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_unload_q);
  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 - MAX_SKB_FRAGS - 2);
 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         for (i = 0; i < num_queues; ++i) {
 355                 queue = &np->queues[i];
 356                 napi_enable(&queue->napi);
 357
 358                 spin_lock_bh(&queue->rx_lock);
 359                 if (netif_carrier_ok(dev)) {
 360                         xennet_alloc_rx_buffers(queue);
 361                         queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
 362                         if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
 363                                 napi_schedule(&queue->napi);
 364                 }
 365                 spin_unlock_bh(&queue->rx_lock);
 366         }
 367
 368         netif_tx_start_all_queues(dev);
 369
 370         return 0;
 371 }
 372
 373 static void xennet_tx_buf_gc(struct netfront_queue *queue)
 374 {
 375         RING_IDX cons, prod;
 376         unsigned short id;
 377         struct sk_buff *skb;
 378         bool more_to_do;
 379
 380         BUG_ON(!netif_carrier_ok(queue->info->netdev));
 381
 382         do {
 383                 prod = queue->tx.sring->rsp_prod;
 384                 rmb(); /* Ensure we see responses up to 'rp'. */
 385
 386                 for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
 387                         struct xen_netif_tx_response *txrsp;
 388
 389                         txrsp = RING_GET_RESPONSE(&queue->tx, cons);
 390                         if (txrsp->status == XEN_NETIF_RSP_NULL)
 391                                 continue;
 392
 393                         id  = txrsp->id;
 394                         skb = queue->tx_skbs[id].skb;
 395                         if (unlikely(gnttab_query_foreign_access(
 396                                 queue->grant_tx_ref[id]) != 0)) {
 397                                 pr_alert("%s: warning -- grant still in use by backend domain\n",
 398                                          __func__);
 399                                 BUG();
 400                         }
 401                         gnttab_end_foreign_access_ref(
 402                                 queue->grant_tx_ref[id], GNTMAP_readonly);
 403                         gnttab_release_grant_reference(
 404                                 &queue->gref_tx_head, queue->grant_tx_ref[id]);
 405                         queue->grant_tx_ref[id] = GRANT_INVALID_REF;
 406                         queue->grant_tx_page[id] = NULL;
 407                         add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, id);
 408                         dev_kfree_skb_irq(skb);
 409                 }
 410
 411                 queue->tx.rsp_cons = prod;
 412
 413                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->tx, more_to_do);
 414         } while (more_to_do);
 415
 416         xennet_maybe_wake_tx(queue);
 417 }
 418
 419 struct xennet_gnttab_make_txreq {
 420         struct netfront_queue *queue;
 421         struct sk_buff *skb;
 422         struct page *page;
 423         struct xen_netif_tx_request *tx; /* Last request */
 424         unsigned int size;
 425 };
 426
 427 static void xennet_tx_setup_grant(unsigned long gfn, unsigned int offset,
 428                                   unsigned int len, void *data)
 429 {
 430         struct xennet_gnttab_make_txreq *info = data;
 431         unsigned int id;
 432         struct xen_netif_tx_request *tx;
 433         grant_ref_t ref;
 434         /* convenient aliases */
 435         struct page *page = info->page;
 436         struct netfront_queue *queue = info->queue;
 437         struct sk_buff *skb = info->skb;
 438
 439         id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
 440         tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 441         ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
 442         WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 443
 444         gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
 445                                         gfn, GNTMAP_readonly);
 446
 447         queue->tx_skbs[id].skb = skb;
 448         queue->grant_tx_page[id] = page;
 449         queue->grant_tx_ref[id] = ref;
 450
 451         tx->id = id;
 452         tx->gref = ref;
 453         tx->offset = offset;
 454         tx->size = len;
 455         tx->flags = 0;
 456
 457         info->tx = tx;
 458         info->size += tx->size;
 459 }
 460
 461 static struct xen_netif_tx_request *xennet_make_first_txreq(
 462         struct netfront_queue *queue, struct sk_buff *skb,
 463         struct page *page, unsigned int offset, unsigned int len)
 464 {
 465         struct xennet_gnttab_make_txreq info = {
 466                 .queue = queue,
 467                 .skb = skb,
 468                 .page = page,
 469                 .size = 0,
 470         };
 471
 472         gnttab_for_one_grant(page, offset, len, xennet_tx_setup_grant, &info);
 473
 474         return info.tx;
 475 }
 476
 477 static void xennet_make_one_txreq(unsigned long gfn, unsigned int offset,
 478                                   unsigned int len, void *data)
 479 {
 480         struct xennet_gnttab_make_txreq *info = data;
 481
 482         info->tx->flags |= XEN_NETTXF_more_data;
 483         skb_get(info->skb);
 484         xennet_tx_setup_grant(gfn, offset, len, data);
 485 }
 486
 487 static struct xen_netif_tx_request *xennet_make_txreqs(
 488         struct netfront_queue *queue, struct xen_netif_tx_request *tx,
 489         struct sk_buff *skb, struct page *page,
 490         unsigned int offset, unsigned int len)
 491 {
 492         struct xennet_gnttab_make_txreq info = {
 493                 .queue = queue,
 494                 .skb = skb,
 495                 .tx = tx,
 496         };
 497
 498         /* Skip unused frames from start of page */
 499         page += offset >> PAGE_SHIFT;
 500         offset &= ~PAGE_MASK;
 501
 502         while (len) {
 503                 info.page = page;
 504                 info.size = 0;
 505
 506                 gnttab_foreach_grant_in_range(page, offset, len,
 507                                               xennet_make_one_txreq,
 508                                               &info);
 509
 510                 page++;
 511                 offset = 0;
 512                 len -= info.size;
 513         }
 514
 515         return info.tx;
 516 }
 517
 518 /*
 519  * Count how many ring slots are required to send this skb. Each frag
 520  * might be a compound page.
 521  */
 522 static int xennet_count_skb_slots(struct sk_buff *skb)
 523 {
 524         int i, frags = skb_shinfo(skb)->nr_frags;
 525         int slots;
 526
 527         slots = gnttab_count_grant(offset_in_page(skb->data),
 528                                    skb_headlen(skb));
 529
 530         for (i = 0; i < frags; i++) {
 531                 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 532                 unsigned long size = skb_frag_size(frag);
 533                 unsigned long offset = frag->page_offset;
 534
 535                 /* Skip unused frames from start of page */
 536                 offset &= ~PAGE_MASK;
 537
 538                 slots += gnttab_count_grant(offset, size);
 539         }
 540
 541         return slots;
 542 }
 543
 544 static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
 545                                void *accel_priv, select_queue_fallback_t fallback)
 546 {
 547         unsigned int num_queues = dev->real_num_tx_queues;
 548         u32 hash;
 549         u16 queue_idx;
 550
 551         /* First, check if there is only one queue */
 552         if (num_queues == 1) {
 553                 queue_idx = 0;
 554         } else {
 555                 hash = skb_get_hash(skb);
 556                 queue_idx = hash % num_queues;
 557         }
 558
 559         return queue_idx;
 560 }
 561
 562 #define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
 563
 564 static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 565 {
 566         struct netfront_info *np = netdev_priv(dev);
 567         struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
 568         struct xen_netif_tx_request *tx, *first_tx;
 569         unsigned int i;
 570         int notify;
 571         int slots;
 572         struct page *page;
 573         unsigned int offset;
 574         unsigned int len;
 575         unsigned long flags;
 576         struct netfront_queue *queue = NULL;
 577         unsigned int num_queues = dev->real_num_tx_queues;
 578         u16 queue_index;
 579         struct sk_buff *nskb;
 580
 581         /* Drop the packet if no queues are set up */
 582         if (num_queues < 1)
 583                 goto drop;
 584         /* Determine which queue to transmit this SKB on */
 585         queue_index = skb_get_queue_mapping(skb);
 586         queue = &np->queues[queue_index];
 587
 588         /* If skb->len is too big for wire format, drop skb and alert
 589          * user about misconfiguration.
