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 #define XENNET_TIMEOUT  (5 * HZ)
  67
  68 static const struct ethtool_ops xennet_ethtool_ops;
  69
  70 struct netfront_cb {
  71         int pull_to;
  72 };
  73
  74 #define NETFRONT_SKB_CB(skb)    ((struct netfront_cb *)((skb)->cb))
  75
  76 #define RX_COPY_THRESHOLD 256
  77
  78 #define GRANT_INVALID_REF       0
  79
  80 #define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE)
  81 #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, XEN_PAGE_SIZE)
  82
  83 /* Minimum number of Rx slots (includes slot for GSO metadata). */
  84 #define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1)
  85
  86 /* Queue name is interface name with "-qNNN" appended */
  87 #define QUEUE_NAME_SIZE (IFNAMSIZ + 6)
  88
  89 /* IRQ name is queue name with "-tx" or "-rx" appended */
  90 #define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
  91
  92 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
  93
  94 struct netfront_stats {
  95         u64                     packets;
  96         u64                     bytes;
  97         struct u64_stats_sync   syncp;
  98 };
  99
 100 struct netfront_info;
 101
 102 struct netfront_queue {
 103         unsigned int id; /* Queue ID, 0-based */
 104         char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
 105         struct netfront_info *info;
 106
 107         struct napi_struct napi;
 108
 109         /* Split event channels support, tx_* == rx_* when using
 110          * single event channel.
 111          */
 112         unsigned int tx_evtchn, rx_evtchn;
 113         unsigned int tx_irq, rx_irq;
 114         /* Only used when split event channels support is enabled */
 115         char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
 116         char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
 117
 118         spinlock_t   tx_lock;
 119         struct xen_netif_tx_front_ring tx;
 120         int tx_ring_ref;
 121
 122         /*
 123          * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
 124          * are linked from tx_skb_freelist through skb_entry.link.
 125          *
 126          *  NB. Freelist index entries are always going to be less than
 127          *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
 128          *  greater than PAGE_OFFSET: we use this property to distinguish
 129          *  them.
 130          */
 131         union skb_entry {
 132                 struct sk_buff *skb;
 133                 unsigned long link;
 134         } tx_skbs[NET_TX_RING_SIZE];
 135         grant_ref_t gref_tx_head;
 136         grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
 137         struct page *grant_tx_page[NET_TX_RING_SIZE];
 138         unsigned tx_skb_freelist;
 139
 140         spinlock_t   rx_lock ____cacheline_aligned_in_smp;
 141         struct xen_netif_rx_front_ring rx;
 142         int rx_ring_ref;
 143
 144         struct timer_list rx_refill_timer;
 145
 146         struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
 147         grant_ref_t gref_rx_head;
 148         grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
 149 };
 150
 151 struct netfront_info {
 152         struct list_head list;
 153         struct net_device *netdev;
 154
 155         struct xenbus_device *xbdev;
 156
 157         /* Multi-queue support */
 158         struct netfront_queue *queues;
 159
 160         /* Statistics */
 161         struct netfront_stats __percpu *rx_stats;
 162         struct netfront_stats __percpu *tx_stats;
 163
 164         atomic_t rx_gso_checksum_fixup;
 165 };
 166
 167 struct netfront_rx_info {
 168         struct xen_netif_rx_response rx;
 169         struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
 170 };
 171
 172 static void skb_entry_set_link(union skb_entry *list, unsigned short id)
 173 {
 174         list->link = id;
 175 }
 176
 177 static int skb_entry_is_link(const union skb_entry *list)
 178 {
 179         BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
 180         return (unsigned long)list->skb < PAGE_OFFSET;
 181 }
 182
 183 /*
 184  * Access macros for acquiring freeing slots in tx_skbs[].
 185  */
 186
 187 static void add_id_to_freelist(unsigned *head, union skb_entry *list,
 188                                unsigned short id)
 189 {
 190         skb_entry_set_link(&list[id], *head);
 191         *head = id;
 192 }
 193
 194 static unsigned short get_id_from_freelist(unsigned *head,
 195                                            union skb_entry *list)
 196 {
 197         unsigned int id = *head;
 198         *head = list[id].link;
 199         return id;
 200 }
 201
 202 static int xennet_rxidx(RING_IDX idx)
 203 {
 204         return idx & (NET_RX_RING_SIZE - 1);
 205 }
 206
 207 static struct sk_buff *xennet_get_rx_skb(struct netfront_queue *queue,
 208                                          RING_IDX ri)
 209 {
 210         int i = xennet_rxidx(ri);
 211         struct sk_buff *skb = queue->rx_skbs[i];
 212         queue->rx_skbs[i] = NULL;
 213         return skb;
 214 }
 215
 216 static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
 217                                             RING_IDX ri)
 218 {
 219         int i = xennet_rxidx(ri);
 220         grant_ref_t ref = queue->grant_rx_ref[i];
 221         queue->grant_rx_ref[i] = GRANT_INVALID_REF;
 222         return ref;
 223 }
 224
 225 #ifdef CONFIG_SYSFS
 226 static const struct attribute_group xennet_dev_group;
 227 #endif
 228
 229 static bool xennet_can_sg(struct net_device *dev)
 230 {
 231         return dev->features & NETIF_F_SG;
 232 }
 233
 234
 235 static void rx_refill_timeout(unsigned long data)
 236 {
 237         struct netfront_queue *queue = (struct netfront_queue *)data;
 238         napi_schedule(&queue->napi);
 239 }
 240
 241 static int netfront_tx_slot_available(struct netfront_queue *queue)
 242 {
 243         return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) <
 244                 (NET_TX_RING_SIZE - XEN_NETIF_NR_SLOTS_MIN - 1);
 245 }
 246
 247 static void xennet_maybe_wake_tx(struct netfront_queue *queue)
 248 {
 249         struct net_device *dev = queue->info->netdev;
 250         struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, queue->id);
 251
 252         if (unlikely(netif_tx_queue_stopped(dev_queue)) &&
 253             netfront_tx_slot_available(queue) &&
 254             likely(netif_running(dev)))
 255                 netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
 256 }
 257
 258
 259 static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
 260 {
 261         struct sk_buff *skb;
 262         struct page *page;
 263
 264         skb = __netdev_alloc_skb(queue->info->netdev,
 265                                  RX_COPY_THRESHOLD + NET_IP_ALIGN,
 266                                  GFP_ATOMIC | __GFP_NOWARN);
 267         if (unlikely(!skb))
 268                 return NULL;
 269
 270         page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 271         if (!page) {
 272                 kfree_skb(skb);
 273                 return NULL;
 274         }
 275         skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE);
 276
 277         /* Align ip header to a 16 bytes boundary */
 278         skb_reserve(skb, NET_IP_ALIGN);
 279         skb->dev = queue->info->netdev;
 280
 281         return skb;
 282 }
 283
 284
 285 static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
 286 {
 287         RING_IDX req_prod = queue->rx.req_prod_pvt;
 288         int notify;
 289         int err = 0;
 290
 291         if (unlikely(!netif_carrier_ok(queue->info->netdev)))
 292                 return;
 293
 294         for (req_prod = queue->rx.req_prod_pvt;
 295              req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE;
 296              req_prod++) {
 297                 struct sk_buff *skb;
 298                 unsigned short id;
 299                 grant_ref_t ref;
 300                 struct page *page;
 301                 struct xen_netif_rx_request *req;
 302
 303                 skb = xennet_alloc_one_rx_buffer(queue);
 304                 if (!skb) {
 305                         err = -ENOMEM;
 306                         break;
 307                 }
 308
 309                 id = xennet_rxidx(req_prod);
 310
 311                 BUG_ON(queue->rx_skbs[id]);
 312                 queue->rx_skbs[id] = skb;
 313
 314                 ref = gnttab_claim_grant_reference(&queue->gref_rx_head);
 315                 WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 316                 queue->grant_rx_ref[id] = ref;
 317
 318                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
 319
 320                 req = RING_GET_REQUEST(&queue->rx, req_prod);
 321                 gnttab_page_grant_foreign_access_ref_one(ref,
 322                                                          queue->info->xbdev->otherend_id,
 323                                                          page,
 324                                                          0);
 325                 req->id = id;
 326                 req->gref = ref;
 327         }
 328
 329         queue->rx.req_prod_pvt = req_prod;
 330
 331         /* Try again later if there are not enough requests or skb allocation
 332          * failed.
 333          * Enough requests is quantified as the sum of newly created slots and
 334          * the unconsumed slots at the backend.
