lock, flags);
588
589         wake_up(&udev->wait_cmdr);
590
591         return handled;
592 }
593
594 static int tcmu_check_expired_cmd(int id, void *p, void *data)
595 {
596         struct tcmu_cmd *cmd = p;
597
598         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
599                 return 0;
600
601         if (!time_after(cmd->deadline, jiffies))
602                 return 0;
603
604         set_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags);
605         target_complete_cmd(cmd->se_cmd, SAM_STAT_CHECK_CONDITION);
606         cmd->se_cmd = NULL;
607
608         kmem_cache_free(tcmu_cmd_cache, cmd);
609
610         return 0;
611 }
612
613 static void tcmu_device_timedout(unsigned long data)
614 {
615         struct tcmu_dev *udev = (struct tcmu_dev *)data;
616         unsigned long flags;
617         int handled;
618
619         handled = tcmu_handle_completions(udev);
620
621         pr_warn("%d completions handled from timeout\n", handled);
622
623         spin_lock_irqsave(&udev->commands_lock, flags);
624         idr_for_each(&udev->commands, tcmu_check_expired_cmd, NULL);
625         spin_unlock_irqrestore(&udev->commands_lock, flags);
626
627         /*
628          * We don't need to wakeup threads on wait_cmdr since they have their
629          * own timeout.
630          */
631 }
632
633 static int tcmu_attach_hba(struct se_hba *hba, u32 host_id)
634 {
635         struct tcmu_hba *tcmu_hba;
636
637         tcmu_hba = kzalloc(sizeof(struct tcmu_hba), GFP_KERNEL);
638         if (!tcmu_hba)
639                 return -ENOMEM;
640
641         tcmu_hba->host_id = host_id;
642         hba->hba_ptr = tcmu_hba;
643
644         return 0;
645 }
646
647 static void tcmu_detach_hba(struct se_hba *hba)
648 {
649         kfree(hba->hba_ptr);
650         hba->hba_ptr = NULL;
651 }
652
653 static struct se_device *tcmu_alloc_device(struct se_hba *hba, const char *name)
654 {
655         struct tcmu_dev *udev;
656
657         udev = kzalloc(sizeof(struct tcmu_dev), GFP_KERNEL);
658         if (!udev)
659                 return NULL;
660
661         udev->name = kstrdup(name, GFP_KERNEL);
662         if (!udev->name) {
663                 kfree(udev);
664                 return NULL;
665         }
666
667         udev->hba = hba;
668
669         init_waitqueue_head(&udev->wait_cmdr);
670         spin_lock_init(&udev->cmdr_lock);
671
672         idr_init(&udev->commands);
673         spin_lock_init(&udev->commands_lock);
674
675         setup_timer(&udev->timeout, tcmu_device_timedout,
676                 (unsigned long)udev);
677
678         return &udev->se_dev;
679 }
680
681 static int tcmu_irqcontrol(struct uio_info *info, s32 irq_on)
682 {
683         struct tcmu_dev *tcmu_dev = container_of(info, struct tcmu_dev, uio_info);
684
685         tcmu_handle_completions(tcmu_dev);
686
687         return 0;
688 }
689
690 /*
691  * mmap code from uio.c. Copied here because we want to hook mmap()
692  * and this stuff must come along.
693  */
694 static int tcmu_find_mem_index(struct vm_area_struct *vma)
695 {
696         struct tcmu_dev *udev = vma->vm_private_data;
697         struct uio_info *info = &udev->uio_info;
698
699         if (vma->vm_pgoff < MAX_UIO_MAPS) {
700                 if (info->mem[vma->vm_pgoff].size == 0)
701                         return -1;
702                 return (int)vma->vm_pgoff;
703         }
704         return -1;
705 }
706
707 static int tcmu_vma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
708 {
709         struct tcmu_dev *udev = vma->vm_private_data;
710         struct uio_info *info = &udev->uio_info;
711         struct page *page;
712         unsigned long offset;
713         void *addr;
714
715         int mi = tcmu_find_mem_index(vma);
716         if (mi < 0)
717                 return VM_FAULT_SIGBUS;
718
719         /*
720          * We need to subtract mi because userspace uses offset = N*PAGE_SIZE
721          * to use mem[N].