 590          */
 591         if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
 592                 net_alert_ratelimited(
 593                         "xennet: skb->len = %u, too big for wire format\n",
 594                         skb->len);
 595                 goto drop;
 596         }
 597
 598         slots = xennet_count_skb_slots(skb);
 599         if (unlikely(slots > MAX_XEN_SKB_FRAGS + 1)) {
 600                 net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
 601                                     slots, skb->len);
 602                 if (skb_linearize(skb))
 603                         goto drop;
 604         }
 605
 606         page = virt_to_page(skb->data);
 607         offset = offset_in_page(skb->data);
 608
 609         /* The first req should be at least ETH_HLEN size or the packet will be
 610          * dropped by netback.
 611          */
 612         if (unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
 613                 nskb = skb_copy(skb, GFP_ATOMIC);
 614                 if (!nskb)
 615                         goto drop;
 616                 dev_consume_skb_any(skb);
 617                 skb = nskb;
 618                 page = virt_to_page(skb->data);
 619                 offset = offset_in_page(skb->data);
 620         }
 621
 622         len = skb_headlen(skb);
 623
 624         spin_lock_irqsave(&queue->tx_lock, flags);
 625
 626         if (unlikely(!netif_carrier_ok(dev) ||
 627                      (slots > 1 && !xennet_can_sg(dev)) ||
 628                      netif_needs_gso(skb, netif_skb_features(skb)))) {
 629                 spin_unlock_irqrestore(&queue->tx_lock, flags);
 630                 goto drop;
 631         }
 632
 633         /* First request for the linear area. */
 634         first_tx = tx = xennet_make_first_txreq(queue, skb,
 635                                                 page, offset, len);
 636         offset += tx->size;
 637         if (offset == PAGE_SIZE) {
 638                 page++;
 639                 offset = 0;
 640         }
 641         len -= tx->size;
 642
 643         if (skb->ip_summed == CHECKSUM_PARTIAL)
 644                 /* local packet? */
 645                 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
 646         else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 647                 /* remote but checksummed. */
 648                 tx->flags |= XEN_NETTXF_data_validated;
 649
 650         /* Optional extra info after the first request. */
 651         if (skb_shinfo(skb)->gso_size) {
 652                 struct xen_netif_extra_info *gso;
 653
 654                 gso = (struct xen_netif_extra_info *)
 655                         RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 656
 657                 tx->flags |= XEN_NETTXF_extra_info;
 658
 659                 gso->u.gso.size = skb_shinfo(skb)->gso_size;
 660                 gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
 661                         XEN_NETIF_GSO_TYPE_TCPV6 :
 662                         XEN_NETIF_GSO_TYPE_TCPV4;
 663                 gso->u.gso.pad = 0;
 664                 gso->u.gso.features = 0;
 665
 666                 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 667                 gso->flags = 0;
 668         }
 669
 670         /* Requests for the rest of the linear area. */
 671         tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);
 672
 673         /* Requests for all the frags. */
 674         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 675                 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 676                 tx = xennet_make_txreqs(queue, tx, skb,
 677                                         skb_frag_page(frag), frag->page_offset,
 678                                         skb_frag_size(frag));
 679         }
 680
 681         /* First request has the packet length. */
 682         first_tx->size = skb->len;
 683
 684         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
 685         if (notify)
 686                 notify_remote_via_irq(queue->tx_irq);
 687
 688         u64_stats_update_begin(&tx_stats->syncp);
 689         tx_stats->bytes += skb->len;
 690         tx_stats->packets++;
 691         u64_stats_update_end(&tx_stats->syncp);
 692
 693         /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
 694         xennet_tx_buf_gc(queue);
 695
 696         if (!netfront_tx_slot_available(queue))
 697                 netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
 698
 699         spin_unlock_irqrestore(&queue->tx_lock, flags);
 700
 701         return NETDEV_TX_OK;
 702
 703  drop:
 704         dev->stats.tx_dropped++;
 705         dev_kfree_skb_any(skb);
 706         return NETDEV_TX_OK;
 707 }
 708
 709 static int xennet_close(struct net_device *dev)
 710 {
 711         struct netfront_info *np = netdev_priv(dev);
 712         unsigned int num_queues = dev->real_num_tx_queues;
 713         unsigned int i;
 714         struct netfront_queue *queue;
 715         netif_tx_stop_all_queues(np->netdev);
 716         for (i = 0; i < num_queues; ++i) {
 717                 queue = &np->queues[i];
 718                 napi_disable(&queue->napi);
 719         }
 720         return 0;
 721 }
 722
 723 static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
 724                                 grant_ref_t ref)
 725 {
 726         int new = xennet_rxidx(queue->rx.req_prod_pvt);
 727
 728         BUG_ON(queue->rx_skbs[new]);
 729         queue->rx_skbs[new] = skb;
 730         queue->grant_rx_ref[new] = ref;
 731         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
 732         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
 733         queue->rx.req_prod_pvt++;
 734 }
 735
 736 static int xennet_get_extras(struct netfront_queue *queue,
 737                              struct xen_netif_extra_info *extras,
 738                              RING_IDX rp)
 739
 740 {
 741         struct xen_netif_extra_info *extra;
 742         struct device *dev = &queue->info->netdev->dev;
 743         RING_IDX cons = queue->rx.rsp_cons;
 744         int err = 0;
 745
 746         do {
 747                 struct sk_buff *skb;
 748                 grant_ref_t ref;
 749
 750                 if (unlikely(cons + 1 == rp)) {
 751                         if (net_ratelimit())
 752                                 dev_warn(dev, "Missing extra info\n");
 753                         err = -EBADR;
 754                         break;
 755                 }
 756
 757                 extra = (struct xen_netif_extra_info *)
 758                         RING_GET_RESPONSE(&queue->rx, ++cons);
 759
 760                 if (unlikely(!extra->type ||
 761                              extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 762                         if (net_ratelimit())