 335          */
 336         if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN ||
 337             unlikely(err)) {
 338                 mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10));
 339                 return;
 340         }
 341
 342         wmb();          /* barrier so backend seens requests */
 343
 344         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify);
 345         if (notify)
 346                 notify_remote_via_irq(queue->rx_irq);
 347 }
 348
 349 static int xennet_open(struct net_device *dev)
 350 {
 351         struct netfront_info *np = netdev_priv(dev);
 352         unsigned int num_queues = dev->real_num_tx_queues;
 353         unsigned int i = 0;
 354         struct netfront_queue *queue = NULL;
 355
 356         if (!np->queues)
 357                 return -ENODEV;
 358
 359         for (i = 0; i < num_queues; ++i) {
 360                 queue = &np->queues[i];
 361                 napi_enable(&queue->napi);
 362
 363                 spin_lock_bh(&queue->rx_lock);
 364                 if (netif_carrier_ok(dev)) {
 365                         xennet_alloc_rx_buffers(queue);
 366                         queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
 367                         if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
 368                                 napi_schedule(&queue->napi);
 369                 }
 370                 spin_unlock_bh(&queue->rx_lock);
 371         }
 372
 373         netif_tx_start_all_queues(dev);
 374
 375         return 0;
 376 }
 377
 378 static void xennet_tx_buf_gc(struct netfront_queue *queue)
 379 {
 380         RING_IDX cons, prod;
 381         unsigned short id;
 382         struct sk_buff *skb;
 383         bool more_to_do;
 384
 385         BUG_ON(!netif_carrier_ok(queue->info->netdev));
 386
 387         do {
 388                 prod = queue->tx.sring->rsp_prod;
 389                 rmb(); /* Ensure we see responses up to 'rp'. */
 390
 391                 for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
 392                         struct xen_netif_tx_response *txrsp;
 393
 394                         txrsp = RING_GET_RESPONSE(&queue->tx, cons);
 395                         if (txrsp->status == XEN_NETIF_RSP_NULL)
 396                                 continue;
 397
 398                         id  = txrsp->id;
 399                         skb = queue->tx_skbs[id].skb;
 400                         if (unlikely(gnttab_query_foreign_access(
 401                                 queue->grant_tx_ref[id]) != 0)) {
 402                                 pr_alert("%s: warning -- grant still in use by backend domain\n",
 403                                          __func__);
 404                                 BUG();
 405                         }
 406                         gnttab_end_foreign_access_ref(
 407                                 queue->grant_tx_ref[id], GNTMAP_readonly);
 408                         gnttab_release_grant_reference(
 409                                 &queue->gref_tx_head, queue->grant_tx_ref[id]);
 410                         queue->grant_tx_ref[id] = GRANT_INVALID_REF;
 411                         queue->grant_tx_page[id] = NULL;
 412                         add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, id);
 413                         dev_kfree_skb_irq(skb);
 414                 }
 415
 416                 queue->tx.rsp_cons = prod;
 417
 418                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->tx, more_to_do);
 419         } while (more_to_do);
 420
 421         xennet_maybe_wake_tx(queue);
 422 }
 423
 424 struct xennet_gnttab_make_txreq {
 425         struct netfront_queue *queue;
 426         struct sk_buff *skb;
 427         struct page *page;
 428         struct xen_netif_tx_request *tx; /* Last request */
 429         unsigned int size;
 430 };
 431
 432 static void xennet_tx_setup_grant(unsigned long gfn, unsigned int offset,
 433                                   unsigned int len, void *data)
 434 {
 435         struct xennet_gnttab_make_txreq *info = data;
 436         unsigned int id;
 437         struct xen_netif_tx_request *tx;
 438         grant_ref_t ref;
 439         /* convenient aliases */
 440         struct page *page = info->page;
 441         struct netfront_queue *queue = info->queue;
 442         struct sk_buff *skb = info->skb;
 443
 444         id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
 445         tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 446         ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
 447         WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 448
 449         gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
 450                                         gfn, GNTMAP_readonly);
 451
 452         queue->tx_skbs[id].skb = skb;
 453         queue->grant_tx_page[id] = page;
 454         queue->grant_tx_ref[id] = ref;
 455
 456         tx->id = id;
 457         tx->gref = ref;
 458         tx->offset = offset;
 459         tx->size = len;
 460         tx->flags = 0;
 461
 462         info->tx = tx;
 463         info->size += tx->size;
 464 }
 465
 466 static struct xen_netif_tx_request *xennet_make_first_txreq(
 467         struct netfront_queue *queue, struct sk_buff *skb,
 468         struct page *page, unsigned int offset, unsigned int len)
 469 {
 470         struct xennet_gnttab_make_txreq info = {
 471                 .queue = queue,
 472                 .skb = skb,
 473                 .page = page,
 474                 .size = 0,
 475         };
 476
 477         gnttab_for_one_grant(page, offset, len, xennet_tx_setup_grant, &info);
 478
 479         return info.tx;
 480 }
 481
 482 static void xennet_make_one_txreq(unsigned long gfn, unsigned int offset,
 483                                   unsigned int len, void *data)
 484 {
 485         struct xennet_gnttab_make_txreq *info = data;
 486
 487         info->tx->flags |= XEN_NETTXF_more_data;
 488         skb_get(info->skb);
 489         xennet_tx_setup_grant(gfn, offset, len, data);
 490 }
 491
 492 static struct xen_netif_tx_request *xennet_make_txreqs(
 493         struct netfront_queue *queue, struct xen_netif_tx_request *tx,
 494         struct sk_buff *skb, struct page *page,
 495         unsigned int offset, unsigned int len)
 496 {
 497         struct xennet_gnttab_make_txreq info = {
 498                 .queue = queue,
 499                 .skb = skb,
 500                 .tx = tx,
 501         };
 502
 503         /* Skip unused frames from start of page */
 504         page += offset >> PAGE_SHIFT;
 505         offset &= ~PAGE_MASK;
 506
 507         while (len) {
 508                 info.page = page;
 509                 info.size = 0;
 510
 511                 gnttab_foreach_grant_in_range(page, offset, len,
 512                                               xennet_make_one_txreq,
 513                                               &info);
 514
 515                 page++;
 516                 offset = 0;
 517                 len -= info.size;
 518         }
 519
 520         return info.tx;
 521 }
 522
 523 /*
 524  * Count how many ring slots are required to send this skb. Each frag
 525  * might be a compound page.
 526  */
 527 static int xennet_count_skb_slots(struct sk_buff *skb)
 528 {
 529         int i, frags = skb_shinfo(skb)->nr_frags;
 530         int slots;
 531
 532         slots = gnttab_count_grant(offset_in_page(skb->data),
 533                                    skb_headlen(skb));
 534
 535         for (i = 0; i < frags; i++) {
 536                 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 537                 unsigned long size = skb_frag_size(frag);
 538                 unsigned long offset = frag->page_offset;
 539
 540                 /* Skip unused frames from start of page */
 541                 offset &= ~PAGE_MASK;
 542
 543                 slots += gnttab_count_grant(offset, size);
 544         }
 545
 546         return slots;
 547 }
 548
 549 static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
 550                                void *accel_priv, select_queue_fallback_t fallback)
 551 {
 552         unsigned int num_queues = dev->real_num_tx_queues;
 553         u32 hash;
 554         u16 queue_idx;
 555
 556         /* First, check if there is only one queue */
 557         if (num_queues == 1) {
 558                 queue_idx = 0;
 559         } else {
 560                 hash = skb_get_hash(skb);
 561                 queue_idx = hash % num_queues;
 562         }
 563
 564         return queue_idx;
 565 }
 566
 567 #define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
 568
 569 static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 570 {
 571         struct netfront_info *np = netdev_priv(dev);
 572         struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
 573         struct xen_netif_tx_request *tx, *first_tx;
 574         unsigned int i;
 575         int notify;
 576         int slots;
 577         struct page *page;
 578         unsigned int offset;
 579         unsigned int len;
 580         unsigned long flags;
 581         struct netfront_queue *queue = NULL;
 582         unsigned int num_queues = dev->real_num_tx_queues;
 583         u16 queue_index;
 584         struct sk_buff *nskb;
 585
 586         /* Drop the packet if no queues are set up */
 587         if (num_queues < 1)
 588                 goto drop;
 589         /* Determine which queue to transmit this SKB on */
 590         queue_index = skb_get_queue_mapping(skb);
 591         queue = &np->queues[queue_index];
 592
 593         /* If skb->len is too big for wire format, drop skb and alert
 594          * user about misconfiguration.
 595          */
 596         if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
 597                 net_alert_ratelimited(
 598                         "xennet: skb->len = %u, too big for wire format\n",
 599                         skb->len);
 600                 goto drop;
 601         }
 602
 603         slots = xennet_count_skb_slots(skb);
 604         if (unlikely(slots > MAX_XEN_SKB_FRAGS + 1)) {
 605                 net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
 606                                     slots, skb->len);
 607                 if (skb_linearize(skb))
 608                         goto drop;
 609         }
 610
 611         page = virt_to_page(skb->data);
 612         offset = offset_in_page(skb->data);
 613
 614         /* The first req should be at least ETH_HLEN size or the packet will be
 615          * dropped by netback.
