drivers/net/xen-netback/netback.c

   1 /*
   2  * Back-end of the driver for virtual network devices. This portion of the
   3  * driver exports a 'unified' network-device interface that can be accessed
   4  * by any operating system that implements a compatible front end. A
   5  * reference front-end implementation can be found in:
   6  *  drivers/net/xen-netfront.c
   7  *
   8  * Copyright (c) 2002-2005, K A Fraser
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License version 2
  12  * as published by the Free Software Foundation; or, when distributed
  13  * separately from the Linux kernel or incorporated into other
  14  * software packages, subject to the following license:
  15  *
  16  * Permission is hereby granted, free of charge, to any person obtaining a copy
  17  * of this source file (the "Software"), to deal in the Software without
  18  * restriction, including without limitation the rights to use, copy, modify,
  19  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  20  * and to permit persons to whom the Software is furnished to do so, subject to
  21  * the following conditions:
  22  *
  23  * The above copyright notice and this permission notice shall be included in
  24  * all copies or substantial portions of the Software.
  25  *
  26  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  27  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  28  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  29  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  30  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  31  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  32  * IN THE SOFTWARE.
  33  */
  34
  35 #include "common.h"
  36
  37 #include <linux/kthread.h>
  38 #include <linux/if_vlan.h>
  39 #include <linux/udp.h>
  40 #include <linux/highmem.h>
  41
  42 #include <net/tcp.h>
  43
  44 #include <xen/xen.h>
  45 #include <xen/events.h>
  46 #include <xen/interface/memory.h>
  47 #include <xen/page.h>
  48
  49 #include <asm/xen/hypercall.h>
  50
  51 /* Provide an option to disable split event channels at load time as
  52  * event channels are limited resource. Split event channels are
  53  * enabled by default.
  54  */
  55 bool separate_tx_rx_irq = true;
  56 module_param(separate_tx_rx_irq, bool, 0644);
  57
  58 /* The time that packets can stay on the guest Rx internal queue
  59  * before they are dropped.
  60  */
  61 unsigned int rx_drain_timeout_msecs = 10000;
  62 module_param(rx_drain_timeout_msecs, uint, 0444);
  63
  64 /* The length of time before the frontend is considered unresponsive
  65  * because it isn't providing Rx slots.
  66  */
  67 unsigned int rx_stall_timeout_msecs = 60000;
  68 module_param(rx_stall_timeout_msecs, uint, 0444);
  69
  70 #define MAX_QUEUES_DEFAULT 8
  71 unsigned int xenvif_max_queues;
  72 module_param_named(max_queues, xenvif_max_queues, uint, 0644);
  73 MODULE_PARM_DESC(max_queues,
  74                  "Maximum number of queues per virtual interface");
  75
  76 /*
  77  * This is the maximum slots a skb can have. If a guest sends a skb
  78  * which exceeds this limit it is considered malicious.
  79  */
  80 #define FATAL_SKB_SLOTS_DEFAULT 20
  81 static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
  82 module_param(fatal_skb_slots, uint, 0444);
  83
  84 /* The amount to copy out of the first guest Tx slot into the skb's
  85  * linear area.  If the first slot has more data, it will be mapped
  86  * and put into the first frag.
  87  *
  88  * This is sized to avoid pulling headers from the frags for most
  89  * TCP/IP packets.
  90  */
  91 #define XEN_NETBACK_TX_COPY_LEN 128
  92
  93 /* This is the maximum number of flows in the hash cache. */
  94 #define XENVIF_HASH_CACHE_SIZE_DEFAULT 64
  95 unsigned int xenvif_hash_cache_size = XENVIF_HASH_CACHE_SIZE_DEFAULT;
  96 module_param_named(hash_cache_size, xenvif_hash_cache_size, uint, 0644);
  97 MODULE_PARM_DESC(hash_cache_size, "Number of flows in the hash cache");
  98
  99 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
 100                                u8 status);
 101
 102 static void make_tx_response(struct xenvif_queue *queue,
 103                              struct xen_netif_tx_request *txp,
 104                              unsigned int extra_count,
 105                              s8       st);
 106 static void push_tx_responses(struct xenvif_queue *queue);
 107
 108 static inline int tx_work_todo(struct xenvif_queue *queue);
 109
 110 static inline unsigned long idx_to_pfn(struct xenvif_queue *queue,
 111                                        u16 idx)
 112 {
 113         return page_to_pfn(queue->mmap_pages[idx]);
 114 }
 115
 116 static inline unsigned long idx_to_kaddr(struct xenvif_queue *queue,
 117                                          u16 idx)
 118 {
 119         return (unsigned long)pfn_to_kaddr(idx_to_pfn(queue, idx));
 120 }
 121
 122 #define callback_param(vif, pending_idx) \
 123         (vif->pending_tx_info[pending_idx].callback_struct)
 124
 125 /* Find the containing VIF's structure from a pointer in pending_tx_info array
 126  */
 127 static inline struct xenvif_queue *ubuf_to_queue(const struct ubuf_info *ubuf)
 128 {
 129         u16 pending_idx = ubuf->desc;
 130         struct pending_tx_info *temp =
 131                 container_of(ubuf, struct pending_tx_info, callback_struct);
 132         return container_of(temp - pending_idx,
 133                             struct xenvif_queue,
 134                             pending_tx_info[0]);
 135 }
 136
 137 static u16 frag_get_pending_idx(skb_frag_t *frag)
 138 {
 139         return (u16)frag->page_offset;
 140 }
 141
 142 static void frag_set_pending_idx(skb_frag_t *frag, u16 pending_idx)
 143 {
 144         frag->page_offset = pending_idx;
 145 }
 146
 147 static inline pending_ring_idx_t pending_index(unsigned i)
 148 {
 149         return i & (MAX_PENDING_REQS-1);
 150 }
 151
 152 void xenvif_kick_thread(struct xenvif_queue *queue)
 153 {
 154         wake_up(&queue->wq);
 155 }
 156
 157 void xenvif_napi_schedule_or_enable_events(struct xenvif_queue *queue)
 158 {
 159         int more_to_do;
 160
 161         RING_FINAL_CHECK_FOR_REQUESTS(&queue->tx, more_to_do);
 162
 163         if (more_to_do)
 164                 napi_schedule(&queue->napi);
 165 }
 166
 167 static void tx_add_credit(struct xenvif_queue *queue)
 168 {
 169         unsigned long max_burst, max_credit;
 170
 171         /*
 172          * Allow a burst big enough to transmit a jumbo packet of up to 128kB.
 173          * Otherwise the interface can seize up due to insufficient credit.
 174          */
 175         max_burst = max(131072UL, queue->credit_bytes);
 176
 177         /* Take care that adding a new chunk of credit doesn't wrap to zero. */
 178         max_credit = queue->remaining_credit + queue->credit_bytes;
 179         if (max_credit < queue->remaining_credit)
 180                 max_credit = ULONG_MAX; /* wrapped: clamp to ULONG_MAX */
 181
 182         queue->remaining_credit = min(max_credit, max_burst);
 183 }
 184
 185 void xenvif_tx_credit_callback(unsigned long data)
 186 {
 187         struct xenvif_queue *queue = (struct xenvif_queue *)data;
 188         tx_add_credit(queue);
 189         xenvif_napi_schedule_or_enable_events(queue);
 190 }
 191
 192 static void xenvif_tx_err(struct xenvif_queue *queue,
 193                           struct xen_netif_tx_request *txp,
 194                           unsigned int extra_count, RING_IDX end)
 195 {
 196         RING_IDX cons = queue->tx.req_cons;
 197         unsigned long flags;
 198
 199         do {
 200                 spin_lock_irqsave(&queue->response_lock, flags);
 201                 make_tx_response(queue, txp, extra_count, XEN_NETIF_RSP_ERROR);
 202                 push_tx_responses(queue);
 203                 spin_unlock_irqrestore(&queue->response_lock, flags);
 204                 if (cons == end)
 205                         break;
 206                 RING_COPY_REQUEST(&queue->tx, cons++, txp);
 207                 extra_count = 0; /* only the first frag can have extras */
 208         } while (1);
 209         queue->tx.req_cons = cons;
 210 }
 211
 212 static void xenvif_fatal_tx_err(struct xenvif *vif)
 213 {
 214         netdev_err(vif->dev, "fatal error; disabling device\n");
 215         vif->disabled = true;
 216         /* Disable the vif from queue 0's kthread */
 217         if (vif->num_queues)
 218                 xenvif_kick_thread(&vif->queues[0]);
 219 }
 220
 221 static int xenvif_count_requests(struct xenvif_queue *queue,
 222                                  struct xen_netif_tx_request *first,
 223                                  unsigned int extra_count,
 224                                  struct xen_netif_tx_request *txp,
 225                                  int work_to_do)
 226 {
 227         RING_IDX cons = queue->tx.req_cons;
 228         int slots = 0;
 229         int drop_err = 0;
 230         int more_data;
 231
 232         if (!(first->flags & XEN_NETTXF_more_data))
 233                 return 0;
 234
 235         do {
 236                 struct xen_netif_tx_request dropped_tx = { 0 };
 237
 238                 if (slots >= work_to_do) {
 239                         netdev_err(queue->vif->dev,
 240                                    "Asked for %d slots but exceeds this limit\n",
 241                                    work_to_do);
 242                         xenvif_fatal_tx_err(queue->vif);
 243                         return -ENODATA;
 244                 }
 245
 246                 /* This guest is really using too many slots and
 247                  * considered malicious.
