drivers/net/xen-netfront.c

   1 /*
   2  * Virtual network driver for conversing with remote driver backends.
   3  *
   4  * Copyright (c) 2002-2005, K A Fraser
   5  * Copyright (c) 2005, XenSource Ltd
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License version 2
   9  * as published by the Free Software Foundation; or, when distributed
  10  * separately from the Linux kernel or incorporated into other
  11  * software packages, subject to the following license:
  12  *
  13  * Permission is hereby granted, free of charge, to any person obtaining a copy
  14  * of this source file (the "Software"), to deal in the Software without
  15  * restriction, including without limitation the rights to use, copy, modify,
  16  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  17  * and to permit persons to whom the Software is furnished to do so, subject to
  18  * the following conditions:
  19  *
  20  * The above copyright notice and this permission notice shall be included in
  21  * all copies or substantial portions of the Software.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  24  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  25  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  26  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  27  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  28  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  29  * IN THE SOFTWARE.
  30  */
  31
  32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  33
  34 #include <linux/module.h>
  35 #include <linux/kernel.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/etherdevice.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/ethtool.h>
  40 #include <linux/if_ether.h>
  41 #include <net/tcp.h>
  42 #include <linux/udp.h>
  43 #include <linux/moduleparam.h>
  44 #include <linux/mm.h>
  45 #include <linux/slab.h>
  46 #include <net/ip.h>
  47
  48 #include <xen/xen.h>
  49 #include <xen/xenbus.h>
  50 #include <xen/events.h>
  51 #include <xen/page.h>
  52 #include <xen/platform_pci.h>
  53 #include <xen/grant_table.h>
  54
  55 #include <xen/interface/io/netif.h>
  56 #include <xen/interface/memory.h>
  57 #include <xen/interface/grant_table.h>
  58
  59 /* Module parameters */
  60 #define MAX_QUEUES_DEFAULT 8
  61 static unsigned int xennet_max_queues;
  62 module_param_named(max_queues, xennet_max_queues, uint, 0644);
  63 MODULE_PARM_DESC(max_queues,
  64                  "Maximum number of queues per virtual interface");
  65
  66 static const struct ethtool_ops xennet_ethtool_ops;
  67
  68 struct netfront_cb {
  69         int pull_to;
  70 };
  71
  72 #define NETFRONT_SKB_CB(skb)    ((struct netfront_cb *)((skb)->cb))
  73
  74 #define RX_COPY_THRESHOLD 256
  75
  76 #define GRANT_INVALID_REF       0
  77
  78 #define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE)
  79 #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, XEN_PAGE_SIZE)
  80
  81 /* Minimum number of Rx slots (includes slot for GSO metadata). */
  82 #define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1)
  83
  84 /* Queue name is interface name with "-qNNN" appended */
  85 #define QUEUE_NAME_SIZE (IFNAMSIZ + 6)
  86
  87 /* IRQ name is queue name with "-tx" or "-rx" appended */
  88 #define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
  89
  90 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
  91
  92 struct netfront_stats {
  93         u64                     packets;
  94         u64                     bytes;
  95         struct u64_stats_sync   syncp;
  96 };
  97
  98 struct netfront_info;
  99
 100 struct netfront_queue {
 101         unsigned int id; /* Queue ID, 0-based */
 102         char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
 103         struct netfront_info *info;
 104
 105         struct napi_struct napi;
 106
 107         /* Split event channels support, tx_* == rx_* when using
 108          * single event channel.
 109          */
 110         unsigned int tx_evtchn, rx_evtchn;
 111         unsigned int tx_irq, rx_irq;
 112         /* Only used when split event channels support is enabled */
 113         char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
 114         char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
 115
 116         spinlock_t   tx_lock;
 117         struct xen_netif_tx_front_ring tx;
 118         int tx_ring_ref;
 119
 120         /*
 121          * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
 122          * are linked from tx_skb_freelist through skb_entry.link.
 123          *
 124          *  NB. Freelist index entries are always going to be less than
 125          *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
 126          *  greater than PAGE_OFFSET: we use this property to distinguish
 127          *  them.
 128          */
 129         union skb_entry {
 130                 struct sk_buff *skb;
 131                 unsigned long link;
 132         } tx_skbs[NET_TX_RING_SIZE];
 133         grant_ref_t gref_tx_head;
 134         grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
 135         struct page *grant_tx_page[NET_TX_RING_SIZE];
 136         unsigned tx_skb_freelist;
 137
 138         spinlock_t   rx_lock ____cacheline_aligned_in_smp;
 139         struct xen_netif_rx_front_ring rx;
 140         int rx_ring_ref;
 141
 142         struct timer_list rx_refill_timer;
 143
 144         struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
 145         grant_ref_t gref_rx_head;
 146         grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
 147 };
 148
 149 struct netfront_info {
 150         struct list_head list;
 151         struct net_device *netdev;
 152
 153         struct xenbus_device *xbdev;
 154
 155         /* Multi-queue support */
 156         struct netfront_queue *queues;
 157
 158         /* Statistics */
 159         struct netfront_stats __percpu *rx_stats;
 160         struct netfront_stats __percpu *tx_stats;
 161
 162         atomic_t rx_gso_checksum_fixup;
 163 };
 164
 165 struct netfront_rx_info {
 166         struct xen_netif_rx_response rx;
 167         struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
 168 };
 169
 170 static void skb_entry_set_link(union skb_entry *list, unsigned short id)
 171 {
 172         list->link = id;
 173 }
 174
 175 static int skb_entry_is_link(const union skb_entry *list)
 176 {
 177         BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
 178         return (unsigned long)list->skb < PAGE_OFFSET;
 179 }
 180
 181 /*
 182  * Access macros for acquiring freeing slots in tx_skbs[].
 183  */
 184
 185 static void add_id_to_freelist(unsigned *head, union skb_entry *list,
 186                                unsigned short id)
 187 {
 188         skb_entry_set_link(&list[id], *head);
 189         *head = id;
 190 }
 191
 192 static unsigned short get_id_from_freelist(unsigned *head,
 193                                            union skb_entry *list)
 194 {
 195         unsigned int id = *head;
 196         *head = list[id].link;
 197         return id;
 198 }
 199
 200 static int xennet_rxidx(RING_IDX idx)
 201 {
 202         return idx & (NET_RX_RING_SIZE - 1);
 203 }
 204
 205 static struct sk_buff *xennet_get_rx_skb(struct netfront_queue *queue,
 206                                          RING_IDX ri)
 207 {
 208         int i = xennet_rxidx(ri);
 209         struct sk_buff *skb = queue->rx_skbs[i];
 210         queue->rx_skbs[i] = NULL;
 211         return skb;
 212 }
 213
 214 static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
 215                                             RING_IDX ri)
 216 {
 217         int i = xennet_rxidx(ri);
 218         grant_ref_t ref = queue->grant_rx_ref[i];
 219         queue->grant_rx_ref[i] = GRANT_INVALID_REF;
 220         return ref;
 221 }
 222
 223 #ifdef CONFIG_SYSFS
 224 static const struct attribute_group xennet_dev_group;
 225 #endif
 226
 227 static bool xennet_can_sg(struct net_device *dev)
 228 {
 229         return dev->features & NETIF_F_SG;
 230 }
 231
 232
 233 static void rx_refill_timeout(struct timer_list *t)
 234 {
 235         struct netfront_queue *queue = from_timer(queue, t, rx_refill_timer);
 236         napi_schedule(&queue->napi);
 237 }
 238
 239 static int netfront_tx_slot_available(struct netfront_queue *queue)
 240 {
 241         return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) <
 242                 (NET_TX_RING_SIZE - XEN_NETIF_NR_SLOTS_MIN - 1);
 243 }
 244
 245 static void xennet_maybe_wake_tx(struct netfront_queue *queue)
 246 {
 247         struct net_device *dev = queue->info->netdev;
 248         struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, queue->id);
 249
 250         if (unlikely(netif_tx_queue_stopped(dev_queue)) &&
 251             netfront_tx_slot_available(queue) &&
 252             likely(netif_running(dev)))
 253                 netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
 254 }
 255
 256
 257 static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
 258 {
 259         struct sk_buff *skb;
 260         struct page *page;
 261
 262         skb = __netdev_alloc_skb(queue->info->netdev,
 263                                  RX_COPY_THRESHOLD + NET_IP_ALIGN,
 264                                  GFP_ATOMIC | __GFP_NOWARN);
 265         if (unlikely(!skb))
 266                 return NULL;
 267
 268         page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 269         if (!page) {
 270                 kfree_skb(skb);
 271                 return NULL;
 272         }
 273         skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE);
 274
 275         /* Align ip header to a 16 bytes boundary */
 276         skb_reserve(skb, NET_IP_ALIGN);
 277         skb->dev = queue->info->netdev;
 278
 279         return skb;
 280 }
 281
 282
 283 static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
 284 {
 285         RING_IDX req_prod = queue->rx.req_prod_pvt;
 286         int notify;
 287         int err = 0;
 288
 289         if (unlikely(!netif_carrier_ok(queue->info->netdev)))
 290                 return;
 291
 292         for (req_prod = queue->rx.req_prod_pvt;
 293              req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE;
 294              req_prod++) {
 295                 struct sk_buff *skb;
 296                 unsigned short id;
 297                 grant_ref_t ref;
 298                 struct page *page;
 299                 struct xen_netif_rx_request *req;
 300
 301                 skb = xennet_alloc_one_rx_buffer(queue);
 302                 if (!skb) {
 303                         err = -ENOMEM;
 304                         break;
 305                 }
 306
 307                 id = xennet_rxidx(req_prod);
 308
 309                 BUG_ON(queue->rx_skbs[id]);
 310                 queue->rx_skbs[id] = skb;
 311
 312                 ref = gnttab_claim_grant_reference(&queue->gref_rx_head);
 313                 WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 314                 queue->grant_rx_ref[id] = ref;
 315
 316                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
 317
 318                 req = RING_GET_REQUEST(&queue->rx, req_prod);
 319                 gnttab_page_grant_foreign_access_ref_one(ref,
 320                                                          queue->info->xbdev->otherend_id,
 321                                                          page,
 322                                                          0);
 323                 req->id = id;
 324                 req->gref = ref;
 325         }
 326
 327         queue->rx.req_prod_pvt = req_prod;
 328
 329         /* Try again later if there are not enough requests or skb allocation
 330          * failed.