722          */
723         offset = (vmf->pgoff - mi) << PAGE_SHIFT;
724
725         addr = (void *)(unsigned long)info->mem[mi].addr + offset;
726         if (info->mem[mi].memtype == UIO_MEM_LOGICAL)
727                 page = virt_to_page(addr);
728         else
729                 page = vmalloc_to_page(addr);
730         get_page(page);
731         vmf->page = page;
732         return 0;
733 }
734
735 static const struct vm_operations_struct tcmu_vm_ops = {
736         .fault = tcmu_vma_fault,
737 };
738
739 static int tcmu_mmap(struct uio_info *info, struct vm_area_struct *vma)
740 {
741         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
742
743         vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
744         vma->vm_ops = &tcmu_vm_ops;
745
746         vma->vm_private_data = udev;
747
748         /* Ensure the mmap is exactly the right size */
749         if (vma_pages(vma) != (TCMU_RING_SIZE >> PAGE_SHIFT))
750                 return -EINVAL;
751
752         return 0;
753 }
754
755 static int tcmu_open(struct uio_info *info, struct inode *inode)
756 {
757         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
758
759         /* O_EXCL not supported for char devs, so fake it? */
760         if (test_and_set_bit(TCMU_DEV_BIT_OPEN, &udev->flags))
761                 return -EBUSY;
762
763         pr_debug("open\n");
764
765         return 0;
766 }
767
768 static int tcmu_release(struct uio_info *info, struct inode *inode)
769 {
770         struct tcmu_dev *udev = container_of(info, struct tcmu_dev, uio_info);
771
772         clear_bit(TCMU_DEV_BIT_OPEN, &udev->flags);
773
774         pr_debug("close\n");
775
776         return 0;
777 }
778
779 static int tcmu_netlink_event(enum tcmu_genl_cmd cmd, const char *name, int minor)
780 {
781         struct sk_buff *skb;
782         void *msg_header;
783         int ret = -ENOMEM;
784
785         skb = genlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
786         if (!skb)
787                 return ret;
788
789         msg_header = genlmsg_put(skb, 0, 0, &tcmu_genl_family, 0, cmd);
790         if (!msg_header)
791                 goto free_skb;
792
793         ret = nla_put_string(skb, TCMU_ATTR_DEVICE, name);
794         if (ret < 0)
795                 goto free_skb;
796
797         ret = nla_put_u32(skb, TCMU_ATTR_MINOR, minor);
798         if (ret < 0)
799                 goto free_skb;
800
801         genlmsg_end(skb, msg_header);
802
803         ret = genlmsg_multicast(&tcmu_genl_family, skb, 0,
804                                 TCMU_MCGRP_CONFIG, GFP_KERNEL);
805
806         /* We don't care if no one is listening */
807         if (ret == -ESRCH)
808                 ret = 0;
809
810         return ret;
811 free_skb:
812         nlmsg_free(skb);
813         return ret;
814 }
815
816 static int tcmu_configure_device(struct se_device *dev)
817 {
818         struct tcmu_dev *udev = TCMU_DEV(dev);
819         struct tcmu_hba *hba = udev->hba->hba_ptr;
820         struct uio_info *info;
821         struct tcmu_mailbox *mb;
822         size_t size;
823         size_t used;
824         int ret = 0;
825         char *str;
826
827         info = &udev->uio_info;
828
829         size = snprintf(NULL, 0, "tcm-user/%u/%s/%s", hba->host_id, udev->name,
830                         udev->dev_config);
831         size += 1; /* for \0 */
832         str = kmalloc(size, GFP_KERNEL);
833         if (!str)
834                 return -ENOMEM;
835
836         used = snprintf(str, size, "tcm-user/%u/%s", hba->host_id, udev->name);
837
838         if (udev->dev_config[0])
839                 snprintf(str + used, size - used, "/%s", udev->dev_config);
840