 616          */
 617         if (unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
 618                 nskb = skb_copy(skb, GFP_ATOMIC);
 619                 if (!nskb)
 620                         goto drop;
 621                 dev_consume_skb_any(skb);
 622                 skb = nskb;
 623                 page = virt_to_page(skb->data);
 624                 offset = offset_in_page(skb->data);
 625         }
 626
 627         len = skb_headlen(skb);
 628
 629         spin_lock_irqsave(&queue->tx_lock, flags);
 630
 631         if (unlikely(!netif_carrier_ok(dev) ||
 632                      (slots > 1 && !xennet_can_sg(dev)) ||
 633                      netif_needs_gso(skb, netif_skb_features(skb)))) {
 634                 spin_unlock_irqrestore(&queue->tx_lock, flags);
 635                 goto drop;
 636         }
 637
 638         /* First request for the linear area. */
 639         first_tx = tx = xennet_make_first_txreq(queue, skb,
 640                                                 page, offset, len);
 641         offset += tx->size;
 642         if (offset == PAGE_SIZE) {
 643                 page++;
 644                 offset = 0;
 645         }
 646         len -= tx->size;
 647
 648         if (skb->ip_summed == CHECKSUM_PARTIAL)
 649                 /* local packet? */
 650                 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
 651         else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 652                 /* remote but checksummed. */
 653                 tx->flags |= XEN_NETTXF_data_validated;
 654
 655         /* Optional extra info after the first request. */
 656         if (skb_shinfo(skb)->gso_size) {
 657                 struct xen_netif_extra_info *gso;
 658
 659                 gso = (struct xen_netif_extra_info *)
 660                         RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 661
 662                 tx->flags |= XEN_NETTXF_extra_info;
 663
 664                 gso->u.gso.size = skb_shinfo(skb)->gso_size;
 665                 gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
 666                         XEN_NETIF_GSO_TYPE_TCPV6 :
 667                         XEN_NETIF_GSO_TYPE_TCPV4;
 668                 gso->u.gso.pad = 0;
 669                 gso->u.gso.features = 0;
 670
 671                 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 672                 gso->flags = 0;
 673         }
 674
 675         /* Requests for the rest of the linear area. */
 676         tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);
 677
 678         /* Requests for all the frags. */
 679         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 680                 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 681                 tx = xennet_make_txreqs(queue, tx, skb,
 682                                         skb_frag_page(frag), frag->page_offset,
 683                                         skb_frag_size(frag));
 684         }
 685
 686         /* First request has the packet length. */
 687         first_tx->size = skb->len;
 688
 689         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
 690         if (notify)
 691                 notify_remote_via_irq(queue->tx_irq);
 692
 693         u64_stats_update_begin(&tx_stats->syncp);
 694         tx_stats->bytes += skb->len;
 695         tx_stats->packets++;
 696         u64_stats_update_end(&tx_stats->syncp);
 697
 698         /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
 699         xennet_tx_buf_gc(queue);
 700
 701         if (!netfront_tx_slot_available(queue))
 702                 netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
 703
 704         spin_unlock_irqrestore(&queue->tx_lock, flags);
 705
 706         return NETDEV_TX_OK;
 707
 708  drop:
 709         dev->stats.tx_dropped++;
 710         dev_kfree_skb_any(skb);
 711         return NETDEV_TX_OK;
 712 }
 713
 714 static int xennet_close(struct net_device *dev)
 715 {
 716         struct netfront_info *np = netdev_priv(dev);
 717         unsigned int num_queues = dev->real_num_tx_queues;
 718         unsigned int i;
 719         struct netfront_queue *queue;
 720         netif_tx_stop_all_queues(np->netdev);
 721         for (i = 0; i < num_queues; ++i) {
 722                 queue = &np->queues[i];
 723                 napi_disable(&queue->napi);
 724         }
 725         return 0;
 726 }
 727
 728 static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
 729                                 grant_ref_t ref)
 730 {
 731         int new = xennet_rxidx(queue->rx.req_prod_pvt);
 732
 733         BUG_ON(queue->rx_skbs[new]);
 734         queue->rx_skbs[new] = skb;
 735         queue->grant_rx_ref[new] = ref;
 736         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
 737         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
 738         queue->rx.req_prod_pvt++;
 739 }
 740
 741 static int xennet_get_extras(struct netfront_queue *queue,
 742                              struct xen_netif_extra_info *extras,
 743                              RING_IDX rp)
 744
 745 {
 746         struct xen_netif_extra_info *extra;
 747         struct device *dev = &queue->info->netdev->dev;
 748         RING_IDX cons = queue->rx.rsp_cons;
 749         int err = 0;
 750
 751         do {
 752                 struct sk_buff *skb;
 753                 grant_ref_t ref;
 754
 755                 if (unlikely(cons + 1 == rp)) {
 756                         if (net_ratelimit())
 757                                 dev_warn(dev, "Missing extra info\n");
 758                         err = -EBADR;
 759                         break;
 760                 }
 761
 762                 extra = (struct xen_netif_extra_info *)
 763                         RING_GET_RESPONSE(&queue->rx, ++cons);
 764
 765                 if (unlikely(!extra->type ||
 766                              extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 767                         if (net_ratelimit())
 768                                 dev_warn(dev, "Invalid extra type: %d\n",
 769                                         extra->type);
 770                         err = -EINVAL;
 771                 } else {
 772                         memcpy(&extras[extra->type - 1], extra,
 773                                sizeof(*extra));
 774                 }
 775
 776                 skb = xennet_get_rx_skb(queue, cons);
 777                 ref = xennet_get_rx_ref(queue, cons);
 778                 xennet_move_rx_slot(queue, skb, ref);
 779         } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
 780
 781         queue->rx.rsp_cons = cons;
 782         return err;
 783 }
 784
 785 static int xennet_get_responses(struct netfront_queue *queue,
 786                                 struct netfront_rx_info *rinfo, RING_IDX rp,
 787                                 struct sk_buff_head *list)
 788 {
 789         struct xen_netif_rx_response *rx = &rinfo->rx;
 790         struct xen_netif_extra_info *extras = rinfo->extras;
 791         struct device *dev = &queue->info->netdev->dev;
 792         RING_IDX cons = queue->rx.rsp_cons;
 793         struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
 794         grant_ref_t ref = xennet_get_rx_ref(queue, cons);
 795         int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD);
 796         int slots = 1;
 797         int err = 0;
 798         unsigned long ret;
 799
 800         if (rx->flags & XEN_NETRXF_extra_info) {
 801                 err = xennet_get_extras(queue, extras, rp);
 802                 cons = queue->rx.rsp_cons;
 803         }
 804
 805         for (;;) {
 806                 if (unlikely(rx->status < 0 ||
 807                              rx->offset + rx->status > XEN_PAGE_SIZE)) {
 808                         if (net_ratelimit())
 809                                 dev_warn(dev, "rx->offset: %u, size: %d\n",
 810                                          rx->offset, rx->status);
 811                         xennet_move_rx_slot(queue, skb, ref);
 812                         err = -EINVAL;
 813                         goto next;
 814                 }
 815
 816                 /*
 817                  * This definitely indicates a bug, either in this driver or in
 818                  * the backend driver. In future this should flag the bad
 819                  * situation to the system controller to reboot the backend.
 820                  */
 821                 if (ref == GRANT_INVALID_REF) {
 822                         if (net_ratelimit())
 823                                 dev_warn(dev, "Bad rx response id %d.\n",
 824                                          rx->id);
 825                         err = -EINVAL;
 826                         goto next;
 827                 }
 828
 829                 ret = gnttab_end_foreign_access_ref(ref, 0);
 830                 BUG_ON(!ret);
 831
 832                 gnttab_release_grant_reference(&queue->gref_rx_head, ref);
 833
 834                 __skb_queue_tail(list, skb);
 835
 836 next:
 837                 if (!(rx->flags & XEN_NETRXF_more_data))
 838                         break;
 839
 840                 if (cons + slots == rp) {
 841                         if (net_ratelimit())
 842                                 dev_warn(dev, "Need more slots\n");
 843                         err = -ENOENT;
 844                         break;
 845                 }
 846
 847                 rx = RING_GET_RESPONSE(&queue->rx, cons + slots);
 848                 skb = xennet_get_rx_skb(queue, cons + slots);
 849                 ref = xennet_get_rx_ref(queue, cons + slots);
 850                 slots++;
 851         }
 852
 853         if (unlikely(slots > max)) {
 854                 if (net_ratelimit())
 855                         dev_warn(dev, "Too many slots\n");
 856                 err = -E2BIG;
 857         }
 858
 859         if (unlikely(err))
 860                 queue->rx.rsp_cons = cons + slots;
 861
 862         return err;
 863 }
 864
 865 static int xennet_set_skb_gso(struct sk_buff *skb,
 866                               struct xen_netif_extra_info *gso)
 867 {
 868         if (!gso->u.gso.size) {
 869                 if (net_ratelimit())
 870                         pr_warn("GSO size must not be zero\n");
 871                 return -EINVAL;
 872         }
 873
 874         if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
 875             gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
 876                 if (net_ratelimit())
 877                         pr_warn("Bad GSO type %d\n", gso->u.gso.type);
 878                 return -EINVAL;
 879         }
 880
 881         skb_shinfo(skb)->gso_size = gso->u.gso.size;
 882         skb_shinfo(skb)->gso_type =
 883                 (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
 884                 SKB_GSO_TCPV4 :
 885                 SKB_GSO_TCPV6;
 886
 887         /* Header must be checked, and gso_segs computed. */
 888         skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 889         skb_shinfo(skb)->gso_segs = 0;
 890
 891         return 0;
 892 }
 893
 894 static int xennet_fill_frags(struct netfront_queue *queue,
 895                              struct sk_buff *skb,
 896                              struct sk_buff_head *list)
 897 {
 898         RING_IDX cons = queue->rx.rsp_cons;
 899         struct sk_buff *nskb;
 900
 901         while ((nskb = __skb_dequeue(list))) {
 902                 struct xen_netif_rx_response *rx =
 903                         RING_GET_RESPONSE(&queue->rx, ++cons);
 904                 skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
 905
 906                 if (skb_shinfo(skb)->nr_frags == MAX_SKB_FRAGS) {
 907                         unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 908
 909                         BUG_ON(pull_to < skb_headlen(skb));
 910                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 911                 }
 912                 if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) {
 913                         queue->rx.rsp_cons = ++cons + skb_queue_len(list);
 914                         kfree_skb(nskb);
 915                         return -ENOENT;
 916                 }
 917
 918                 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
 919                                 skb_frag_page(nfrag),
 920                                 rx->offset, rx->status, PAGE_SIZE);
 921
 922                 skb_shinfo(nskb)->nr_frags = 0;
 923                 kfree_skb(nskb);
 924         }
 925
 926         queue->rx.rsp_cons = cons;
 927
 928         return 0;
 929 }
 930
 931 static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 932 {
 933         bool recalculate_partial_csum = false;
 934
 935         /*
 936          * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 937          * peers can fail to set NETRXF_csum_blank when sending a GSO
 938          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 939          * recalculate the partial checksum.