 248                  */
 249                 if (unlikely(slots >= fatal_skb_slots)) {
 250                         netdev_err(queue->vif->dev,
 251                                    "Malicious frontend using %d slots, threshold %u\n",
 252                                    slots, fatal_skb_slots);
 253                         xenvif_fatal_tx_err(queue->vif);
 254                         return -E2BIG;
 255                 }
 256
 257                 /* Xen network protocol had implicit dependency on
 258                  * MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
 259                  * the historical MAX_SKB_FRAGS value 18 to honor the
 260                  * same behavior as before. Any packet using more than
 261                  * 18 slots but less than fatal_skb_slots slots is
 262                  * dropped
 263                  */
 264                 if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
 265                         if (net_ratelimit())
 266                                 netdev_dbg(queue->vif->dev,
 267                                            "Too many slots (%d) exceeding limit (%d), dropping packet\n",
 268                                            slots, XEN_NETBK_LEGACY_SLOTS_MAX);
 269                         drop_err = -E2BIG;
 270                 }
 271
 272                 if (drop_err)
 273                         txp = &dropped_tx;
 274
 275                 RING_COPY_REQUEST(&queue->tx, cons + slots, txp);
 276
 277                 /* If the guest submitted a frame >= 64 KiB then
 278                  * first->size overflowed and following slots will
 279                  * appear to be larger than the frame.
 280                  *
 281                  * This cannot be fatal error as there are buggy
 282                  * frontends that do this.
 283                  *
 284                  * Consume all slots and drop the packet.
 285                  */
 286                 if (!drop_err && txp->size > first->size) {
 287                         if (net_ratelimit())
 288                                 netdev_dbg(queue->vif->dev,
 289                                            "Invalid tx request, slot size %u > remaining size %u\n",
 290                                            txp->size, first->size);
 291                         drop_err = -EIO;
 292                 }
 293
 294                 first->size -= txp->size;
 295                 slots++;
 296
 297                 if (unlikely((txp->offset + txp->size) > XEN_PAGE_SIZE)) {
 298                         netdev_err(queue->vif->dev, "Cross page boundary, txp->offset: %u, size: %u\n",
 299                                  txp->offset, txp->size);
 300                         xenvif_fatal_tx_err(queue->vif);
 301                         return -EINVAL;
 302                 }
 303
 304                 more_data = txp->flags & XEN_NETTXF_more_data;
 305
 306                 if (!drop_err)
 307                         txp++;
 308
 309         } while (more_data);
 310
 311         if (drop_err) {
 312                 xenvif_tx_err(queue, first, extra_count, cons + slots);
 313                 return drop_err;
 314         }
 315
 316         return slots;
 317 }
 318
 319
 320 struct xenvif_tx_cb {
 321         u16 pending_idx;
 322 };
 323
 324 #define XENVIF_TX_CB(skb) ((struct xenvif_tx_cb *)(skb)->cb)
 325
 326 static inline void xenvif_tx_create_map_op(struct xenvif_queue *queue,
 327                                            u16 pending_idx,
 328                                            struct xen_netif_tx_request *txp,
 329                                            unsigned int extra_count,
 330                                            struct gnttab_map_grant_ref *mop)
 331 {
 332         queue->pages_to_map[mop-queue->tx_map_ops] = queue->mmap_pages[pending_idx];
 333         gnttab_set_map_op(mop, idx_to_kaddr(queue, pending_idx),
 334                           GNTMAP_host_map | GNTMAP_readonly,
 335                           txp->gref, queue->vif->domid);
 336
 337         memcpy(&queue->pending_tx_info[pending_idx].req, txp,
 338                sizeof(*txp));
 339         queue->pending_tx_info[pending_idx].extra_count = extra_count;
 340 }
 341
 342 static inline struct sk_buff *xenvif_alloc_skb(unsigned int size)
 343 {
 344         struct sk_buff *skb =
 345                 alloc_skb(size + NET_SKB_PAD + NET_IP_ALIGN,
 346                           GFP_ATOMIC | __GFP_NOWARN);
 347         if (unlikely(skb == NULL))
 348                 return NULL;
 349
 350         /* Packets passed to netif_rx() must have some headroom. */
 351         skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
 352
 353         /* Initialize it here to avoid later surprises */
 354         skb_shinfo(skb)->destructor_arg = NULL;
 355
 356         return skb;
 357 }
 358
 359 static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif_queue *queue,
 360                                                         struct sk_buff *skb,
 361                                                         struct xen_netif_tx_request *txp,
 362                                                         struct gnttab_map_grant_ref *gop,
 363                                                         unsigned int frag_overflow,
 364                                                         struct sk_buff *nskb)
 365 {
 366         struct skb_shared_info *shinfo = skb_shinfo(skb);
 367         skb_frag_t *frags = shinfo->frags;
 368         u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 369         int start;
 370         pending_ring_idx_t index;
 371         unsigned int nr_slots;
 372
 373         nr_slots = shinfo->nr_frags;
 374
 375         /* Skip first skb fragment if it is on same page as header fragment. */
 376         start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
 377
 378         for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
 379              shinfo->nr_frags++, txp++, gop++) {
 380                 index = pending_index(queue->pending_cons++);
 381                 pending_idx = queue->pending_ring[index];
 382                 xenvif_tx_create_map_op(queue, pending_idx, txp, 0, gop);
 383                 frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
 384         }
 385
 386         if (frag_overflow) {
 387
 388                 shinfo = skb_shinfo(nskb);
 389                 frags = shinfo->frags;
 390
 391                 for (shinfo->nr_frags = 0; shinfo->nr_frags < frag_overflow;
 392                      shinfo->nr_frags++, txp++, gop++) {
 393                         index = pending_index(queue->pending_cons++);
 394                         pending_idx = queue->pending_ring[index];
 395                         xenvif_tx_create_map_op(queue, pending_idx, txp, 0,
 396                                                 gop);
 397                         frag_set_pending_idx(&frags[shinfo->nr_frags],
 398                                              pending_idx);
 399                 }
 400
 401                 skb_shinfo(skb)->frag_list = nskb;
 402         }
 403
 404         return gop;
 405 }
 406
 407 static inline void xenvif_grant_handle_set(struct xenvif_queue *queue,
 408                                            u16 pending_idx,
 409                                            grant_handle_t handle)
 410 {
 411         if (unlikely(queue->grant_tx_handle[pending_idx] !=
 412                      NETBACK_INVALID_HANDLE)) {
 413                 netdev_err(queue->vif->dev,
 414                            "Trying to overwrite active handle! pending_idx: 0x%x\n",
 415                            pending_idx);
 416                 BUG();
 417         }
 418         queue->grant_tx_handle[pending_idx] = handle;
 419 }
 420
 421 static inline void xenvif_grant_handle_reset(struct xenvif_queue *queue,
 422                                              u16 pending_idx)
 423 {
 424         if (unlikely(queue->grant_tx_handle[pending_idx] ==
 425                      NETBACK_INVALID_HANDLE)) {
 426                 netdev_err(queue->vif->dev,
 427                            "Trying to unmap invalid handle! pending_idx: 0x%x\n",
 428                            pending_idx);
 429                 BUG();
 430         }
 431         queue->grant_tx_handle[pending_idx] = NETBACK_INVALID_HANDLE;
 432 }
 433
 434 static int xenvif_tx_check_gop(struct xenvif_queue *queue,
 435                                struct sk_buff *skb,
 436                                struct gnttab_map_grant_ref **gopp_map,
 437                                struct gnttab_copy **gopp_copy)
 438 {
 439         struct gnttab_map_grant_ref *gop_map = *gopp_map;
 440         u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
 441         /* This always points to the shinfo of the skb being checked, which
 442          * could be either the first or the one on the frag_list
 443          */
 444         struct skb_shared_info *shinfo = skb_shinfo(skb);
 445         /* If this is non-NULL, we are currently checking the frag_list skb, and
 446          * this points to the shinfo of the first one
 447          */
 448         struct skb_shared_info *first_shinfo = NULL;
 449         int nr_frags = shinfo->nr_frags;
 450         const bool sharedslot = nr_frags &&
 451                                 frag_get_pending_idx(&shinfo->frags[0]) == pending_idx;
 452         int i, err;
 453
 454         /* Check status of header. */
 455         err = (*gopp_copy)->status;
 456         if (unlikely(err)) {
 457                 if (net_ratelimit())