 331          * Enough requests is quantified as the sum of newly created slots and
 332          * the unconsumed slots at the backend.
 333          */
 334         if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN ||
 335             unlikely(err)) {
 336                 mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10));
 337                 return;
 338         }
 339
 340         wmb();          /* barrier so backend seens requests */
 341
 342         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify);
 343         if (notify)
 344                 notify_remote_via_irq(queue->rx_irq);
 345 }
 346
 347 static int xennet_open(struct net_device *dev)
 348 {
 349         struct netfront_info *np = netdev_priv(dev);
 350         unsigned int num_queues = dev->real_num_tx_queues;
 351         unsigned int i = 0;
 352         struct netfront_queue *queue = NULL;
 353
 354         if (!np->queues)
 355                 return -ENODEV;
 356
 357         for (i = 0; i < num_queues; ++i) {
 358                 queue = &np->queues[i];
 359                 napi_enable(&queue->napi);
 360
 361                 spin_lock_bh(&queue->rx_lock);
 362                 if (netif_carrier_ok(dev)) {
 363                         xennet_alloc_rx_buffers(queue);
 364                         queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
 365                         if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
 366                                 napi_schedule(&queue->napi);
 367                 }
 368                 spin_unlock_bh(&queue->rx_lock);
 369         }
 370
 371         netif_tx_start_all_queues(dev);
 372
 373         return 0;
 374 }
 375
 376 static void xennet_tx_buf_gc(struct netfront_queue *queue)
 377 {
 378         RING_IDX cons, prod;
 379         unsigned short id;
 380         struct sk_buff *skb;
 381         bool more_to_do;
 382
 383         BUG_ON(!netif_carrier_ok(queue->info->netdev));
 384
 385         do {
 386                 prod = queue->tx.sring->rsp_prod;
 387                 rmb(); /* Ensure we see responses up to 'rp'. */
 388
 389                 for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
 390                         struct xen_netif_tx_response *txrsp;
 391
 392                         txrsp = RING_GET_RESPONSE(&queue->tx, cons);
 393                         if (txrsp->status == XEN_NETIF_RSP_NULL)
 394                                 continue;
 395
 396                         id  = txrsp->id;
 397                         skb = queue->tx_skbs[id].skb;
 398                         if (unlikely(gnttab_query_foreign_access(
 399                                 queue->grant_tx_ref[id]) != 0)) {
 400                                 pr_alert("%s: warning -- grant still in use by backend domain\n",
 401                                          __func__);
 402                                 BUG();
 403                         }
 404                         gnttab_end_foreign_access_ref(
 405                                 queue->grant_tx_ref[id], GNTMAP_readonly);
 406                         gnttab_release_grant_reference(
 407                                 &queue->gref_tx_head, queue->grant_tx_ref[id]);
 408                         queue->grant_tx_ref[id] = GRANT_INVALID_REF;
 409                         queue->grant_tx_page[id] = NULL;
 410                         add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, id);
 411                         dev_kfree_skb_irq(skb);
 412                 }
 413
 414                 queue->tx.rsp_cons = prod;
 415
 416                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->tx, more_to_do);
 417         } while (more_to_do);
 418
 419         xennet_maybe_wake_tx(queue);
 420 }
 421
 422 struct xennet_gnttab_make_txreq {
 423         struct netfront_queue *queue;
 424         struct sk_buff *skb;
 425         struct page *page;
 426         struct xen_netif_tx_request *tx; /* Last request */
 427         unsigned int size;
 428 };
 429
 430 static void xennet_tx_setup_grant(unsigned long gfn, unsigned int offset,
 431                                   unsigned int len, void *data)
 432 {
 433         struct xennet_gnttab_make_txreq *info = data;
 434         unsigned int id;
 435         struct xen_netif_tx_request *tx;
 436         grant_ref_t ref;
 437         /* convenient aliases */
 438         struct page *page = info->page;
 439         struct netfront_queue *queue = info->queue;
 440         struct sk_buff *skb = info->skb;
 441
 442         id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
 443         tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 444         ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
 445         WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 446
 447         gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
 448                                         gfn, GNTMAP_readonly);
 449
 450         queue->tx_skbs[id].skb = skb;
 451         queue->grant_tx_page[id] = page;
 452         queue->grant_tx_ref[id] = ref;
 453
 454         tx->id = id;
 455         tx->gref = ref;
 456         tx->offset = offset;
 457         tx->size = len;
 458         tx->flags = 0;
 459
 460         info->tx = tx;
 461         info->size += tx->size;
 462 }
 463
 464 static struct xen_netif_tx_request *xennet_make_first_txreq(
 465         struct netfront_queue *queue, struct sk_buff *skb,
 466         struct page *page, unsigned int offset, unsigned int len)
 467 {
 468         struct xennet_gnttab_make_txreq info = {
 469                 .queue = queue,
 470                 .skb = skb,
 471                 .page = page,
 472                 .size = 0,
 473         };
 474
 475         gnttab_for_one_grant(page, offset, len, xennet_tx_setup_grant, &info);
 476
 477         return info.tx;
 478 }
 479
 480 static void xennet_make_one_txreq(unsigned long gfn, unsigned int offset,
 481                                   unsigned int len, void *data)
 482 {
 483         struct xennet_gnttab_make_txreq *info = data;
 484
 485         info->tx->flags |= XEN_NETTXF_more_data;
 486         skb_get(info->skb);
 487         xennet_tx_setup_grant(gfn, offset, len, data);
 488 }
 489
 490 static struct xen_netif_tx_request *xennet_make_txreqs(
 491         struct netfront_queue *queue, struct xen_netif_tx_request *tx,
 492         struct sk_buff *skb, struct page *page,
 493         unsigned int offset, unsigned int len)
 494 {
 495         struct xennet_gnttab_make_txreq info = {
 496                 .queue = queue,
 497                 .skb = skb,
 498                 .tx = tx,
 499         };
 500
 501         /* Skip unused frames from start of page */
 502         page += offset >> PAGE_SHIFT;
 503         offset &= ~PAGE_MASK;
 504
 505         while (len) {
 506                 info.page = page;
 507                 info.size = 0;
 508
 509                 gnttab_foreach_grant_in_range(page, offset, len,
 510                                               xennet_make_one_txreq,
 511                                               &info);
 512
 513                 page++;
 514                 offset = 0;
 515                 len -= info.size;
 516         }
 517
 518         return info.tx;
 519 }
 520
 521 /*
 522  * Count how many ring slots are required to send this skb. Each frag
 523  * might be a compound page.
 524  */
 525 static int xennet_count_skb_slots(struct sk_buff *skb)
 526 {
 527         int i, frags = skb_shinfo(skb)->nr_frags;
 528         int slots;
 529
 530         slots = gnttab_count_grant(offset_in_page(skb->data),
 531                                    skb_headlen(skb));
 532
 533         for (i = 0; i < frags; i++) {
 534                 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 535                 unsigned long size = skb_frag_size(frag);
 536                 unsigned long offset = frag->page_offset;
 537
 538                 /* Skip unused frames from start of page */
 539                 offset &= ~PAGE_MASK;
 540
 541                 slots += gnttab_count_grant(offset, size);
 542         }
 543
 544         return slots;
 545 }
 546
 547 static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
 548                                struct net_device *sb_dev,
 549                                select_queue_fallback_t fallback)
 550 {
 551         unsigned int num_queues = dev->real_num_tx_queues;
 552         u32 hash;
 553         u16 queue_idx;
 554
 555         /* First, check if there is only one queue */
 556         if (num_queues == 1) {
 557                 queue_idx = 0;
 558         } else {
 559                 hash = skb_get_hash(skb);
 560                 queue_idx = hash % num_queues;
 561         }
 562
 563         return queue_idx;
 564 }
 565
 566 #define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
 567
 568 static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 569 {
 570         struct netfront_info *np = netdev_priv(dev);
 571         struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
 572         struct xen_netif_tx_request *tx, *first_tx;
 573         unsigned int i;
 574         int notify;
 575         int slots;
 576         struct page *page;
 577         unsigned int offset;
 578         unsigned int len;
 579         unsigned long flags;
 580         struct netfront_queue *queue = NULL;
 581         unsigned int num_queues = dev->real_num_tx_queues;
 582         u16 queue_index;
 583         struct sk_buff *nskb;
 584
 585         /* Drop the packet if no queues are set up */
 586         if (num_queues < 1)
 587                 goto drop;
 588         /* Determine which queue to transmit this SKB on */
 589         queue_index = skb_get_queue_mapping(skb);
 590         queue = &np->queues[queue_index];
 591
 592         /* If skb->len is too big for wire format, drop skb and alert
 593          * user about misconfiguration.