 940          */
 941         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 942                 struct netfront_info *np = netdev_priv(dev);
 943                 atomic_inc(&np->rx_gso_checksum_fixup);
 944                 skb->ip_summed = CHECKSUM_PARTIAL;
 945                 recalculate_partial_csum = true;
 946         }
 947
 948         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 949         if (skb->ip_summed != CHECKSUM_PARTIAL)
 950                 return 0;
 951
 952         return skb_checksum_setup(skb, recalculate_partial_csum);
 953 }
 954
 955 static int handle_incoming_queue(struct netfront_queue *queue,
 956                                  struct sk_buff_head *rxq)
 957 {
 958         struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats);
 959         int packets_dropped = 0;
 960         struct sk_buff *skb;
 961
 962         while ((skb = __skb_dequeue(rxq)) != NULL) {
 963                 int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 964
 965                 if (pull_to > skb_headlen(skb))
 966                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 967
 968                 /* Ethernet work: Delayed to here as it peeks the header. */
 969                 skb->protocol = eth_type_trans(skb, queue->info->netdev);
 970                 skb_reset_network_header(skb);
 971
 972                 if (checksum_setup(queue->info->netdev, skb)) {
 973                         kfree_skb(skb);
 974                         packets_dropped++;
 975                         queue->info->netdev->stats.rx_errors++;
 976                         continue;
 977                 }
 978
 979                 u64_stats_update_begin(&rx_stats->syncp);
 980                 rx_stats->packets++;
 981                 rx_stats->bytes += skb->len;
 982                 u64_stats_update_end(&rx_stats->syncp);
 983
 984                 /* Pass it up. */
 985                 napi_gro_receive(&queue->napi, skb);
 986         }
 987
 988         return packets_dropped;
 989 }
 990
 991 static int xennet_poll(struct napi_struct *napi, int budget)
 992 {
 993         struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
 994         struct net_device *dev = queue->info->netdev;
 995         struct sk_buff *skb;
 996         struct netfront_rx_info rinfo;
 997         struct xen_netif_rx_response *rx = &rinfo.rx;
 998         struct xen_netif_extra_info *extras = rinfo.extras;
 999         RING_IDX i, rp;
1000         int work_done;
1001         struct sk_buff_head rxq;
1002         struct sk_buff_head errq;
1003         struct sk_buff_head tmpq;
1004         int err;
1005
1006         spin_lock(&queue->rx_lock);
1007
1008         skb_queue_head_init(&rxq);
1009         skb_queue_head_init(&errq);
1010         skb_queue_head_init(&tmpq);
1011
1012         rp = queue->rx.sring->rsp_prod;
1013         rmb(); /* Ensure we see queued responses up to 'rp'. */
1014
1015         i = queue->rx.rsp_cons;
1016         work_done = 0;
1017         while ((i != rp) && (work_done < budget)) {
1018                 memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
1019                 memset(extras, 0, sizeof(rinfo.extras));
1020
1021                 err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
1022
1023                 if (unlikely(err)) {
1024 err:
1025                         while ((skb = __skb_dequeue(&tmpq)))
1026                                 __skb_queue_tail(&errq, skb);
1027                         dev->stats.rx_errors++;
1028                         i = queue->rx.rsp_cons;
1029                         continue;
1030                 }
1031
1032                 skb = __skb_dequeue(&tmpq);
1033
1034                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1035                         struct xen_netif_extra_info *gso;
1036                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1037
1038                         if (unlikely(xennet_set_skb_gso(skb, gso))) {
1039                                 __skb_queue_head(&tmpq, skb);
1040                                 queue->rx.rsp_cons += skb_queue_len(&tmpq);
1041                                 goto err;
1042                         }
1043                 }
1044
1045                 NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1046                 if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1047                         NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1048
1049                 skb_shinfo(skb)->frags[0].page_offset = rx->offset;
1050                 skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1051                 skb->data_len = rx->status;
1052                 skb->len += rx->status;
1053
1054                 if (unlikely(xennet_fill_frags(queue, skb, &tmpq)))
1055                         goto err;
1056
1057                 if (rx->flags & XEN_NETRXF_csum_blank)
1058                         skb->ip_summed = CHECKSUM_PARTIAL;
1059                 else if (rx->flags & XEN_NETRXF_data_validated)
1060                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1061
1062                 __skb_queue_tail(&rxq, skb);
1063
1064                 i = ++queue->rx.rsp_cons;
1065                 work_done++;
1066         }
1067
1068         __skb_queue_purge(&errq);
1069
1070         work_done -= handle_incoming_queue(queue, &rxq);
1071
1072         xennet_alloc_rx_buffers(queue);
1073
1074         if (work_done < budget) {
1075                 int more_to_do = 0;
1076
1077                 napi_complete_done(napi, work_done);
1078
1079                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
1080                 if (more_to_do)
1081                         napi_schedule(napi);
1082         }
1083
1084         spin_unlock(&queue->rx_lock);
1085
1086         return work_done;
1087 }
1088
1089 static int xennet_change_mtu(struct net_device *dev, int mtu)
1090 {
1091         int max = xennet_can_sg(dev) ? XEN_NETIF_MAX_TX_SIZE : ETH_DATA_LEN;
1092
1093         if (mtu > max)
1094                 return -EINVAL;
1095         dev->mtu = mtu;
1096         return 0;
1097 }
1098
1099 static void xennet_get_stats64(struct net_device *dev,
1100                                struct rtnl_link_stats64 *tot)
1101 {
1102         struct netfront_info *np = netdev_priv(dev);
1103         int cpu;
1104
1105         for_each_possible_cpu(cpu) {
1106                 struct netfront_stats *rx_stats = per_cpu_ptr(np->rx_stats, cpu);
1107                 struct netfront_stats *tx_stats = per_cpu_ptr(np->tx_stats, cpu);
1108                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1109                 unsigned int start;
1110
1111                 do {
1112                         start = u64_stats_fetch_begin_irq(&tx_stats->syncp);
1113                         tx_packets = tx_stats->packets;
1114                         tx_bytes = tx_stats->bytes;
1115                 } while (u64_stats_fetch_retry_irq(&tx_stats->syncp, start));
1116
1117                 do {
1118                         start = u64_stats_fetch_begin_irq(&rx_stats->syncp);
1119                         rx_packets = rx_stats->packets;
1120                         rx_bytes = rx_stats->bytes;
1121                 } while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start));
1122
1123                 tot->rx_packets += rx_packets;
1124                 tot->tx_packets += tx_packets;
1125                 tot->rx_bytes   += rx_bytes;
1126                 tot->tx_bytes   += tx_bytes;
1127         }
1128
1129         tot->rx_errors  = dev->stats.rx_errors;
1130         tot->tx_dropped = dev->stats.tx_dropped;
1131 }
1132
1133 static void xennet_release_tx_bufs(struct netfront_queue *queue)
1134 {
1135         struct sk_buff *skb;
1136         int i;
1137
1138         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1139                 /* Skip over entries which are actually freelist references */
1140                 if (skb_entry_is_link(&queue->tx_skbs[i]))
1141                         continue;
1142
1143                 skb = queue->tx_skbs[i].skb;
1144                 get_page(queue->grant_tx_page[i]);
1145                 gnttab_end_foreign_access(queue->grant_tx_ref[i],
1146                                           GNTMAP_readonly,
1147                                           (unsigned long)page_address(queue->grant_tx_page[i]));
1148                 queue->grant_tx_page[i] = NULL;
1149                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1150                 add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, i);
1151                 dev_kfree_skb_irq(skb);
1152         }
1153 }
1154
1155 static void xennet_release_rx_bufs(struct netfront_queue *queue)
1156 {
1157         int id, ref;
1158
1159         spin_lock_bh(&queue->rx_lock);
1160
1161         for (id = 0; id < NET_RX_RING_SIZE; id++) {
1162                 struct sk_buff *skb;
1163                 struct page *page;
1164
1165                 skb = queue->rx_skbs[id];
1166                 if (!skb)
1167                         continue;
1168
1169                 ref = queue->grant_rx_ref[id];
1170                 if (ref == GRANT_INVALID_REF)
1171                         continue;
1172
1173                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
1174
1175                 /* gnttab_end_foreign_access() needs a page ref until
1176                  * foreign access is ended (which may be deferred).