 458                         netdev_dbg(queue->vif->dev,
 459                                    "Grant copy of header failed! status: %d pending_idx: %u ref: %u\n",
 460                                    (*gopp_copy)->status,
 461                                    pending_idx,
 462                                    (*gopp_copy)->source.u.ref);
 463                 /* The first frag might still have this slot mapped */
 464                 if (!sharedslot)
 465                         xenvif_idx_release(queue, pending_idx,
 466                                            XEN_NETIF_RSP_ERROR);
 467         }
 468         (*gopp_copy)++;
 469
 470 check_frags:
 471         for (i = 0; i < nr_frags; i++, gop_map++) {
 472                 int j, newerr;
 473
 474                 pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
 475
 476                 /* Check error status: if okay then remember grant handle. */
 477                 newerr = gop_map->status;
 478
 479                 if (likely(!newerr)) {
 480                         xenvif_grant_handle_set(queue,
 481                                                 pending_idx,
 482                                                 gop_map->handle);
 483                         /* Had a previous error? Invalidate this fragment. */
 484                         if (unlikely(err)) {
 485                                 xenvif_idx_unmap(queue, pending_idx);
 486                                 /* If the mapping of the first frag was OK, but
 487                                  * the header's copy failed, and they are
 488                                  * sharing a slot, send an error
 489                                  */
 490                                 if (i == 0 && sharedslot)
 491                                         xenvif_idx_release(queue, pending_idx,
 492                                                            XEN_NETIF_RSP_ERROR);
 493                                 else
 494                                         xenvif_idx_release(queue, pending_idx,
 495                                                            XEN_NETIF_RSP_OKAY);
 496                         }
 497                         continue;
 498                 }
 499
 500                 /* Error on this fragment: respond to client with an error. */
 501                 if (net_ratelimit())
 502                         netdev_dbg(queue->vif->dev,
 503                                    "Grant map of %d. frag failed! status: %d pending_idx: %u ref: %u\n",
 504                                    i,
 505                                    gop_map->status,
 506                                    pending_idx,
 507                                    gop_map->ref);
 508
 509                 xenvif_idx_release(queue, pending_idx, XEN_NETIF_RSP_ERROR);
 510
 511                 /* Not the first error? Preceding frags already invalidated. */
 512                 if (err)
 513                         continue;
 514
 515                 /* First error: if the header haven't shared a slot with the
 516                  * first frag, release it as well.
 517                  */
 518                 if (!sharedslot)
 519                         xenvif_idx_release(queue,
 520                                            XENVIF_TX_CB(skb)->pending_idx,
 521                                            XEN_NETIF_RSP_OKAY);
 522
 523                 /* Invalidate preceding fragments of this skb. */
 524                 for (j = 0; j < i; j++) {
 525                         pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
 526                         xenvif_idx_unmap(queue, pending_idx);
 527                         xenvif_idx_release(queue, pending_idx,
 528                                            XEN_NETIF_RSP_OKAY);
 529                 }
 530
 531                 /* And if we found the error while checking the frag_list, unmap
 532                  * the first skb's frags
 533                  */
 534                 if (first_shinfo) {
 535                         for (j = 0; j < first_shinfo->nr_frags; j++) {
 536                                 pending_idx = frag_get_pending_idx(&first_shinfo->frags[j]);
 537                                 xenvif_idx_unmap(queue, pending_idx);
 538                                 xenvif_idx_release(queue, pending_idx,
 539                                                    XEN_NETIF_RSP_OKAY);
 540                         }
 541                 }
 542
 543                 /* Remember the error: invalidate all subsequent fragments. */
 544                 err = newerr;
 545         }
 546
 547         if (skb_has_frag_list(skb) && !first_shinfo) {
 548                 first_shinfo = skb_shinfo(skb);
 549                 shinfo = skb_shinfo(skb_shinfo(skb)->frag_list);
 550                 nr_frags = shinfo->nr_frags;
 551
 552                 goto check_frags;
 553         }
 554
 555         *gopp_map = gop_map;
 556         return err;
 557 }
 558
 559 static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb)
 560 {
 561         struct skb_shared_info *shinfo = skb_shinfo(skb);
 562         int nr_frags = shinfo->nr_frags;
 563         int i;
 564         u16 prev_pending_idx = INVALID_PENDING_IDX;
 565
 566         for (i = 0; i < nr_frags; i++) {
 567                 skb_frag_t *frag = shinfo->frags + i;
 568                 struct xen_netif_tx_request *txp;
 569                 struct page *page;
 570                 u16 pending_idx;
 571
 572                 pending_idx = frag_get_pending_idx(frag);
 573
 574                 /* If this is not the first frag, chain it to the previous*/
 575                 if (prev_pending_idx == INVALID_PENDING_IDX)
 576                         skb_shinfo(skb)->destructor_arg =
 577                                 &callback_param(queue, pending_idx);
 578                 else
 579                         callback_param(queue, prev_pending_idx).ctx =
 580                                 &callback_param(queue, pending_idx);
 581
 582                 callback_param(queue, pending_idx).ctx = NULL;
 583                 prev_pending_idx = pending_idx;
 584
 585                 txp = &queue->pending_tx_info[pending_idx].req;
 586                 page = virt_to_page(idx_to_kaddr(queue, pending_idx));
 587                 __skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
 588                 skb->len += txp->size;
 589                 skb->data_len += txp->size;
 590                 skb->truesize += txp->size;
 591
 592                 /* Take an extra reference to offset network stack's put_page */
 593                 get_page(queue->mmap_pages[pending_idx]);
 594         }
 595 }
 596
 597 static int xenvif_get_extras(struct xenvif_queue *queue,
 598                              struct xen_netif_extra_info *extras,
 599                              unsigned int *extra_count,
 600                              int work_to_do)
 601 {
 602         struct xen_netif_extra_info extra;
 603         RING_IDX cons = queue->tx.req_cons;
 604
 605         do {
 606                 if (unlikely(work_to_do-- <= 0)) {
 607                         netdev_err(queue->vif->dev, "Missing extra info\n");
 608                         xenvif_fatal_tx_err(queue->vif);
 609                         return -EBADR;
 610                 }
 611
 612                 RING_COPY_REQUEST(&queue->tx, cons, &extra);
 613
 614                 queue->tx.req_cons = ++cons;
 615                 (*extra_count)++;
 616
 617                 if (unlikely(!extra.type ||
 618                              extra.type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 619                         netdev_err(queue->vif->dev,
 620                                    "Invalid extra type: %d\n", extra.type);
 621                         xenvif_fatal_tx_err(queue->vif);
 622                         return -EINVAL;
 623                 }
 624
 625                 memcpy(&extras[extra.type - 1], &extra, sizeof(extra));
 626         } while (extra.flags & XEN_NETIF_EXTRA_FLAG_MORE);
 627
 628         return work_to_do;
 629 }
 630
 631 static int xenvif_set_skb_gso(struct xenvif *vif,
 632                               struct sk_buff *skb,
 633                               struct xen_netif_extra_info *gso)
 634 {
 635         if (!gso->u.gso.size) {
 636                 netdev_err(vif->dev, "GSO size must not be zero.\n");
 637                 xenvif_fatal_tx_err(vif);
 638                 return -EINVAL;
 639         }
 640
 641         switch (gso->u.gso.type) {
 642         case XEN_NETIF_GSO_TYPE_TCPV4:
 643                 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 644                 break;
 645         case XEN_NETIF_GSO_TYPE_TCPV6:
 646                 skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 647                 break;
 648         default:
 649                 netdev_err(vif->dev, "Bad GSO type %d.\n", gso->u.gso.type);
 650                 xenvif_fatal_tx_err(vif);
 651                 return -EINVAL;
 652         }
 653
 654         skb_shinfo(skb)->gso_size = gso->u.gso.size;
 655         /* gso_segs will be calculated later */
 656
 657         return 0;
 658 }
 659
 660 static int checksum_setup(struct xenvif_queue *queue, struct sk_buff *skb)
 661 {
 662         bool recalculate_partial_csum = false;
 663
 664         /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 665          * peers can fail to set NETRXF_csum_blank when sending a GSO
 666          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 667          * recalculate the partial checksum.