 594          */
 595         if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
 596                 net_alert_ratelimited(
 597                         "xennet: skb->len = %u, too big for wire format\n",
 598                         skb->len);
 599                 goto drop;
 600         }
 601
 602         slots = xennet_count_skb_slots(skb);
 603         if (unlikely(slots > MAX_XEN_SKB_FRAGS + 1)) {
 604                 net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
 605                                     slots, skb->len);
 606                 if (skb_linearize(skb))
 607                         goto drop;
 608         }
 609
 610         page = virt_to_page(skb->data);
 611         offset = offset_in_page(skb->data);
 612
 613         /* The first req should be at least ETH_HLEN size or the packet will be
 614          * dropped by netback.
 615          */
 616         if (unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
 617                 nskb = skb_copy(skb, GFP_ATOMIC);
 618                 if (!nskb)
 619                         goto drop;
 620                 dev_consume_skb_any(skb);
 621                 skb = nskb;
 622                 page = virt_to_page(skb->data);
 623                 offset = offset_in_page(skb->data);
 624         }
 625
 626         len = skb_headlen(skb);
 627
 628         spin_lock_irqsave(&queue->tx_lock, flags);
 629
 630         if (unlikely(!netif_carrier_ok(dev) ||
 631                      (slots > 1 && !xennet_can_sg(dev)) ||
 632                      netif_needs_gso(skb, netif_skb_features(skb)))) {
 633                 spin_unlock_irqrestore(&queue->tx_lock, flags);
 634                 goto drop;
 635         }
 636
 637         /* First request for the linear area. */
 638         first_tx = tx = xennet_make_first_txreq(queue, skb,
 639                                                 page, offset, len);
 640         offset += tx->size;
 641         if (offset == PAGE_SIZE) {
 642                 page++;
 643                 offset = 0;
 644         }
 645         len -= tx->size;
 646
 647         if (skb->ip_summed == CHECKSUM_PARTIAL)
 648                 /* local packet? */
 649                 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
 650         else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 651                 /* remote but checksummed. */
 652                 tx->flags |= XEN_NETTXF_data_validated;
 653
 654         /* Optional extra info after the first request. */
 655         if (skb_shinfo(skb)->gso_size) {
 656                 struct xen_netif_extra_info *gso;
 657
 658                 gso = (struct xen_netif_extra_info *)
 659                         RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 660
 661                 tx->flags |= XEN_NETTXF_extra_info;
 662
 663                 gso->u.gso.size = skb_shinfo(skb)->gso_size;
 664                 gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
 665                         XEN_NETIF_GSO_TYPE_TCPV6 :
 666                         XEN_NETIF_GSO_TYPE_TCPV4;
 667                 gso->u.gso.pad = 0;
 668                 gso->u.gso.features = 0;
 669
 670                 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 671                 gso->flags = 0;
 672         }
 673
 674         /* Requests for the rest of the linear area. */
 675         tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);
 676
 677         /* Requests for all the frags. */
 678         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 679                 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 680                 tx = xennet_make_txreqs(queue, tx, skb,
 681                                         skb_frag_page(frag), frag->page_offset,
 682                                         skb_frag_size(frag));
 683         }
 684
 685         /* First request has the packet length. */
 686         first_tx->size = skb->len;
 687
 688         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
 689         if (notify)
 690                 notify_remote_via_irq(queue->tx_irq);
 691
 692         u64_stats_update_begin(&tx_stats->syncp);
 693         tx_stats->bytes += skb->len;
 694         tx_stats->packets++;
 695         u64_stats_update_end(&tx_stats->syncp);
 696
 697         /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
 698         xennet_tx_buf_gc(queue);
 699
 700         if (!netfront_tx_slot_available(queue))
 701                 netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
 702
 703         spin_unlock_irqrestore(&queue->tx_lock, flags);
 704
 705         return NETDEV_TX_OK;
 706
 707  drop:
 708         dev->stats.tx_dropped++;
 709         dev_kfree_skb_any(skb);
 710         return NETDEV_TX_OK;
 711 }
 712
 713 static int xennet_close(struct net_device *dev)
 714 {
 715         struct netfront_info *np = netdev_priv(dev);
 716         unsigned int num_queues = dev->real_num_tx_queues;
 717         unsigned int i;
 718         struct netfront_queue *queue;
 719         netif_tx_stop_all_queues(np->netdev);
 720         for (i = 0; i < num_queues; ++i) {
 721                 queue = &np->queues[i];
 722                 napi_disable(&queue->napi);
 723         }
 724         return 0;
 725 }
 726
 727 static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
 728                                 grant_ref_t ref)
 729 {
 730         int new = xennet_rxidx(queue->rx.req_prod_pvt);
 731
 732         BUG_ON(queue->rx_skbs[new]);
 733         queue->rx_skbs[new] = skb;
 734         queue->grant_rx_ref[new] = ref;
 735         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
 736         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
 737         queue->rx.req_prod_pvt++;
 738 }
 739
 740 static int xennet_get_extras(struct netfront_queue *queue,
 741                              struct xen_netif_extra_info *extras,
 742                              RING_IDX rp)
 743
 744 {
 745         struct xen_netif_extra_info *extra;
 746         struct device *dev = &queue->info->netdev->dev;
 747         RING_IDX cons = queue->rx.rsp_cons;
 748         int err = 0;
 749
 750         do {
 751                 struct sk_buff *skb;
 752                 grant_ref_t ref;
 753
 754                 if (unlikely(cons + 1 == rp)) {
 755                         if (net_ratelimit())
 756                                 dev_warn(dev, "Missing extra info\n");
 757                         err = -EBADR;
 758                         break;
 759                 }
 760
 761                 extra = (struct xen_netif_extra_info *)
 762                         RING_GET_RESPONSE(&queue->rx, ++cons);
 763
 764                 if (unlikely(!extra->type ||
 765                              extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 766                         if (net_ratelimit())
 767                                 dev_warn(dev, "Invalid extra type: %d\n",
 768                                         extra->type);
 769                         err = -EINVAL;
 770                 } else {
 771                         memcpy(&extras[extra->type - 1], extra,
 772                                sizeof(*extra));
 773                 }
 774
 775                 skb = xennet_get_rx_skb(queue, cons);
 776                 ref = xennet_get_rx_ref(queue, cons);
 777                 xennet_move_rx_slot(queue, skb, ref);
 778         } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
 779
 780         queue->rx.rsp_cons = cons;
 781         return err;
 782 }
 783
 784 static int xennet_get_responses(struct netfront_queue *queue,
 785                                 struct netfront_rx_info *rinfo, RING_IDX rp,
 786                                 struct sk_buff_head *list)
 787 {
 788         struct xen_netif_rx_response *rx = &rinfo->rx;
 789         struct xen_netif_extra_info *extras = rinfo->extras;
 790         struct device *dev = &queue->info->netdev->dev;
 791         RING_IDX cons = queue->rx.rsp_cons;
 792         struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
 793         grant_ref_t ref = xennet_get_rx_ref(queue, cons);
 794         int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD);
 795         int slots = 1;
 796         int err = 0;
 797         unsigned long ret;
 798
 799         if (rx->flags & XEN_NETRXF_extra_info) {
 800                 err = xennet_get_extras(queue, extras, rp);
 801                 cons = queue->rx.rsp_cons;
 802         }
 803
 804         for (;;) {
 805                 if (unlikely(rx->status < 0 ||
 806                              rx->offset + rx->status > XEN_PAGE_SIZE)) {
 807                         if (net_ratelimit())
 808                                 dev_warn(dev, "rx->offset: %u, size: %d\n",
 809                                          rx->offset, rx->status);
 810                         xennet_move_rx_slot(queue, skb, ref);
 811                         err = -EINVAL;
 812                         goto next;
 813                 }
 814
 815                 /*
 816                  * This definitely indicates a bug, either in this driver or in
 817                  * the backend driver. In future this should flag the bad
 818                  * situation to the system controller to reboot the backend.
