drivers/net/xen-netfront.c

   1 /*
   2  * Virtual network driver for conversing with remote driver backends.
   3  *
   4  * Copyright (c) 2002-2005, K A Fraser
   5  * Copyright (c) 2005, XenSource Ltd
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License version 2
   9  * as published by the Free Software Foundation; or, when distributed
  10  * separately from the Linux kernel or incorporated into other
  11  * software packages, subject to the following license:
  12  *
  13  * Permission is hereby granted, free of charge, to any person obtaining a copy
  14  * of this source file (the "Software"), to deal in the Software without
  15  * restriction, including without limitation the rights to use, copy, modify,
  16  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  17  * and to permit persons to whom the Software is furnished to do so, subject to
  18  * the following conditions:
  19  *
  20  * The above copyright notice and this permission notice shall be included in
  21  * all copies or substantial portions of the Software.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  24  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  25  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  26  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  27  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  28  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  29  * IN THE SOFTWARE.
  30  */
  31
  32 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  33
  34 #include <linux/module.h>
  35 #include <linux/kernel.h>
  36 #include <linux/netdevice.h>
  37 #include <linux/etherdevice.h>
  38 #include <linux/skbuff.h>
  39 #include <linux/ethtool.h>
  40 #include <linux/if_ether.h>
  41 #include <net/tcp.h>
  42 #include <linux/udp.h>
  43 #include <linux/moduleparam.h>
  44 #include <linux/mm.h>
  45 #include <linux/slab.h>
  46 #include <net/ip.h>
  47
  48 #include <xen/xen.h>
  49 #include <xen/xenbus.h>
  50 #include <xen/events.h>
  51 #include <xen/page.h>
  52 #include <xen/platform_pci.h>
  53 #include <xen/grant_table.h>
  54
  55 #include <xen/interface/io/netif.h>
  56 #include <xen/interface/memory.h>
  57 #include <xen/interface/grant_table.h>
  58
  59 /* Module parameters */
  60 #define MAX_QUEUES_DEFAULT 8
  61 static unsigned int xennet_max_queues;
  62 module_param_named(max_queues, xennet_max_queues, uint, 0644);
  63 MODULE_PARM_DESC(max_queues,
  64                  "Maximum number of queues per virtual interface");
  65
  66 static const struct ethtool_ops xennet_ethtool_ops;
  67
  68 struct netfront_cb {
  69         int pull_to;
  70 };
  71
  72 #define NETFRONT_SKB_CB(skb)    ((struct netfront_cb *)((skb)->cb))
  73
  74 #define RX_COPY_THRESHOLD 256
  75
  76 #define GRANT_INVALID_REF       0
  77
  78 #define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, XEN_PAGE_SIZE)
  79 #define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, XEN_PAGE_SIZE)
  80
  81 /* Minimum number of Rx slots (includes slot for GSO metadata). */
  82 #define NET_RX_SLOTS_MIN (XEN_NETIF_NR_SLOTS_MIN + 1)
  83
  84 /* Queue name is interface name with "-qNNN" appended */
  85 #define QUEUE_NAME_SIZE (IFNAMSIZ + 6)
  86
  87 /* IRQ name is queue name with "-tx" or "-rx" appended */
  88 #define IRQ_NAME_SIZE (QUEUE_NAME_SIZE + 3)
  89
  90 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
  91
  92 struct netfront_stats {
  93         u64                     packets;
  94         u64                     bytes;
  95         struct u64_stats_sync   syncp;
  96 };
  97
  98 struct netfront_info;
  99
 100 struct netfront_queue {
 101         unsigned int id; /* Queue ID, 0-based */
 102         char name[QUEUE_NAME_SIZE]; /* DEVNAME-qN */
 103         struct netfront_info *info;
 104
 105         struct napi_struct napi;
 106
 107         /* Split event channels support, tx_* == rx_* when using
 108          * single event channel.
 109          */
 110         unsigned int tx_evtchn, rx_evtchn;
 111         unsigned int tx_irq, rx_irq;
 112         /* Only used when split event channels support is enabled */
 113         char tx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-tx */
 114         char rx_irq_name[IRQ_NAME_SIZE]; /* DEVNAME-qN-rx */
 115
 116         spinlock_t   tx_lock;
 117         struct xen_netif_tx_front_ring tx;
 118         int tx_ring_ref;
 119
 120         /*
 121          * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
 122          * are linked from tx_skb_freelist through skb_entry.link.
 123          *
 124          *  NB. Freelist index entries are always going to be less than
 125          *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
 126          *  greater than PAGE_OFFSET: we use this property to distinguish
 127          *  them.
 128          */
 129         union skb_entry {
 130                 struct sk_buff *skb;
 131                 unsigned long link;
 132         } tx_skbs[NET_TX_RING_SIZE];
 133         grant_ref_t gref_tx_head;
 134         grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
 135         struct page *grant_tx_page[NET_TX_RING_SIZE];
 136         unsigned tx_skb_freelist;
 137
 138         spinlock_t   rx_lock ____cacheline_aligned_in_smp;
 139         struct xen_netif_rx_front_ring rx;
 140         int rx_ring_ref;
 141
 142         struct timer_list rx_refill_timer;
 143
 144         struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
 145         grant_ref_t gref_rx_head;
 146         grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
 147 };
 148
 149 struct netfront_info {
 150         struct list_head list;
 151         struct net_device *netdev;
 152
 153         struct xenbus_device *xbdev;
 154
 155         /* Multi-queue support */
 156         struct netfront_queue *queues;
 157
 158         /* Statistics */
 159         struct netfront_stats __percpu *rx_stats;
 160         struct netfront_stats __percpu *tx_stats;
 161
 162         atomic_t rx_gso_checksum_fixup;
 163 };
 164
 165 struct netfront_rx_info {
 166         struct xen_netif_rx_response rx;
 167         struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
 168 };
 169
 170 static void skb_entry_set_link(union skb_entry *list, unsigned short id)
 171 {
 172         list->link = id;
 173 }
 174
 175 static int skb_entry_is_link(const union skb_entry *list)
 176 {
 177         BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
 178         return (unsigned long)list->skb < PAGE_OFFSET;
 179 }
 180
 181 /*
 182  * Access macros for acquiring freeing slots in tx_skbs[].
 183  */
 184
 185 static void add_id_to_freelist(unsigned *head, union skb_entry *list,
 186                                unsigned short id)
 187 {
 188         skb_entry_set_link(&list[id], *head);
 189         *head = id;
 190 }
 191
 192 static unsigned short get_id_from_freelist(unsigned *head,
 193                                            union skb_entry *list)
 194 {
 195         unsigned int id = *head;
 196         *head = list[id].link;
 197         return id;
 198 }
 199
 200 static int xennet_rxidx(RING_IDX idx)
 201 {
 202         return idx & (NET_RX_RING_SIZE - 1);
 203 }
 204
 205 static struct sk_buff *xennet_get_rx_skb(struct netfront_queue *queue,
 206                                          RING_IDX ri)
 207 {
 208         int i = xennet_rxidx(ri);
 209         struct sk_buff *skb = queue->rx_skbs[i];
 210         queue->rx_skbs[i] = NULL;
 211         return skb;
 212 }
 213
 214 static grant_ref_t xennet_get_rx_ref(struct netfront_queue *queue,
 215                                             RING_IDX ri)
 216 {
 217         int i = xennet_rxidx(ri);
 218         grant_ref_t ref = queue->grant_rx_ref[i];
 219         queue->grant_rx_ref[i] = GRANT_INVALID_REF;
 220         return ref;
 221 }
 222
 223 #ifdef CONFIG_SYSFS
 224 static const struct attribute_group xennet_dev_group;
 225 #endif
 226
 227 static bool xennet_can_sg(struct net_device *dev)
 228 {
 229         return dev->features & NETIF_F_SG;
 230 }
 231
 232
 233 static void rx_refill_timeout(struct timer_list *t)
 234 {
 235         struct netfront_queue *queue = from_timer(queue, t, rx_refill_timer);
 236         napi_schedule(&queue->napi);
 237 }
 238
 239 static int netfront_tx_slot_available(struct netfront_queue *queue)
 240 {
 241         return (queue->tx.req_prod_pvt - queue->tx.rsp_cons) <
 242                 (NET_TX_RING_SIZE - XEN_NETIF_NR_SLOTS_MIN - 1);
 243 }
 244
 245 static void xennet_maybe_wake_tx(struct netfront_queue *queue)
 246 {
 247         struct net_device *dev = queue->info->netdev;
 248         struct netdev_queue *dev_queue = netdev_get_tx_queue(dev, queue->id);
 249
 250         if (unlikely(netif_tx_queue_stopped(dev_queue)) &&
 251             netfront_tx_slot_available(queue) &&
 252             likely(netif_running(dev)))
 253                 netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id));
 254 }
 255
 256
 257 static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
 258 {
 259         struct sk_buff *skb;
 260         struct page *page;
 261
 262         skb = __netdev_alloc_skb(queue->info->netdev,
 263                                  RX_COPY_THRESHOLD + NET_IP_ALIGN,
 264                                  GFP_ATOMIC | __GFP_NOWARN);
 265         if (unlikely(!skb))
 266                 return NULL;
 267
 268         page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 269         if (!page) {
 270                 kfree_skb(skb);
 271                 return NULL;
 272         }
 273         skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE);
 274
 275         /* Align ip header to a 16 bytes boundary */
 276         skb_reserve(skb, NET_IP_ALIGN);
 277         skb->dev = queue->info->netdev;
 278
 279         return skb;
 280 }
 281
 282
 283 static void xennet_alloc_rx_buffers(struct netfront_queue *queue)
 284 {
 285         RING_IDX req_prod = queue->rx.req_prod_pvt;
 286         int notify;
 287         int err = 0;
 288
 289         if (unlikely(!netif_carrier_ok(queue->info->netdev)))
 290                 return;
 291
 292         for (req_prod = queue->rx.req_prod_pvt;
 293              req_prod - queue->rx.rsp_cons < NET_RX_RING_SIZE;
 294              req_prod++) {
 295                 struct sk_buff *skb;
 296                 unsigned short id;
 297                 grant_ref_t ref;
 298                 struct page *page;
 299                 struct xen_netif_rx_request *req;
 300
 301                 skb = xennet_alloc_one_rx_buffer(queue);
 302                 if (!skb) {
 303                         err = -ENOMEM;
 304                         break;
 305                 }
 306
 307                 id = xennet_rxidx(req_prod);
 308
 309                 BUG_ON(queue->rx_skbs[id]);
 310                 queue->rx_skbs[id] = skb;
 311
 312                 ref = gnttab_claim_grant_reference(&queue->gref_rx_head);
 313                 WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 314                 queue->grant_rx_ref[id] = ref;
 315
 316                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
 317
 318                 req = RING_GET_REQUEST(&queue->rx, req_prod);
 319                 gnttab_page_grant_foreign_access_ref_one(ref,
 320                                                          queue->info->xbdev->otherend_id,
 321                                                          page,
 322                                                          0);
 323                 req->id = id;
 324                 req->gref = ref;
 325         }
 326
 327         queue->rx.req_prod_pvt = req_prod;
 328
 329         /* Try again later if there are not enough requests or skb allocation
 330          * failed.