 763                                 dev_warn(dev, "Invalid extra type: %d\n",
 764                                         extra->type);
 765                         err = -EINVAL;
 766                 } else {
 767                         memcpy(&extras[extra->type - 1], extra,
 768                                sizeof(*extra));
 769                 }
 770
 771                 skb = xennet_get_rx_skb(queue, cons);
 772                 ref = xennet_get_rx_ref(queue, cons);
 773                 xennet_move_rx_slot(queue, skb, ref);
 774         } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
 775
 776         queue->rx.rsp_cons = cons;
 777         return err;
 778 }
 779
 780 static int xennet_get_responses(struct netfront_queue *queue,
 781                                 struct netfront_rx_info *rinfo, RING_IDX rp,
 782                                 struct sk_buff_head *list)
 783 {
 784         struct xen_netif_rx_response *rx = &rinfo->rx;
 785         struct xen_netif_extra_info *extras = rinfo->extras;
 786         struct device *dev = &queue->info->netdev->dev;
 787         RING_IDX cons = queue->rx.rsp_cons;
 788         struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
 789         grant_ref_t ref = xennet_get_rx_ref(queue, cons);
 790         int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
 791         int slots = 1;
 792         int err = 0;
 793         unsigned long ret;
 794
 795         if (rx->flags & XEN_NETRXF_extra_info) {
 796                 err = xennet_get_extras(queue, extras, rp);
 797                 cons = queue->rx.rsp_cons;
 798         }
 799
 800         for (;;) {
 801                 if (unlikely(rx->status < 0 ||
 802                              rx->offset + rx->status > XEN_PAGE_SIZE)) {
 803                         if (net_ratelimit())
 804                                 dev_warn(dev, "rx->offset: %u, size: %d\n",
 805                                          rx->offset, rx->status);
 806                         xennet_move_rx_slot(queue, skb, ref);
 807                         err = -EINVAL;
 808                         goto next;
 809                 }
 810
 811                 /*
 812                  * This definitely indicates a bug, either in this driver or in
 813                  * the backend driver. In future this should flag the bad
 814                  * situation to the system controller to reboot the backend.
 815                  */
 816                 if (ref == GRANT_INVALID_REF) {
 817                         if (net_ratelimit())
 818                                 dev_warn(dev, "Bad rx response id %d.\n",
 819                                          rx->id);
 820                         err = -EINVAL;
 821                         goto next;
 822                 }
 823
 824                 ret = gnttab_end_foreign_access_ref(ref, 0);
 825                 BUG_ON(!ret);
 826
 827                 gnttab_release_grant_reference(&queue->gref_rx_head, ref);
 828
 829                 __skb_queue_tail(list, skb);
 830
 831 next:
 832                 if (!(rx->flags & XEN_NETRXF_more_data))
 833                         break;
 834
 835                 if (cons + slots == rp) {
 836                         if (net_ratelimit())
 837                                 dev_warn(dev, "Need more slots\n");
 838                         err = -ENOENT;
 839                         break;
 840                 }
 841
 842                 rx = RING_GET_RESPONSE(&queue->rx, cons + slots);
 843                 skb = xennet_get_rx_skb(queue, cons + slots);
 844                 ref = xennet_get_rx_ref(queue, cons + slots);
 845                 slots++;
 846         }
 847
 848         if (unlikely(slots > max)) {
 849                 if (net_ratelimit())
 850                         dev_warn(dev, "Too many slots\n");
 851                 err = -E2BIG;
 852         }
 853
 854         if (unlikely(err))
 855                 queue->rx.rsp_cons = cons + slots;
 856
 857         return err;
 858 }
 859
 860 static int xennet_set_skb_gso(struct sk_buff *skb,
 861                               struct xen_netif_extra_info *gso)
 862 {
 863         if (!gso->u.gso.size) {
 864                 if (net_ratelimit())
 865                         pr_warn("GSO size must not be zero\n");
 866                 return -EINVAL;
 867         }
 868
 869         if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
 870             gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
 871                 if (net_ratelimit())
 872                         pr_warn("Bad GSO type %d\n", gso->u.gso.type);
 873                 return -EINVAL;
 874         }
 875
 876         skb_shinfo(skb)->gso_size = gso->u.gso.size;
 877         skb_shinfo(skb)->gso_type =
 878                 (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
 879                 SKB_GSO_TCPV4 :
 880                 SKB_GSO_TCPV6;
 881
 882         /* Header must be checked, and gso_segs computed. */
 883         skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 884         skb_shinfo(skb)->gso_segs = 0;
 885
 886         return 0;
 887 }
 888
 889 static RING_IDX xennet_fill_frags(struct netfront_queue *queue,
 890                                   struct sk_buff *skb,
 891                                   struct sk_buff_head *list)
 892 {
 893         struct skb_shared_info *shinfo = skb_shinfo(skb);
 894         RING_IDX cons = queue->rx.rsp_cons;
 895         struct sk_buff *nskb;
 896
 897         while ((nskb = __skb_dequeue(list))) {
 898                 struct xen_netif_rx_response *rx =
 899                         RING_GET_RESPONSE(&queue->rx, ++cons);
 900                 skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
 901
 902                 if (shinfo->nr_frags == MAX_SKB_FRAGS) {
 903                         unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 904
 905                         BUG_ON(pull_to <= skb_headlen(skb));
 906                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 907                 }
 908                 BUG_ON(shinfo->nr_frags >= MAX_SKB_FRAGS);
 909
 910                 skb_add_rx_frag(skb, shinfo->nr_frags, skb_frag_page(nfrag),
 911                                 rx->offset, rx->status, PAGE_SIZE);
 912
 913                 skb_shinfo(nskb)->nr_frags = 0;
 914                 kfree_skb(nskb);
 915         }
 916
 917         return cons;
 918 }
 919
 920 static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 921 {
 922         bool recalculate_partial_csum = false;
 923
 924         /*
 925          * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 926          * peers can fail to set NETRXF_csum_blank when sending a GSO
 927          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 928          * recalculate the partial checksum.