 819                  */
 820                 if (ref == GRANT_INVALID_REF) {
 821                         if (net_ratelimit())
 822                                 dev_warn(dev, "Bad rx response id %d.\n",
 823                                          rx->id);
 824                         err = -EINVAL;
 825                         goto next;
 826                 }
 827
 828                 ret = gnttab_end_foreign_access_ref(ref, 0);
 829                 BUG_ON(!ret);
 830
 831                 gnttab_release_grant_reference(&queue->gref_rx_head, ref);
 832
 833                 __skb_queue_tail(list, skb);
 834
 835 next:
 836                 if (!(rx->flags & XEN_NETRXF_more_data))
 837                         break;
 838
 839                 if (cons + slots == rp) {
 840                         if (net_ratelimit())
 841                                 dev_warn(dev, "Need more slots\n");
 842                         err = -ENOENT;
 843                         break;
 844                 }
 845
 846                 rx = RING_GET_RESPONSE(&queue->rx, cons + slots);
 847                 skb = xennet_get_rx_skb(queue, cons + slots);
 848                 ref = xennet_get_rx_ref(queue, cons + slots);
 849                 slots++;
 850         }
 851
 852         if (unlikely(slots > max)) {
 853                 if (net_ratelimit())
 854                         dev_warn(dev, "Too many slots\n");
 855                 err = -E2BIG;
 856         }
 857
 858         if (unlikely(err))
 859                 queue->rx.rsp_cons = cons + slots;
 860
 861         return err;
 862 }
 863
 864 static int xennet_set_skb_gso(struct sk_buff *skb,
 865                               struct xen_netif_extra_info *gso)
 866 {
 867         if (!gso->u.gso.size) {
 868                 if (net_ratelimit())
 869                         pr_warn("GSO size must not be zero\n");
 870                 return -EINVAL;
 871         }
 872
 873         if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
 874             gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
 875                 if (net_ratelimit())
 876                         pr_warn("Bad GSO type %d\n", gso->u.gso.type);
 877                 return -EINVAL;
 878         }
 879
 880         skb_shinfo(skb)->gso_size = gso->u.gso.size;
 881         skb_shinfo(skb)->gso_type =
 882                 (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
 883                 SKB_GSO_TCPV4 :
 884                 SKB_GSO_TCPV6;
 885
 886         /* Header must be checked, and gso_segs computed. */
 887         skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 888         skb_shinfo(skb)->gso_segs = 0;
 889
 890         return 0;
 891 }
 892
 893 static RING_IDX xennet_fill_frags(struct netfront_queue *queue,
 894                                   struct sk_buff *skb,
 895                                   struct sk_buff_head *list)
 896 {
 897         RING_IDX cons = queue->rx.rsp_cons;
 898         struct sk_buff *nskb;
 899
 900         while ((nskb = __skb_dequeue(list))) {
 901                 struct xen_netif_rx_response *rx =
 902                         RING_GET_RESPONSE(&queue->rx, ++cons);
 903                 skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
 904
 905                 if (skb_shinfo(skb)->nr_frags == MAX_SKB_FRAGS) {
 906                         unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 907
 908                         BUG_ON(pull_to <= skb_headlen(skb));
 909                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 910                 }
 911                 BUG_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS);
 912
 913                 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
 914                                 skb_frag_page(nfrag),
 915                                 rx->offset, rx->status, PAGE_SIZE);
 916
 917                 skb_shinfo(nskb)->nr_frags = 0;
 918                 kfree_skb(nskb);
 919         }
 920
 921         return cons;
 922 }
 923
 924 static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 925 {
 926         bool recalculate_partial_csum = false;
 927
 928         /*
 929          * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 930          * peers can fail to set NETRXF_csum_blank when sending a GSO
 931          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 932          * recalculate the partial checksum.
 933          */
 934         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 935                 struct netfront_info *np = netdev_priv(dev);
 936                 atomic_inc(&np->rx_gso_checksum_fixup);
 937                 skb->ip_summed = CHECKSUM_PARTIAL;
 938                 recalculate_partial_csum = true;
 939         }
 940
 941         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 942         if (skb->ip_summed != CHECKSUM_PARTIAL)
 943                 return 0;
 944
 945         return skb_checksum_setup(skb, recalculate_partial_csum);
 946 }
 947
 948 static int handle_incoming_queue(struct netfront_queue *queue,
 949                                  struct sk_buff_head *rxq)
 950 {
 951         struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats);
 952         int packets_dropped = 0;
 953         struct sk_buff *skb;
 954
 955         while ((skb = __skb_dequeue(rxq)) != NULL) {
 956                 int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 957
 958                 if (pull_to > skb_headlen(skb))
 959                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 960
 961                 /* Ethernet work: Delayed to here as it peeks the header. */
 962                 skb->protocol = eth_type_trans(skb, queue->info->netdev);
 963                 skb_reset_network_header(skb);
 964
 965                 if (checksum_setup(queue->info->netdev, skb)) {
 966                         kfree_skb(skb);
 967                         packets_dropped++;
 968                         queue->info->netdev->stats.rx_errors++;
 969                         continue;
 970                 }
 971
 972                 u64_stats_update_begin(&rx_stats->syncp);
 973                 rx_stats->packets++;
 974                 rx_stats->bytes += skb->len;
 975                 u64_stats_update_end(&rx_stats->syncp);
 976
 977                 /* Pass it up. */
 978                 napi_gro_receive(&queue->napi, skb);
 979         }
 980
 981         return packets_dropped;
 982 }
 983
 984 static int xennet_poll(struct napi_struct *napi, int budget)
 985 {
 986         struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
 987         struct net_device *dev = queue->info->netdev;
 988         struct sk_buff *skb;
 989         struct netfront_rx_info rinfo;
 990         struct xen_netif_rx_response *rx = &rinfo.rx;
 991         struct xen_netif_extra_info *extras = rinfo.extras;
 992         RING_IDX i, rp;
 993         int work_done;
 994         struct sk_buff_head rxq;
 995         struct sk_buff_head errq;
 996         struct sk_buff_head tmpq;
 997         int err;
 998
 999         spin_lock(&queue->rx_lock);
1000
1001         skb_queue_head_init(&rxq);
1002         skb_queue_head_init(&errq);
1003         skb_queue_head_init(&tmpq);
1004
1005         rp = queue->rx.sring->rsp_prod;
1006         rmb(); /* Ensure we see queued responses up to 'rp'. */
1007
1008         i = queue->rx.rsp_cons;
1009         work_done = 0;
1010         while ((i != rp) && (work_done < budget)) {
1011                 memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
1012                 memset(extras, 0, sizeof(rinfo.extras));
1013
1014                 err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
1015
1016                 if (unlikely(err)) {
1017 err:
1018                         while ((skb = __skb_dequeue(&tmpq)))
1019                                 __skb_queue_tail(&errq, skb);
1020                         dev->stats.rx_errors++;
1021                         i = queue->rx.rsp_cons;
1022                         continue;
1023                 }
1024
1025                 skb = __skb_dequeue(&tmpq);
1026
1027                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1028                         struct xen_netif_extra_info *gso;
1029                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1030
1031                         if (unlikely(xennet_set_skb_gso(skb, gso))) {
1032                                 __skb_queue_head(&tmpq, skb);
1033                                 queue->rx.rsp_cons += skb_queue_len(&tmpq);
1034                                 goto err;
1035                         }
1036                 }
1037
1038                 NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1039                 if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1040                         NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1041
1042                 skb_shinfo(skb)->frags[0].page_offset = rx->offset;
1043                 skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1044                 skb->data_len = rx->status;
1045                 skb->len += rx->status;
1046
1047                 i = xennet_fill_frags(queue, skb, &tmpq);
1048
1049                 if (rx->flags & XEN_NETRXF_csum_blank)
1050                         skb->ip_summed = CHECKSUM_PARTIAL;
1051                 else if (rx->flags & XEN_NETRXF_data_validated)
1052                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1053
1054                 __skb_queue_tail(&rxq, skb);
1055
1056                 queue->rx.rsp_cons = ++i;
1057                 work_done++;
1058         }
1059
1060         __skb_queue_purge(&errq);
1061
1062         work_done -= handle_incoming_queue(queue, &rxq);
1063
1064         xennet_alloc_rx_buffers(queue);
1065
1066         if (work_done < budget) {
1067                 int more_to_do = 0;
1068
1069                 napi_complete_done(napi, work_done);
1070
1071                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
1072                 if (more_to_do)
1073                         napi_schedule(napi);
1074         }
1075
1076         spin_unlock(&queue->rx_lock);
1077
1078         return work_done;
1079 }
1080
1081 static int xennet_change_mtu(struct net_device *dev, int mtu)
1082 {
1083         int max = xennet_can_sg(dev) ? XEN_NETIF_MAX_TX_SIZE : ETH_DATA_LEN;
1084
1085         if (mtu > max)
1086                 return -EINVAL;
1087         dev->mtu = mtu;
1088         return 0;
1089 }
1090
1091 static void xennet_get_stats64(struct net_device *dev,
1092                                struct rtnl_link_stats64 *tot)
1093 {
1094         struct netfront_info *np = netdev_priv(dev);
1095         int cpu;
1096
1097         for_each_possible_cpu(cpu) {
1098                 struct netfront_stats *rx_stats = per_cpu_ptr(np->rx_stats, cpu);
1099                 struct netfront_stats *tx_stats = per_cpu_ptr(np->tx_stats, cpu);
1100                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1101                 unsigned int start;
1102
1103                 do {
1104                         start = u64_stats_fetch_begin_irq(&tx_stats->syncp);
1105                         tx_packets = tx_stats->packets;
1106                         tx_bytes = tx_stats->bytes;
1107                 } while (u64_stats_fetch_retry_irq(&tx_stats->syncp, start));
1108
1109                 do {
1110                         start = u64_stats_fetch_begin_irq(&rx_stats->syncp);
1111                         rx_packets = rx_stats->packets;
1112                         rx_bytes = rx_stats->bytes;
1113                 } while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start));
1114
1115                 tot->rx_packets += rx_packets;
1116                 tot->tx_packets += tx_packets;
1117                 tot->rx_bytes   += rx_bytes;
1118                 tot->tx_bytes   += tx_bytes;
1119         }
1120
1121         tot->rx_errors  = dev->stats.rx_errors;
1122         tot->tx_dropped = dev->stats.tx_dropped;
1123 }
1124
1125 static void xennet_release_tx_bufs(struct netfront_queue *queue)
1126 {
1127         struct sk_buff *skb;
1128         int i;
1129
1130         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1131                 /* Skip over entries which are actually freelist references */
1132                 if (skb_entry_is_link(&queue->tx_skbs[i]))
1133                         continue;
1134
1135                 skb = queue->tx_skbs[i].skb;
1136                 get_page(queue->grant_tx_page[i]);
1137                 gnttab_end_foreign_access(queue->grant_tx_ref[i],
1138                                           GNTMAP_readonly,
1139                                           (unsigned long)page_address(queue->grant_tx_page[i]));
1140                 queue->grant_tx_page[i] = NULL;
1141                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1142                 add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, i);
1143                 dev_kfree_skb_irq(skb);
1144         }
1145 }
1146
1147 static void xennet_release_rx_bufs(struct netfront_queue *queue)
1148 {
1149         int id, ref;
1150
1151         spin_lock_bh(&queue->rx_lock);
1152
1153         for (id = 0; id < NET_RX_RING_SIZE; id++) {
1154                 struct sk_buff *skb;
1155                 struct page *page;
1156
1157                 skb = queue->rx_skbs[id];
1158                 if (!skb)
1159                         continue;
1160
1161                 ref = queue->grant_rx_ref[id];
1162                 if (ref == GRANT_INVALID_REF)
1163                         continue;
1164
1165                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
1166
1167                 /* gnttab_end_foreign_access() needs a page ref until
1168                  * foreign access is ended (which may be deferred).
