linux/drivers/net/xen-netfront.c
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   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#include <linux/module.h>
  33#include <linux/kernel.h>
  34#include <linux/netdevice.h>
  35#include <linux/etherdevice.h>
  36#include <linux/skbuff.h>
  37#include <linux/ethtool.h>
  38#include <linux/if_ether.h>
  39#include <linux/tcp.h>
  40#include <linux/udp.h>
  41#include <linux/moduleparam.h>
  42#include <linux/mm.h>
  43#include <linux/slab.h>
  44#include <net/ip.h>
  45
  46#include <xen/xen.h>
  47#include <xen/xenbus.h>
  48#include <xen/events.h>
  49#include <xen/page.h>
  50#include <xen/platform_pci.h>
  51#include <xen/grant_table.h>
  52
  53#include <xen/interface/io/netif.h>
  54#include <xen/interface/memory.h>
  55#include <xen/interface/grant_table.h>
  56
  57static const struct ethtool_ops xennet_ethtool_ops;
  58
  59struct netfront_cb {
  60        int pull_to;
  61};
  62
  63#define NETFRONT_SKB_CB(skb)    ((struct netfront_cb *)((skb)->cb))
  64
  65#define RX_COPY_THRESHOLD 256
  66
  67#define GRANT_INVALID_REF       0
  68
  69#define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
  70#define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
  71#define TX_MAX_TARGET min_t(int, NET_TX_RING_SIZE, 256)
  72
  73struct netfront_stats {
  74        u64                     rx_packets;
  75        u64                     tx_packets;
  76        u64                     rx_bytes;
  77        u64                     tx_bytes;
  78        struct u64_stats_sync   syncp;
  79};
  80
  81struct netfront_info {
  82        struct list_head list;
  83        struct net_device *netdev;
  84
  85        struct napi_struct napi;
  86
  87        unsigned int evtchn;
  88        struct xenbus_device *xbdev;
  89
  90        spinlock_t   tx_lock;
  91        struct xen_netif_tx_front_ring tx;
  92        int tx_ring_ref;
  93
  94        /*
  95         * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
  96         * are linked from tx_skb_freelist through skb_entry.link.
  97         *
  98         *  NB. Freelist index entries are always going to be less than
  99         *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
 100         *  greater than PAGE_OFFSET: we use this property to distinguish
 101         *  them.
 102         */
 103        union skb_entry {
 104                struct sk_buff *skb;
 105                unsigned long link;
 106        } tx_skbs[NET_TX_RING_SIZE];
 107        grant_ref_t gref_tx_head;
 108        grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
 109        unsigned tx_skb_freelist;
 110
 111        spinlock_t   rx_lock ____cacheline_aligned_in_smp;
 112        struct xen_netif_rx_front_ring rx;
 113        int rx_ring_ref;
 114
 115        /* Receive-ring batched refills. */
 116#define RX_MIN_TARGET 8
 117#define RX_DFL_MIN_TARGET 64
 118#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
 119        unsigned rx_min_target, rx_max_target, rx_target;
 120        struct sk_buff_head rx_batch;
 121
 122        struct timer_list rx_refill_timer;
 123
 124        struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
 125        grant_ref_t gref_rx_head;
 126        grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
 127
 128        unsigned long rx_pfn_array[NET_RX_RING_SIZE];
 129        struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
 130        struct mmu_update rx_mmu[NET_RX_RING_SIZE];
 131
 132        /* Statistics */
 133        struct netfront_stats __percpu *stats;
 134
 135        unsigned long rx_gso_checksum_fixup;
 136};
 137
 138struct netfront_rx_info {
 139        struct xen_netif_rx_response rx;
 140        struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
 141};
 142
 143static void skb_entry_set_link(union skb_entry *list, unsigned short id)
 144{
 145        list->link = id;
 146}
 147
 148static int skb_entry_is_link(const union skb_entry *list)
 149{
 150        BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
 151        return (unsigned long)list->skb < PAGE_OFFSET;
 152}
 153
 154/*
 155 * Access macros for acquiring freeing slots in tx_skbs[].