 331          * Enough requests is quantified as the sum of newly created slots and
 332          * the unconsumed slots at the backend.
 333          */
 334         if (req_prod - queue->rx.rsp_cons < NET_RX_SLOTS_MIN ||
 335             unlikely(err)) {
 336                 mod_timer(&queue->rx_refill_timer, jiffies + (HZ/10));
 337                 return;
 338         }
 339
 340         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->rx, notify);
 341         if (notify)
 342                 notify_remote_via_irq(queue->rx_irq);
 343 }
 344
 345 static int xennet_open(struct net_device *dev)
 346 {
 347         struct netfront_info *np = netdev_priv(dev);
 348         unsigned int num_queues = dev->real_num_tx_queues;
 349         unsigned int i = 0;
 350         struct netfront_queue *queue = NULL;
 351
 352         if (!np->queues)
 353                 return -ENODEV;
 354
 355         for (i = 0; i < num_queues; ++i) {
 356                 queue = &np->queues[i];
 357                 napi_enable(&queue->napi);
 358
 359                 spin_lock_bh(&queue->rx_lock);
 360                 if (netif_carrier_ok(dev)) {
 361                         xennet_alloc_rx_buffers(queue);
 362                         queue->rx.sring->rsp_event = queue->rx.rsp_cons + 1;
 363                         if (RING_HAS_UNCONSUMED_RESPONSES(&queue->rx))
 364                                 napi_schedule(&queue->napi);
 365                 }
 366                 spin_unlock_bh(&queue->rx_lock);
 367         }
 368
 369         netif_tx_start_all_queues(dev);
 370
 371         return 0;
 372 }
 373
 374 static void xennet_tx_buf_gc(struct netfront_queue *queue)
 375 {
 376         RING_IDX cons, prod;
 377         unsigned short id;
 378         struct sk_buff *skb;
 379         bool more_to_do;
 380
 381         BUG_ON(!netif_carrier_ok(queue->info->netdev));
 382
 383         do {
 384                 prod = queue->tx.sring->rsp_prod;
 385                 rmb(); /* Ensure we see responses up to 'rp'. */
 386
 387                 for (cons = queue->tx.rsp_cons; cons != prod; cons++) {
 388                         struct xen_netif_tx_response *txrsp;
 389
 390                         txrsp = RING_GET_RESPONSE(&queue->tx, cons);
 391                         if (txrsp->status == XEN_NETIF_RSP_NULL)
 392                                 continue;
 393
 394                         id  = txrsp->id;
 395                         skb = queue->tx_skbs[id].skb;
 396                         if (unlikely(gnttab_query_foreign_access(
 397                                 queue->grant_tx_ref[id]) != 0)) {
 398                                 pr_alert("%s: warning -- grant still in use by backend domain\n",
 399                                          __func__);
 400                                 BUG();
 401                         }
 402                         gnttab_end_foreign_access_ref(
 403                                 queue->grant_tx_ref[id], GNTMAP_readonly);
 404                         gnttab_release_grant_reference(
 405                                 &queue->gref_tx_head, queue->grant_tx_ref[id]);
 406                         queue->grant_tx_ref[id] = GRANT_INVALID_REF;
 407                         queue->grant_tx_page[id] = NULL;
 408                         add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, id);
 409                         dev_kfree_skb_irq(skb);
 410                 }
 411
 412                 queue->tx.rsp_cons = prod;
 413
 414                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->tx, more_to_do);
 415         } while (more_to_do);
 416
 417         xennet_maybe_wake_tx(queue);
 418 }
 419
 420 struct xennet_gnttab_make_txreq {
 421         struct netfront_queue *queue;
 422         struct sk_buff *skb;
 423         struct page *page;
 424         struct xen_netif_tx_request *tx; /* Last request */
 425         unsigned int size;
 426 };
 427
 428 static void xennet_tx_setup_grant(unsigned long gfn, unsigned int offset,
 429                                   unsigned int len, void *data)
 430 {
 431         struct xennet_gnttab_make_txreq *info = data;
 432         unsigned int id;
 433         struct xen_netif_tx_request *tx;
 434         grant_ref_t ref;
 435         /* convenient aliases */
 436         struct page *page = info->page;
 437         struct netfront_queue *queue = info->queue;
 438         struct sk_buff *skb = info->skb;
 439
 440         id = get_id_from_freelist(&queue->tx_skb_freelist, queue->tx_skbs);
 441         tx = RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 442         ref = gnttab_claim_grant_reference(&queue->gref_tx_head);
 443         WARN_ON_ONCE(IS_ERR_VALUE((unsigned long)(int)ref));
 444
 445         gnttab_grant_foreign_access_ref(ref, queue->info->xbdev->otherend_id,
 446                                         gfn, GNTMAP_readonly);
 447
 448         queue->tx_skbs[id].skb = skb;
 449         queue->grant_tx_page[id] = page;
 450         queue->grant_tx_ref[id] = ref;
 451
 452         tx->id = id;
 453         tx->gref = ref;
 454         tx->offset = offset;
 455         tx->size = len;
 456         tx->flags = 0;
 457
 458         info->tx = tx;
 459         info->size += tx->size;
 460 }
 461
 462 static struct xen_netif_tx_request *xennet_make_first_txreq(
 463         struct netfront_queue *queue, struct sk_buff *skb,
 464         struct page *page, unsigned int offset, unsigned int len)
 465 {
 466         struct xennet_gnttab_make_txreq info = {
 467                 .queue = queue,
 468                 .skb = skb,
 469                 .page = page,
 470                 .size = 0,
 471         };
 472
 473         gnttab_for_one_grant(page, offset, len, xennet_tx_setup_grant, &info);
 474
 475         return info.tx;
 476 }
 477
 478 static void xennet_make_one_txreq(unsigned long gfn, unsigned int offset,
 479                                   unsigned int len, void *data)
 480 {
 481         struct xennet_gnttab_make_txreq *info = data;
 482
 483         info->tx->flags |= XEN_NETTXF_more_data;
 484         skb_get(info->skb);
 485         xennet_tx_setup_grant(gfn, offset, len, data);
 486 }
 487
 488 static struct xen_netif_tx_request *xennet_make_txreqs(
 489         struct netfront_queue *queue, struct xen_netif_tx_request *tx,
 490         struct sk_buff *skb, struct page *page,
 491         unsigned int offset, unsigned int len)
 492 {
 493         struct xennet_gnttab_make_txreq info = {
 494                 .queue = queue,
 495                 .skb = skb,
 496                 .tx = tx,
 497         };
 498
 499         /* Skip unused frames from start of page */
 500         page += offset >> PAGE_SHIFT;
 501         offset &= ~PAGE_MASK;
 502
 503         while (len) {
 504                 info.page = page;
 505                 info.size = 0;
 506
 507                 gnttab_foreach_grant_in_range(page, offset, len,
 508                                               xennet_make_one_txreq,
 509                                               &info);
 510
 511                 page++;
 512                 offset = 0;
 513                 len -= info.size;
 514         }
 515
 516         return info.tx;
 517 }
 518
 519 /*
 520  * Count how many ring slots are required to send this skb. Each frag
 521  * might be a compound page.