1169                  */
1170                 get_page(page);
1171                 gnttab_end_foreign_access(ref, 0,
1172                                           (unsigned long)page_address(page));
1173                 queue->grant_rx_ref[id] = GRANT_INVALID_REF;
1174
1175                 kfree_skb(skb);
1176         }
1177
1178         spin_unlock_bh(&queue->rx_lock);
1179 }
1180
1181 static netdev_features_t xennet_fix_features(struct net_device *dev,
1182         netdev_features_t features)
1183 {
1184         struct netfront_info *np = netdev_priv(dev);
1185
1186         if (features & NETIF_F_SG &&
1187             !xenbus_read_unsigned(np->xbdev->otherend, "feature-sg", 0))
1188                 features &= ~NETIF_F_SG;
1189
1190         if (features & NETIF_F_IPV6_CSUM &&
1191             !xenbus_read_unsigned(np->xbdev->otherend,
1192                                   "feature-ipv6-csum-offload", 0))
1193                 features &= ~NETIF_F_IPV6_CSUM;
1194
1195         if (features & NETIF_F_TSO &&
1196             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv4", 0))
1197                 features &= ~NETIF_F_TSO;
1198
1199         if (features & NETIF_F_TSO6 &&
1200             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv6", 0))
1201                 features &= ~NETIF_F_TSO6;
1202
1203         return features;
1204 }
1205
1206 static int xennet_set_features(struct net_device *dev,
1207         netdev_features_t features)
1208 {
1209         if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1210                 netdev_info(dev, "Reducing MTU because no SG offload");
1211                 dev->mtu = ETH_DATA_LEN;
1212         }
1213
1214         return 0;
1215 }
1216
1217 static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1218 {
1219         struct netfront_queue *queue = dev_id;
1220         unsigned long flags;
1221
1222         spin_lock_irqsave(&queue->tx_lock, flags);
1223         xennet_tx_buf_gc(queue);
1224         spin_unlock_irqrestore(&queue->tx_lock, flags);
1225
1226         return IRQ_HANDLED;
1227 }
1228
1229 static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1230 {
1231         struct netfront_queue *queue = dev_id;
1232         struct net_device *dev = queue->info->netdev;
1233
1234         if (likely(netif_carrier_ok(dev) &&
1235                    RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)))
1236                 napi_schedule(&queue->napi);
1237
1238         return IRQ_HANDLED;
1239 }
1240
1241 static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1242 {
1243         xennet_tx_interrupt(irq, dev_id);
1244         xennet_rx_interrupt(irq, dev_id);
1245         return IRQ_HANDLED;
1246 }
1247
1248 #ifdef CONFIG_NET_POLL_CONTROLLER
1249 static void xennet_poll_controller(struct net_device *dev)
1250 {
1251         /* Poll each queue */
1252         struct netfront_info *info = netdev_priv(dev);
1253         unsigned int num_queues = dev->real_num_tx_queues;
1254         unsigned int i;
1255         for (i = 0; i < num_queues; ++i)
1256                 xennet_interrupt(0, &info->queues[i]);
1257 }
1258 #endif
1259
1260 static const struct net_device_ops xennet_netdev_ops = {
1261         .ndo_open            = xennet_open,
1262         .ndo_stop            = xennet_close,
1263         .ndo_start_xmit      = xennet_start_xmit,
1264         .ndo_change_mtu      = xennet_change_mtu,
1265         .ndo_get_stats64     = xennet_get_stats64,
1266         .ndo_set_mac_address = eth_mac_addr,
1267         .ndo_validate_addr   = eth_validate_addr,
1268         .ndo_fix_features    = xennet_fix_features,
1269         .ndo_set_features    = xennet_set_features,
1270         .ndo_select_queue    = xennet_select_queue,
1271 #ifdef CONFIG_NET_POLL_CONTROLLER
1272         .ndo_poll_controller = xennet_poll_controller,
1273 #endif
1274 };
1275
1276 static void xennet_free_netdev(struct net_device *netdev)
1277 {
1278         struct netfront_info *np = netdev_priv(netdev);
1279
1280         free_percpu(np->rx_stats);
1281         free_percpu(np->tx_stats);
1282         free_netdev(netdev);
1283 }
1284
1285 static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1286 {
1287         int err;
1288         struct net_device *netdev;
1289         struct netfront_info *np;
1290
1291         netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues);
1292         if (!netdev)
1293                 return ERR_PTR(-ENOMEM);
1294
1295         np                   = netdev_priv(netdev);
1296         np->xbdev            = dev;
1297
1298         np->queues = NULL;
1299
1300         err = -ENOMEM;
1301         np->rx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1302         if (np->rx_stats == NULL)
1303                 goto exit;
1304         np->tx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1305         if (np->tx_stats == NULL)
1306                 goto exit;
1307
1308         netdev->netdev_ops      = &xennet_netdev_ops;
1309
1310         netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1311                                   NETIF_F_GSO_ROBUST;
1312         netdev->hw_features     = NETIF_F_SG |
1313                                   NETIF_F_IPV6_CSUM |
1314                                   NETIF_F_TSO | NETIF_F_TSO6;
1315
1316         /*
1317          * Assume that all hw features are available for now. This set
1318          * will be adjusted by the call to netdev_update_features() in
1319          * xennet_connect() which is the earliest point where we can
1320          * negotiate with the backend regarding supported features.
1321          */
1322         netdev->features |= netdev->hw_features;
1323
1324         netdev->ethtool_ops = &xennet_ethtool_ops;
1325         netdev->min_mtu = ETH_MIN_MTU;
1326         netdev->max_mtu = XEN_NETIF_MAX_TX_SIZE;
1327         SET_NETDEV_DEV(netdev, &dev->dev);
1328
1329         np->netdev = netdev;
1330
1331         netif_carrier_off(netdev);
1332
1333         xenbus_switch_state(dev, XenbusStateInitialising);
1334         wait_event(module_wq,
1335                    xenbus_read_driver_state(dev->otherend) !=
1336                    XenbusStateClosed &&
1337                    xenbus_read_driver_state(dev->otherend) !=
1338                    XenbusStateUnknown);
1339         return netdev;
1340
1341  exit:
1342         xennet_free_netdev(netdev);
1343         return ERR_PTR(err);
1344 }
1345
1346 /**
1347  * Entry point to this code when a new device is created.  Allocate the basic
1348  * structures and the ring buffers for communication with the backend, and
1349  * inform the backend of the appropriate details for those.