1177                  */
1178                 get_page(page);
1179                 gnttab_end_foreign_access(ref, 0,
1180                                           (unsigned long)page_address(page));
1181                 queue->grant_rx_ref[id] = GRANT_INVALID_REF;
1182
1183                 kfree_skb(skb);
1184         }
1185
1186         spin_unlock_bh(&queue->rx_lock);
1187 }
1188
1189 static netdev_features_t xennet_fix_features(struct net_device *dev,
1190         netdev_features_t features)
1191 {
1192         struct netfront_info *np = netdev_priv(dev);
1193
1194         if (features & NETIF_F_SG &&
1195             !xenbus_read_unsigned(np->xbdev->otherend, "feature-sg", 0))
1196                 features &= ~NETIF_F_SG;
1197
1198         if (features & NETIF_F_IPV6_CSUM &&
1199             !xenbus_read_unsigned(np->xbdev->otherend,
1200                                   "feature-ipv6-csum-offload", 0))
1201                 features &= ~NETIF_F_IPV6_CSUM;
1202
1203         if (features & NETIF_F_TSO &&
1204             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv4", 0))
1205                 features &= ~NETIF_F_TSO;
1206
1207         if (features & NETIF_F_TSO6 &&
1208             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv6", 0))
1209                 features &= ~NETIF_F_TSO6;
1210
1211         return features;
1212 }
1213
1214 static int xennet_set_features(struct net_device *dev,
1215         netdev_features_t features)
1216 {
1217         if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1218                 netdev_info(dev, "Reducing MTU because no SG offload");
1219                 dev->mtu = ETH_DATA_LEN;
1220         }
1221
1222         return 0;
1223 }
1224
1225 static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1226 {
1227         struct netfront_queue *queue = dev_id;
1228         unsigned long flags;
1229
1230         spin_lock_irqsave(&queue->tx_lock, flags);
1231         xennet_tx_buf_gc(queue);
1232         spin_unlock_irqrestore(&queue->tx_lock, flags);
1233
1234         return IRQ_HANDLED;
1235 }
1236
1237 static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1238 {
1239         struct netfront_queue *queue = dev_id;
1240         struct net_device *dev = queue->info->netdev;
1241
1242         if (likely(netif_carrier_ok(dev) &&
1243                    RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)))
1244                 napi_schedule(&queue->napi);
1245
1246         return IRQ_HANDLED;
1247 }
1248
1249 static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1250 {
1251         xennet_tx_interrupt(irq, dev_id);
1252         xennet_rx_interrupt(irq, dev_id);
1253         return IRQ_HANDLED;
1254 }
1255
1256 #ifdef CONFIG_NET_POLL_CONTROLLER
1257 static void xennet_poll_controller(struct net_device *dev)
1258 {
1259         /* Poll each queue */
1260         struct netfront_info *info = netdev_priv(dev);
1261         unsigned int num_queues = dev->real_num_tx_queues;
1262         unsigned int i;
1263         for (i = 0; i < num_queues; ++i)
1264                 xennet_interrupt(0, &info->queues[i]);
1265 }
1266 #endif
1267
1268 static const struct net_device_ops xennet_netdev_ops = {
1269         .ndo_open            = xennet_open,
1270         .ndo_stop            = xennet_close,
1271         .ndo_start_xmit      = xennet_start_xmit,
1272         .ndo_change_mtu      = xennet_change_mtu,
1273         .ndo_get_stats64     = xennet_get_stats64,
1274         .ndo_set_mac_address = eth_mac_addr,
1275         .ndo_validate_addr   = eth_validate_addr,
1276         .ndo_fix_features    = xennet_fix_features,
1277         .ndo_set_features    = xennet_set_features,
1278         .ndo_select_queue    = xennet_select_queue,
1279 #ifdef CONFIG_NET_POLL_CONTROLLER
1280         .ndo_poll_controller = xennet_poll_controller,
1281 #endif
1282 };
1283
1284 static void xennet_free_netdev(struct net_device *netdev)
1285 {
1286         struct netfront_info *np = netdev_priv(netdev);
1287
1288         free_percpu(np->rx_stats);
1289         free_percpu(np->tx_stats);
1290         free_netdev(netdev);
1291 }
1292
1293 static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1294 {
1295         int err;
1296         struct net_device *netdev;
1297         struct netfront_info *np;
1298
1299         netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues);
1300         if (!netdev)
1301                 return ERR_PTR(-ENOMEM);
1302
1303         np                   = netdev_priv(netdev);
1304         np->xbdev            = dev;
1305
1306         np->queues = NULL;
1307
1308         err = -ENOMEM;
1309         np->rx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1310         if (np->rx_stats == NULL)
1311                 goto exit;
1312         np->tx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1313         if (np->tx_stats == NULL)
1314                 goto exit;
1315
1316         netdev->netdev_ops      = &xennet_netdev_ops;
1317
1318         netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1319                                   NETIF_F_GSO_ROBUST;
1320         netdev->hw_features     = NETIF_F_SG |
1321                                   NETIF_F_IPV6_CSUM |
1322                                   NETIF_F_TSO | NETIF_F_TSO6;
1323
1324         /*
1325          * Assume that all hw features are available for now. This set
1326          * will be adjusted by the call to netdev_update_features() in
1327          * xennet_connect() which is the earliest point where we can
1328          * negotiate with the backend regarding supported features.
1329          */
1330         netdev->features |= netdev->hw_features;
1331
1332         netdev->ethtool_ops = &xennet_ethtool_ops;
1333         netdev->min_mtu = ETH_MIN_MTU;
1334         netdev->max_mtu = XEN_NETIF_MAX_TX_SIZE;
1335         SET_NETDEV_DEV(netdev, &dev->dev);
1336
1337         np->netdev = netdev;
1338
1339         netif_carrier_off(netdev);
1340
1341         do {
1342                 xenbus_switch_state(dev, XenbusStateInitialising);
1343                 err = wait_event_timeout(module_wq,
1344                                  xenbus_read_driver_state(dev->otherend) !=
1345                                  XenbusStateClosed &&
1346                                  xenbus_read_driver_state(dev->otherend) !=
1347                                  XenbusStateUnknown, XENNET_TIMEOUT);
1348         } while (!err);
1349
1350         return netdev;
1351
1352  exit:
1353         xennet_free_netdev(netdev);
1354         return ERR_PTR(err);
1355 }
1356
1357 /**
1358  * Entry point to this code when a new device is created.  Allocate the basic
1359  * structures and the ring buffers for communication with the backend, and
1360  * inform the backend of the appropriate details for those.
1361  */
1362 static int netfront_probe(struct xenbus_device *dev,
1363                           const struct xenbus_device_id *id)
1364 {
1365         int err;
1366         struct net_device *netdev;
1367         struct netfront_info *info;
1368
1369         netdev = xennet_create_dev(dev);
1370         if (IS_ERR(netdev)) {
1371                 err = PTR_ERR(netdev);
1372                 xenbus_dev_fatal(dev, err, "creating netdev");
1373                 return err;
1374         }
1375
1376         info = netdev_priv(netdev);
1377         dev_set_drvdata(&dev->dev, info);
1378 #ifdef CONFIG_SYSFS
1379         info->netdev->sysfs_groups[0] = &xennet_dev_group;
1380 #endif
1381
1382         return 0;
1383 }
1384
1385 static void xennet_end_access(int ref, void *page)
1386 {
1387         /* This frees the page as a side-effect */
1388         if (ref != GRANT_INVALID_REF)
1389                 gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1390 }
1391
1392 static void xennet_disconnect_backend(struct netfront_info *info)
1393 {
1394         unsigned int i = 0;
1395         unsigned int num_queues = info->netdev->real_num_tx_queues;
1396
1397         netif_carrier_off(info->netdev);
1398
1399         for (i = 0; i < num_queues && info->queues; ++i) {
1400                 struct netfront_queue *queue = &info->queues[i];
1401
1402                 del_timer_sync(&queue->rx_refill_timer);
1403
1404                 if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
1405                         unbind_from_irqhandler(queue->tx_irq, queue);
1406                 if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) {
1407                         unbind_from_irqhandler(queue->tx_irq, queue);
1408                         unbind_from_irqhandler(queue->rx_irq, queue);
1409                 }
1410                 queue->tx_evtchn = queue->rx_evtchn = 0;
1411                 queue->tx_irq = queue->rx_irq = 0;
1412
1413                 if (netif_running(info->netdev))
1414                         napi_synchronize(&queue->napi);
1415
1416                 xennet_release_tx_bufs(queue);
1417                 xennet_release_rx_bufs(queue);
1418                 gnttab_free_grant_references(queue->gref_tx_head);
1419                 gnttab_free_grant_references(queue->gref_rx_head);
1420
1421                 /* End access and free the pages */
1422                 xennet_end_access(queue->tx_ring_ref, queue->tx.sring);
1423                 xennet_end_access(queue->rx_ring_ref, queue->rx.sring);
1424
1425                 queue->tx_ring_ref = GRANT_INVALID_REF;
1426                 queue->rx_ring_ref = GRANT_INVALID_REF;
1427                 queue->tx.sring = NULL;
1428                 queue->rx.sring = NULL;
1429         }
1430 }
1431
1432 /**
1433  * We are reconnecting to the backend, due to a suspend/resume, or a backend
1434  * driver restart.  We tear down our netif structure and recreate it, but
1435  * leave the device-layer structures intact so that this is transparent to the
1436  * rest of the kernel.