 929          */
 930         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 931                 struct netfront_info *np = netdev_priv(dev);
 932                 atomic_inc(&np->rx_gso_checksum_fixup);
 933                 skb->ip_summed = CHECKSUM_PARTIAL;
 934                 recalculate_partial_csum = true;
 935         }
 936
 937         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 938         if (skb->ip_summed != CHECKSUM_PARTIAL)
 939                 return 0;
 940
 941         return skb_checksum_setup(skb, recalculate_partial_csum);
 942 }
 943
 944 static int handle_incoming_queue(struct netfront_queue *queue,
 945                                  struct sk_buff_head *rxq)
 946 {
 947         struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats);
 948         int packets_dropped = 0;
 949         struct sk_buff *skb;
 950
 951         while ((skb = __skb_dequeue(rxq)) != NULL) {
 952                 int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 953
 954                 if (pull_to > skb_headlen(skb))
 955                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 956
 957                 /* Ethernet work: Delayed to here as it peeks the header. */
 958                 skb->protocol = eth_type_trans(skb, queue->info->netdev);
 959                 skb_reset_network_header(skb);
 960
 961                 if (checksum_setup(queue->info->netdev, skb)) {
 962                         kfree_skb(skb);
 963                         packets_dropped++;
 964                         queue->info->netdev->stats.rx_errors++;
 965                         continue;
 966                 }
 967
 968                 u64_stats_update_begin(&rx_stats->syncp);
 969                 rx_stats->packets++;
 970                 rx_stats->bytes += skb->len;
 971                 u64_stats_update_end(&rx_stats->syncp);
 972
 973                 /* Pass it up. */
 974                 napi_gro_receive(&queue->napi, skb);
 975         }
 976
 977         return packets_dropped;
 978 }
 979
 980 static int xennet_poll(struct napi_struct *napi, int budget)
 981 {
 982         struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
 983         struct net_device *dev = queue->info->netdev;
 984         struct sk_buff *skb;
 985         struct netfront_rx_info rinfo;
 986         struct xen_netif_rx_response *rx = &rinfo.rx;
 987         struct xen_netif_extra_info *extras = rinfo.extras;
 988         RING_IDX i, rp;
 989         int work_done;
 990         struct sk_buff_head rxq;
 991         struct sk_buff_head errq;
 992         struct sk_buff_head tmpq;
 993         int err;
 994
 995         spin_lock(&queue->rx_lock);
 996
 997         skb_queue_head_init(&rxq);
 998         skb_queue_head_init(&errq);
 999         skb_queue_head_init(&tmpq);
1000
1001         rp = queue->rx.sring->rsp_prod;
1002         rmb(); /* Ensure we see queued responses up to 'rp'. */
1003
1004         i = queue->rx.rsp_cons;
1005         work_done = 0;
1006         while ((i != rp) && (work_done < budget)) {
1007                 memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
1008                 memset(extras, 0, sizeof(rinfo.extras));
1009
1010                 err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
1011
1012                 if (unlikely(err)) {
1013 err:
1014                         while ((skb = __skb_dequeue(&tmpq)))
1015                                 __skb_queue_tail(&errq, skb);
1016                         dev->stats.rx_errors++;
1017                         i = queue->rx.rsp_cons;
1018                         continue;
1019                 }
1020
1021                 skb = __skb_dequeue(&tmpq);
1022
1023                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1024                         struct xen_netif_extra_info *gso;
1025                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1026
1027                         if (unlikely(xennet_set_skb_gso(skb, gso))) {
1028                                 __skb_queue_head(&tmpq, skb);
1029                                 queue->rx.rsp_cons += skb_queue_len(&tmpq);
1030                                 goto err;
1031                         }
1032                 }
1033
1034                 NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1035                 if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1036                         NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1037
1038                 skb_shinfo(skb)->frags[0].page_offset = rx->offset;
1039                 skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1040                 skb->data_len = rx->status;
1041                 skb->len += rx->status;
1042
1043                 i = xennet_fill_frags(queue, skb, &tmpq);
1044
1045                 if (rx->flags & XEN_NETRXF_csum_blank)
1046                         skb->ip_summed = CHECKSUM_PARTIAL;
1047                 else if (rx->flags & XEN_NETRXF_data_validated)
1048                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1049
1050                 __skb_queue_tail(&rxq, skb);
1051
1052                 queue->rx.rsp_cons = ++i;
1053                 work_done++;
1054         }
1055
1056         __skb_queue_purge(&errq);
1057
1058         work_done -= handle_incoming_queue(queue, &rxq);
1059
1060         xennet_alloc_rx_buffers(queue);
1061
1062         if (work_done < budget) {
1063                 int more_to_do = 0;
1064
1065                 napi_complete_done(napi, work_done);
1066
1067                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
1068                 if (more_to_do)
1069                         napi_schedule(napi);
1070         }
1071
1072         spin_unlock(&queue->rx_lock);
1073
1074         return work_done;
1075 }
1076
1077 static int xennet_change_mtu(struct net_device *dev, int mtu)
1078 {
1079         int max = xennet_can_sg(dev) ? XEN_NETIF_MAX_TX_SIZE : ETH_DATA_LEN;
1080
1081         if (mtu > max)
1082                 return -EINVAL;
1083         dev->mtu = mtu;
1084         return 0;
1085 }
1086
1087 static void xennet_get_stats64(struct net_device *dev,
1088                                struct rtnl_link_stats64 *tot)
1089 {
1090         struct netfront_info *np = netdev_priv(dev);
1091         int cpu;
1092
1093         for_each_possible_cpu(cpu) {
1094                 struct netfront_stats *rx_stats = per_cpu_ptr(np->rx_stats, cpu);
1095                 struct netfront_stats *tx_stats = per_cpu_ptr(np->tx_stats, cpu);
1096                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1097                 unsigned int start;
1098
1099                 do {
1100                         start = u64_stats_fetch_begin_irq(&tx_stats->syncp);
1101                         tx_packets = tx_stats->packets;
1102                         tx_bytes = tx_stats->bytes;
1103                 } while (u64_stats_fetch_retry_irq(&tx_stats->syncp, start));
1104
1105                 do {
1106                         start = u64_stats_fetch_begin_irq(&rx_stats->syncp);
1107                         rx_packets = rx_stats->packets;
1108                         rx_bytes = rx_stats->bytes;
1109                 } while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start));
1110
1111                 tot->rx_packets += rx_packets;
1112                 tot->tx_packets += tx_packets;
1113                 tot->rx_bytes   += rx_bytes;
1114                 tot->tx_bytes   += tx_bytes;
1115         }
1116
1117         tot->rx_errors  = dev->stats.rx_errors;
1118         tot->tx_dropped = dev->stats.tx_dropped;
1119 }
1120
1121 static void xennet_release_tx_bufs(struct netfront_queue *queue)
1122 {
1123         struct sk_buff *skb;
1124         int i;
1125
1126         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1127                 /* Skip over entries which are actually freelist references */
1128                 if (skb_entry_is_link(&queue->tx_skbs[i]))
1129                         continue;
1130
1131                 skb = queue->tx_skbs[i].skb;
1132                 get_page(queue->grant_tx_page[i]);
1133                 gnttab_end_foreign_access(queue->grant_tx_ref[i],
1134                                           GNTMAP_readonly,
1135                                           (unsigned long)page_address(queue->grant_tx_page[i]));
1136                 queue->grant_tx_page[i] = NULL;
1137                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1138                 add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, i);
1139                 dev_kfree_skb_irq(skb);
1140         }
1141 }
1142
1143 static void xennet_release_rx_bufs(struct netfront_queue *queue)
1144 {
1145         int id, ref;
1146
1147         spin_lock_bh(&queue->rx_lock);
1148
1149         for (id = 0; id < NET_RX_RING_SIZE; id++) {
1150                 struct sk_buff *skb;
1151                 struct page *page;
1152
1153                 skb = queue->rx_skbs[id];
1154                 if (!skb)
1155                         continue;
1156
1157                 ref = queue->grant_rx_ref[id];
1158                 if (ref == GRANT_INVALID_REF)
1159                         continue;
1160
1161                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
1162
1163                 /* gnttab_end_foreign_access() needs a page ref until
1164                  * foreign access is ended (which may be deferred).