841         info->name = str;
842
843         udev->mb_addr = vzalloc(TCMU_RING_SIZE);
844         if (!udev->mb_addr) {
845                 ret = -ENOMEM;
846                 goto err_vzalloc;
847         }
848
849         /* mailbox fits in first part of CMDR space */
850         udev->cmdr_size = CMDR_SIZE - CMDR_OFF;
851         udev->data_off = CMDR_SIZE;
852         udev->data_size = TCMU_RING_SIZE - CMDR_SIZE;
853
854         mb = udev->mb_addr;
855         mb->version = TCMU_MAILBOX_VERSION;
856         mb->cmdr_off = CMDR_OFF;
857         mb->cmdr_size = udev->cmdr_size;
858
859         WARN_ON(!PAGE_ALIGNED(udev->data_off));
860         WARN_ON(udev->data_size % PAGE_SIZE);
861
862         info->version = xstr(TCMU_MAILBOX_VERSION);
863
864         info->mem[0].name = "tcm-user command & data buffer";
865         info->mem[0].addr = (phys_addr_t) udev->mb_addr;
866         info->mem[0].size = TCMU_RING_SIZE;
867         info->mem[0].memtype = UIO_MEM_VIRTUAL;
868
869         info->irqcontrol = tcmu_irqcontrol;
870         info->irq = UIO_IRQ_CUSTOM;
871
872         info->mmap = tcmu_mmap;
873         info->open = tcmu_open;
874         info->release = tcmu_release;
875
876         ret = uio_register_device(tcmu_root_device, info);
877         if (ret)
878                 goto err_register;
879
880         /* Other attributes can be configured in userspace */
881         dev->dev_attrib.hw_block_size = 512;
882         dev->dev_attrib.hw_max_sectors = 128;
883         dev->dev_attrib.hw_queue_depth = 128;
884
885         ret = tcmu_netlink_event(TCMU_CMD_ADDED_DEVICE, udev->uio_info.name,
886                                  udev->uio_info.uio_dev->minor);
887         if (ret)
888                 goto err_netlink;
889
890         return 0;
891
892 err_netlink:
893         uio_unregister_device(&udev->uio_info);
894 err_register:
895         vfree(udev->mb_addr);
896 err_vzalloc:
897         kfree(info->name);
898
899         return ret;
900 }
901
902 static int tcmu_check_pending_cmd(int id, void *p, void *data)
903 {
904         struct tcmu_cmd *cmd = p;
905
906         if (test_bit(TCMU_CMD_BIT_EXPIRED, &cmd->flags))
907                 return 0;
908         return -EINVAL;
909 }
910
911 static void tcmu_free_device(struct se_device *dev)
912 {
913         struct tcmu_dev *udev = TCMU_DEV(dev);
914         int i;
915
916         del_timer_sync(&udev->timeout);
917
918         vfree(udev->mb_addr);
919
920         /* Upper layer should drain all requests before calling this */
921         spin_lock_irq(&udev->commands_lock);
922         i = idr_for_each(&udev->commands, tcmu_check_pending_cmd, NULL);
923         idr_destroy(&udev->commands);
924         spin_unlock_irq(&udev->commands_lock);
925         WARN_ON(i);
926
927         /* Device was configured */
928         if (udev->uio_info.uio_dev) {
929                 tcmu_netlink_event(TCMU_CMD_REMOVED_DEVICE, udev->uio_info.name,
930                                    udev->uio_info.uio_dev->minor);
931
932                 uio_unregister_device(&udev->uio_info);
933                 kfree(udev->uio_info.name);
934                 kfree(udev->name);
935         }
936
937         kfree(udev);
938 }
939
940 enum {
941         Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_err,
942 };
943
944 static match_table_t tokens = {
945         {Opt_dev_config, "dev_config=%s"},
946         {Opt_dev_size, "dev_size=%u"},
947         {Opt_hw_block_size, "hw_block_size=%u"},
948         {Opt_err, NULL}
949 };
950
951 static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev,
952                 const char *page, ssize_t count)
953 {
954         struct tcmu_dev *udev = TCMU_DEV(dev);