 522  */
 523 static int xennet_count_skb_slots(struct sk_buff *skb)
 524 {
 525         int i, frags = skb_shinfo(skb)->nr_frags;
 526         int slots;
 527
 528         slots = gnttab_count_grant(offset_in_page(skb->data),
 529                                    skb_headlen(skb));
 530
 531         for (i = 0; i < frags; i++) {
 532                 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 533                 unsigned long size = skb_frag_size(frag);
 534                 unsigned long offset = skb_frag_off(frag);
 535
 536                 /* Skip unused frames from start of page */
 537                 offset &= ~PAGE_MASK;
 538
 539                 slots += gnttab_count_grant(offset, size);
 540         }
 541
 542         return slots;
 543 }
 544
 545 static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb,
 546                                struct net_device *sb_dev)
 547 {
 548         unsigned int num_queues = dev->real_num_tx_queues;
 549         u32 hash;
 550         u16 queue_idx;
 551
 552         /* First, check if there is only one queue */
 553         if (num_queues == 1) {
 554                 queue_idx = 0;
 555         } else {
 556                 hash = skb_get_hash(skb);
 557                 queue_idx = hash % num_queues;
 558         }
 559
 560         return queue_idx;
 561 }
 562
 563 #define MAX_XEN_SKB_FRAGS (65536 / XEN_PAGE_SIZE + 1)
 564
 565 static netdev_tx_t xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 566 {
 567         struct netfront_info *np = netdev_priv(dev);
 568         struct netfront_stats *tx_stats = this_cpu_ptr(np->tx_stats);
 569         struct xen_netif_tx_request *tx, *first_tx;
 570         unsigned int i;
 571         int notify;
 572         int slots;
 573         struct page *page;
 574         unsigned int offset;
 575         unsigned int len;
 576         unsigned long flags;
 577         struct netfront_queue *queue = NULL;
 578         unsigned int num_queues = dev->real_num_tx_queues;
 579         u16 queue_index;
 580         struct sk_buff *nskb;
 581
 582         /* Drop the packet if no queues are set up */
 583         if (num_queues < 1)
 584                 goto drop;
 585         /* Determine which queue to transmit this SKB on */
 586         queue_index = skb_get_queue_mapping(skb);
 587         queue = &np->queues[queue_index];
 588
 589         /* If skb->len is too big for wire format, drop skb and alert
 590          * user about misconfiguration.
 591          */
 592         if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
 593                 net_alert_ratelimited(
 594                         "xennet: skb->len = %u, too big for wire format\n",
 595                         skb->len);
 596                 goto drop;
 597         }
 598
 599         slots = xennet_count_skb_slots(skb);
 600         if (unlikely(slots > MAX_XEN_SKB_FRAGS + 1)) {
 601                 net_dbg_ratelimited("xennet: skb rides the rocket: %d slots, %d bytes\n",
 602                                     slots, skb->len);
 603                 if (skb_linearize(skb))
 604                         goto drop;
 605         }
 606
 607         page = virt_to_page(skb->data);
 608         offset = offset_in_page(skb->data);
 609
 610         /* The first req should be at least ETH_HLEN size or the packet will be
 611          * dropped by netback.
 612          */
 613         if (unlikely(PAGE_SIZE - offset < ETH_HLEN)) {
 614                 nskb = skb_copy(skb, GFP_ATOMIC);
 615                 if (!nskb)
 616                         goto drop;
 617                 dev_consume_skb_any(skb);
 618                 skb = nskb;
 619                 page = virt_to_page(skb->data);
 620                 offset = offset_in_page(skb->data);
 621         }
 622
 623         len = skb_headlen(skb);
 624
 625         spin_lock_irqsave(&queue->tx_lock, flags);
 626
 627         if (unlikely(!netif_carrier_ok(dev) ||
 628                      (slots > 1 && !xennet_can_sg(dev)) ||
 629                      netif_needs_gso(skb, netif_skb_features(skb)))) {
 630                 spin_unlock_irqrestore(&queue->tx_lock, flags);
 631                 goto drop;
 632         }
 633
 634         /* First request for the linear area. */
 635         first_tx = tx = xennet_make_first_txreq(queue, skb,
 636                                                 page, offset, len);
 637         offset += tx->size;
 638         if (offset == PAGE_SIZE) {
 639                 page++;
 640                 offset = 0;
 641         }
 642         len -= tx->size;
 643
 644         if (skb->ip_summed == CHECKSUM_PARTIAL)
 645                 /* local packet? */
 646                 tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
 647         else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 648                 /* remote but checksummed. */
 649                 tx->flags |= XEN_NETTXF_data_validated;
 650
 651         /* Optional extra info after the first request. */
 652         if (skb_shinfo(skb)->gso_size) {
 653                 struct xen_netif_extra_info *gso;
 654
 655                 gso = (struct xen_netif_extra_info *)
 656                         RING_GET_REQUEST(&queue->tx, queue->tx.req_prod_pvt++);
 657
 658                 tx->flags |= XEN_NETTXF_extra_info;
 659
 660                 gso->u.gso.size = skb_shinfo(skb)->gso_size;
 661                 gso->u.gso.type = (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6) ?
 662                         XEN_NETIF_GSO_TYPE_TCPV6 :
 663                         XEN_NETIF_GSO_TYPE_TCPV4;
 664                 gso->u.gso.pad = 0;
 665                 gso->u.gso.features = 0;
 666
 667                 gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 668                 gso->flags = 0;
 669         }
 670
 671         /* Requests for the rest of the linear area. */
 672         tx = xennet_make_txreqs(queue, tx, skb, page, offset, len);
 673
 674         /* Requests for all the frags. */
 675         for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
 676                 skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
 677                 tx = xennet_make_txreqs(queue, tx, skb, skb_frag_page(frag),
 678                                         skb_frag_off(frag),
 679                                         skb_frag_size(frag));
 680         }
 681
 682         /* First request has the packet length. */
 683         first_tx->size = skb->len;
 684
 685         RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&queue->tx, notify);
 686         if (notify)
 687                 notify_remote_via_irq(queue->tx_irq);
 688
 689         u64_stats_update_begin(&tx_stats->syncp);
 690         tx_stats->bytes += skb->len;
 691         tx_stats->packets++;
 692         u64_stats_update_end(&tx_stats->syncp);
 693
 694         /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
 695         xennet_tx_buf_gc(queue);
 696
 697         if (!netfront_tx_slot_available(queue))
 698                 netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
 699
 700         spin_unlock_irqrestore(&queue->tx_lock, flags);
 701
 702         return NETDEV_TX_OK;
 703
 704  drop:
 705         dev->stats.tx_dropped++;
 706         dev_kfree_skb_any(skb);
 707         return NETDEV_TX_OK;
 708 }
 709
 710 static int xennet_close(struct net_device *dev)
 711 {
 712         struct netfront_info *np = netdev_priv(dev);
 713         unsigned int num_queues = dev->real_num_tx_queues;
 714         unsigned int i;
 715         struct netfront_queue *queue;
 716         netif_tx_stop_all_queues(np->netdev);
 717         for (i = 0; i < num_queues; ++i) {
 718                 queue = &np->queues[i];
 719                 napi_disable(&queue->napi);
 720         }
 721         return 0;
 722 }
 723
 724 static void xennet_move_rx_slot(struct netfront_queue *queue, struct sk_buff *skb,
 725                                 grant_ref_t ref)
 726 {
 727         int new = xennet_rxidx(queue->rx.req_prod_pvt);
 728
 729         BUG_ON(queue->rx_skbs[new]);
 730         queue->rx_skbs[new] = skb;
 731         queue->grant_rx_ref[new] = ref;
 732         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->id = new;
 733         RING_GET_REQUEST(&queue->rx, queue->rx.req_prod_pvt)->gref = ref;
 734         queue->rx.req_prod_pvt++;
 735 }
 736
 737 static int xennet_get_extras(struct netfront_queue *queue,
 738                              struct xen_netif_extra_info *extras,
 739                              RING_IDX rp)
 740
 741 {
 742         struct xen_netif_extra_info *extra;
 743         struct device *dev = &queue->info->netdev->dev;
 744         RING_IDX cons = queue->rx.rsp_cons;
 745         int err = 0;
 746
 747         do {
 748                 struct sk_buff *skb;
 749                 grant_ref_t ref;
 750
 751                 if (unlikely(cons + 1 == rp)) {
 752                         if (net_ratelimit())
 753                                 dev_warn(dev, "Missing extra info\n");
 754                         err = -EBADR;
 755                         break;
 756                 }
 757
 758                 extra = (struct xen_netif_extra_info *)
 759                         RING_GET_RESPONSE(&queue->rx, ++cons);
 760
 761                 if (unlikely(!extra->type ||
 762                              extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 763                         if (net_ratelimit())
 764                                 dev_warn(dev, "Invalid extra type: %d\n",
 765                                         extra->type);
 766                         err = -EINVAL;
 767                 } else {
 768                         memcpy(&extras[extra->type - 1], extra,
 769                                sizeof(*extra));
 770                 }
 771
 772                 skb = xennet_get_rx_skb(queue, cons);
 773                 ref = xennet_get_rx_ref(queue, cons);
 774                 xennet_move_rx_slot(queue, skb, ref);
 775         } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
 776
 777         queue->rx.rsp_cons = cons;
 778         return err;
 779 }
 780
 781 static int xennet_get_responses(struct netfront_queue *queue,
 782                                 struct netfront_rx_info *rinfo, RING_IDX rp,
 783                                 struct sk_buff_head *list)
 784 {
 785         struct xen_netif_rx_response *rx = &rinfo->rx;
 786         struct xen_netif_extra_info *extras = rinfo->extras;
 787         struct device *dev = &queue->info->netdev->dev;
 788         RING_IDX cons = queue->rx.rsp_cons;
 789         struct sk_buff *skb = xennet_get_rx_skb(queue, cons);
 790         grant_ref_t ref = xennet_get_rx_ref(queue, cons);
 791         int max = XEN_NETIF_NR_SLOTS_MIN + (rx->status <= RX_COPY_THRESHOLD);
 792         int slots = 1;
 793         int err = 0;
 794         unsigned long ret;
 795
 796         if (rx->flags & XEN_NETRXF_extra_info) {
 797                 err = xennet_get_extras(queue, extras, rp);
 798                 cons = queue->rx.rsp_cons;
 799         }
 800
 801         for (;;) {
 802                 if (unlikely(rx->status < 0 ||
 803                              rx->offset + rx->status > XEN_PAGE_SIZE)) {
 804                         if (net_ratelimit())
 805                                 dev_warn(dev, "rx->offset: %u, size: %d\n",
 806                                          rx->offset, rx->status);
 807                         xennet_move_rx_slot(queue, skb, ref);
 808                         err = -EINVAL;
 809                         goto next;
 810                 }
 811
 812                 /*
 813                  * This definitely indicates a bug, either in this driver or in
 814                  * the backend driver. In future this should flag the bad
 815                  * situation to the system controller to reboot the backend.