 668          */
 669         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 670                 queue->stats.rx_gso_checksum_fixup++;
 671                 skb->ip_summed = CHECKSUM_PARTIAL;
 672                 recalculate_partial_csum = true;
 673         }
 674
 675         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 676         if (skb->ip_summed != CHECKSUM_PARTIAL)
 677                 return 0;
 678
 679         return skb_checksum_setup(skb, recalculate_partial_csum);
 680 }
 681
 682 static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
 683 {
 684         u64 now = get_jiffies_64();
 685         u64 next_credit = queue->credit_window_start +
 686                 msecs_to_jiffies(queue->credit_usec / 1000);
 687
 688         /* Timer could already be pending in rare cases. */
 689         if (timer_pending(&queue->credit_timeout))
 690                 return true;
 691
 692         /* Passed the point where we can replenish credit? */
 693         if (time_after_eq64(now, next_credit)) {
 694                 queue->credit_window_start = now;
 695                 tx_add_credit(queue);
 696         }
 697
 698         /* Still too big to send right now? Set a callback. */
 699         if (size > queue->remaining_credit) {
 700                 queue->credit_timeout.data     =
 701                         (unsigned long)queue;
 702                 mod_timer(&queue->credit_timeout,
 703                           next_credit);
 704                 queue->credit_window_start = next_credit;
 705
 706                 return true;
 707         }
 708
 709         return false;
 710 }
 711
 712 /* No locking is required in xenvif_mcast_add/del() as they are
 713  * only ever invoked from NAPI poll. An RCU list is used because
 714  * xenvif_mcast_match() is called asynchronously, during start_xmit.
 715  */
 716
 717 static int xenvif_mcast_add(struct xenvif *vif, const u8 *addr)
 718 {
 719         struct xenvif_mcast_addr *mcast;
 720
 721         if (vif->fe_mcast_count == XEN_NETBK_MCAST_MAX) {
 722                 if (net_ratelimit())
 723                         netdev_err(vif->dev,
 724                                    "Too many multicast addresses\n");
 725                 return -ENOSPC;
 726         }
 727
 728         mcast = kzalloc(sizeof(*mcast), GFP_ATOMIC);
 729         if (!mcast)
 730                 return -ENOMEM;
 731
 732         ether_addr_copy(mcast->addr, addr);
 733         list_add_tail_rcu(&mcast->entry, &vif->fe_mcast_addr);
 734         vif->fe_mcast_count++;
 735
 736         return 0;
 737 }
 738
 739 static void xenvif_mcast_del(struct xenvif *vif, const u8 *addr)
 740 {
 741         struct xenvif_mcast_addr *mcast;
 742
 743         list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 744                 if (ether_addr_equal(addr, mcast->addr)) {
 745                         --vif->fe_mcast_count;
 746                         list_del_rcu(&mcast->entry);
 747                         kfree_rcu(mcast, rcu);
 748                         break;
 749                 }
 750         }
 751 }
 752
 753 bool xenvif_mcast_match(struct xenvif *vif, const u8 *addr)
 754 {
 755         struct xenvif_mcast_addr *mcast;
 756
 757         rcu_read_lock();
 758         list_for_each_entry_rcu(mcast, &vif->fe_mcast_addr, entry) {
 759                 if (ether_addr_equal(addr, mcast->addr)) {
 760                         rcu_read_unlock();
 761                         return true;
 762                 }
 763         }
 764         rcu_read_unlock();
 765
 766         return false;
 767 }
 768
 769 void xenvif_mcast_addr_list_free(struct xenvif *vif)
 770 {
 771         /* No need for locking or RCU here. NAPI poll and TX queue
 772          * are stopped.
 773          */
 774         while (!list_empty(&vif->fe_mcast_addr)) {
 775                 struct xenvif_mcast_addr *mcast;
 776
 777                 mcast = list_first_entry(&vif->fe_mcast_addr,
 778                                          struct xenvif_mcast_addr,
 779                                          entry);
 780                 --vif->fe_mcast_count;
 781                 list_del(&mcast->entry);
 782                 kfree(mcast);
 783         }
 784 }
 785
 786 static void xenvif_tx_build_gops(struct xenvif_queue *queue,
 787                                      int budget,
 788                                      unsigned *copy_ops,
 789                                      unsigned *map_ops)
 790 {
 791         struct gnttab_map_grant_ref *gop = queue->tx_map_ops;
 792         struct sk_buff *skb, *nskb;
 793         int ret;
 794         unsigned int frag_overflow;
 795
 796         while (skb_queue_len(&queue->tx_queue) < budget) {
 797                 struct xen_netif_tx_request txreq;
 798                 struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
 799                 struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
 800                 unsigned int extra_count;
 801                 u16 pending_idx;
 802                 RING_IDX idx;
 803                 int work_to_do;
 804                 unsigned int data_len;
 805                 pending_ring_idx_t index;
 806
 807                 if (queue->tx.sring->req_prod - queue->tx.req_cons >
 808                     XEN_NETIF_TX_RING_SIZE) {
 809                         netdev_err(queue->vif->dev,
 810                                    "Impossible number of requests. "
 811                                    "req_prod %d, req_cons %d, size %ld\n",
 812                                    queue->tx.sring->req_prod, queue->tx.req_cons,
 813                                    XEN_NETIF_TX_RING_SIZE);
 814                         xenvif_fatal_tx_err(queue->vif);
 815                         break;
 816                 }
 817
 818                 work_to_do = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
 819                 if (!work_to_do)
 820                         break;
 821
 822                 idx = queue->tx.req_cons;
 823                 rmb(); /* Ensure that we see the request before we copy it. */
 824                 RING_COPY_REQUEST(&queue->tx, idx, &txreq);
 825
 826                 /* Credit-based scheduling. */
 827                 if (txreq.size > queue->remaining_credit &&
 828                     tx_credit_exceeded(queue, txreq.size))
 829                         break;
 830
 831                 queue->remaining_credit -= txreq.size;
 832
 833                 work_to_do--;
 834                 queue->tx.req_cons = ++idx;
 835
 836                 memset(extras, 0, sizeof(extras));
 837                 extra_count = 0;
 838                 if (txreq.flags & XEN_NETTXF_extra_info) {
 839                         work_to_do = xenvif_get_extras(queue, extras,
 840                                                        &extra_count,
 841                                                        work_to_do);
 842                         idx = queue->tx.req_cons;
 843                         if (unlikely(work_to_do < 0))
 844                                 break;
 845                 }
 846
 847                 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1].type) {
 848                         struct xen_netif_extra_info *extra;
 849
 850                         extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_ADD - 1];
 851                         ret = xenvif_mcast_add(queue->vif, extra->u.mcast.addr);
 852
 853                         make_tx_response(queue, &txreq, extra_count,
 854                                          (ret == 0) ?