1165                  */
1166                 get_page(page);
1167                 gnttab_end_foreign_access(ref, 0,
1168                                           (unsigned long)page_address(page));
1169                 queue->grant_rx_ref[id] = GRANT_INVALID_REF;
1170
1171                 kfree_skb(skb);
1172         }
1173
1174         spin_unlock_bh(&queue->rx_lock);
1175 }
1176
1177 static netdev_features_t xennet_fix_features(struct net_device *dev,
1178         netdev_features_t features)
1179 {
1180         struct netfront_info *np = netdev_priv(dev);
1181
1182         if (features & NETIF_F_SG &&
1183             !xenbus_read_unsigned(np->xbdev->otherend, "feature-sg", 0))
1184                 features &= ~NETIF_F_SG;
1185
1186         if (features & NETIF_F_IPV6_CSUM &&
1187             !xenbus_read_unsigned(np->xbdev->otherend,
1188                                   "feature-ipv6-csum-offload", 0))
1189                 features &= ~NETIF_F_IPV6_CSUM;
1190
1191         if (features & NETIF_F_TSO &&
1192             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv4", 0))
1193                 features &= ~NETIF_F_TSO;
1194
1195         if (features & NETIF_F_TSO6 &&
1196             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv6", 0))
1197                 features &= ~NETIF_F_TSO6;
1198
1199         return features;
1200 }
1201
1202 static int xennet_set_features(struct net_device *dev,
1203         netdev_features_t features)
1204 {
1205         if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1206                 netdev_info(dev, "Reducing MTU because no SG offload");
1207                 dev->mtu = ETH_DATA_LEN;
1208         }
1209
1210         return 0;
1211 }
1212
1213 static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1214 {
1215         struct netfront_queue *queue = dev_id;
1216         unsigned long flags;
1217
1218         spin_lock_irqsave(&queue->tx_lock, flags);
1219         xennet_tx_buf_gc(queue);
1220         spin_unlock_irqrestore(&queue->tx_lock, flags);
1221
1222         return IRQ_HANDLED;
1223 }
1224
1225 static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1226 {
1227         struct netfront_queue *queue = dev_id;
1228         struct net_device *dev = queue->info->netdev;
1229
1230         if (likely(netif_carrier_ok(dev) &&
1231                    RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)))
1232                 napi_schedule(&queue->napi);
1233
1234         return IRQ_HANDLED;
1235 }
1236
1237 static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1238 {
1239         xennet_tx_interrupt(irq, dev_id);
1240         xennet_rx_interrupt(irq, dev_id);
1241         return IRQ_HANDLED;
1242 }
1243
1244 #ifdef CONFIG_NET_POLL_CONTROLLER
1245 static void xennet_poll_controller(struct net_device *dev)
1246 {
1247         /* Poll each queue */
1248         struct netfront_info *info = netdev_priv(dev);
1249         unsigned int num_queues = dev->real_num_tx_queues;
1250         unsigned int i;
1251         for (i = 0; i < num_queues; ++i)
1252                 xennet_interrupt(0, &info->queues[i]);
1253 }
1254 #endif
1255
1256 static const struct net_device_ops xennet_netdev_ops = {
1257         .ndo_open            = xennet_open,
1258         .ndo_stop            = xennet_close,
1259         .ndo_start_xmit      = xennet_start_xmit,
1260         .ndo_change_mtu      = xennet_change_mtu,
1261         .ndo_get_stats64     = xennet_get_stats64,
1262         .ndo_set_mac_address = eth_mac_addr,
1263         .ndo_validate_addr   = eth_validate_addr,
1264         .ndo_fix_features    = xennet_fix_features,
1265         .ndo_set_features    = xennet_set_features,
1266         .ndo_select_queue    = xennet_select_queue,
1267 #ifdef CONFIG_NET_POLL_CONTROLLER
1268         .ndo_poll_controller = xennet_poll_controller,
1269 #endif
1270 };
1271
1272 static void xennet_free_netdev(struct net_device *netdev)
1273 {
1274         struct netfront_info *np = netdev_priv(netdev);
1275
1276         free_percpu(np->rx_stats);
1277         free_percpu(np->tx_stats);
1278         free_netdev(netdev);
1279 }
1280
1281 static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1282 {
1283         int err;
1284         struct net_device *netdev;
1285         struct netfront_info *np;
1286
1287         netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues);
1288         if (!netdev)
1289                 return ERR_PTR(-ENOMEM);
1290
1291         np                   = netdev_priv(netdev);
1292         np->xbdev            = dev;
1293
1294         np->queues = NULL;
1295
1296         err = -ENOMEM;
1297         np->rx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1298         if (np->rx_stats == NULL)
1299                 goto exit;
1300         np->tx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1301         if (np->tx_stats == NULL)
1302                 goto exit;
1303
1304         netdev->netdev_ops      = &xennet_netdev_ops;
1305
1306         netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1307                                   NETIF_F_GSO_ROBUST;
1308         netdev->hw_features     = NETIF_F_SG |
1309                                   NETIF_F_IPV6_CSUM |
1310                                   NETIF_F_TSO | NETIF_F_TSO6;
1311
1312         /*
1313          * Assume that all hw features are available for now. This set
1314          * will be adjusted by the call to netdev_update_features() in
1315          * xennet_connect() which is the earliest point where we can
1316          * negotiate with the backend regarding supported features.
1317          */
1318         netdev->features |= netdev->hw_features;
1319
1320         netdev->ethtool_ops = &xennet_ethtool_ops;
1321         netdev->min_mtu = ETH_MIN_MTU;
1322         netdev->max_mtu = XEN_NETIF_MAX_TX_SIZE;
1323         SET_NETDEV_DEV(netdev, &dev->dev);
1324
1325         np->netdev = netdev;
1326
1327         netif_carrier_off(netdev);
1328
1329         return netdev;
1330
1331  exit:
1332         xennet_free_netdev(netdev);
1333         return ERR_PTR(err);
1334 }
1335
1336 /**
1337  * Entry point to this code when a new device is created.  Allocate the basic
1338  * structures and the ring buffers for communication with the backend, and
1339  * inform the backend of the appropriate details for those.