1350  */
1351 static int netfront_probe(struct xenbus_device *dev,
1352                           const struct xenbus_device_id *id)
1353 {
1354         int err;
1355         struct net_device *netdev;
1356         struct netfront_info *info;
1357
1358         netdev = xennet_create_dev(dev);
1359         if (IS_ERR(netdev)) {
1360                 err = PTR_ERR(netdev);
1361                 xenbus_dev_fatal(dev, err, "creating netdev");
1362                 return err;
1363         }
1364
1365         info = netdev_priv(netdev);
1366         dev_set_drvdata(&dev->dev, info);
1367 #ifdef CONFIG_SYSFS
1368         info->netdev->sysfs_groups[0] = &xennet_dev_group;
1369 #endif
1370
1371         return 0;
1372 }
1373
1374 static void xennet_end_access(int ref, void *page)
1375 {
1376         /* This frees the page as a side-effect */
1377         if (ref != GRANT_INVALID_REF)
1378                 gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1379 }
1380
1381 static void xennet_disconnect_backend(struct netfront_info *info)
1382 {
1383         unsigned int i = 0;
1384         unsigned int num_queues = info->netdev->real_num_tx_queues;
1385
1386         netif_carrier_off(info->netdev);
1387
1388         for (i = 0; i < num_queues && info->queues; ++i) {
1389                 struct netfront_queue *queue = &info->queues[i];
1390
1391                 del_timer_sync(&queue->rx_refill_timer);
1392
1393                 if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
1394                         unbind_from_irqhandler(queue->tx_irq, queue);
1395                 if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) {
1396                         unbind_from_irqhandler(queue->tx_irq, queue);
1397                         unbind_from_irqhandler(queue->rx_irq, queue);
1398                 }
1399                 queue->tx_evtchn = queue->rx_evtchn = 0;
1400                 queue->tx_irq = queue->rx_irq = 0;
1401
1402                 if (netif_running(info->netdev))
1403                         napi_synchronize(&queue->napi);
1404
1405                 xennet_release_tx_bufs(queue);
1406                 xennet_release_rx_bufs(queue);
1407                 gnttab_free_grant_references(queue->gref_tx_head);
1408                 gnttab_free_grant_references(queue->gref_rx_head);
1409
1410                 /* End access and free the pages */
1411                 xennet_end_access(queue->tx_ring_ref, queue->tx.sring);
1412                 xennet_end_access(queue->rx_ring_ref, queue->rx.sring);
1413
1414                 queue->tx_ring_ref = GRANT_INVALID_REF;
1415                 queue->rx_ring_ref = GRANT_INVALID_REF;
1416                 queue->tx.sring = NULL;
1417                 queue->rx.sring = NULL;
1418         }
1419 }
1420
1421 /**
1422  * We are reconnecting to the backend, due to a suspend/resume, or a backend
1423  * driver restart.  We tear down our netif structure and recreate it, but
1424  * leave the device-layer structures intact so that this is transparent to the
1425  * rest of the kernel.
1426  */
1427 static int netfront_resume(struct xenbus_device *dev)
1428 {
1429         struct netfront_info *info = dev_get_drvdata(&dev->dev);
1430
1431         dev_dbg(&dev->dev, "%s\n", dev->nodename);
1432
1433         xennet_disconnect_backend(info);
1434         return 0;
1435 }
1436
1437 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1438 {
1439         char *s, *e, *macstr;
1440         int i;
1441
1442         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1443         if (IS_ERR(macstr))
1444                 return PTR_ERR(macstr);
1445
1446         for (i = 0; i < ETH_ALEN; i++) {
1447                 mac[i] = simple_strtoul(s, &e, 16);
1448                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1449                         kfree(macstr);
1450                         return -ENOENT;
1451                 }
1452                 s = e+1;
1453         }
1454
1455         kfree(macstr);
1456         return 0;
1457 }
1458
1459 static int setup_netfront_single(struct netfront_queue *queue)
1460 {
1461         int err;
1462
1463         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1464         if (err < 0)
1465                 goto fail;
1466
1467         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1468                                         xennet_interrupt,
1469                                         0, queue->info->netdev->name, queue);
1470         if (err < 0)
1471                 goto bind_fail;
1472         queue->rx_evtchn = queue->tx_evtchn;
1473         queue->rx_irq = queue->tx_irq = err;
1474
1475         return 0;
1476
1477 bind_fail:
1478         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1479         queue->tx_evtchn = 0;
1480 fail:
1481         return err;
1482 }
1483
1484 static int setup_netfront_split(struct netfront_queue *queue)
1485 {
1486         int err;
1487
1488         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1489         if (err < 0)
1490                 goto fail;
1491         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->rx_evtchn);
1492         if (err < 0)
1493                 goto alloc_rx_evtchn_fail;
1494
1495         snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
1496                  "%s-tx", queue->name);
1497         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1498                                         xennet_tx_interrupt,
1499                                         0, queue->tx_irq_name, queue);
1500         if (err < 0)
1501                 goto bind_tx_fail;
1502         queue->tx_irq = err;
1503
1504         snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
1505                  "%s-rx", queue->name);
1506         err = bind_evtchn_to_irqhandler(queue->rx_evtchn,
1507                                         xennet_rx_interrupt,
1508                                         0, queue->rx_irq_name, queue);
1509         if (err < 0)
1510                 goto bind_rx_fail;
1511         queue->rx_irq = err;
1512
1513         return 0;
1514
1515 bind_rx_fail:
1516         unbind_from_irqhandler(queue->tx_irq, queue);
1517         queue->tx_irq = 0;
1518 bind_tx_fail:
1519         xenbus_free_evtchn(queue->info->xbdev, queue->rx_evtchn);
1520         queue->rx_evtchn = 0;
1521 alloc_rx_evtchn_fail:
1522         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1523         queue->tx_evtchn = 0;
1524 fail:
1525         return err;
1526 }
1527
1528 static int setup_netfront(struct xenbus_device *dev,
1529                         struct netfront_queue *queue, unsigned int feature_split_evtchn)
1530 {
1531         struct xen_netif_tx_sring *txs;
1532         struct xen_netif_rx_sring *rxs;
1533         grant_ref_t gref;
1534         int err;
1535
1536         queue->tx_ring_ref = GRANT_INVALID_REF;
1537         queue->rx_ring_ref = GRANT_INVALID_REF;
1538         queue->rx.sring = NULL;
1539         queue->tx.sring = NULL;
1540
1541         txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1542         if (!txs) {
1543                 err = -ENOMEM;
1544                 xenbus_dev_fatal(dev, err, "allocating tx ring page");
1545                 goto fail;
1546         }
1547         SHARED_RING_INIT(txs);
1548         FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1549
1550         err = xenbus_grant_ring(dev, txs, 1, &gref);
1551         if (err < 0)
1552                 goto grant_tx_ring_fail;
1553         queue->tx_ring_ref = gref;
1554
1555         rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1556         if (!rxs) {
1557                 err = -ENOMEM;
1558                 xenbus_dev_fatal(dev, err, "allocating rx ring page");
1559                 goto alloc_rx_ring_fail;
1560         }
1561         SHARED_RING_INIT(rxs);
1562         FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1563
1564         err = xenbus_grant_ring(dev, rxs, 1, &gref);
1565         if (err < 0)
1566                 goto grant_rx_ring_fail;
1567         queue->rx_ring_ref = gref;
1568
1569         if (feature_split_evtchn)
1570                 err = setup_netfront_split(queue);
1571         /* setup single event channel if
1572          *  a) feature-split-event-channels == 0
1573          *  b) feature-split-event-channels == 1 but failed to setup
1574          */
1575         if (!feature_split_evtchn || (feature_split_evtchn && err))
1576                 err = setup_netfront_single(queue);
1577
1578         if (err)
1579                 goto alloc_evtchn_fail;
1580
1581         return 0;
1582
1583         /* If we fail to setup netfront, it is safe to just revoke access to
1584          * granted pages because backend is not accessing it at this point.
1585          */
1586 alloc_evtchn_fail:
1587         gnttab_end_foreign_access_ref(queue->rx_ring_ref, 0);
1588 grant_rx_ring_fail:
1589         free_page((unsigned long)rxs);
1590 alloc_rx_ring_fail:
1591         gnttab_end_foreign_access_ref(queue->tx_ring_ref, 0);
1592 grant_tx_ring_fail:
1593         free_page((unsigned long)txs);
1594 fail:
1595         return err;
1596 }
1597
1598 /* Queue-specific initialisation
1599  * This used to be done in xennet_create_dev() but must now
1600  * be run per-queue.
1601  */
1602 static int xennet_init_queue(struct netfront_queue *queue)
1603 {
1604         unsigned short i;
1605         int err = 0;
1606         char *devid;
1607
1608         spin_lock_init(&queue->tx_lock);
1609         spin_lock_init(&queue->rx_lock);
1610
1611         timer_setup(&queue->rx_refill_timer, rx_refill_timeout, 0);
1612
1613         devid = strrchr(queue->info->xbdev->nodename, '/') + 1;
1614         snprintf(queue->name, sizeof(queue->name), "vif%s-q%u",
1615                  devid, queue->id);
1616
1617         /* Initialise tx_skbs as a free chain containing every entry. */
1618         queue->tx_skb_freelist = 0;
1619         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1620                 skb_entry_set_link(&queue->tx_skbs[i], i+1);
1621                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1622                 queue->grant_tx_page[i] = NULL;
1623         }
1624
1625         /* Clear out rx_skbs */
1626         for (i = 0; i < NET_RX_RING_SIZE; i++) {
1627                 queue->rx_skbs[i] = NULL;
1628                 queue->grant_rx_ref[i] = GRANT_INVALID_REF;
1629         }
1630
1631         /* A grant for every tx ring slot */
1632         if (gnttab_alloc_grant_references(NET_TX_RING_SIZE,
1633                                           &queue->gref_tx_head) < 0) {
1634                 pr_alert("can't alloc tx grant refs\n");
1635                 err = -ENOMEM;
1636                 goto exit;
1637         }
1638
1639         /* A grant for every rx ring slot */
1640         if (gnttab_alloc_grant_references(NET_RX_RING_SIZE,
1641                                           &queue->gref_rx_head) < 0) {
1642                 pr_alert("can't alloc rx grant refs\n");
1643                 err = -ENOMEM;
1644                 goto exit_free_tx;
1645         }
1646
1647         return 0;
1648
1649  exit_free_tx:
1650         gnttab_free_grant_references(queue->gref_tx_head);
1651  exit:
1652         return err;
1653 }
1654
1655 static int write_queue_xenstore_keys(struct netfront_queue *queue,
1656                            struct xenbus_transaction *xbt, int write_hierarchical)
1657 {
1658         /* Write the queue-specific keys into XenStore in the traditional
1659          * way for a single queue, or in a queue subkeys for multiple
1660          * queues.