 855                                          XEN_NETIF_RSP_OKAY :
 856                                          XEN_NETIF_RSP_ERROR);
 857                         push_tx_responses(queue);
 858                         continue;
 859                 }
 860
 861                 if (extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1].type) {
 862                         struct xen_netif_extra_info *extra;
 863
 864                         extra = &extras[XEN_NETIF_EXTRA_TYPE_MCAST_DEL - 1];
 865                         xenvif_mcast_del(queue->vif, extra->u.mcast.addr);
 866
 867                         make_tx_response(queue, &txreq, extra_count,
 868                                          XEN_NETIF_RSP_OKAY);
 869                         push_tx_responses(queue);
 870                         continue;
 871                 }
 872
 873                 ret = xenvif_count_requests(queue, &txreq, extra_count,
 874                                             txfrags, work_to_do);
 875                 if (unlikely(ret < 0))
 876                         break;
 877
 878                 idx += ret;
 879
 880                 if (unlikely(txreq.size < ETH_HLEN)) {
 881                         netdev_dbg(queue->vif->dev,
 882                                    "Bad packet size: %d\n", txreq.size);
 883                         xenvif_tx_err(queue, &txreq, extra_count, idx);
 884                         break;
 885                 }
 886
 887                 /* No crossing a page as the payload mustn't fragment. */
 888                 if (unlikely((txreq.offset + txreq.size) > XEN_PAGE_SIZE)) {
 889                         netdev_err(queue->vif->dev,
 890                                    "txreq.offset: %u, size: %u, end: %lu\n",
 891                                    txreq.offset, txreq.size,
 892                                    (unsigned long)(txreq.offset&~XEN_PAGE_MASK) + txreq.size);
 893                         xenvif_fatal_tx_err(queue->vif);
 894                         break;
 895                 }
 896
 897                 index = pending_index(queue->pending_cons);
 898                 pending_idx = queue->pending_ring[index];
 899
 900                 data_len = (txreq.size > XEN_NETBACK_TX_COPY_LEN &&
 901                             ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
 902                         XEN_NETBACK_TX_COPY_LEN : txreq.size;
 903
 904                 skb = xenvif_alloc_skb(data_len);
 905                 if (unlikely(skb == NULL)) {
 906                         netdev_dbg(queue->vif->dev,
 907                                    "Can't allocate a skb in start_xmit.\n");
 908                         xenvif_tx_err(queue, &txreq, extra_count, idx);
 909                         break;
 910                 }
 911
 912                 skb_shinfo(skb)->nr_frags = ret;
 913                 if (data_len < txreq.size)
 914                         skb_shinfo(skb)->nr_frags++;
 915                 /* At this point shinfo->nr_frags is in fact the number of
 916                  * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
 917                  */
 918                 frag_overflow = 0;
 919                 nskb = NULL;
 920                 if (skb_shinfo(skb)->nr_frags > MAX_SKB_FRAGS) {
 921                         frag_overflow = skb_shinfo(skb)->nr_frags - MAX_SKB_FRAGS;
 922                         BUG_ON(frag_overflow > MAX_SKB_FRAGS);
 923                         skb_shinfo(skb)->nr_frags = MAX_SKB_FRAGS;
 924                         nskb = xenvif_alloc_skb(0);
 925                         if (unlikely(nskb == NULL)) {
 926                                 kfree_skb(skb);
 927                                 xenvif_tx_err(queue, &txreq, extra_count, idx);
 928                                 if (net_ratelimit())
 929                                         netdev_err(queue->vif->dev,
 930                                                    "Can't allocate the frag_list skb.\n");
 931                                 break;
 932                         }
 933                 }
 934
 935                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
 936                         struct xen_netif_extra_info *gso;
 937                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
 938
 939                         if (xenvif_set_skb_gso(queue->vif, skb, gso)) {
 940                                 /* Failure in xenvif_set_skb_gso is fatal. */
 941                                 kfree_skb(skb);
 942                                 kfree_skb(nskb);
 943                                 break;
 944                         }
 945                 }
 946
 947                 if (extras[XEN_NETIF_EXTRA_TYPE_HASH - 1].type) {
 948                         struct xen_netif_extra_info *extra;
 949                         enum pkt_hash_types type = PKT_HASH_TYPE_NONE;
 950
 951                         extra = &extras[XEN_NETIF_EXTRA_TYPE_HASH - 1];
 952
 953                         switch (extra->u.hash.type) {
 954                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV4:
 955                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV6:
 956                                 type = PKT_HASH_TYPE_L3;
 957                                 break;
 958
 959                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV4_TCP:
 960                         case _XEN_NETIF_CTRL_HASH_TYPE_IPV6_TCP:
 961                                 type = PKT_HASH_TYPE_L4;
 962                                 break;
 963
 964                         default:
 965                                 break;
 966                         }
 967
 968                         if (type != PKT_HASH_TYPE_NONE)
 969                                 skb_set_hash(skb,
 970                                              *(u32 *)extra->u.hash.value,
 971                                              type);
 972                 }
 973
 974                 XENVIF_TX_CB(skb)->pending_idx = pending_idx;
 975
 976                 __skb_put(skb, data_len);
 977                 queue->tx_copy_ops[*copy_ops].source.u.ref = txreq.gref;
 978                 queue->tx_copy_ops[*copy_ops].source.domid = queue->vif->domid;
 979                 queue->tx_copy_ops[*copy_ops].source.offset = txreq.offset;
 980
 981                 queue->tx_copy_ops[*copy_ops].dest.u.gmfn =
 982                         virt_to_gfn(skb->data);
 983                 queue->tx_copy_ops[*copy_ops].dest.domid = DOMID_SELF;
 984                 queue->tx_copy_ops[*copy_ops].dest.offset =
 985                         offset_in_page(skb->data) & ~XEN_PAGE_MASK;
 986
 987                 queue->tx_copy_ops[*copy_ops].len = data_len;
 988                 queue->tx_copy_ops[*copy_ops].flags = GNTCOPY_source_gref;
 989
 990                 (*copy_ops)++;
 991
 992                 if (data_len < txreq.size) {
 993                         frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
 994                                              pending_idx);
 995                         xenvif_tx_create_map_op(queue, pending_idx, &txreq,
 996                                                 extra_count, gop);
 997                         gop++;
 998                 } else {
 999                         frag_set_pending_idx(&skb_shinfo(skb)->frags[0],
1000                                              INVALID_PENDING_IDX);
1001                         memcpy(&queue->pending_tx_info[pending_idx].req,
1002                                &txreq, sizeof(txreq));
1003                         queue->pending_tx_info[pending_idx].extra_count =
1004                                 extra_count;
1005                 }
1006
1007                 queue->pending_cons++;
1008
1009                 gop = xenvif_get_requests(queue, skb, txfrags, gop,
1010                                           frag_overflow, nskb);
1011
1012                 __skb_queue_tail(&queue->tx_queue, skb);
1013
1014                 queue->tx.req_cons = idx;
1015
1016                 if (((gop-queue->tx_map_ops) >= ARRAY_SIZE(queue->tx_map_ops)) ||
1017                     (*copy_ops >= ARRAY_SIZE(queue->tx_copy_ops)))
1018                         break;
1019         }
1020
1021         (*map_ops) = gop - queue->tx_map_ops;
1022         return;
1023 }
1024
1025 /* Consolidate skb with a frag_list into a brand new one with local pages on
1026  * frags. Returns 0 or -ENOMEM if can't allocate new pages.