955         char *orig, *ptr, *opts, *arg_p;
956         substring_t args[MAX_OPT_ARGS];
957         int ret = 0, token;
958         unsigned long tmp_ul;
959
960         opts = kstrdup(page, GFP_KERNEL);
961         if (!opts)
962                 return -ENOMEM;
963
964         orig = opts;
965
966         while ((ptr = strsep(&opts, ",\n")) != NULL) {
967                 if (!*ptr)
968                         continue;
969
970                 token = match_token(ptr, tokens, args);
971                 switch (token) {
972                 case Opt_dev_config:
973                         if (match_strlcpy(udev->dev_config, &args[0],
974                                           TCMU_CONFIG_LEN) == 0) {
975                                 ret = -EINVAL;
976                                 break;
977                         }
978                         pr_debug("TCMU: Referencing Path: %s\n", udev->dev_config);
979                         break;
980                 case Opt_dev_size:
981                         arg_p = match_strdup(&args[0]);
982                         if (!arg_p) {
983                                 ret = -ENOMEM;
984                                 break;
985                         }
986                         ret = kstrtoul(arg_p, 0, (unsigned long *) &udev->dev_size);
987                         kfree(arg_p);
988                         if (ret < 0)
989                                 pr_err("kstrtoul() failed for dev_size=\n");
990                         break;
991                 case Opt_hw_block_size:
992                         arg_p = match_strdup(&args[0]);
993                         if (!arg_p) {
994                                 ret = -ENOMEM;
995                                 break;
996                         }
997                         ret = kstrtoul(arg_p, 0, &tmp_ul);
998                         kfree(arg_p);
999                         if (ret < 0) {
1000                                 pr_err("kstrtoul() failed for hw_block_size=\n");
1001                                 break;
1002                         }
1003                         if (!tmp_ul) {
1004                                 pr_err("hw_block_size must be nonzero\n");
1005                                 break;
1006                         }
1007                         dev->dev_attrib.hw_block_size = tmp_ul;
1008                         break;
1009                 default:
1010                         break;
1011                 }
1012         }
1013
1014         kfree(orig);
1015         return (!ret) ? count : ret;
1016 }
1017
1018 static ssize_t tcmu_show_configfs_dev_params(struct se_device *dev, char *b)
1019 {
1020         struct tcmu_dev *udev = TCMU_DEV(dev);
1021         ssize_t bl = 0;
1022
1023         bl = sprintf(b + bl, "Config: %s ",
1024                      udev->dev_config[0] ? udev->dev_config : "NULL");
1025         bl += sprintf(b + bl, "Size: %zu\n", udev->dev_size);
1026
1027         return bl;
1028 }
1029
1030 static sector_t tcmu_get_blocks(struct se_device *dev)
1031 {
1032         struct tcmu_dev *udev = TCMU_DEV(dev);
1033
1034         return div_u64(udev->dev_size - dev->dev_attrib.block_size,
1035                        dev->dev_attrib.block_size);
1036 }
1037
1038 static sense_reason_t
1039 tcmu_pass_op(struct se_cmd *se_cmd)
1040 {
1041         int ret = tcmu_queue_cmd(se_cmd);
1042
1043         if (ret != 0)
1044                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1045         else
1046                 return TCM_NO_SENSE;
1047 }
1048
1049 static sense_reason_t
1050 tcmu_parse_cdb(struct se_cmd *cmd)
1051 {
1052         return passthrough_parse_cdb(cmd, tcmu_pass_op);