 816                  */
 817                 if (ref == GRANT_INVALID_REF) {
 818                         if (net_ratelimit())
 819                                 dev_warn(dev, "Bad rx response id %d.\n",
 820                                          rx->id);
 821                         err = -EINVAL;
 822                         goto next;
 823                 }
 824
 825                 ret = gnttab_end_foreign_access_ref(ref, 0);
 826                 BUG_ON(!ret);
 827
 828                 gnttab_release_grant_reference(&queue->gref_rx_head, ref);
 829
 830                 __skb_queue_tail(list, skb);
 831
 832 next:
 833                 if (!(rx->flags & XEN_NETRXF_more_data))
 834                         break;
 835
 836                 if (cons + slots == rp) {
 837                         if (net_ratelimit())
 838                                 dev_warn(dev, "Need more slots\n");
 839                         err = -ENOENT;
 840                         break;
 841                 }
 842
 843                 rx = RING_GET_RESPONSE(&queue->rx, cons + slots);
 844                 skb = xennet_get_rx_skb(queue, cons + slots);
 845                 ref = xennet_get_rx_ref(queue, cons + slots);
 846                 slots++;
 847         }
 848
 849         if (unlikely(slots > max)) {
 850                 if (net_ratelimit())
 851                         dev_warn(dev, "Too many slots\n");
 852                 err = -E2BIG;
 853         }
 854
 855         if (unlikely(err))
 856                 queue->rx.rsp_cons = cons + slots;
 857
 858         return err;
 859 }
 860
 861 static int xennet_set_skb_gso(struct sk_buff *skb,
 862                               struct xen_netif_extra_info *gso)
 863 {
 864         if (!gso->u.gso.size) {
 865                 if (net_ratelimit())
 866                         pr_warn("GSO size must not be zero\n");
 867                 return -EINVAL;
 868         }
 869
 870         if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4 &&
 871             gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV6) {
 872                 if (net_ratelimit())
 873                         pr_warn("Bad GSO type %d\n", gso->u.gso.type);
 874                 return -EINVAL;
 875         }
 876
 877         skb_shinfo(skb)->gso_size = gso->u.gso.size;
 878         skb_shinfo(skb)->gso_type =
 879                 (gso->u.gso.type == XEN_NETIF_GSO_TYPE_TCPV4) ?
 880                 SKB_GSO_TCPV4 :
 881                 SKB_GSO_TCPV6;
 882
 883         /* Header must be checked, and gso_segs computed. */
 884         skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 885         skb_shinfo(skb)->gso_segs = 0;
 886
 887         return 0;
 888 }
 889
 890 static int xennet_fill_frags(struct netfront_queue *queue,
 891                              struct sk_buff *skb,
 892                              struct sk_buff_head *list)
 893 {
 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 (skb_shinfo(skb)->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                 if (unlikely(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS)) {
 909                         queue->rx.rsp_cons = ++cons + skb_queue_len(list);
 910                         kfree_skb(nskb);
 911                         return -ENOENT;
 912                 }
 913
 914                 skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
 915                                 skb_frag_page(nfrag),
 916                                 rx->offset, rx->status, PAGE_SIZE);
 917
 918                 skb_shinfo(nskb)->nr_frags = 0;
 919                 kfree_skb(nskb);
 920         }
 921
 922         queue->rx.rsp_cons = cons;
 923
 924         return 0;
 925 }
 926
 927 static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 928 {
 929         bool recalculate_partial_csum = false;
 930
 931         /*
 932          * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 933          * peers can fail to set NETRXF_csum_blank when sending a GSO
 934          * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 935          * recalculate the partial checksum.
 936          */
 937         if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 938                 struct netfront_info *np = netdev_priv(dev);
 939                 atomic_inc(&np->rx_gso_checksum_fixup);
 940                 skb->ip_summed = CHECKSUM_PARTIAL;
 941                 recalculate_partial_csum = true;
 942         }
 943
 944         /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 945         if (skb->ip_summed != CHECKSUM_PARTIAL)
 946                 return 0;
 947
 948         return skb_checksum_setup(skb, recalculate_partial_csum);
 949 }
 950
 951 static int handle_incoming_queue(struct netfront_queue *queue,
 952                                  struct sk_buff_head *rxq)
 953 {
 954         struct netfront_stats *rx_stats = this_cpu_ptr(queue->info->rx_stats);
 955         int packets_dropped = 0;
 956         struct sk_buff *skb;
 957
 958         while ((skb = __skb_dequeue(rxq)) != NULL) {
 959                 int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 960
 961                 if (pull_to > skb_headlen(skb))
 962                         __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 963
 964                 /* Ethernet work: Delayed to here as it peeks the header. */
 965                 skb->protocol = eth_type_trans(skb, queue->info->netdev);
 966                 skb_reset_network_header(skb);
 967
 968                 if (checksum_setup(queue->info->netdev, skb)) {
 969                         kfree_skb(skb);
 970                         packets_dropped++;
 971                         queue->info->netdev->stats.rx_errors++;
 972                         continue;
 973                 }
 974
 975                 u64_stats_update_begin(&rx_stats->syncp);
 976                 rx_stats->packets++;
 977                 rx_stats->bytes += skb->len;
 978                 u64_stats_update_end(&rx_stats->syncp);
 979
 980                 /* Pass it up. */
 981                 napi_gro_receive(&queue->napi, skb);
 982         }
 983
 984         return packets_dropped;
 985 }
 986
 987 static int xennet_poll(struct napi_struct *napi, int budget)
 988 {
 989         struct netfront_queue *queue = container_of(napi, struct netfront_queue, napi);
 990         struct net_device *dev = queue->info->netdev;
 991         struct sk_buff *skb;
 992         struct netfront_rx_info rinfo;
 993         struct xen_netif_rx_response *rx = &rinfo.rx;
 994         struct xen_netif_extra_info *extras = rinfo.extras;
 995         RING_IDX i, rp;
 996         int work_done;
 997         struct sk_buff_head rxq;
 998         struct sk_buff_head errq;
 999         struct sk_buff_head tmpq;
1000         int err;
1001
1002         spin_lock(&queue->rx_lock);
1003
1004         skb_queue_head_init(&rxq);
1005         skb_queue_head_init(&errq);
1006         skb_queue_head_init(&tmpq);
1007
1008         rp = queue->rx.sring->rsp_prod;
1009         rmb(); /* Ensure we see queued responses up to 'rp'. */
1010
1011         i = queue->rx.rsp_cons;
1012         work_done = 0;
1013         while ((i != rp) && (work_done < budget)) {
1014                 memcpy(rx, RING_GET_RESPONSE(&queue->rx, i), sizeof(*rx));
1015                 memset(extras, 0, sizeof(rinfo.extras));
1016
1017                 err = xennet_get_responses(queue, &rinfo, rp, &tmpq);
1018
1019                 if (unlikely(err)) {
1020 err:
1021                         while ((skb = __skb_dequeue(&tmpq)))
1022                                 __skb_queue_tail(&errq, skb);
1023                         dev->stats.rx_errors++;
1024                         i = queue->rx.rsp_cons;
1025                         continue;
1026                 }
1027
1028                 skb = __skb_dequeue(&tmpq);
1029
1030                 if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1031                         struct xen_netif_extra_info *gso;
1032                         gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1033
1034                         if (unlikely(xennet_set_skb_gso(skb, gso))) {
1035                                 __skb_queue_head(&tmpq, skb);
1036                                 queue->rx.rsp_cons += skb_queue_len(&tmpq);
1037                                 goto err;
1038                         }
1039                 }
1040
1041                 NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1042                 if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1043                         NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1044
1045                 skb_frag_off_set(&skb_shinfo(skb)->frags[0], rx->offset);
1046                 skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1047                 skb->data_len = rx->status;
1048                 skb->len += rx->status;
1049
1050                 if (unlikely(xennet_fill_frags(queue, skb, &tmpq)))
1051                         goto err;
1052
1053                 if (rx->flags & XEN_NETRXF_csum_blank)
1054                         skb->ip_summed = CHECKSUM_PARTIAL;
1055                 else if (rx->flags & XEN_NETRXF_data_validated)
1056                         skb->ip_summed = CHECKSUM_UNNECESSARY;
1057
1058                 __skb_queue_tail(&rxq, skb);
1059
1060                 i = ++queue->rx.rsp_cons;
1061                 work_done++;
1062         }
1063
1064         __skb_queue_purge(&errq);
1065
1066         work_done -= handle_incoming_queue(queue, &rxq);
1067
1068         xennet_alloc_rx_buffers(queue);
1069
1070         if (work_done < budget) {