1661          */
1662         struct xenbus_device *dev = queue->info->xbdev;
1663         int err;
1664         const char *message;
1665         char *path;
1666         size_t pathsize;
1667
1668         /* Choose the correct place to write the keys */
1669         if (write_hierarchical) {
1670                 pathsize = strlen(dev->nodename) + 10;
1671                 path = kzalloc(pathsize, GFP_KERNEL);
1672                 if (!path) {
1673                         err = -ENOMEM;
1674                         message = "out of memory while writing ring references";
1675                         goto error;
1676                 }
1677                 snprintf(path, pathsize, "%s/queue-%u",
1678                                 dev->nodename, queue->id);
1679         } else {
1680                 path = (char *)dev->nodename;
1681         }
1682
1683         /* Write ring references */
1684         err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u",
1685                         queue->tx_ring_ref);
1686         if (err) {
1687                 message = "writing tx-ring-ref";
1688                 goto error;
1689         }
1690
1691         err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u",
1692                         queue->rx_ring_ref);
1693         if (err) {
1694                 message = "writing rx-ring-ref";
1695                 goto error;
1696         }
1697
1698         /* Write event channels; taking into account both shared
1699          * and split event channel scenarios.
1700          */
1701         if (queue->tx_evtchn == queue->rx_evtchn) {
1702                 /* Shared event channel */
1703                 err = xenbus_printf(*xbt, path,
1704                                 "event-channel", "%u", queue->tx_evtchn);
1705                 if (err) {
1706                         message = "writing event-channel";
1707                         goto error;
1708                 }
1709         } else {
1710                 /* Split event channels */
1711                 err = xenbus_printf(*xbt, path,
1712                                 "event-channel-tx", "%u", queue->tx_evtchn);
1713                 if (err) {
1714                         message = "writing event-channel-tx";
1715                         goto error;
1716                 }
1717
1718                 err = xenbus_printf(*xbt, path,
1719                                 "event-channel-rx", "%u", queue->rx_evtchn);
1720                 if (err) {
1721                         message = "writing event-channel-rx";
1722                         goto error;
1723                 }
1724         }
1725
1726         if (write_hierarchical)
1727                 kfree(path);
1728         return 0;
1729
1730 error:
1731         if (write_hierarchical)
1732                 kfree(path);
1733         xenbus_dev_fatal(dev, err, "%s", message);
1734         return err;
1735 }
1736
1737 static void xennet_destroy_queues(struct netfront_info *info)
1738 {
1739         unsigned int i;
1740
1741         for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
1742                 struct netfront_queue *queue = &info->queues[i];
1743
1744                 if (netif_running(info->netdev))
1745                         napi_disable(&queue->napi);
1746                 netif_napi_del(&queue->napi);
1747         }
1748
1749         kfree(info->queues);
1750         info->queues = NULL;
1751 }
1752
1753 static int xennet_create_queues(struct netfront_info *info,
1754                                 unsigned int *num_queues)
1755 {
1756         unsigned int i;
1757         int ret;
1758
1759         info->queues = kcalloc(*num_queues, sizeof(struct netfront_queue),
1760                                GFP_KERNEL);
1761         if (!info->queues)
1762                 return -ENOMEM;
1763
1764         for (i = 0; i < *num_queues; i++) {
1765                 struct netfront_queue *queue = &info->queues[i];
1766
1767                 queue->id = i;
1768                 queue->info = info;
1769
1770                 ret = xennet_init_queue(queue);
1771                 if (ret < 0) {
1772                         dev_warn(&info->xbdev->dev,
1773                                  "only created %d queues\n", i);
1774                         *num_queues = i;
1775                         break;
1776                 }
1777
1778                 netif_napi_add(queue->info->netdev, &queue->napi,
1779                                xennet_poll, 64);
1780                 if (netif_running(info->netdev))
1781                         napi_enable(&queue->napi);
1782         }
1783
1784         netif_set_real_num_tx_queues(info->netdev, *num_queues);
1785
1786         if (*num_queues == 0) {
1787                 dev_err(&info->xbdev->dev, "no queues\n");
1788                 return -EINVAL;
1789         }
1790         return 0;
1791 }
1792
1793 /* Common code used when first setting up, and when resuming. */
1794 static int talk_to_netback(struct xenbus_device *dev,
1795                            struct netfront_info *info)
1796 {
1797         const char *message;
1798         struct xenbus_transaction xbt;
1799         int err;
1800         unsigned int feature_split_evtchn;
1801         unsigned int i = 0;
1802         unsigned int max_queues = 0;
1803         struct netfront_queue *queue = NULL;
1804         unsigned int num_queues = 1;
1805
1806         info->netdev->irq = 0;
1807
1808         /* Check if backend supports multiple queues */
1809         max_queues = xenbus_read_unsigned(info->xbdev->otherend,
1810                                           "multi-queue-max-queues", 1);
1811         num_queues = min(max_queues, xennet_max_queues);
1812
1813         /* Check feature-split-event-channels */
1814         feature_split_evtchn = xenbus_read_unsigned(info->xbdev->otherend,
1815                                         "feature-split-event-channels", 0);
1816
1817         /* Read mac addr. */
1818         err = xen_net_read_mac(dev, info->netdev->dev_addr);
1819         if (err) {
1820                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1821                 goto out_unlocked;
1822         }
1823
1824         rtnl_lock();
1825         if (info->queues)
1826                 xennet_destroy_queues(info);
1827
1828         err = xennet_create_queues(info, &num_queues);
1829         if (err < 0) {
1830                 xenbus_dev_fatal(dev, err, "creating queues");
1831                 kfree(info->queues);
1832                 info->queues = NULL;
1833                 goto out;
1834         }
1835         rtnl_unlock();
1836
1837         /* Create shared ring, alloc event channel -- for each queue */
1838         for (i = 0; i < num_queues; ++i) {
1839                 queue = &info->queues[i];
1840                 err = setup_netfront(dev, queue, feature_split_evtchn);
1841                 if (err)
1842                         goto destroy_ring;
1843         }
1844
1845 again:
1846         err = xenbus_transaction_start(&xbt);
1847         if (err) {
1848                 xenbus_dev_fatal(dev, err, "starting transaction");
1849                 goto destroy_ring;
1850         }
1851
1852         if (xenbus_exists(XBT_NIL,
1853                           info->xbdev->otherend, "multi-queue-max-queues")) {
1854                 /* Write the number of queues */
1855                 err = xenbus_printf(xbt, dev->nodename,
1856                                     "multi-queue-num-queues", "%u", num_queues);
1857                 if (err) {
1858                         message = "writing multi-queue-num-queues";
1859                         goto abort_transaction_no_dev_fatal;
1860                 }
1861         }
1862
1863         if (num_queues == 1) {
1864                 err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
1865                 if (err)
1866                         goto abort_transaction_no_dev_fatal;
1867         } else {
1868                 /* Write the keys for each queue */
1869                 for (i = 0; i < num_queues; ++i) {
1870                         queue = &info->queues[i];
1871                         err = write_queue_xenstore_keys(queue, &xbt, 1); /* hierarchical */
1872                         if (err)
1873                                 goto abort_transaction_no_dev_fatal;
1874                 }
1875         }
1876
1877         /* The remaining keys are not queue-specific */
1878         err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1879                             1);
1880         if (err) {
1881                 message = "writing request-rx-copy";
1882                 goto abort_transaction;
1883         }
1884
1885         err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1886         if (err) {
1887                 message = "writing feature-rx-notify";
1888                 goto abort_transaction;
1889         }
1890
1891         err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1892         if (err) {
1893                 message = "writing feature-sg";
1894                 goto abort_transaction;
1895         }
1896
1897         err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1898         if (err) {
1899                 message = "writing feature-gso-tcpv4";
1900                 goto abort_transaction;
1901         }
1902
1903         err = xenbus_write(xbt, dev->nodename, "feature-gso-tcpv6", "1");
1904         if (err) {
1905                 message = "writing feature-gso-tcpv6";
1906                 goto abort_transaction;
1907         }
1908
1909         err = xenbus_write(xbt, dev->nodename, "feature-ipv6-csum-offload",
1910                            "1");
1911         if (err) {
1912                 message = "writing feature-ipv6-csum-offload";
1913                 goto abort_transaction;
1914         }
1915
1916         err = xenbus_transaction_end(xbt, 0);
1917         if (err) {
1918                 if (err == -EAGAIN)
1919                         goto again;
1920                 xenbus_dev_fatal(dev, err, "completing transaction");
1921                 goto destroy_ring;
1922         }
1923
1924         return 0;
1925
1926  abort_transaction:
1927         xenbus_dev_fatal(dev, err, "%s", message);
1928 abort_transaction_no_dev_fatal:
1929         xenbus_transaction_end(xbt, 1);
1930  destroy_ring:
1931         xennet_disconnect_backend(info);
1932         rtnl_lock();
1933         xennet_destroy_queues(info);
1934  out:
1935         rtnl_unlock();
1936 out_unlocked:
1937         device_unregister(&dev->dev);
1938         return err;
1939 }
1940
1941 static int xennet_connect(struct net_device *dev)
1942 {
1943         struct netfront_info *np = netdev_priv(dev);
1944         unsigned int num_queues = 0;
1945         int err;
1946         unsigned int j = 0;
1947         struct netfront_queue *queue = NULL;
1948
1949         if (!xenbus_read_unsigned(np->xbdev->otherend, "feature-rx-copy", 0)) {
1950                 dev_info(&dev->dev,
1951                          "backend does not support copying receive path\n");
1952                 return -ENODEV;
1953         }
1954
1955         err = talk_to_netback(np->xbdev, np);
1956         if (err)
1957                 return err;
1958
1959         /* talk_to_netback() sets the correct number of queues */
1960         num_queues = dev->real_num_tx_queues;
1961
1962         if (dev->reg_state == NETREG_UNINITIALIZED) {
1963                 err = register_netdev(dev);
1964                 if (err) {
1965                         pr_warn("%s: register_netdev err=%d\n", __func__, err);
1966                         device_unregister(&np->xbdev->dev);
1967                         return err;
1968                 }
1969         }
1970
1971         rtnl_lock();
1972         netdev_update_features(dev);
1973         rtnl_unlock();
1974
1975         /*
1976          * All public and private state should now be sane.  Get
1977          * ready to start sending and receiving packets and give the driver
1978          * domain a kick because we've probably just requeued some
1979          * packets.