1027  */
1028 static int xenvif_handle_frag_list(struct xenvif_queue *queue, struct sk_buff *skb)
1029 {
1030         unsigned int offset = skb_headlen(skb);
1031         skb_frag_t frags[MAX_SKB_FRAGS];
1032         int i, f;
1033         struct ubuf_info *uarg;
1034         struct sk_buff *nskb = skb_shinfo(skb)->frag_list;
1035
1036         queue->stats.tx_zerocopy_sent += 2;
1037         queue->stats.tx_frag_overflow++;
1038
1039         xenvif_fill_frags(queue, nskb);
1040         /* Subtract frags size, we will correct it later */
1041         skb->truesize -= skb->data_len;
1042         skb->len += nskb->len;
1043         skb->data_len += nskb->len;
1044
1045         /* create a brand new frags array and coalesce there */
1046         for (i = 0; offset < skb->len; i++) {
1047                 struct page *page;
1048                 unsigned int len;
1049
1050                 BUG_ON(i >= MAX_SKB_FRAGS);
1051                 page = alloc_page(GFP_ATOMIC);
1052                 if (!page) {
1053                         int j;
1054                         skb->truesize += skb->data_len;
1055                         for (j = 0; j < i; j++)
1056                                 put_page(frags[j].page.p);
1057                         return -ENOMEM;
1058                 }
1059
1060                 if (offset + PAGE_SIZE < skb->len)
1061                         len = PAGE_SIZE;
1062                 else
1063                         len = skb->len - offset;
1064                 if (skb_copy_bits(skb, offset, page_address(page), len))
1065                         BUG();
1066
1067                 offset += len;
1068                 frags[i].page.p = page;
1069                 frags[i].page_offset = 0;
1070                 skb_frag_size_set(&frags[i], len);
1071         }
1072
1073         /* Copied all the bits from the frag list -- free it. */
1074         skb_frag_list_init(skb);
1075         xenvif_skb_zerocopy_prepare(queue, nskb);
1076         kfree_skb(nskb);
1077
1078         /* Release all the original (foreign) frags. */
1079         for (f = 0; f < skb_shinfo(skb)->nr_frags; f++)
1080                 skb_frag_unref(skb, f);
1081         uarg = skb_shinfo(skb)->destructor_arg;
1082         /* increase inflight counter to offset decrement in callback */
1083         atomic_inc(&queue->inflight_packets);
1084         uarg->callback(uarg, true);
1085         skb_shinfo(skb)->destructor_arg = NULL;
1086
1087         /* Fill the skb with the new (local) frags. */
1088         memcpy(skb_shinfo(skb)->frags, frags, i * sizeof(skb_frag_t));
1089         skb_shinfo(skb)->nr_frags = i;
1090         skb->truesize += i * PAGE_SIZE;
1091
1092         return 0;
1093 }
1094
1095 static int xenvif_tx_submit(struct xenvif_queue *queue)
1096 {
1097         struct gnttab_map_grant_ref *gop_map = queue->tx_map_ops;
1098         struct gnttab_copy *gop_copy = queue->tx_copy_ops;
1099         struct sk_buff *skb;
1100         int work_done = 0;
1101
1102         while ((skb = __skb_dequeue(&queue->tx_queue)) != NULL) {
1103                 struct xen_netif_tx_request *txp;
1104                 u16 pending_idx;
1105                 unsigned data_len;
1106
1107                 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
1108                 txp = &queue->pending_tx_info[pending_idx].req;
1109
1110                 /* Check the remap error code. */
1111                 if (unlikely(xenvif_tx_check_gop(queue, skb, &gop_map, &gop_copy))) {
1112                         /* If there was an error, xenvif_tx_check_gop is
1113                          * expected to release all the frags which were mapped,
1114                          * so kfree_skb shouldn't do it again
1115                          */
1116                         skb_shinfo(skb)->nr_frags = 0;
1117                         if (skb_has_frag_list(skb)) {
1118                                 struct sk_buff *nskb =
1119                                                 skb_shinfo(skb)->frag_list;
1120                                 skb_shinfo(nskb)->nr_frags = 0;
1121                         }
1122                         kfree_skb(skb);
1123                         continue;
1124                 }
1125
1126                 data_len = skb->len;
1127                 callback_param(queue, pending_idx).ctx = NULL;
1128                 if (data_len < txp->size) {
1129                         /* Append the packet payload as a fragment. */
1130                         txp->offset += data_len;
1131                         txp->size -= data_len;
1132                 } else {
1133                         /* Schedule a response immediately. */
1134                         xenvif_idx_release(queue, pending_idx,
1135                                            XEN_NETIF_RSP_OKAY);
1136                 }
1137
1138                 if (txp->flags & XEN_NETTXF_csum_blank)
1139                         skb->ip_summed = CHECKSUM_PARTIAL;
1140                 else if (txp->flags & XEN_NETTXF_data_validated)
1141                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1142
1143                 xenvif_fill_frags(queue, skb);
1144
1145                 if (unlikely(skb_has_frag_list(skb))) {
1146                         if (xenvif_handle_frag_list(queue, skb)) {
1147                                 if (net_ratelimit())
1148                                         netdev_err(queue->vif->dev,
1149                                                    "Not enough memory to consolidate frag_list!\n");
1150                                 xenvif_skb_zerocopy_prepare(queue, skb);
1151                                 kfree_skb(skb);
1152                                 continue;
1153                         }
1154                 }
1155
1156                 skb->dev      = queue->vif->dev;
1157                 skb->protocol = eth_type_trans(skb, skb->dev);
1158                 skb_reset_network_header(skb);
1159
1160                 if (checksum_setup(queue, skb)) {
1161                         netdev_dbg(queue->vif->dev,
1162                                    "Can't setup checksum in net_tx_action\n");
1163                         /* We have to set this flag to trigger the callback */
1164                         if (skb_shinfo(skb)->destructor_arg)
1165                                 xenvif_skb_zerocopy_prepare(queue, skb);
1166                         kfree_skb(skb);
1167                         continue;
1168                 }
1169
1170                 skb_probe_transport_header(skb, 0);
1171
1172                 /* If the packet is GSO then we will have just set up the
1173                  * transport header offset in checksum_setup so it's now
1174                  * straightforward to calculate gso_segs.
1175                  */
1176                 if (skb_is_gso(skb)) {
1177                         int mss = skb_shinfo(skb)->gso_size;
1178                         int hdrlen = skb_transport_header(skb) -
1179                                 skb_mac_header(skb) +
1180                                 tcp_hdrlen(skb);
1181
1182                         skb_shinfo(skb)->gso_segs =
1183                                 DIV_ROUND_UP(skb->len - hdrlen, mss);
1184                 }
1185
1186                 queue->stats.rx_bytes += skb->len;
1187                 queue->stats.rx_packets++;
1188
1189                 work_done++;
1190
1191                 /* Set this flag right before netif_receive_skb, otherwise
1192                  * someone might think this packet already left netback, and
1193                  * do a skb_copy_ubufs while we are still in control of the
1194                  * skb. E.g. the __pskb_pull_tail earlier can do such thing.
1195                  */
1196                 if (skb_shinfo(skb)->destructor_arg) {
1197                         xenvif_skb_zerocopy_prepare(queue, skb);
1198                         queue->stats.tx_zerocopy_sent++;
1199                 }
1200
1201                 netif_receive_skb(skb);
1202         }
1203
1204         return work_done;
1205 }
1206
1207 void xenvif_zerocopy_callback(struct ubuf_info *ubuf, bool zerocopy_success)
1208 {
1209         unsigned long flags;
1210         pending_ring_idx_t index;
1211         struct xenvif_queue *queue = ubuf_to_queue(ubuf);
1212
1213         /* This is the only place where we grab this lock, to protect callbacks
1214          * from each other.
1215          */
1216         spin_lock_irqsave(&queue->callback_lock, flags);
1217         do {
1218                 u16 pending_idx = ubuf->desc;
1219                 ubuf = (struct ubuf_info *) ubuf->ctx;
1220                 BUG_ON(queue->dealloc_prod - queue->dealloc_cons >=
1221                         MAX_PENDING_REQS);
1222                 index = pending_index(queue->dealloc_prod);
1223                 queue->dealloc_ring[index] = pending_idx;
1224                 /* Sync with xenvif_tx_dealloc_action:
1225                  * insert idx then incr producer.