1071                 int more_to_do = 0;
1072
1073                 napi_complete_done(napi, work_done);
1074
1075                 RING_FINAL_CHECK_FOR_RESPONSES(&queue->rx, more_to_do);
1076                 if (more_to_do)
1077                         napi_schedule(napi);
1078         }
1079
1080         spin_unlock(&queue->rx_lock);
1081
1082         return work_done;
1083 }
1084
1085 static int xennet_change_mtu(struct net_device *dev, int mtu)
1086 {
1087         int max = xennet_can_sg(dev) ? XEN_NETIF_MAX_TX_SIZE : ETH_DATA_LEN;
1088
1089         if (mtu > max)
1090                 return -EINVAL;
1091         dev->mtu = mtu;
1092         return 0;
1093 }
1094
1095 static void xennet_get_stats64(struct net_device *dev,
1096                                struct rtnl_link_stats64 *tot)
1097 {
1098         struct netfront_info *np = netdev_priv(dev);
1099         int cpu;
1100
1101         for_each_possible_cpu(cpu) {
1102                 struct netfront_stats *rx_stats = per_cpu_ptr(np->rx_stats, cpu);
1103                 struct netfront_stats *tx_stats = per_cpu_ptr(np->tx_stats, cpu);
1104                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1105                 unsigned int start;
1106
1107                 do {
1108                         start = u64_stats_fetch_begin_irq(&tx_stats->syncp);
1109                         tx_packets = tx_stats->packets;
1110                         tx_bytes = tx_stats->bytes;
1111                 } while (u64_stats_fetch_retry_irq(&tx_stats->syncp, start));
1112
1113                 do {
1114                         start = u64_stats_fetch_begin_irq(&rx_stats->syncp);
1115                         rx_packets = rx_stats->packets;
1116                         rx_bytes = rx_stats->bytes;
1117                 } while (u64_stats_fetch_retry_irq(&rx_stats->syncp, start));
1118
1119                 tot->rx_packets += rx_packets;
1120                 tot->tx_packets += tx_packets;
1121                 tot->rx_bytes   += rx_bytes;
1122                 tot->tx_bytes   += tx_bytes;
1123         }
1124
1125         tot->rx_errors  = dev->stats.rx_errors;
1126         tot->tx_dropped = dev->stats.tx_dropped;
1127 }
1128
1129 static void xennet_release_tx_bufs(struct netfront_queue *queue)
1130 {
1131         struct sk_buff *skb;
1132         int i;
1133
1134         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1135                 /* Skip over entries which are actually freelist references */
1136                 if (skb_entry_is_link(&queue->tx_skbs[i]))
1137                         continue;
1138
1139                 skb = queue->tx_skbs[i].skb;
1140                 get_page(queue->grant_tx_page[i]);
1141                 gnttab_end_foreign_access(queue->grant_tx_ref[i],
1142                                           GNTMAP_readonly,
1143                                           (unsigned long)page_address(queue->grant_tx_page[i]));
1144                 queue->grant_tx_page[i] = NULL;
1145                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1146                 add_id_to_freelist(&queue->tx_skb_freelist, queue->tx_skbs, i);
1147                 dev_kfree_skb_irq(skb);
1148         }
1149 }
1150
1151 static void xennet_release_rx_bufs(struct netfront_queue *queue)
1152 {
1153         int id, ref;
1154
1155         spin_lock_bh(&queue->rx_lock);
1156
1157         for (id = 0; id < NET_RX_RING_SIZE; id++) {
1158                 struct sk_buff *skb;
1159                 struct page *page;
1160
1161                 skb = queue->rx_skbs[id];
1162                 if (!skb)
1163                         continue;
1164
1165                 ref = queue->grant_rx_ref[id];
1166                 if (ref == GRANT_INVALID_REF)
1167                         continue;
1168
1169                 page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
1170
1171                 /* gnttab_end_foreign_access() needs a page ref until
1172                  * foreign access is ended (which may be deferred).
1173                  */
1174                 get_page(page);
1175                 gnttab_end_foreign_access(ref, 0,
1176                                           (unsigned long)page_address(page));
1177                 queue->grant_rx_ref[id] = GRANT_INVALID_REF;
1178
1179                 kfree_skb(skb);
1180         }
1181
1182         spin_unlock_bh(&queue->rx_lock);
1183 }
1184
1185 static netdev_features_t xennet_fix_features(struct net_device *dev,
1186         netdev_features_t features)
1187 {
1188         struct netfront_info *np = netdev_priv(dev);
1189
1190         if (features & NETIF_F_SG &&
1191             !xenbus_read_unsigned(np->xbdev->otherend, "feature-sg", 0))
1192                 features &= ~NETIF_F_SG;
1193
1194         if (features & NETIF_F_IPV6_CSUM &&
1195             !xenbus_read_unsigned(np->xbdev->otherend,
1196                                   "feature-ipv6-csum-offload", 0))
1197                 features &= ~NETIF_F_IPV6_CSUM;
1198
1199         if (features & NETIF_F_TSO &&
1200             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv4", 0))
1201                 features &= ~NETIF_F_TSO;
1202
1203         if (features & NETIF_F_TSO6 &&
1204             !xenbus_read_unsigned(np->xbdev->otherend, "feature-gso-tcpv6", 0))
1205                 features &= ~NETIF_F_TSO6;
1206
1207         return features;
1208 }
1209
1210 static int xennet_set_features(struct net_device *dev,
1211         netdev_features_t features)
1212 {
1213         if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1214                 netdev_info(dev, "Reducing MTU because no SG offload");
1215                 dev->mtu = ETH_DATA_LEN;
1216         }
1217
1218         return 0;
1219 }
1220
1221 static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1222 {
1223         struct netfront_queue *queue = dev_id;
1224         unsigned long flags;
1225
1226         spin_lock_irqsave(&queue->tx_lock, flags);
1227         xennet_tx_buf_gc(queue);
1228         spin_unlock_irqrestore(&queue->tx_lock, flags);
1229
1230         return IRQ_HANDLED;
1231 }
1232
1233 static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1234 {
1235         struct netfront_queue *queue = dev_id;
1236         struct net_device *dev = queue->info->netdev;
1237
1238         if (likely(netif_carrier_ok(dev) &&
1239                    RING_HAS_UNCONSUMED_RESPONSES(&queue->rx)))
1240                 napi_schedule(&queue->napi);
1241
1242         return IRQ_HANDLED;
1243 }
1244
1245 static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1246 {
1247         xennet_tx_interrupt(irq, dev_id);
1248         xennet_rx_interrupt(irq, dev_id);
1249         return IRQ_HANDLED;
1250 }
1251
1252 #ifdef CONFIG_NET_POLL_CONTROLLER
1253 static void xennet_poll_controller(struct net_device *dev)
1254 {
1255         /* Poll each queue */
1256         struct netfront_info *info = netdev_priv(dev);
1257         unsigned int num_queues = dev->real_num_tx_queues;
1258         unsigned int i;
1259         for (i = 0; i < num_queues; ++i)
1260                 xennet_interrupt(0, &info->queues[i]);
1261 }
1262 #endif
1263
1264 static const struct net_device_ops xennet_netdev_ops = {
1265         .ndo_open            = xennet_open,
1266         .ndo_stop            = xennet_close,
1267         .ndo_start_xmit      = xennet_start_xmit,
1268         .ndo_change_mtu      = xennet_change_mtu,
1269         .ndo_get_stats64     = xennet_get_stats64,
1270         .ndo_set_mac_address = eth_mac_addr,
1271         .ndo_validate_addr   = eth_validate_addr,
1272         .ndo_fix_features    = xennet_fix_features,
1273         .ndo_set_features    = xennet_set_features,
1274         .ndo_select_queue    = xennet_select_queue,
1275 #ifdef CONFIG_NET_POLL_CONTROLLER
1276         .ndo_poll_controller = xennet_poll_controller,
1277 #endif
1278 };
1279
1280 static void xennet_free_netdev(struct net_device *netdev)
1281 {
1282         struct netfront_info *np = netdev_priv(netdev);
1283
1284         free_percpu(np->rx_stats);
1285         free_percpu(np->tx_stats);
1286         free_netdev(netdev);
1287 }
1288
1289 static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1290 {
1291         int err;
1292         struct net_device *netdev;
1293         struct netfront_info *np;
1294
1295         netdev = alloc_etherdev_mq(sizeof(struct netfront_info), xennet_max_queues);
1296         if (!netdev)
1297                 return ERR_PTR(-ENOMEM);
1298
1299         np                   = netdev_priv(netdev);
1300         np->xbdev            = dev;
1301
1302         np->queues = NULL;
1303
1304         err = -ENOMEM;
1305         np->rx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1306         if (np->rx_stats == NULL)
1307                 goto exit;
1308         np->tx_stats = netdev_alloc_pcpu_stats(struct netfront_stats);
1309         if (np->tx_stats == NULL)
1310                 goto exit;
1311
1312         netdev->netdev_ops      = &xennet_netdev_ops;
1313
1314         netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1315                                   NETIF_F_GSO_ROBUST;
1316         netdev->hw_features     = NETIF_F_SG |
1317                                   NETIF_F_IPV6_CSUM |
1318                                   NETIF_F_TSO | NETIF_F_TSO6;
1319
1320         /*
1321          * Assume that all hw features are available for now. This set
1322          * will be adjusted by the call to netdev_update_features() in
1323          * xennet_connect() which is the earliest point where we can
1324          * negotiate with the backend regarding supported features.