1340  */
1341 static int netfront_probe(struct xenbus_device *dev,
1342                           const struct xenbus_device_id *id)
1343 {
1344         int err;
1345         struct net_device *netdev;
1346         struct netfront_info *info;
1347
1348         netdev = xennet_create_dev(dev);
1349         if (IS_ERR(netdev)) {
1350                 err = PTR_ERR(netdev);
1351                 xenbus_dev_fatal(dev, err, "creating netdev");
1352                 return err;
1353         }
1354
1355         info = netdev_priv(netdev);
1356         dev_set_drvdata(&dev->dev, info);
1357 #ifdef CONFIG_SYSFS
1358         info->netdev->sysfs_groups[0] = &xennet_dev_group;
1359 #endif
1360         err = register_netdev(info->netdev);
1361         if (err) {
1362                 pr_warn("%s: register_netdev err=%d\n", __func__, err);
1363                 goto fail;
1364         }
1365
1366         return 0;
1367
1368  fail:
1369         xennet_free_netdev(netdev);
1370         dev_set_drvdata(&dev->dev, NULL);
1371         return err;
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
1607         spin_lock_init(&queue->tx_lock);
1608         spin_lock_init(&queue->rx_lock);
1609
1610         timer_setup(&queue->rx_refill_timer, rx_refill_timeout, 0);
1611
1612         snprintf(queue->name, sizeof(queue->name), "%s-q%u",
1613                  queue->info->netdev->name, queue->id);
1614
1615         /* Initialise tx_skbs as a free chain containing every entry. */
1616         queue->tx_skb_freelist = 0;
1617         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1618                 skb_entry_set_link(&queue->tx_skbs[i], i+1);
1619                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1620                 queue->grant_tx_page[i] = NULL;
1621         }
1622
1623         /* Clear out rx_skbs */
1624         for (i = 0; i < NET_RX_RING_SIZE; i++) {
1625                 queue->rx_skbs[i] = NULL;
1626                 queue->grant_rx_ref[i] = GRANT_INVALID_REF;
1627         }
1628
1629         /* A grant for every tx ring slot */
1630         if (gnttab_alloc_grant_references(NET_TX_RING_SIZE,
1631                                           &queue->gref_tx_head) < 0) {
1632                 pr_alert("can't alloc tx grant refs\n");
1633                 err = -ENOMEM;
1634                 goto exit;
1635         }
1636
1637         /* A grant for every rx ring slot */
1638         if (gnttab_alloc_grant_references(NET_RX_RING_SIZE,
1639                                           &queue->gref_rx_head) < 0) {
1640                 pr_alert("can't alloc rx grant refs\n");
1641                 err = -ENOMEM;
1642                 goto exit_free_tx;
1643         }
1644
1645         return 0;
1646
1647  exit_free_tx:
1648         gnttab_free_grant_references(queue->gref_tx_head);
1649  exit:
1650         return err;
1651 }
1652
1653 static int write_queue_xenstore_keys(struct netfront_queue *queue,
1654                            struct xenbus_transaction *xbt, int write_hierarchical)
1655 {
1656         /* Write the queue-specific keys into XenStore in the traditional
1657          * way for a single queue, or in a queue subkeys for multiple
1658          * queues.
1659          */
1660         struct xenbus_device *dev = queue->info->xbdev;
1661         int err;
1662         const char *message;
1663         char *path;
1664         size_t pathsize;
1665
1666         /* Choose the correct place to write the keys */
1667         if (write_hierarchical) {
1668                 pathsize = strlen(dev->nodename) + 10;
1669                 path = kzalloc(pathsize, GFP_KERNEL);
1670                 if (!path) {
1671                         err = -ENOMEM;
1672                         message = "out of memory while writing ring references";
1673                         goto error;
1674                 }
1675                 snprintf(path, pathsize, "%s/queue-%u",
1676                                 dev->nodename, queue->id);
1677         } else {
1678                 path = (char *)dev->nodename;
1679         }
1680
1681         /* Write ring references */
1682         err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u",
1683                         queue->tx_ring_ref);
1684         if (err) {
1685                 message = "writing tx-ring-ref";
1686                 goto error;
1687         }
1688
1689         err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u",
1690                         queue->rx_ring_ref);
1691         if (err) {
1692                 message = "writing rx-ring-ref";
1693                 goto error;
1694         }
1695
1696         /* Write event channels; taking into account both shared
1697          * and split event channel scenarios.
1698          */
1699         if (queue->tx_evtchn == queue->rx_evtchn) {
1700                 /* Shared event channel */
1701                 err = xenbus_printf(*xbt, path,
1702                                 "event-channel", "%u", queue->tx_evtchn);
1703                 if (err) {
1704                         message = "writing event-channel";
1705                         goto error;
1706                 }
1707         } else {
1708                 /* Split event channels */
1709                 err = xenbus_printf(*xbt, path,
1710                                 "event-channel-tx", "%u", queue->tx_evtchn);
1711                 if (err) {
1712                         message = "writing event-channel-tx";
1713                         goto error;
1714                 }
1715
1716                 err = xenbus_printf(*xbt, path,
1717                                 "event-channel-rx", "%u", queue->rx_evtchn);
1718                 if (err) {
1719                         message = "writing event-channel-rx";
1720                         goto error;
1721                 }
1722         }
1723
1724         if (write_hierarchical)
1725                 kfree(path);
1726         return 0;
1727
1728 error:
1729         if (write_hierarchical)
1730                 kfree(path);
1731         xenbus_dev_fatal(dev, err, "%s", message);
1732         return err;
1733 }
1734
1735 static void xennet_destroy_queues(struct netfront_info *info)
1736 {
1737         unsigned int i;
1738
1739         rtnl_lock();
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         rtnl_unlock();
1750
1751         kfree(info->queues);
1752         info->queues = NULL;
1753 }
1754
1755 static int xennet_create_queues(struct netfront_info *info,
1756                                 unsigned int *num_queues)
1757 {
1758         unsigned int i;
1759         int ret;
1760
1761         info->queues = kcalloc(*num_queues, sizeof(struct netfront_queue),
1762                                GFP_KERNEL);
1763         if (!info->queues)
1764                 return -ENOMEM;
1765
1766         rtnl_lock();
1767
1768         for (i = 0; i < *num_queues; i++) {
1769                 struct netfront_queue *queue = &info->queues[i];
1770
1771                 queue->id = i;
1772                 queue->info = info;
1773
1774                 ret = xennet_init_queue(queue);
1775                 if (ret < 0) {
1776                         dev_warn(&info->netdev->dev,
1777                                  "only created %d queues\n", i);
1778                         *num_queues = i;
1779                         break;
1780                 }
1781
1782                 netif_napi_add(queue->info->netdev, &queue->napi,
1783                                xennet_poll, 64);
1784                 if (netif_running(info->netdev))
1785                         napi_enable(&queue->napi);
1786         }
1787
1788         netif_set_real_num_tx_queues(info->netdev, *num_queues);
1789