1053 }
1054
1055 DEF_TB_DEV_ATTRIB_RO(tcmu, hw_pi_prot_type);
1056 TB_DEV_ATTR_RO(tcmu, hw_pi_prot_type);
1057
1058 DEF_TB_DEV_ATTRIB_RO(tcmu, hw_block_size);
1059 TB_DEV_ATTR_RO(tcmu, hw_block_size);
1060
1061 DEF_TB_DEV_ATTRIB_RO(tcmu, hw_max_sectors);
1062 TB_DEV_ATTR_RO(tcmu, hw_max_sectors);
1063
1064 DEF_TB_DEV_ATTRIB_RO(tcmu, hw_queue_depth);
1065 TB_DEV_ATTR_RO(tcmu, hw_queue_depth);
1066
1067 static struct configfs_attribute *tcmu_backend_dev_attrs[] = {
1068         &tcmu_dev_attrib_hw_pi_prot_type.attr,
1069         &tcmu_dev_attrib_hw_block_size.attr,
1070         &tcmu_dev_attrib_hw_max_sectors.attr,
1071         &tcmu_dev_attrib_hw_queue_depth.attr,
1072         NULL,
1073 };
1074
1075 static struct se_subsystem_api tcmu_template = {
1076         .name                   = "user",
1077         .inquiry_prod           = "USER",
1078         .inquiry_rev            = TCMU_VERSION,
1079         .owner                  = THIS_MODULE,
1080         .transport_flags        = TRANSPORT_FLAG_PASSTHROUGH,
1081         .attach_hba             = tcmu_attach_hba,
1082         .detach_hba             = tcmu_detach_hba,
1083         .alloc_device           = tcmu_alloc_device,
1084         .configure_device       = tcmu_configure_device,
1085         .free_device            = tcmu_free_device,
1086         .parse_cdb              = tcmu_parse_cdb,
1087         .set_configfs_dev_params = tcmu_set_configfs_dev_params,
1088         .show_configfs_dev_params = tcmu_show_configfs_dev_params,
1089         .get_device_type        = sbc_get_device_type,
1090         .get_blocks             = tcmu_get_blocks,
1091 };
1092
1093 static int __init tcmu_module_init(void)
1094 {
1095         struct target_backend_cits *tbc = &tcmu_template.tb_cits;
1096         int ret;
1097
1098         BUILD_BUG_ON((sizeof(struct tcmu_cmd_entry) % TCMU_OP_ALIGN_SIZE) != 0);
1099
1100         tcmu_cmd_cache = kmem_cache_create("tcmu_cmd_cache",
1101                                 sizeof(struct tcmu_cmd),
1102                                 __alignof__(struct tcmu_cmd),
1103                                 0, NULL);
1104         if (!tcmu_cmd_cache)
1105                 return -ENOMEM;
1106
1107         tcmu_root_device = root_device_register("tcm_user");
1108         if (IS_ERR(tcmu_root_device)) {
1109                 ret = PTR_ERR(tcmu_root_device);
1110                 goto out_free_cache;
1111         }
1112
1113         ret = genl_register_family(&tcmu_genl_family);
1114         if (ret < 0) {
1115                 goto out_unreg_device;
1116         }
1117
1118         target_core_setup_sub_cits(&tcmu_template);
1119         tbc->tb_dev_attrib_cit.ct_attrs = tcmu_backend_dev_attrs;
1120
1121         ret = transport_subsystem_register(&tcmu_template);
1122         if (ret)
1123                 goto out_unreg_genl;
1124
1125         return 0;
1126
1127 out_unreg_genl:
1128         genl_unregister_family(&tcmu_genl_family);
1129 out_unreg_device:
1130         root_device_unregister(tcmu_root_device);
1131 out_free_cache:
1132         kmem_cache_destroy(tcmu_cmd_cache);
1133
1134         return ret;
1135 }
1136
1137 static void __exit tcmu_module_exit(void)
1138 {
1139         transport_subsystem_release(&tcmu_template);
1140         genl_unregister_family(&tcmu_genl_family);
1141         root_device_unregister(tcmu_root_device);
1142         kmem_cache_destroy(tcmu_cmd_cache);
1143 }
1144
1145 MODULE_DESCRIPTION("TCM USER subsystem plugin");
1146 MODULE_AUTHOR("Shaohua Li <shli@kernel.org>");
1147 MODULE_AUTHOR("Andy Grover <agrover@redhat.com>");
1148 MODULE_LICENSE("GPL");
1149
1150 module_init(tcmu_module_init);
1151 module_exit(tcmu_module_exit);