1325          */
1326         netdev->features |= netdev->hw_features;
1327
1328         netdev->ethtool_ops = &xennet_ethtool_ops;
1329         netdev->min_mtu = ETH_MIN_MTU;
1330         netdev->max_mtu = XEN_NETIF_MAX_TX_SIZE;
1331         SET_NETDEV_DEV(netdev, &dev->dev);
1332
1333         np->netdev = netdev;
1334
1335         netif_carrier_off(netdev);
1336
1337         xenbus_switch_state(dev, XenbusStateInitialising);
1338         wait_event(module_wq,
1339                    xenbus_read_driver_state(dev->otherend) !=
1340                    XenbusStateClosed &&
1341                    xenbus_read_driver_state(dev->otherend) !=
1342                    XenbusStateUnknown);
1343         return netdev;
1344
1345  exit:
1346         xennet_free_netdev(netdev);
1347         return ERR_PTR(err);
1348 }
1349
1350 /**
1351  * Entry point to this code when a new device is created.  Allocate the basic
1352  * structures and the ring buffers for communication with the backend, and
1353  * inform the backend of the appropriate details for those.
1354  */
1355 static int netfront_probe(struct xenbus_device *dev,
1356                           const struct xenbus_device_id *id)
1357 {
1358         int err;
1359         struct net_device *netdev;
1360         struct netfront_info *info;
1361
1362         netdev = xennet_create_dev(dev);
1363         if (IS_ERR(netdev)) {
1364                 err = PTR_ERR(netdev);
1365                 xenbus_dev_fatal(dev, err, "creating netdev");
1366                 return err;
1367         }
1368
1369         info = netdev_priv(netdev);
1370         dev_set_drvdata(&dev->dev, info);
1371 #ifdef CONFIG_SYSFS
1372         info->netdev->sysfs_groups[0] = &xennet_dev_group;
1373 #endif
1374
1375         return 0;
1376 }
1377
1378 static void xennet_end_access(int ref, void *page)
1379 {
1380         /* This frees the page as a side-effect */
1381         if (ref != GRANT_INVALID_REF)
1382                 gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1383 }
1384
1385 static void xennet_disconnect_backend(struct netfront_info *info)
1386 {
1387         unsigned int i = 0;
1388         unsigned int num_queues = info->netdev->real_num_tx_queues;
1389
1390         netif_carrier_off(info->netdev);
1391
1392         for (i = 0; i < num_queues && info->queues; ++i) {
1393                 struct netfront_queue *queue = &info->queues[i];
1394
1395                 del_timer_sync(&queue->rx_refill_timer);
1396
1397                 if (queue->tx_irq && (queue->tx_irq == queue->rx_irq))
1398                         unbind_from_irqhandler(queue->tx_irq, queue);
1399                 if (queue->tx_irq && (queue->tx_irq != queue->rx_irq)) {
1400                         unbind_from_irqhandler(queue->tx_irq, queue);
1401                         unbind_from_irqhandler(queue->rx_irq, queue);
1402                 }
1403                 queue->tx_evtchn = queue->rx_evtchn = 0;
1404                 queue->tx_irq = queue->rx_irq = 0;
1405
1406                 if (netif_running(info->netdev))
1407                         napi_synchronize(&queue->napi);
1408
1409                 xennet_release_tx_bufs(queue);
1410                 xennet_release_rx_bufs(queue);
1411                 gnttab_free_grant_references(queue->gref_tx_head);
1412                 gnttab_free_grant_references(queue->gref_rx_head);
1413
1414                 /* End access and free the pages */
1415                 xennet_end_access(queue->tx_ring_ref, queue->tx.sring);
1416                 xennet_end_access(queue->rx_ring_ref, queue->rx.sring);
1417
1418                 queue->tx_ring_ref = GRANT_INVALID_REF;
1419                 queue->rx_ring_ref = GRANT_INVALID_REF;
1420                 queue->tx.sring = NULL;
1421                 queue->rx.sring = NULL;
1422         }
1423 }
1424
1425 /**
1426  * We are reconnecting to the backend, due to a suspend/resume, or a backend
1427  * driver restart.  We tear down our netif structure and recreate it, but
1428  * leave the device-layer structures intact so that this is transparent to the
1429  * rest of the kernel.
1430  */
1431 static int netfront_resume(struct xenbus_device *dev)
1432 {
1433         struct netfront_info *info = dev_get_drvdata(&dev->dev);
1434
1435         dev_dbg(&dev->dev, "%s\n", dev->nodename);
1436
1437         xennet_disconnect_backend(info);
1438         return 0;
1439 }
1440
1441 static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1442 {
1443         char *s, *e, *macstr;
1444         int i;
1445
1446         macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1447         if (IS_ERR(macstr))
1448                 return PTR_ERR(macstr);
1449
1450         for (i = 0; i < ETH_ALEN; i++) {
1451                 mac[i] = simple_strtoul(s, &e, 16);
1452                 if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1453                         kfree(macstr);
1454                         return -ENOENT;
1455                 }
1456                 s = e+1;
1457         }
1458
1459         kfree(macstr);
1460         return 0;
1461 }
1462
1463 static int setup_netfront_single(struct netfront_queue *queue)
1464 {
1465         int err;
1466
1467         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1468         if (err < 0)
1469                 goto fail;
1470
1471         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1472                                         xennet_interrupt,
1473                                         0, queue->info->netdev->name, queue);
1474         if (err < 0)
1475                 goto bind_fail;
1476         queue->rx_evtchn = queue->tx_evtchn;
1477         queue->rx_irq = queue->tx_irq = err;
1478
1479         return 0;
1480
1481 bind_fail:
1482         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1483         queue->tx_evtchn = 0;
1484 fail:
1485         return err;
1486 }
1487
1488 static int setup_netfront_split(struct netfront_queue *queue)
1489 {
1490         int err;
1491
1492         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->tx_evtchn);
1493         if (err < 0)
1494                 goto fail;
1495         err = xenbus_alloc_evtchn(queue->info->xbdev, &queue->rx_evtchn);
1496         if (err < 0)
1497                 goto alloc_rx_evtchn_fail;
1498
1499         snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
1500                  "%s-tx", queue->name);
1501         err = bind_evtchn_to_irqhandler(queue->tx_evtchn,
1502                                         xennet_tx_interrupt,
1503                                         0, queue->tx_irq_name, queue);
1504         if (err < 0)
1505                 goto bind_tx_fail;
1506         queue->tx_irq = err;
1507
1508         snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
1509                  "%s-rx", queue->name);
1510         err = bind_evtchn_to_irqhandler(queue->rx_evtchn,
1511                                         xennet_rx_interrupt,
1512                                         0, queue->rx_irq_name, queue);
1513         if (err < 0)
1514                 goto bind_rx_fail;
1515         queue->rx_irq = err;
1516
1517         return 0;
1518
1519 bind_rx_fail:
1520         unbind_from_irqhandler(queue->tx_irq, queue);
1521         queue->tx_irq = 0;
1522 bind_tx_fail:
1523         xenbus_free_evtchn(queue->info->xbdev, queue->rx_evtchn);
1524         queue->rx_evtchn = 0;
1525 alloc_rx_evtchn_fail:
1526         xenbus_free_evtchn(queue->info->xbdev, queue->tx_evtchn);
1527         queue->tx_evtchn = 0;
1528 fail:
1529         return err;
1530 }
1531
1532 static int setup_netfront(struct xenbus_device *dev,
1533                         struct netfront_queue *queue, unsigned int feature_split_evtchn)
1534 {
1535         struct xen_netif_tx_sring *txs;
1536         struct xen_netif_rx_sring *rxs;
1537         grant_ref_t gref;
1538         int err;
1539
1540         queue->tx_ring_ref = GRANT_INVALID_REF;
1541         queue->rx_ring_ref = GRANT_INVALID_REF;
1542         queue->rx.sring = NULL;
1543         queue->tx.sring = NULL;
1544
1545         txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1546         if (!txs) {
1547                 err = -ENOMEM;
1548                 xenbus_dev_fatal(dev, err, "allocating tx ring page");
1549                 goto fail;
1550         }
1551         SHARED_RING_INIT(txs);
1552         FRONT_RING_INIT(&queue->tx, txs, XEN_PAGE_SIZE);
1553
1554         err = xenbus_grant_ring(dev, txs, 1, &gref);
1555         if (err < 0)
1556                 goto grant_tx_ring_fail;
1557         queue->tx_ring_ref = gref;
1558
1559         rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1560         if (!rxs) {
1561                 err = -ENOMEM;
1562                 xenbus_dev_fatal(dev, err, "allocating rx ring page");
1563                 goto alloc_rx_ring_fail;
1564         }
1565         SHARED_RING_INIT(rxs);
1566         FRONT_RING_INIT(&queue->rx, rxs, XEN_PAGE_SIZE);
1567
1568         err = xenbus_grant_ring(dev, rxs, 1, &gref);
1569         if (err < 0)
1570                 goto grant_rx_ring_fail;
1571         queue->rx_ring_ref = gref;
1572
1573         if (feature_split_evtchn)
1574                 err = setup_netfront_split(queue);
1575         /* setup single event channel if
1576          *  a) feature-split-event-channels == 0
1577          *  b) feature-split-event-channels == 1 but failed to setup
1578          */
1579         if (!feature_split_evtchn || (feature_split_evtchn && err))
1580                 err = setup_netfront_single(queue);
1581
1582         if (err)
1583                 goto alloc_evtchn_fail;
1584
1585         return 0;
1586
1587         /* If we fail to setup netfront, it is safe to just revoke access to
1588          * granted pages because backend is not accessing it at this point.