1437  */
1438 static int netfront_resume(struct xenbus_device *dev)
1439 {
1440         struct netfront_info *info = dev_get_drvdata(&dev->dev);
1441
1442         dev_dbg(&dev->dev, "%s\n", dev->nodename);
1443
1444         xennet_disconnect_backend(info);
1445         return 0;
1446 }
1447
1448 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1449 {
1450         char *s, *e, *macstr;
1451         int i;
1452
1453         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1454         if (IS_ERR(macstr))
1455                 return PTR_ERR(macstr);
1456
1457         for (i = 0; i < ETH_ALEN; i++) {
1458                 mac[i] = simple_strtoul(s, &e, 16);
1459                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1460                         kfree(macstr);
1461                         return -ENOENT;
1462                 }
1463                 s = e+1;
1464         }
1465
1466         kfree(macstr);
1467         return 0;
1468 }
1469
1470 static int setup_netfront_single(struct netfront_queue *queue)
1471 {
1472         int err;
1473
1474         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1475         if (err < 0)
1476                 goto fail;
1477
1478         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1479                                         xennet_interrupt,
1480                                         0, queue->info->netdev->name, queue);
1481         if (err < 0)
1482                 goto bind_fail;
1483         queue->rx_evtchn = queue->tx_evtchn;
1484         queue->rx_irq = queue->tx_irq = err;
1485
1486         return 0;
1487
1488 bind_fail:
1489         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1490         queue->tx_evtchn = 0;
1491 fail:
1492         return err;
1493 }
1494
1495 static int setup_netfront_split(struct netfront_queue *queue)
1496 {
1497         int err;
1498
1499         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1500         if (err < 0)
1501                 goto fail;
1502         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->rx_evtchn);
1503         if (err < 0)
1504                 goto alloc_rx_evtchn_fail;
1505
1506         snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
1507                  "%s-tx", queue->name);
1508         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1509                                         xennet_tx_interrupt,
1510                                         0, queue->tx_irq_name, queue);
1511         if (err < 0)
1512                 goto bind_tx_fail;
1513         queue->tx_irq = err;
1514
1515         snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
1516                  "%s-rx", queue->name);
1517         err = bind_evtchn_to_irqhandler(queue->rx_evtchn,
1518                                         xennet_rx_interrupt,
1519                                         0, queue->rx_irq_name, queue);
1520         if (err < 0)
1521                 goto bind_rx_fail;
1522         queue->rx_irq = err;
1523
1524         return 0;
1525
1526 bind_rx_fail:
1527         unbind_from_irqhandler(queue->tx_irq, queue);
1528         queue->tx_irq = 0;
1529 bind_tx_fail:
1530         xenbus_free_evtchn(queue->info->xbdev, queue->rx_evtchn);
1531         queue->rx_evtchn = 0;
1532 alloc_rx_evtchn_fail:
1533         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1534         queue->tx_evtchn = 0;
1535 fail:
1536         return err;
1537 }
1538
1539 static int setup_netfront(struct xenbus_device *dev,
1540                         struct netfront_queue *queue, unsigned int feature_split_evtchn)
1541 {
1542         struct xen_netif_tx_sring *txs;
1543         struct xen_netif_rx_sring *rxs;
1544         grant_ref_t gref;
1545         int err;
1546
1547         queue->tx_ring_ref = GRANT_INVALID_REF;
1548         queue->rx_ring_ref = GRANT_INVALID_REF;
1549         queue->rx.sring = NULL;
1550         queue->tx.sring = NULL;
1551
1552         txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1553         if (!txs) {
1554                 err = -ENOMEM;
1555                 xenbus_dev_fatal(dev, err, "allocating tx ring page");
1556                 goto fail;
1557         }
1558         SHARED_RING_INIT(txs);
1559         FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1560
1561         err = xenbus_grant_ring(dev, txs, 1, &gref);
1562         if (err < 0)
1563                 goto grant_tx_ring_fail;
1564         queue->tx_ring_ref = gref;
1565
1566         rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1567         if (!rxs) {
1568                 err = -ENOMEM;
1569                 xenbus_dev_fatal(dev, err, "allocating rx ring page");
1570                 goto alloc_rx_ring_fail;
1571         }
1572         SHARED_RING_INIT(rxs);
1573         FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1574
1575         err = xenbus_grant_ring(dev, rxs, 1, &gref);
1576         if (err < 0)
1577                 goto grant_rx_ring_fail;
1578         queue->rx_ring_ref = gref;
1579
1580         if (feature_split_evtchn)
1581                 err = setup_netfront_split(queue);
1582         /* setup single event channel if
1583          *  a) feature-split-event-channels == 0
1584          *  b) feature-split-event-channels == 1 but failed to setup
1585          */
1586         if (!feature_split_evtchn || (feature_split_evtchn && err))
1587                 err = setup_netfront_single(queue);
1588
1589         if (err)
1590                 goto alloc_evtchn_fail;
1591
1592         return 0;
1593
1594         /* If we fail to setup netfront, it is safe to just revoke access to
1595          * granted pages because backend is not accessing it at this point.
1596          */
1597 alloc_evtchn_fail:
1598         gnttab_end_foreign_access_ref(queue->rx_ring_ref, 0);
1599 grant_rx_ring_fail:
1600         free_page((unsigned long)rxs);
1601 alloc_rx_ring_fail:
1602         gnttab_end_foreign_access_ref(queue->tx_ring_ref, 0);
1603 grant_tx_ring_fail:
1604         free_page((unsigned long)txs);
1605 fail:
1606         return err;
1607 }
1608
1609 /* Queue-specific initialisation
1610  * This used to be done in xennet_create_dev() but must now
1611  * be run per-queue.
1612  */
1613 static int xennet_init_queue(struct netfront_queue *queue)
1614 {
1615         unsigned short i;
1616         int err = 0;
1617         char *devid;
1618
1619         spin_lock_init(&queue->tx_lock);
1620         spin_lock_init(&queue->rx_lock);
1621
1622         setup_timer(&queue->rx_refill_timer, rx_refill_timeout,
1623                     (unsigned long)queue);
1624
1625         devid = strrchr(queue->info->xbdev->nodename, '/') + 1;
1626         snprintf(queue->name, sizeof(queue->name), "vif%s-q%u",
1627                  devid, queue->id);
1628
1629         /* Initialise tx_skbs as a free chain containing every entry. */
1630         queue->tx_skb_freelist = 0;
1631         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1632                 skb_entry_set_link(&queue->tx_skbs[i], i+1);
1633                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1634                 queue->grant_tx_page[i] = NULL;
1635         }
1636
1637         /* Clear out rx_skbs */
1638         for (i = 0; i < NET_RX_RING_SIZE; i++) {
1639                 queue->rx_skbs[i] = NULL;
1640                 queue->grant_rx_ref[i] = GRANT_INVALID_REF;
1641         }
1642
1643         /* A grant for every tx ring slot */
1644         if (gnttab_alloc_grant_references(NET_TX_RING_SIZE,
1645                                           &queue->gref_tx_head) < 0) {
1646                 pr_alert("can't alloc tx grant refs\n");
1647                 err = -ENOMEM;
1648                 goto exit;
1649         }
1650
1651         /* A grant for every rx ring slot */
1652         if (gnttab_alloc_grant_references(NET_RX_RING_SIZE,
1653                                           &queue->gref_rx_head) < 0) {
1654                 pr_alert("can't alloc rx grant refs\n");
1655                 err = -ENOMEM;
1656                 goto exit_free_tx;
1657         }
1658
1659         return 0;
1660
1661  exit_free_tx:
1662         gnttab_free_grant_references(queue->gref_tx_head);
1663  exit:
1664         return err;
1665 }
1666
1667 static int write_queue_xenstore_keys(struct netfront_queue *queue,
1668                            struct xenbus_transaction *xbt, int write_hierarchical)
1669 {
1670         /* Write the queue-specific keys into XenStore in the traditional
1671          * way for a single queue, or in a queue subkeys for multiple
1672          * queues.