1226                  */
1227                 smp_wmb();
1228                 queue->dealloc_prod++;
1229         } while (ubuf);
1230         spin_unlock_irqrestore(&queue->callback_lock, flags);
1231
1232         if (likely(zerocopy_success))
1233                 queue->stats.tx_zerocopy_success++;
1234         else
1235                 queue->stats.tx_zerocopy_fail++;
1236         xenvif_skb_zerocopy_complete(queue);
1237 }
1238
1239 static inline void xenvif_tx_dealloc_action(struct xenvif_queue *queue)
1240 {
1241         struct gnttab_unmap_grant_ref *gop;
1242         pending_ring_idx_t dc, dp;
1243         u16 pending_idx, pending_idx_release[MAX_PENDING_REQS];
1244         unsigned int i = 0;
1245
1246         dc = queue->dealloc_cons;
1247         gop = queue->tx_unmap_ops;
1248
1249         /* Free up any grants we have finished using */
1250         do {
1251                 dp = queue->dealloc_prod;
1252
1253                 /* Ensure we see all indices enqueued by all
1254                  * xenvif_zerocopy_callback().
1255                  */
1256                 smp_rmb();
1257
1258                 while (dc != dp) {
1259                         BUG_ON(gop - queue->tx_unmap_ops >= MAX_PENDING_REQS);
1260                         pending_idx =
1261                                 queue->dealloc_ring[pending_index(dc++)];
1262
1263                         pending_idx_release[gop - queue->tx_unmap_ops] =
1264                                 pending_idx;
1265                         queue->pages_to_unmap[gop - queue->tx_unmap_ops] =
1266                                 queue->mmap_pages[pending_idx];
1267                         gnttab_set_unmap_op(gop,
1268                                             idx_to_kaddr(queue, pending_idx),
1269                                             GNTMAP_host_map,
1270                                             queue->grant_tx_handle[pending_idx]);
1271                         xenvif_grant_handle_reset(queue, pending_idx);
1272                         ++gop;
1273                 }
1274
1275         } while (dp != queue->dealloc_prod);
1276
1277         queue->dealloc_cons = dc;
1278
1279         if (gop - queue->tx_unmap_ops > 0) {
1280                 int ret;
1281                 ret = gnttab_unmap_refs(queue->tx_unmap_ops,
1282                                         NULL,
1283                                         queue->pages_to_unmap,
1284                                         gop - queue->tx_unmap_ops);
1285                 if (ret) {
1286                         netdev_err(queue->vif->dev, "Unmap fail: nr_ops %tu ret %d\n",
1287                                    gop - queue->tx_unmap_ops, ret);
1288                         for (i = 0; i < gop - queue->tx_unmap_ops; ++i) {
1289                                 if (gop[i].status != GNTST_okay)
1290                                         netdev_err(queue->vif->dev,
1291                                                    " host_addr: 0x%llx handle: 0x%x status: %d\n",
1292                                                    gop[i].host_addr,
1293                                                    gop[i].handle,
1294                                                    gop[i].status);
1295                         }
1296                         BUG();
1297                 }
1298         }
1299
1300         for (i = 0; i < gop - queue->tx_unmap_ops; ++i)
1301                 xenvif_idx_release(queue, pending_idx_release[i],
1302                                    XEN_NETIF_RSP_OKAY);
1303 }
1304
1305
1306 /* Called after netfront has transmitted */
1307 int xenvif_tx_action(struct xenvif_queue *queue, int budget)
1308 {
1309         unsigned nr_mops, nr_cops = 0;
1310         int work_done, ret;
1311
1312         if (unlikely(!tx_work_todo(queue)))
1313                 return 0;
1314
1315         xenvif_tx_build_gops(queue, budget, &nr_cops, &nr_mops);
1316
1317         if (nr_cops == 0)
1318                 return 0;
1319
1320         gnttab_batch_copy(queue->tx_copy_ops, nr_cops);
1321         if (nr_mops != 0) {
1322                 ret = gnttab_map_refs(queue->tx_map_ops,
1323                                       NULL,
1324                                       queue->pages_to_map,
1325                                       nr_mops);
1326                 BUG_ON(ret);
1327         }
1328
1329         work_done = xenvif_tx_submit(queue);
1330
1331         return work_done;
1332 }
1333
1334 static void xenvif_idx_release(struct xenvif_queue *queue, u16 pending_idx,
1335                                u8 status)
1336 {
1337         struct pending_tx_info *pending_tx_info;
1338         pending_ring_idx_t index;
1339         unsigned long flags;
1340
1341         pending_tx_info = &queue->pending_tx_info[pending_idx];
1342
1343         spin_lock_irqsave(&queue->response_lock, flags);
1344
1345         make_tx_response(queue, &pending_tx_info->req,
1346                          pending_tx_info->extra_count, status);
1347
1348         /* Release the pending index before pusing the Tx response so
1349          * its available before a new Tx request is pushed by the
1350          * frontend.
1351          */
1352         index = pending_index(queue->pending_prod++);
1353         queue->pending_ring[index] = pending_idx;
1354
1355         push_tx_responses(queue);
1356
1357         spin_unlock_irqrestore(&queue->response_lock, flags);
1358 }
1359
1360
1361 static void make_tx_response(struct xenvif_queue *queue,
1362                              struct xen_netif_tx_request *txp,
1363                              unsigned int extra_count,
1364                              s8       st)
1365 {
1366         RING_IDX i = queue->tx.rsp_prod_pvt;
1367         struct xen_netif_tx_response *resp;
1368
1369         resp = RING_GET_RESPONSE(&queue->tx, i);
1370         resp->id     = txp->id;
1371         resp->status = st;
1372
1373         while (extra_count-- != 0)
1374                 RING_GET_RESPONSE(&queue->tx, ++i)->status = XEN_NETIF_RSP_NULL;
1375
1376         queue->tx.rsp_prod_pvt = ++i;
1377 }
1378
1379 static void push_tx_responses(struct xenvif_queue *queue)
1380 {
1381         int notify;
1382
1383         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&queue->tx, notify);
1384         if (notify)
1385                 notify_remote_via_irq(queue->tx_irq);
1386 }
1387
1388 void xenvif_idx_unmap(struct xenvif_queue *queue, u16 pending_idx)
1389 {
1390         int ret;
1391         struct gnttab_unmap_grant_ref tx_unmap_op;
1392
1393         gnttab_set_unmap_op(&tx_unmap_op,
1394                             idx_to_kaddr(queue, pending_idx),
1395                             GNTMAP_host_map,
1396                             queue->grant_tx_handle[pending_idx]);
1397         xenvif_grant_handle_reset(queue, pending_idx);
1398
1399         ret = gnttab_unmap_refs(&tx_unmap_op, NULL,
1400                                 &queue->mmap_pages[pending_idx], 1);
1401         if (ret) {
1402                 netdev_err(queue->vif->dev,
1403                            "Unmap fail: ret: %d pending_idx: %d host_addr: %llx handle: 0x%x status: %d\n",
1404                            ret,
1405                            pending_idx,
1406                            tx_unmap_op.host_addr,
1407                            tx_unmap_op.handle,
1408                            tx_unmap_op.status);
1409                 BUG();
1410         }
1411 }
1412
1413 static inline int tx_work_todo(struct xenvif_queue *queue)
1414 {
1415         if (likely(RING_HAS_UNCONSUMED_REQUESTS(&queue->tx)))
1416                 return 1;
1417
1418         return 0;
1419 }
1420
1421 static inline bool tx_dealloc_work_todo(struct xenvif_queue *queue)
1422 {
1423         return queue->dealloc_cons != queue->dealloc_prod;
1424 }
1425
1426 void xenvif_unmap_frontend_data_rings(struct xenvif_queue *queue)
1427 {
1428         if (queue->tx.sring)
1429                 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1430                                         queue->tx.sring);
1431         if (queue->rx.sring)
1432                 xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(queue->vif),
1433                                         queue->rx.sring);
1434 }
1435
1436 int xenvif_map_frontend_data_rings(struct xenvif_queue *queue,
1437                                    grant_ref_t tx_ring_ref,
1438                                    grant_ref_t rx_ring_ref)
1439 {
1440         void *addr;
1441         struct xen_netif_tx_sring *txs;
1442         struct xen_netif_rx_sring *rxs;
1443
1444         int err = -ENOMEM;
1445
1446         err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1447                                      &tx_ring_ref, 1, &addr);
1448         if (err)
1449                 goto err;
1450
1451         txs = (struct xen_netif_tx_sring *)addr;
1452         BACK_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1453
1454         err = xenbus_map_ring_valloc(xenvif_to_xenbus_device(queue->vif),
1455                                      &rx_ring_ref, 1, &addr);
1456         if (err)
1457                 goto err;
1458
1459         rxs = (struct xen_netif_rx_sring *)addr;
1460         BACK_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1461
1462         return 0;
1463
1464 err:
1465         xenvif_unmap_frontend_data_rings(queue);
1466         return err;
1467 }
1468
1469 static bool xenvif_dealloc_kthread_should_stop(struct xenvif_queue *queue)
1470 {
1471         /* Dealloc thread must remain running until all inflight
1472          * packets complete.