1589          */
1590 alloc_evtchn_fail:
1591         gnttab_end_foreign_access_ref(queue->rx_ring_ref, 0);
1592 grant_rx_ring_fail:
1593         free_page((unsigned long)rxs);
1594 alloc_rx_ring_fail:
1595         gnttab_end_foreign_access_ref(queue->tx_ring_ref, 0);
1596 grant_tx_ring_fail:
1597         free_page((unsigned long)txs);
1598 fail:
1599         return err;
1600 }
1601
1602 /* Queue-specific initialisation
1603  * This used to be done in xennet_create_dev() but must now
1604  * be run per-queue.
1605  */
1606 static int xennet_init_queue(struct netfront_queue *queue)
1607 {
1608         unsigned short i;
1609         int err = 0;
1610         char *devid;
1611
1612         spin_lock_init(&queue->tx_lock);
1613         spin_lock_init(&queue->rx_lock);
1614
1615         timer_setup(&queue->rx_refill_timer, rx_refill_timeout, 0);
1616
1617         devid = strrchr(queue->info->xbdev->nodename, '/') + 1;
1618         snprintf(queue->name, sizeof(queue->name), "vif%s-q%u",
1619                  devid, queue->id);
1620
1621         /* Initialise tx_skbs as a free chain containing every entry. */
1622         queue->tx_skb_freelist = 0;
1623         for (i = 0; i < NET_TX_RING_SIZE; i++) {
1624                 skb_entry_set_link(&queue->tx_skbs[i], i+1);
1625                 queue->grant_tx_ref[i] = GRANT_INVALID_REF;
1626                 queue->grant_tx_page[i] = NULL;
1627         }
1628
1629         /* Clear out rx_skbs */
1630         for (i = 0; i < NET_RX_RING_SIZE; i++) {
1631                 queue->rx_skbs[i] = NULL;
1632                 queue->grant_rx_ref[i] = GRANT_INVALID_REF;
1633         }
1634
1635         /* A grant for every tx ring slot */
1636         if (gnttab_alloc_grant_references(NET_TX_RING_SIZE,
1637                                           &queue->gref_tx_head) < 0) {
1638                 pr_alert("can't alloc tx grant refs\n");
1639                 err = -ENOMEM;
1640                 goto exit;
1641         }
1642
1643         /* A grant for every rx ring slot */
1644         if (gnttab_alloc_grant_references(NET_RX_RING_SIZE,
1645                                           &queue->gref_rx_head) < 0) {
1646                 pr_alert("can't alloc rx grant refs\n");
1647                 err = -ENOMEM;
1648                 goto exit_free_tx;
1649         }
1650
1651         return 0;
1652
1653  exit_free_tx:
1654         gnttab_free_grant_references(queue->gref_tx_head);
1655  exit:
1656         return err;
1657 }
1658
1659 static int write_queue_xenstore_keys(struct netfront_queue *queue,
1660                            struct xenbus_transaction *xbt, int write_hierarchical)
1661 {
1662         /* Write the queue-specific keys into XenStore in the traditional
1663          * way for a single queue, or in a queue subkeys for multiple
1664          * queues.
1665          */
1666         struct xenbus_device *dev = queue->info->xbdev;
1667         int err;
1668         const char *message;
1669         char *path;
1670         size_t pathsize;
1671
1672         /* Choose the correct place to write the keys */
1673         if (write_hierarchical) {
1674                 pathsize = strlen(dev->nodename) + 10;
1675                 path = kzalloc(pathsize, GFP_KERNEL);
1676                 if (!path) {
1677                         err = -ENOMEM;
1678                         message = "out of memory while writing ring references";
1679                         goto error;
1680                 }
1681                 snprintf(path, pathsize, "%s/queue-%u",
1682                                 dev->nodename, queue->id);
1683         } else {
1684                 path = (char *)dev->nodename;
1685         }
1686
1687         /* Write ring references */
1688         err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u",
1689                         queue->tx_ring_ref);
1690         if (err) {
1691                 message = "writing tx-ring-ref";
1692                 goto error;
1693         }
1694
1695         err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u",
1696                         queue->rx_ring_ref);
1697         if (err) {
1698                 message = "writing rx-ring-ref";
1699                 goto error;
1700         }
1701
1702         /* Write event channels; taking into account both shared
1703          * and split event channel scenarios.
1704          */
1705         if (queue->tx_evtchn == queue->rx_evtchn) {
1706                 /* Shared event channel */
1707                 err = xenbus_printf(*xbt, path,
1708                                 "event-channel", "%u", queue->tx_evtchn);
1709                 if (err) {
1710                         message = "writing event-channel";
1711                         goto error;
1712                 }
1713         } else {
1714                 /* Split event channels */
1715                 err = xenbus_printf(*xbt, path,
1716                                 "event-channel-tx", "%u", queue->tx_evtchn);
1717                 if (err) {
1718                         message = "writing event-channel-tx";
1719                         goto error;
1720                 }
1721
1722                 err = xenbus_printf(*xbt, path,
1723                                 "event-channel-rx", "%u", queue->rx_evtchn);
1724                 if (err) {
1725                         message = "writing event-channel-rx";
1726                         goto error;
1727                 }
1728         }
1729
1730         if (write_hierarchical)
1731                 kfree(path);
1732         return 0;
1733
1734 error:
1735         if (write_hierarchical)
1736                 kfree(path);
1737         xenbus_dev_fatal(dev, err, "%s", message);
1738         return err;
1739 }
1740
1741 static void xennet_destroy_queues(struct netfront_info *info)
1742 {
1743         unsigned int i;
1744
1745         for (i = 0; i < info->netdev->real_num_tx_queues; i++) {
1746                 struct netfront_queue *queue = &info->queues[i];
1747
1748                 if (netif_running(info->netdev))
1749                         napi_disable(&queue->napi);
1750                 netif_napi_del(&queue->napi);
1751         }
1752
1753         kfree(info->queues);
1754         info->queues = NULL;
1755 }
1756
1757 static int xennet_create_queues(struct netfront_info *info,
1758                                 unsigned int *num_queues)
1759 {
1760         unsigned int i;
1761         int ret;
1762
1763         info->queues = kcalloc(*num_queues, sizeof(struct netfront_queue),
1764                                GFP_KERNEL);
1765         if (!info->queues)
1766                 return -ENOMEM;
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->xbdev->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         if (*num_queues == 0) {
1791                 dev_err(&info->xbdev->dev, "no queues\n");
1792                 return -EINVAL;
1793         }
1794         return 0;
1795 }
1796
1797 /* Common code used when first setting up, and when resuming. */
1798 static int talk_to_netback(struct xenbus_device *dev,
1799                            struct netfront_info *info)
1800 {
1801         const char *message;
1802         struct xenbus_transaction xbt;
1803         int err;
1804         unsigned int feature_split_evtchn;
1805         unsigned int i = 0;
1806         unsigned int max_queues = 0;
1807         struct netfront_queue *queue = NULL;
1808         unsigned int num_queues = 1;
1809
1810         info->netdev->irq = 0;
1811
1812         /* Check if backend supports multiple queues */
1813         max_queues = xenbus_read_unsigned(info->xbdev->otherend,
1814                                           "multi-queue-max-queues", 1);
1815         num_queues = min(max_queues, xennet_max_queues);
1816
1817         /* Check feature-split-event-channels */
1818         feature_split_evtchn = xenbus_read_unsigned(info->xbdev->otherend,
1819                                         "feature-split-event-channels", 0);
1820
1821         /* Read mac addr. */
1822         err = xen_net_read_mac(dev, info->netdev->dev_addr);
1823         if (err) {
1824                 xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1825                 goto out_unlocked;
1826         }
1827
1828         rtnl_lock();
1829         if (info->queues)
1830                 xennet_destroy_queues(info);
1831
1832         err = xennet_create_queues(info, &num_queues);
1833         if (err < 0) {
1834                 xenbus_dev_fatal(dev, err, "creating queues");
1835                 kfree(info->queues);
1836                 info->queues = NULL;
1837                 goto out;
1838         }
1839         rtnl_unlock();
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         rtnl_lock();
1937         xennet_destroy_queues(info);
1938  out:
1939         rtnl_unlock();
1940 out_unlocked:
1941         device_unregister(&dev->dev);
1942         return err;
1943 }
1944
1945 static int xennet_connect(struct net_device *dev)
1946 {
1947         struct netfront_info *np = netdev_priv(dev);
1948         unsigned int num_queues = 0;
1949         int err;
1950         unsigned int j = 0;
1951         struct netfront_queue *queue = NULL;
1952
1953         if (!xenbus_read_unsigned(np->xbdev->otherend, "feature-rx-copy", 0)) {
1954                 dev_info(&dev->dev,
1955                          "backend does not support copying receive path\n");
1956                 return -ENODEV;
1957         }
1958
1959         err = talk_to_netback(np->xbdev, np);
1960         if (err)
1961                 return err;
1962
1963         /* talk_to_netback() sets the correct number of queues */
1964         num_queues = dev->real_num_tx_queues;
1965
1966         if (dev->reg_state == NETREG_UNINITIALIZED) {
1967                 err = register_netdev(dev);
1968                 if (err) {
1969                         pr_warn("%s: register_netdev err=%d\n", __func__, err);
1970                         device_unregister(&np->xbdev->dev);
1971                         return err;
1972                 }
1973         }
1974
1975         rtnl_lock();
1976         netdev_update_features(dev);
1977         rtnl_unlock();
1978
1979         /*
1980          * All public and private state should now be sane.  Get
1981          * ready to start sending and receiving packets and give the driver
1982          * domain a kick because we've probably just requeued some
1983          * packets.