1673          */
1674         struct xenbus_device *dev = queue->info->xbdev;
1675         int err;
1676         const char *message;
1677         char *path;
1678         size_t pathsize;
1679
1680         /* Choose the correct place to write the keys */
1681         if (write_hierarchical) {
1682                 pathsize = strlen(dev->nodename) + 10;
1683                 path = kzalloc(pathsize, GFP_KERNEL);
1684                 if (!path) {
1685                         err = -ENOMEM;
1686                         message = "out of memory while writing ring references";
1687                         goto error;
1688                 }
1689                 snprintf(path, pathsize, "%s/queue-%u",
1690                                 dev->nodename, queue->id);
1691         } else {
1692                 path = (char *)dev->nodename;
1693         }
1694
1695         /* Write ring references */
1696         err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u",
1697                         queue->tx_ring_ref);
1698         if (err) {
1699                 message = "writing tx-ring-ref";
1700                 goto error;
1701         }
1702
1703         err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u",
1704                         queue->rx_ring_ref);
1705         if (err) {
1706                 message = "writing rx-ring-ref";
1707                 goto error;
1708         }
1709
1710         /* Write event channels; taking into account both shared
1711          * and split event channel scenarios.
1712          */
1713         if (queue->tx_evtchn == queue->rx_evtchn) {
1714                 /* Shared event channel */
1715                 err = xenbus_printf(*xbt, path,
1716                                 "event-channel", "%u", queue->tx_evtchn);
1717                 if (err) {
1718                         message = "writing event-channel";
1719                         goto error;
1720                 }
1721         } else {
1722                 /* Split event channels */
1723                 err = xenbus_printf(*xbt, path,
1724                                 "event-channel-tx", "%u", queue->tx_evtchn);
1725                 if (err) {
1726                         message = "writing event-channel-tx";
1727                         goto error;
1728                 }
1729
1730                 err = xenbus_printf(*xbt, path,
1731                                 "event-channel-rx", "%u", queue->rx_evtchn);
1732                 if (err) {
1733                         message = "writing event-channel-rx";
1734                         goto error;
1735                 }
1736         }
1737
1738         if (write_hierarchical)
1739                 kfree(path);
1740         return 0;
1741
1742 error:
1743         if (write_hierarchical)
1744                 kfree(path);
1745         xenbus_dev_fatal(dev, err, "%s", message);
1746         return err;
1747 }
1748
1749 static void xennet_destroy_queues(struct netfront_info *info)
1750 {
1751         unsigned int i;
1752
1753         for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
1754                 struct netfront_queue *queue = &info->queues[i];
1755
1756                 if (netif_running(info->netdev))
1757                         napi_disable(&queue->napi);
1758                 netif_napi_del(&queue->napi);
1759         }
1760
1761         kfree(info->queues);
1762         info->queues = NULL;
1763 }
1764
1765 static int xennet_create_queues(struct netfront_info *info,
1766                                 unsigned int *num_queues)
1767 {
1768         unsigned int i;
1769         int ret;
1770
1771         info->queues = kcalloc(*num_queues, sizeof(struct netfront_queue),
1772                                GFP_KERNEL);
1773         if (!info->queues)
1774                 return -ENOMEM;
1775
1776         for (i = 0; i < *num_queues; i++) {
1777                 struct netfront_queue *queue = &info->queues[i];
1778
1779                 queue->id = i;
1780                 queue->info = info;
1781
1782                 ret = xennet_init_queue(queue);
1783                 if (ret < 0) {
1784                         dev_warn(&info->xbdev->dev,
1785                                  "only created %d queues\n", i);
1786                         *num_queues = i;
1787                         break;
1788                 }
1789
1790                 netif_napi_add(queue->info->netdev, &queue->napi,
1791                                xennet_poll, 64);
1792                 if (netif_running(info->netdev))
1793                         napi_enable(&queue->napi);
1794         }
1795
1796         netif_set_real_num_tx_queues(info->netdev, *num_queues);
1797
1798         if (*num_queues == 0) {
1799                 dev_err(&info->xbdev->dev, "no queues\n");
1800                 return -EINVAL;
1801         }
1802         return 0;
1803 }
1804
1805 /* Common code used when first setting up, and when resuming. */
1806 static int talk_to_netback(struct xenbus_device *dev,
1807                            struct netfront_info *info)
1808 {
1809         const char *message;
1810         struct xenbus_transaction xbt;
1811         int err;
1812         unsigned int feature_split_evtchn;
1813         unsigned int i = 0;
1814         unsigned int max_queues = 0;
1815         struct netfront_queue *queue = NULL;
1816         unsigned int num_queues = 1;
1817
1818         info->netdev->irq = 0;
1819
1820         /* Check if backend supports multiple queues */
1821         max_queues = xenbus_read_unsigned(info->xbdev->otherend,
1822                                           "multi-queue-max-queues", 1);
1823         num_queues = min(max_queues, xennet_max_queues);
1824
1825         /* Check feature-split-event-channels */
1826         feature_split_evtchn = xenbus_read_unsigned(info->xbdev->otherend,
1827                                         "feature-split-event-channels", 0);
1828
1829         /* Read mac addr. */
1830         err = xen_net_read_mac(dev, info->netdev->dev_addr);
1831         if (err) {
1832                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1833                 goto out_unlocked;
1834         }
1835
1836         rtnl_lock();
1837         if (info->queues)
1838                 xennet_destroy_queues(info);
1839
1840         err = xennet_create_queues(info, &num_queues);
1841         if (err < 0) {
1842                 xenbus_dev_fatal(dev, err, "creating queues");
1843                 kfree(info->queues);
1844                 info->queues = NULL;
1845                 goto out;
1846         }
1847         rtnl_unlock();
1848
1849         /* Create shared ring, alloc event channel -- for each queue */
1850         for (i = 0; i < num_queues; ++i) {
1851                 queue = &info->queues[i];
1852                 err = setup_netfront(dev, queue, feature_split_evtchn);
1853                 if (err)
1854                         goto destroy_ring;
1855         }
1856
1857 again:
1858         err = xenbus_transaction_start(&xbt);
1859         if (err) {
1860                 xenbus_dev_fatal(dev, err, "starting transaction");
1861                 goto destroy_ring;
1862         }
1863
1864         if (xenbus_exists(XBT_NIL,
1865                           info->xbdev->otherend, "multi-queue-max-queues")) {
1866                 /* Write the number of queues */
1867                 err = xenbus_printf(xbt, dev->nodename,
1868                                     "multi-queue-num-queues", "%u", num_queues);
1869                 if (err) {
1870                         message = "writing multi-queue-num-queues";
1871                         goto abort_transaction_no_dev_fatal;
1872                 }
1873         }
1874
1875         if (num_queues == 1) {
1876                 err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
1877                 if (err)
1878                         goto abort_transaction_no_dev_fatal;
1879         } else {
1880                 /* Write the keys for each queue */
1881                 for (i = 0; i < num_queues; ++i) {
1882                         queue = &info->queues[i];
1883                         err = write_queue_xenstore_keys(queue, &xbt, 1); /* hierarchical */
1884                         if (err)
1885                                 goto abort_transaction_no_dev_fatal;
1886                 }
1887         }
1888
1889         /* The remaining keys are not queue-specific */
1890         err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1891                             1);
1892         if (err) {
1893                 message = "writing request-rx-copy";
1894                 goto abort_transaction;
1895         }
1896
1897         err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1898         if (err) {
1899                 message = "writing feature-rx-notify";
1900                 goto abort_transaction;
1901         }
1902
1903         err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1904         if (err) {
1905                 message = "writing feature-sg";
1906                 goto abort_transaction;
1907         }
1908
1909         err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1910         if (err) {
1911                 message = "writing feature-gso-tcpv4";
1912                 goto abort_transaction;
1913         }
1914
1915         err = xenbus_write(xbt, dev->nodename, "feature-gso-tcpv6", "1");
1916         if (err) {
1917                 message = "writing feature-gso-tcpv6";
1918                 goto abort_transaction;
1919         }
1920
1921         err = xenbus_write(xbt, dev->nodename, "feature-ipv6-csum-offload",
1922                            "1");
1923         if (err) {
1924                 message = "writing feature-ipv6-csum-offload";
1925                 goto abort_transaction;
1926         }
1927
1928         err = xenbus_transaction_end(xbt, 0);
1929         if (err) {
1930                 if (err == -EAGAIN)
1931                         goto again;
1932                 xenbus_dev_fatal(dev, err, "completing transaction");
1933                 goto destroy_ring;
1934         }
1935
1936         return 0;
1937
1938  abort_transaction:
1939         xenbus_dev_fatal(dev, err, "%s", message);
1940 abort_transaction_no_dev_fatal:
1941         xenbus_transaction_end(xbt, 1);
1942  destroy_ring:
1943         xennet_disconnect_backend(info);
1944         rtnl_lock();
1945         xennet_destroy_queues(info);
1946  out:
1947         rtnl_unlock();
1948 out_unlocked:
1949         device_unregister(&dev->dev);
1950         return err;
1951 }
1952
1953 static int xennet_connect(struct net_device *dev)
1954 {
1955         struct netfront_info *np = netdev_priv(dev);
1956         unsigned int num_queues = 0;
1957         int err;
1958         unsigned int j = 0;
1959         struct netfront_queue *queue = NULL;
1960
1961         if (!xenbus_read_unsigned(np->xbdev->otherend, "feature-rx-copy", 0)) {
1962                 dev_info(&dev->dev,
1963                          "backend does not support copying receive path\n");
1964                 return -ENODEV;
1965         }
1966
1967         err = talk_to_netback(np->xbdev, np);
1968         if (err)
1969                 return err;
1970
1971         /* talk_to_netback() sets the correct number of queues */
1972         num_queues = dev->real_num_tx_queues;
1973
1974         if (dev->reg_state == NETREG_UNINITIALIZED) {
1975                 err = register_netdev(dev);
1976                 if (err) {
1977                         pr_warn("%s: register_netdev err=%d\n", __func__, err);
1978                         device_unregister(&np->xbdev->dev);
1979                         return err;
1980                 }
1981         }
1982
1983         rtnl_lock();
1984         netdev_update_features(dev);
1985         rtnl_unlock();
1986
1987         /*
1988          * All public and private state should now be sane.  Get
1989          * ready to start sending and receiving packets and give the driver
1990          * domain a kick because we've probably just requeued some
1991          * packets.