1790         rtnl_unlock();
1791
1792         if (*num_queues == 0) {
1793                 dev_err(&info->netdev->dev, "no queues\n");
1794                 return -EINVAL;
1795         }
1796         return 0;
1797 }
1798
1799 /* Common code used when first setting up, and when resuming. */
1800 static int talk_to_netback(struct xenbus_device *dev,
1801                            struct netfront_info *info)
1802 {
1803         const char *message;
1804         struct xenbus_transaction xbt;
1805         int err;
1806         unsigned int feature_split_evtchn;
1807         unsigned int i = 0;
1808         unsigned int max_queues = 0;
1809         struct netfront_queue *queue = NULL;
1810         unsigned int num_queues = 1;
1811
1812         info->netdev->irq = 0;
1813
1814         /* Check if backend supports multiple queues */
1815         max_queues = xenbus_read_unsigned(info->xbdev->otherend,
1816                                           "multi-queue-max-queues", 1);
1817         num_queues = min(max_queues, xennet_max_queues);
1818
1819         /* Check feature-split-event-channels */
1820         feature_split_evtchn = xenbus_read_unsigned(info->xbdev->otherend,
1821                                         "feature-split-event-channels", 0);
1822
1823         /* Read mac addr. */
1824         err = xen_net_read_mac(dev, info->netdev->dev_addr);
1825         if (err) {
1826                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1827                 goto out;
1828         }
1829
1830         if (info->queues)
1831                 xennet_destroy_queues(info);
1832
1833         err = xennet_create_queues(info, &num_queues);
1834         if (err < 0) {
1835                 xenbus_dev_fatal(dev, err, "creating queues");
1836                 kfree(info->queues);
1837                 info->queues = NULL;
1838                 goto out;
1839         }
1840
1841         /* Create shared ring, alloc event channel -- for each queue */
1842         for (i = 0; i < num_queues; ++i) {
1843                 queue = &info->queues[i];
1844                 err = setup_netfront(dev, queue, feature_split_evtchn);
1845                 if (err)
1846                         goto destroy_ring;
1847         }
1848
1849 again:
1850         err = xenbus_transaction_start(&xbt);
1851         if (err) {
1852                 xenbus_dev_fatal(dev, err, "starting transaction");
1853                 goto destroy_ring;
1854         }
1855
1856         if (xenbus_exists(XBT_NIL,
1857                           info->xbdev->otherend, "multi-queue-max-queues")) {
1858                 /* Write the number of queues */
1859                 err = xenbus_printf(xbt, dev->nodename,
1860                                     "multi-queue-num-queues", "%u", num_queues);
1861                 if (err) {
1862                         message = "writing multi-queue-num-queues";
1863                         goto abort_transaction_no_dev_fatal;
1864                 }
1865         }
1866
1867         if (num_queues == 1) {
1868                 err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
1869                 if (err)
1870                         goto abort_transaction_no_dev_fatal;
1871         } else {
1872                 /* Write the keys for each queue */
1873                 for (i = 0; i < num_queues; ++i) {
1874                         queue = &info->queues[i];
1875                         err = write_queue_xenstore_keys(queue, &xbt, 1); /* hierarchical */
1876                         if (err)
1877                                 goto abort_transaction_no_dev_fatal;
1878                 }
1879         }
1880
1881         /* The remaining keys are not queue-specific */
1882         err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1883                             1);
1884         if (err) {
1885                 message = "writing request-rx-copy";
1886                 goto abort_transaction;
1887         }
1888
1889         err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1890         if (err) {
1891                 message = "writing feature-rx-notify";
1892                 goto abort_transaction;
1893         }
1894
1895         err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1896         if (err) {
1897                 message = "writing feature-sg";
1898                 goto abort_transaction;
1899         }
1900
1901         err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1902         if (err) {
1903                 message = "writing feature-gso-tcpv4";
1904                 goto abort_transaction;
1905         }
1906
1907         err = xenbus_write(xbt, dev->nodename, "feature-gso-tcpv6", "1");
1908         if (err) {
1909                 message = "writing feature-gso-tcpv6";
1910                 goto abort_transaction;
1911         }
1912
1913         err = xenbus_write(xbt, dev->nodename, "feature-ipv6-csum-offload",
1914                            "1");
1915         if (err) {
1916                 message = "writing feature-ipv6-csum-offload";
1917                 goto abort_transaction;
1918         }
1919
1920         err = xenbus_transaction_end(xbt, 0);
1921         if (err) {
1922                 if (err == -EAGAIN)
1923                         goto again;
1924                 xenbus_dev_fatal(dev, err, "completing transaction");
1925                 goto destroy_ring;
1926         }
1927
1928         return 0;
1929
1930  abort_transaction:
1931         xenbus_dev_fatal(dev, err, "%s", message);
1932 abort_transaction_no_dev_fatal:
1933         xenbus_transaction_end(xbt, 1);
1934  destroy_ring:
1935         xennet_disconnect_backend(info);
1936         xennet_destroy_queues(info);
1937  out:
1938         device_unregister(&dev->dev);
1939         return err;
1940 }
1941
1942 static int xennet_connect(struct net_device *dev)
1943 {
1944         struct netfront_info *np = netdev_priv(dev);
1945         unsigned int num_queues = 0;
1946         int err;
1947         unsigned int j = 0;
1948         struct netfront_queue *queue = NULL;
1949
1950         if (!xenbus_read_unsigned(np->xbdev->otherend, "feature-rx-copy", 0)) {
1951                 dev_info(&dev->dev,
1952                          "backend does not support copying receive path\n");
1953                 return -ENODEV;
1954         }
1955
1956         err = talk_to_netback(np->xbdev, np);
1957         if (err)
1958                 return err;
1959
1960         /* talk_to_netback() sets the correct number of queues */
1961         num_queues = dev->real_num_tx_queues;
1962
1963         rtnl_lock();
1964         netdev_update_features(dev);
1965         rtnl_unlock();
1966
1967         /*
1968          * All public and private state should now be sane.  Get
1969          * ready to start sending and receiving packets and give the driver
1970          * domain a kick because we've probably just requeued some
1971          * packets.
1972          */
1973         netif_carrier_on(np->netdev);
1974         for (j = 0; j < num_queues; ++j) {
1975                 queue = &np->queues[j];
1976
1977                 notify_remote_via_irq(queue->tx_irq);
1978                 if (queue->tx_irq != queue->rx_irq)
1979                         notify_remote_via_irq(queue->rx_irq);
1980
1981                 spin_lock_irq(&queue->tx_lock);
1982                 xennet_tx_buf_gc(queue);
1983                 spin_unlock_irq(&queue->tx_lock);
1984
1985                 spin_lock_bh(&queue->rx_lock);
1986                 xennet_alloc_rx_buffers(queue);
1987                 spin_unlock_bh(&queue->rx_lock);
1988         }
1989
1990         return 0;
1991 }
1992
1993 /**
1994  * Callback received when the backend's state changes.