1984          */
1985         netif_carrier_on(np->netdev);
1986         for (j = 0; j < num_queues; ++j) {
1987                 queue = &np->queues[j];
1988
1989                 notify_remote_via_irq(queue->tx_irq);
1990                 if (queue->tx_irq != queue->rx_irq)
1991                         notify_remote_via_irq(queue->rx_irq);
1992
1993                 spin_lock_irq(&queue->tx_lock);
1994                 xennet_tx_buf_gc(queue);
1995                 spin_unlock_irq(&queue->tx_lock);
1996
1997                 spin_lock_bh(&queue->rx_lock);
1998                 xennet_alloc_rx_buffers(queue);
1999                 spin_unlock_bh(&queue->rx_lock);
2000         }
2001
2002         return 0;
2003 }
2004
2005 /**
2006  * Callback received when the backend's state changes.
2007  */
2008 static void netback_changed(struct xenbus_device *dev,
2009                             enum xenbus_state backend_state)
2010 {
2011         struct netfront_info *np = dev_get_drvdata(&dev->dev);
2012         struct net_device *netdev = np->netdev;
2013
2014         dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
2015
2016         wake_up_all(&module_wq);
2017
2018         switch (backend_state) {
2019         case XenbusStateInitialising:
2020         case XenbusStateInitialised:
2021         case XenbusStateReconfiguring:
2022         case XenbusStateReconfigured:
2023         case XenbusStateUnknown:
2024                 break;
2025
2026         case XenbusStateInitWait:
2027                 if (dev->state != XenbusStateInitialising)
2028                         break;
2029                 if (xennet_connect(netdev) != 0)
2030                         break;
2031                 xenbus_switch_state(dev, XenbusStateConnected);
2032                 break;
2033
2034         case XenbusStateConnected:
2035                 netdev_notify_peers(netdev);
2036                 break;
2037
2038         case XenbusStateClosed:
2039                 if (dev->state == XenbusStateClosed)
2040                         break;
2041                 /* Fall through - Missed the backend's CLOSING state. */
2042         case XenbusStateClosing:
2043                 xenbus_frontend_closed(dev);
2044                 break;
2045         }
2046 }
2047
2048 static const struct xennet_stat {
2049         char name[ETH_GSTRING_LEN];
2050         u16 offset;
2051 } xennet_stats[] = {
2052         {
2053                 "rx_gso_checksum_fixup",
2054                 offsetof(struct netfront_info, rx_gso_checksum_fixup)
2055         },
2056 };
2057
2058 static int xennet_get_sset_count(struct net_device *dev, int string_set)
2059 {
2060         switch (string_set) {
2061         case ETH_SS_STATS:
2062                 return ARRAY_SIZE(xennet_stats);
2063         default:
2064                 return -EINVAL;
2065         }
2066 }
2067
2068 static void xennet_get_ethtool_stats(struct net_device *dev,
2069                                      struct ethtool_stats *stats, u64 * data)
2070 {
2071         void *np = netdev_priv(dev);
2072         int i;
2073
2074         for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2075                 data[i] = atomic_read((atomic_t *)(np + xennet_stats[i].offset));
2076 }
2077
2078 static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
2079 {
2080         int i;
2081
2082         switch (stringset) {
2083         case ETH_SS_STATS:
2084                 for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
2085                         memcpy(data + i * ETH_GSTRING_LEN,
2086                                xennet_stats[i].name, ETH_GSTRING_LEN);
2087                 break;
2088         }
2089 }
2090
2091 static const struct ethtool_ops xennet_ethtool_ops =
2092 {
2093         .get_link = ethtool_op_get_link,
2094
2095         .get_sset_count = xennet_get_sset_count,
2096         .get_ethtool_stats = xennet_get_ethtool_stats,
2097         .get_strings = xennet_get_strings,
2098 };
2099
2100 #ifdef CONFIG_SYSFS
2101 static ssize_t show_rxbuf(struct device *dev,
2102                           struct device_attribute *attr, char *buf)
2103 {
2104         return sprintf(buf, "%lu\n", NET_RX_RING_SIZE);
2105 }
2106
2107 static ssize_t store_rxbuf(struct device *dev,
2108                            struct device_attribute *attr,
2109                            const char *buf, size_t len)
2110 {
2111         char *endp;
2112         unsigned long target;
2113
2114         if (!capable(CAP_NET_ADMIN))
2115                 return -EPERM;
2116
2117         target = simple_strtoul(buf, &endp, 0);
2118         if (endp == buf)
2119                 return -EBADMSG;
2120
2121         /* rxbuf_min and rxbuf_max are no longer configurable. */
2122
2123         return len;
2124 }
2125
2126 static DEVICE_ATTR(rxbuf_min, 0644, show_rxbuf, store_rxbuf);
2127 static DEVICE_ATTR(rxbuf_max, 0644, show_rxbuf, store_rxbuf);
2128 static DEVICE_ATTR(rxbuf_cur, 0444, show_rxbuf, NULL);
2129
2130 static struct attribute *xennet_dev_attrs[] = {
2131         &dev_attr_rxbuf_min.attr,
2132         &dev_attr_rxbuf_max.attr,
2133         &dev_attr_rxbuf_cur.attr,
2134         NULL
2135 };
2136
2137 static const struct attribute_group xennet_dev_group = {
2138         .attrs = xennet_dev_attrs
2139 };
2140 #endif /* CONFIG_SYSFS */
2141
2142 static int xennet_remove(struct xenbus_device *dev)
2143 {
2144         struct netfront_info *info = dev_get_drvdata(&dev->dev);
2145
2146         dev_dbg(&dev->dev, "%s\n", dev->nodename);
2147
2148         if (xenbus_read_driver_state(dev->otherend) != XenbusStateClosed) {
2149                 xenbus_switch_state(dev, XenbusStateClosing);
2150                 wait_event(module_wq,
2151                            xenbus_read_driver_state(dev->otherend) ==
2152                            XenbusStateClosing ||
2153                            xenbus_read_driver_state(dev->otherend) ==
2154                            XenbusStateUnknown);
2155
2156                 xenbus_switch_state(dev, XenbusStateClosed);
2157                 wait_event(module_wq,
2158                            xenbus_read_driver_state(dev->otherend) ==
2159                            XenbusStateClosed ||
2160                            xenbus_read_driver_state(dev->otherend) ==
2161                            XenbusStateUnknown);
2162         }
2163
2164         xennet_disconnect_backend(info);
2165
2166         if (info->netdev->reg_state == NETREG_REGISTERED)
2167                 unregister_netdev(info->netdev);
2168
2169         if (info->queues) {
2170                 rtnl_lock();
2171                 xennet_destroy_queues(info);
2172                 rtnl_unlock();
2173         }
2174         xennet_free_netdev(info->netdev);
2175
2176         return 0;
2177 }
2178
2179 static const struct xenbus_device_id netfront_ids[] = {
2180         { "vif" },
2181         { "" }
2182 };
2183
2184 static struct xenbus_driver netfront_driver = {
2185         .ids = netfront_ids,
2186         .probe = netfront_probe,
2187         .remove = xennet_remove,
2188         .resume = netfront_resume,
2189         .otherend_changed = netback_changed,
2190 };
2191
2192 static int __init netif_init(void)
2193 {
2194         if (!xen_domain())
2195                 return -ENODEV;
2196
2197         if (!xen_has_pv_nic_devices())
2198                 return -ENODEV;
2199
2200         pr_info("Initialising Xen virtual ethernet driver\n");
2201
2202         /* Allow as many queues as there are CPUs inut max. 8 if user has not
2203          * specified a value.
2204          */
2205         if (xennet_max_queues == 0)
2206                 xennet_max_queues = min_t(unsigned int, MAX_QUEUES_DEFAULT,
2207                                           num_online_cpus());
2208
2209         return xenbus_register_frontend(&netfront_driver);
2210 }
2211 module_init(netif_init);
2212
2213
2214 static void __exit netif_exit(void)
2215 {
2216         xenbus_unregister_driver(&netfront_driver);
2217 }
2218 module_exit(netif_exit);
2219
2220 MODULE_DESCRIPTION("Xen virtual network device frontend");
2221 MODULE_LICENSE("GPL");
2222 MODULE_ALIAS("xen:vif");
2223 MODULE_ALIAS("xennet");