1992          */
1993         netif_carrier_on(np->netdev);
1994         for (j = 0; j < num_queues; ++j) {
1995                 queue = &np->queues[j];
1996
1997                 notify_remote_via_irq(queue->tx_irq);
1998                 if (queue->tx_irq != queue->rx_irq)
1999                         notify_remote_via_irq(queue->rx_irq);
2000
2001                 spin_lock_irq(&queue->tx_lock);
2002                 xennet_tx_buf_gc(queue);
2003                 spin_unlock_irq(&queue->tx_lock);
2004
2005                 spin_lock_bh(&queue->rx_lock);
2006                 xennet_alloc_rx_buffers(queue);
2007                 spin_unlock_bh(&queue->rx_lock);
2008         }
2009
2010         return 0;
2011 }
2012
2013 /**
2014  * Callback received when the backend's state changes.
2015  */
2016 static void netback_changed(struct xenbus_device *dev,
2017                             enum xenbus_state backend_state)
2018 {
2019         struct netfront_info *np = dev_get_drvdata(&dev->dev);
2020         struct net_device *netdev = np->netdev;
2021
2022         dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
2023
2024         wake_up_all(&module_wq);
2025
2026         switch (backend_state) {
2027         case XenbusStateInitialising:
2028         case XenbusStateInitialised:
2029         case XenbusStateReconfiguring:
2030         case XenbusStateReconfigured:
2031         case XenbusStateUnknown:
2032                 break;
2033
2034         case XenbusStateInitWait:
2035                 if (dev->state != XenbusStateInitialising)
2036                         break;
2037                 if (xennet_connect(netdev) != 0)
2038                         break;
2039                 xenbus_switch_state(dev, XenbusStateConnected);
2040                 break;
2041
2042         case XenbusStateConnected:
2043                 netdev_notify_peers(netdev);
2044                 break;
2045
2046         case XenbusStateClosed:
2047                 if (dev->state == XenbusStateClosed)
2048                         break;
2049                 /* Missed the backend's CLOSING state -- fallthrough */
2050         case XenbusStateClosing:
2051                 xenbus_frontend_closed(dev);
2052                 break;
2053         }
2054 }
2055
2056 static const struct xennet_stat {
2057         char name[ETH_GSTRING_LEN];
2058         u16 offset;
2059 } xennet_stats[] = {
2060         {
2061                 "rx_gso_checksum_fixup",
2062                 offsetof(struct netfront_info, rx_gso_checksum_fixup)
2063         },
2064 };
2065
2066 static int xennet_get_sset_count(struct net_device *dev, int string_set)
2067 {
2068         switch (string_set) {
2069         case ETH_SS_STATS:
2070                 return ARRAY_SIZE(xennet_stats);
2071         default:
2072                 return -EINVAL;
2073         }
2074 }
2075
2076 static void xennet_get_ethtool_stats(struct net_device *dev,
2077                                      struct ethtool_stats *stats, u64 * data)
2078 {
2079         void *np = netdev_priv(dev);
2080         int i;
2081
2082         for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2083                 data[i] = atomic_read((atomic_t *)(np + xennet_stats[i].offset));
2084 }
2085
2086 static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
2087 {
2088         int i;
2089
2090         switch (stringset) {
2091         case ETH_SS_STATS:
2092                 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2093                         memcpy(data + i * ETH_GSTRING_LEN,
2094                                xennet_stats[i].name, ETH_GSTRING_LEN);
2095                 break;
2096         }
2097 }
2098
2099 static const struct ethtool_ops xennet_ethtool_ops =
2100 {
2101         .get_link = ethtool_op_get_link,
2102
2103         .get_sset_count = xennet_get_sset_count,
2104         .get_ethtool_stats = xennet_get_ethtool_stats,
2105         .get_strings = xennet_get_strings,
2106 };
2107
2108 #ifdef CONFIG_SYSFS
2109 static ssize_t show_rxbuf(struct device *dev,
2110                           struct device_attribute *attr, char *buf)
2111 {
2112         return sprintf(buf, "%lu\n", NET_RX_RING_SIZE);
2113 }
2114
2115 static ssize_t store_rxbuf(struct device *dev,
2116                            struct device_attribute *attr,
2117                            const char *buf, size_t len)
2118 {
2119         char *endp;
2120         unsigned long target;
2121
2122         if (!capable(CAP_NET_ADMIN))
2123                 return -EPERM;
2124
2125         target = simple_strtoul(buf, &endp, 0);
2126         if (endp == buf)
2127                 return -EBADMSG;
2128
2129         /* rxbuf_min and rxbuf_max are no longer configurable. */
2130
2131         return len;
2132 }
2133
2134 static DEVICE_ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf, store_rxbuf);
2135 static DEVICE_ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf, store_rxbuf);
2136 static DEVICE_ATTR(rxbuf_cur, S_IRUGO, show_rxbuf, NULL);
2137
2138 static struct attribute *xennet_dev_attrs[] = {
2139         &dev_attr_rxbuf_min.attr,
2140         &dev_attr_rxbuf_max.attr,
2141         &dev_attr_rxbuf_cur.attr,
2142         NULL
2143 };
2144
2145 static const struct attribute_group xennet_dev_group = {
2146         .attrs = xennet_dev_attrs
2147 };
2148 #endif /* CONFIG_SYSFS */
2149
2150 static void xennet_bus_close(struct xenbus_device *dev)
2151 {
2152         int ret;
2153
2154         if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed)
2155                 return;
2156         do {
2157                 xenbus_switch_state(dev, XenbusStateClosing);
2158                 ret = wait_event_timeout(module_wq,
2159                                    xenbus_read_driver_state(dev->otherend) ==
2160                                    XenbusStateClosing ||
2161                                    xenbus_read_driver_state(dev->otherend) ==
2162                                    XenbusStateClosed ||
2163                                    xenbus_read_driver_state(dev->otherend) ==
2164                                    XenbusStateUnknown,
2165                                    XENNET_TIMEOUT);
2166         } while (!ret);
2167
2168         if (xenbus_read_driver_state(dev->otherend) == XenbusStateClosed)
2169                 return;
2170
2171         do {
2172                 xenbus_switch_state(dev, XenbusStateClosed);
2173                 ret = wait_event_timeout(module_wq,
2174                                    xenbus_read_driver_state(dev->otherend) ==
2175                                    XenbusStateClosed ||
2176                                    xenbus_read_driver_state(dev->otherend) ==
2177                                    XenbusStateUnknown,
2178                                    XENNET_TIMEOUT);
2179         } while (!ret);
2180 }
2181
2182 static int xennet_remove(struct xenbus_device *dev)
2183 {
2184         struct netfront_info *info = dev_get_drvdata(&dev->dev);
2185
2186         xennet_bus_close(dev);
2187         xennet_disconnect_backend(info);
2188
2189         if (info->netdev->reg_state == NETREG_REGISTERED)
2190                 unregister_netdev(info->netdev);
2191
2192         if (info->queues) {
2193                 rtnl_lock();
2194                 xennet_destroy_queues(info);
2195                 rtnl_unlock();
2196         }
2197         xennet_free_netdev(info->netdev);
2198
2199         return 0;
2200 }
2201
2202 static const struct xenbus_device_id netfront_ids[] = {
2203         { "vif" },
2204         { "" }
2205 };
2206
2207 static struct xenbus_driver netfront_driver = {
2208         .ids = netfront_ids,
2209         .probe = netfront_probe,
2210         .remove = xennet_remove,
2211         .resume = netfront_resume,
2212         .otherend_changed = netback_changed,
2213 };
2214
2215 static int __init netif_init(void)
2216 {
2217         if (!xen_domain())
2218                 return -ENODEV;
2219
2220         if (!xen_has_pv_nic_devices())
2221                 return -ENODEV;
2222
2223         pr_info("Initialising Xen virtual ethernet driver\n");
2224
2225         /* Allow as many queues as there are CPUs inut max. 8 if user has not
2226          * specified a value.
2227          */
2228         if (xennet_max_queues == 0)
2229                 xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
2230                                           num_online_cpus());
2231
2232         return xenbus_register_frontend(&netfront_driver);
2233 }
2234 module_init(netif_init);
2235
2236
2237 static void __exit netif_exit(void)
2238 {
2239         xenbus_unregister_driver(&netfront_driver);
2240 }
2241 module_exit(netif_exit);
2242
2243 MODULE_DESCRIPTION("Xen virtual network device frontend");
2244 MODULE_LICENSE("GPL");
2245 MODULE_ALIAS("xen:vif");
2246 MODULE_ALIAS("xennet");