1995  */
1996 static void netback_changed(struct xenbus_device *dev,
1997                             enum xenbus_state backend_state)
1998 {
1999         struct netfront_info *np = dev_get_drvdata(&dev->dev);
2000         struct net_device *netdev = np->netdev;
2001
2002         dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
2003
2004         switch (backend_state) {
2005         case XenbusStateInitialising:
2006         case XenbusStateInitialised:
2007         case XenbusStateReconfiguring:
2008         case XenbusStateReconfigured:
2009         case XenbusStateUnknown:
2010                 break;
2011
2012         case XenbusStateInitWait:
2013                 if (dev->state != XenbusStateInitialising)
2014                         break;
2015                 if (xennet_connect(netdev) != 0)
2016                         break;
2017                 xenbus_switch_state(dev, XenbusStateConnected);
2018                 break;
2019
2020         case XenbusStateConnected:
2021                 netdev_notify_peers(netdev);
2022                 break;
2023
2024         case XenbusStateClosed:
2025                 wake_up_all(&module_unload_q);
2026                 if (dev->state == XenbusStateClosed)
2027                         break;
2028                 /* Missed the backend's CLOSING state -- fallthrough */
2029         case XenbusStateClosing:
2030                 wake_up_all(&module_unload_q);
2031                 xenbus_frontend_closed(dev);
2032                 break;
2033         }
2034 }
2035
2036 static const struct xennet_stat {
2037         char name[ETH_GSTRING_LEN];
2038         u16 offset;
2039 } xennet_stats[] = {
2040         {
2041                 "rx_gso_checksum_fixup",
2042                 offsetof(struct netfront_info, rx_gso_checksum_fixup)
2043         },
2044 };
2045
2046 static int xennet_get_sset_count(struct net_device *dev, int string_set)
2047 {
2048         switch (string_set) {
2049         case ETH_SS_STATS:
2050                 return ARRAY_SIZE(xennet_stats);
2051         default:
2052                 return -EINVAL;
2053         }
2054 }
2055
2056 static void xennet_get_ethtool_stats(struct net_device *dev,
2057                                      struct ethtool_stats *stats, u64 * data)
2058 {
2059         void *np = netdev_priv(dev);
2060         int i;
2061
2062         for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2063                 data[i] = atomic_read((atomic_t *)(np + xennet_stats[i].offset));
2064 }
2065
2066 static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
2067 {
2068         int i;
2069
2070         switch (stringset) {
2071         case ETH_SS_STATS:
2072                 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2073                         memcpy(data + i * ETH_GSTRING_LEN,
2074                                xennet_stats[i].name, ETH_GSTRING_LEN);
2075                 break;
2076         }
2077 }
2078
2079 static const struct ethtool_ops xennet_ethtool_ops =
2080 {
2081         .get_link = ethtool_op_get_link,
2082
2083         .get_sset_count = xennet_get_sset_count,
2084         .get_ethtool_stats = xennet_get_ethtool_stats,
2085         .get_strings = xennet_get_strings,
2086 };
2087
2088 #ifdef CONFIG_SYSFS
2089 static ssize_t show_rxbuf(struct device *dev,
2090                           struct device_attribute *attr, char *buf)
2091 {
2092         return sprintf(buf, "%lu\n", NET_RX_RING_SIZE);
2093 }
2094
2095 static ssize_t store_rxbuf(struct device *dev,
2096                            struct device_attribute *attr,
2097                            const char *buf, size_t len)
2098 {
2099         char *endp;
2100         unsigned long target;
2101
2102         if (!capable(CAP_NET_ADMIN))
2103                 return -EPERM;
2104
2105         target = simple_strtoul(buf, &endp, 0);
2106         if (endp == buf)
2107                 return -EBADMSG;
2108
2109         /* rxbuf_min and rxbuf_max are no longer configurable. */
2110
2111         return len;
2112 }
2113
2114 static DEVICE_ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf, store_rxbuf);
2115 static DEVICE_ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf, store_rxbuf);
2116 static DEVICE_ATTR(rxbuf_cur, S_IRUGO, show_rxbuf, NULL);
2117
2118 static struct attribute *xennet_dev_attrs[] = {
2119         &dev_attr_rxbuf_min.attr,
2120         &dev_attr_rxbuf_max.attr,
2121         &dev_attr_rxbuf_cur.attr,
2122         NULL
2123 };
2124
2125 static const struct attribute_group xennet_dev_group = {
2126         .attrs = xennet_dev_attrs
2127 };
2128 #endif /* CONFIG_SYSFS */
2129
2130 static int xennet_remove(struct xenbus_device *dev)
2131 {
2132         struct netfront_info *info = dev_get_drvdata(&dev->dev);
2133
2134         dev_dbg(&dev->dev, "%s\n", dev->nodename);
2135
2136         if (xenbus_read_driver_state(dev->otherend) != XenbusStateClosed) {
2137                 xenbus_switch_state(dev, XenbusStateClosing);
2138                 wait_event(module_unload_q,
2139                            xenbus_read_driver_state(dev->otherend) ==
2140                            XenbusStateClosing);
2141
2142                 xenbus_switch_state(dev, XenbusStateClosed);
2143                 wait_event(module_unload_q,
2144                            xenbus_read_driver_state(dev->otherend) ==
2145                            XenbusStateClosed ||
2146                            xenbus_read_driver_state(dev->otherend) ==
2147                            XenbusStateUnknown);
2148         }
2149
2150         xennet_disconnect_backend(info);
2151
2152         unregister_netdev(info->netdev);
2153
2154         if (info->queues)
2155                 xennet_destroy_queues(info);
2156         xennet_free_netdev(info->netdev);
2157
2158         return 0;
2159 }
2160
2161 static const struct xenbus_device_id netfront_ids[] = {
2162         { "vif" },
2163         { "" }
2164 };
2165
2166 static struct xenbus_driver netfront_driver = {
2167         .ids = netfront_ids,
2168         .probe = netfront_probe,
2169         .remove = xennet_remove,
2170         .resume = netfront_resume,
2171         .otherend_changed = netback_changed,
2172 };
2173
2174 static int __init netif_init(void)
2175 {
2176         if (!xen_domain())
2177                 return -ENODEV;
2178
2179         if (!xen_has_pv_nic_devices())
2180                 return -ENODEV;
2181
2182         pr_info("Initialising Xen virtual ethernet driver\n");
2183
2184         /* Allow as many queues as there are CPUs inut max. 8 if user has not
2185          * specified a value.
2186          */
2187         if (xennet_max_queues == 0)
2188                 xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
2189                                           num_online_cpus());
2190
2191         return xenbus_register_frontend(&netfront_driver);
2192 }
2193 module_init(netif_init);
2194
2195
2196 static void __exit netif_exit(void)
2197 {
2198         xenbus_unregister_driver(&netfront_driver);
2199 }
2200 module_exit(netif_exit);
2201
2202 MODULE_DESCRIPTION("Xen virtual network device frontend");
2203 MODULE_LICENSE("GPL");
2204 MODULE_ALIAS("xen:vif");
2205 MODULE_ALIAS("xennet");