1980          */
1981         netif_carrier_on(np->netdev);
1982         for (j = 0; j < num_queues; ++j) {
1983                 queue = &np->queues[j];
1984
1985                 notify_remote_via_irq(queue->tx_irq);
1986                 if (queue->tx_irq != queue->rx_irq)
1987                         notify_remote_via_irq(queue->rx_irq);
1988
1989                 spin_lock_irq(&queue->tx_lock);
1990                 xennet_tx_buf_gc(queue);
1991                 spin_unlock_irq(&queue->tx_lock);
1992
1993                 spin_lock_bh(&queue->rx_lock);
1994                 xennet_alloc_rx_buffers(queue);
1995                 spin_unlock_bh(&queue->rx_lock);
1996         }
1997
1998         return 0;
1999 }
2000
2001 /**
2002  * Callback received when the backend's state changes.
2003  */
2004 static void netback_changed(struct xenbus_device *dev,
2005                             enum xenbus_state backend_state)
2006 {
2007         struct netfront_info *np = dev_get_drvdata(&dev->dev);
2008         struct net_device *netdev = np->netdev;
2009
2010         dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
2011
2012         wake_up_all(&module_wq);
2013
2014         switch (backend_state) {
2015         case XenbusStateInitialising:
2016         case XenbusStateInitialised:
2017         case XenbusStateReconfiguring:
2018         case XenbusStateReconfigured:
2019         case XenbusStateUnknown:
2020                 break;
2021
2022         case XenbusStateInitWait:
2023                 if (dev->state != XenbusStateInitialising)
2024                         break;
2025                 if (xennet_connect(netdev) != 0)
2026                         break;
2027                 xenbus_switch_state(dev, XenbusStateConnected);
2028                 break;
2029
2030         case XenbusStateConnected:
2031                 netdev_notify_peers(netdev);
2032                 break;
2033
2034         case XenbusStateClosed:
2035                 if (dev->state == XenbusStateClosed)
2036                         break;
2037                 /* Missed the backend's CLOSING state -- fallthrough */
2038         case XenbusStateClosing:
2039                 xenbus_frontend_closed(dev);
2040                 break;
2041         }
2042 }
2043
2044 static const struct xennet_stat {
2045         char name[ETH_GSTRING_LEN];
2046         u16 offset;
2047 } xennet_stats[] = {
2048         {
2049                 "rx_gso_checksum_fixup",
2050                 offsetof(struct netfront_info, rx_gso_checksum_fixup)
2051         },
2052 };
2053
2054 static int xennet_get_sset_count(struct net_device *dev, int string_set)
2055 {
2056         switch (string_set) {
2057         case ETH_SS_STATS:
2058                 return ARRAY_SIZE(xennet_stats);
2059         default:
2060                 return -EINVAL;
2061         }
2062 }
2063
2064 static void xennet_get_ethtool_stats(struct net_device *dev,
2065                                      struct ethtool_stats *stats, u64 * data)
2066 {
2067         void *np = netdev_priv(dev);
2068         int i;
2069
2070         for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2071                 data[i] = atomic_read((atomic_t *)(np + xennet_stats[i].offset));
2072 }
2073
2074 static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
2075 {
2076         int i;
2077
2078         switch (stringset) {
2079         case ETH_SS_STATS:
2080                 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2081                         memcpy(data + i * ETH_GSTRING_LEN,
2082                                xennet_stats[i].name, ETH_GSTRING_LEN);
2083                 break;
2084         }
2085 }
2086
2087 static const struct ethtool_ops xennet_ethtool_ops =
2088 {
2089         .get_link = ethtool_op_get_link,
2090
2091         .get_sset_count = xennet_get_sset_count,
2092         .get_ethtool_stats = xennet_get_ethtool_stats,
2093         .get_strings = xennet_get_strings,
2094 };
2095
2096 #ifdef CONFIG_SYSFS
2097 static ssize_t show_rxbuf(struct device *dev,
2098                           struct device_attribute *attr, char *buf)
2099 {
2100         return sprintf(buf, "%lu\n", NET_RX_RING_SIZE);
2101 }
2102
2103 static ssize_t store_rxbuf(struct device *dev,
2104                            struct device_attribute *attr,
2105                            const char *buf, size_t len)
2106 {
2107         char *endp;
2108         unsigned long target;
2109
2110         if (!capable(CAP_NET_ADMIN))
2111                 return -EPERM;
2112
2113         target = simple_strtoul(buf, &endp, 0);
2114         if (endp == buf)
2115                 return -EBADMSG;
2116
2117         /* rxbuf_min and rxbuf_max are no longer configurable. */
2118
2119         return len;
2120 }
2121
2122 static DEVICE_ATTR(rxbuf_min, 0644, show_rxbuf, store_rxbuf);
2123 static DEVICE_ATTR(rxbuf_max, 0644, show_rxbuf, store_rxbuf);
2124 static DEVICE_ATTR(rxbuf_cur, 0444, show_rxbuf, NULL);
2125
2126 static struct attribute *xennet_dev_attrs[] = {
2127         &dev_attr_rxbuf_min.attr,
2128         &dev_attr_rxbuf_max.attr,
2129         &dev_attr_rxbuf_cur.attr,
2130         NULL
2131 };
2132
2133 static const struct attribute_group xennet_dev_group = {
2134         .attrs = xennet_dev_attrs
2135 };
2136 #endif /* CONFIG_SYSFS */
2137
2138 static int xennet_remove(struct xenbus_device *dev)
2139 {
2140         struct netfront_info *info = dev_get_drvdata(&dev->dev);
2141
2142         dev_dbg(&dev->dev, "%s\n", dev->nodename);
2143
2144         if (xenbus_read_driver_state(dev->otherend) != XenbusStateClosed) {
2145                 xenbus_switch_state(dev, XenbusStateClosing);
2146                 wait_event(module_wq,
2147                            xenbus_read_driver_state(dev->otherend) ==
2148                            XenbusStateClosing ||
2149                            xenbus_read_driver_state(dev->otherend) ==
2150                            XenbusStateUnknown);
2151
2152                 xenbus_switch_state(dev, XenbusStateClosed);
2153                 wait_event(module_wq,
2154                            xenbus_read_driver_state(dev->otherend) ==
2155                            XenbusStateClosed ||
2156                            xenbus_read_driver_state(dev->otherend) ==
2157                            XenbusStateUnknown);
2158         }
2159
2160         xennet_disconnect_backend(info);
2161
2162         if (info->netdev->reg_state == NETREG_REGISTERED)
2163                 unregister_netdev(info->netdev);
2164
2165         if (info->queues) {
2166                 rtnl_lock();
2167                 xennet_destroy_queues(info);
2168                 rtnl_unlock();
2169         }
2170         xennet_free_netdev(info->netdev);
2171
2172         return 0;
2173 }
2174
2175 static const struct xenbus_device_id netfront_ids[] = {
2176         { "vif" },
2177         { "" }
2178 };
2179
2180 static struct xenbus_driver netfront_driver = {
2181         .ids = netfront_ids,
2182         .probe = netfront_probe,
2183         .remove = xennet_remove,
2184         .resume = netfront_resume,
2185         .otherend_changed = netback_changed,
2186 };
2187
2188 static int __init netif_init(void)
2189 {
2190         if (!xen_domain())
2191                 return -ENODEV;
2192
2193         if (!xen_has_pv_nic_devices())
2194                 return -ENODEV;
2195
2196         pr_info("Initialising Xen virtual ethernet driver\n");
2197
2198         /* Allow as many queues as there are CPUs inut max. 8 if user has not
2199          * specified a value.
2200          */
2201         if (xennet_max_queues == 0)
2202                 xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
2203                                           num_online_cpus());
2204
2205         return xenbus_register_frontend(&netfront_driver);
2206 }
2207 module_init(netif_init);
2208
2209
2210 static void __exit netif_exit(void)
2211 {
2212         xenbus_unregister_driver(&netfront_driver);
2213 }
2214 module_exit(netif_exit);
2215
2216 MODULE_DESCRIPTION("Xen virtual network device frontend");
2217 MODULE_LICENSE("GPL");
2218 MODULE_ALIAS("xen:vif");
2219 MODULE_ALIAS("xennet");