1473          */
1474         return kthread_should_stop() &&
1475                 !atomic_read(&queue->inflight_packets);
1476 }
1477
1478 int xenvif_dealloc_kthread(void *data)
1479 {
1480         struct xenvif_queue *queue = data;
1481
1482         for (;;) {
1483                 wait_event_interruptible(queue->dealloc_wq,
1484                                          tx_dealloc_work_todo(queue) ||
1485                                          xenvif_dealloc_kthread_should_stop(queue));
1486                 if (xenvif_dealloc_kthread_should_stop(queue))
1487                         break;
1488
1489                 xenvif_tx_dealloc_action(queue);
1490                 cond_resched();
1491         }
1492
1493         /* Unmap anything remaining*/
1494         if (tx_dealloc_work_todo(queue))
1495                 xenvif_tx_dealloc_action(queue);
1496
1497         return 0;
1498 }
1499
1500 static void make_ctrl_response(struct xenvif *vif,
1501                                const struct xen_netif_ctrl_request *req,
1502                                u32 status, u32 data)
1503 {
1504         RING_IDX idx = vif->ctrl.rsp_prod_pvt;
1505         struct xen_netif_ctrl_response rsp = {
1506                 .id = req->id,
1507                 .type = req->type,
1508                 .status = status,
1509                 .data = data,
1510         };
1511
1512         *RING_GET_RESPONSE(&vif->ctrl, idx) = rsp;
1513         vif->ctrl.rsp_prod_pvt = ++idx;
1514 }
1515
1516 static void push_ctrl_response(struct xenvif *vif)
1517 {
1518         int notify;
1519
1520         RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->ctrl, notify);
1521         if (notify)
1522                 notify_remote_via_irq(vif->ctrl_irq);
1523 }
1524
1525 static void process_ctrl_request(struct xenvif *vif,
1526                                  const struct xen_netif_ctrl_request *req)
1527 {
1528         u32 status = XEN_NETIF_CTRL_STATUS_NOT_SUPPORTED;
1529         u32 data = 0;
1530
1531         switch (req->type) {
1532         case XEN_NETIF_CTRL_TYPE_SET_HASH_ALGORITHM:
1533                 status = xenvif_set_hash_alg(vif, req->data[0]);
1534                 break;
1535
1536         case XEN_NETIF_CTRL_TYPE_GET_HASH_FLAGS:
1537                 status = xenvif_get_hash_flags(vif, &data);
1538                 break;
1539
1540         case XEN_NETIF_CTRL_TYPE_SET_HASH_FLAGS:
1541                 status = xenvif_set_hash_flags(vif, req->data[0]);
1542                 break;
1543
1544         case XEN_NETIF_CTRL_TYPE_SET_HASH_KEY:
1545                 status = xenvif_set_hash_key(vif, req->data[0],
1546                                              req->data[1]);
1547                 break;
1548
1549         case XEN_NETIF_CTRL_TYPE_GET_HASH_MAPPING_SIZE:
1550                 status = XEN_NETIF_CTRL_STATUS_SUCCESS;
1551                 data = XEN_NETBK_MAX_HASH_MAPPING_SIZE;
1552                 break;
1553
1554         case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING_SIZE:
1555                 status = xenvif_set_hash_mapping_size(vif,
1556                                                       req->data[0]);
1557                 break;
1558
1559         case XEN_NETIF_CTRL_TYPE_SET_HASH_MAPPING:
1560                 status = xenvif_set_hash_mapping(vif, req->data[0],
1561                                                  req->data[1],
1562                                                  req->data[2]);
1563                 break;
1564
1565         default:
1566                 break;
1567         }
1568
1569         make_ctrl_response(vif, req, status, data);
1570         push_ctrl_response(vif);
1571 }
1572
1573 static void xenvif_ctrl_action(struct xenvif *vif)
1574 {
1575         for (;;) {
1576                 RING_IDX req_prod, req_cons;
1577
1578                 req_prod = vif->ctrl.sring->req_prod;
1579                 req_cons = vif->ctrl.req_cons;
1580
1581                 /* Make sure we can see requests before we process them. */
1582                 rmb();
1583
1584                 if (req_cons == req_prod)
1585                         break;
1586
1587                 while (req_cons != req_prod) {
1588                         struct xen_netif_ctrl_request req;
1589
1590                         RING_COPY_REQUEST(&vif->ctrl, req_cons, &req);
1591                         req_cons++;
1592
1593                         process_ctrl_request(vif, &req);
1594                 }
1595
1596                 vif->ctrl.req_cons = req_cons;
1597                 vif->ctrl.sring->req_event = req_cons + 1;
1598         }
1599 }
1600
1601 static bool xenvif_ctrl_work_todo(struct xenvif *vif)
1602 {
1603         if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->ctrl)))
1604                 return 1;
1605
1606         return 0;
1607 }
1608
1609 irqreturn_t xenvif_ctrl_irq_fn(int irq, void *data)
1610 {
1611         struct xenvif *vif = data;
1612
1613         while (xenvif_ctrl_work_todo(vif))
1614                 xenvif_ctrl_action(vif);
1615
1616         return IRQ_HANDLED;
1617 }
1618
1619 static int __init netback_init(void)
1620 {
1621         int rc = 0;
1622
1623         if (!xen_domain())
1624                 return -ENODEV;
1625
1626         /* Allow as many queues as there are CPUs but max. 8 if user has not
1627          * specified a value.
1628          */
1629         if (xenvif_max_queues == 0)
1630                 xenvif_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
1631                                           num_online_cpus());
1632
1633         if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
1634                 pr_info("fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
1635                         fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
1636                 fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
1637         }
1638
1639         rc = xenvif_xenbus_init();
1640         if (rc)
1641                 goto failed_init;
1642
1643 #ifdef CONFIG_DEBUG_FS
1644         xen_netback_dbg_root = debugfs_create_dir("xen-netback", NULL);
1645         if (IS_ERR_OR_NULL(xen_netback_dbg_root))
1646                 pr_warn("Init of debugfs returned %ld!\n",
1647                         PTR_ERR(xen_netback_dbg_root));
1648 #endif /* CONFIG_DEBUG_FS */
1649
1650         return 0;
1651
1652 failed_init:
1653         return rc;
1654 }
1655
1656 module_init(netback_init);
1657
1658 static void __exit netback_fini(void)
1659 {
1660 #ifdef CONFIG_DEBUG_FS
1661         if (!IS_ERR_OR_NULL(xen_netback_dbg_root))
1662                 debugfs_remove_recursive(xen_netback_dbg_root);
1663 #endif /* CONFIG_DEBUG_FS */
1664         xenvif_xenbus_fini();
1665 }
1666 module_exit(netback_fini);
1667
1668 MODULE_LICENSE("Dual BSD/GPL");
1669 MODULE_ALIAS("xen-backend:vif");