 156 */
 157
 158static void add_id_to_freelist(unsigned *head, union skb_entry *list,
 159                               unsigned short id)
 160{
 161        skb_entry_set_link(&list[id], *head);
 162        *head = id;
 163}
 164
 165static unsigned short get_id_from_freelist(unsigned *head,
 166                                           union skb_entry *list)
 167{
 168        unsigned int id = *head;
 169        *head = list[id].link;
 170        return id;
 171}
 172
 173static int xennet_rxidx(RING_IDX idx)
 174{
 175        return idx & (NET_RX_RING_SIZE - 1);
 176}
 177
 178static struct sk_buff *xennet_get_rx_skb(struct netfront_info *np,
 179                                         RING_IDX ri)
 180{
 181        int i = xennet_rxidx(ri);
 182        struct sk_buff *skb = np->rx_skbs[i];
 183        np->rx_skbs[i] = NULL;
 184        return skb;
 185}
 186
 187static grant_ref_t xennet_get_rx_ref(struct netfront_info *np,
 188                                            RING_IDX ri)
 189{
 190        int i = xennet_rxidx(ri);
 191        grant_ref_t ref = np->grant_rx_ref[i];
 192        np->grant_rx_ref[i] = GRANT_INVALID_REF;
 193        return ref;
 194}
 195
 196#ifdef CONFIG_SYSFS
 197static int xennet_sysfs_addif(struct net_device *netdev);
 198static void xennet_sysfs_delif(struct net_device *netdev);
 199#else /* !CONFIG_SYSFS */
 200#define xennet_sysfs_addif(dev) (0)
 201#define xennet_sysfs_delif(dev) do { } while (0)
 202#endif
 203
 204static bool xennet_can_sg(struct net_device *dev)
 205{
 206        return dev->features & NETIF_F_SG;
 207}
 208
 209
 210static void rx_refill_timeout(unsigned long data)
 211{
 212        struct net_device *dev = (struct net_device *)data;
 213        struct netfront_info *np = netdev_priv(dev);
 214        napi_schedule(&np->napi);
 215}
 216
 217static int netfront_tx_slot_available(struct netfront_info *np)
 218{
 219        return (np->tx.req_prod_pvt - np->tx.rsp_cons) <
 220                (TX_MAX_TARGET - MAX_SKB_FRAGS - 2);
 221}
 222
 223static void xennet_maybe_wake_tx(struct net_device *dev)
 224{
 225        struct netfront_info *np = netdev_priv(dev);
 226
 227        if (unlikely(netif_queue_stopped(dev)) &&
 228            netfront_tx_slot_available(np) &&
 229            likely(netif_running(dev)))
 230                netif_wake_queue(dev);
 231}
 232
 233static void xennet_alloc_rx_buffers(struct net_device *dev)
 234{
 235        unsigned short id;
 236        struct netfront_info *np = netdev_priv(dev);
 237        struct sk_buff *skb;
 238        struct page *page;
 239        int i, batch_target, notify;
 240        RING_IDX req_prod = np->rx.req_prod_pvt;
 241        grant_ref_t ref;
 242        unsigned long pfn;
 243        void *vaddr;
 244        struct xen_netif_rx_request *req;
 245
 246        if (unlikely(!netif_carrier_ok(dev)))
 247                return;
 248
 249        /*
 250         * Allocate skbuffs greedily, even though we batch updates to the
 251         * receive ring. This creates a less bursty demand on the memory
 252         * allocator, so should reduce the chance of failed allocation requests
 253         * both for ourself and for other kernel subsystems.
 254         */
 255        batch_target = np->rx_target - (req_prod - np->rx.rsp_cons);
 256        for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) {
 257                skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD + NET_IP_ALIGN,
 258                                         GFP_ATOMIC | __GFP_NOWARN);
 259                if (unlikely(!skb))
 260                        goto no_skb;
 261
 262                /* Align ip header to a 16 bytes boundary */
 263                skb_reserve(skb, NET_IP_ALIGN);
 264
 265                page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 266                if (!page) {
 267                        kfree_skb(skb);
 268no_skb:
 269                        /* Any skbuffs queued for refill? Force them out. */
 270                        if (i != 0)
 271                                goto refill;
 272                        /* Could not allocate any skbuffs. Try again later. */
 273                        mod_timer(&np->rx_refill_timer,
 274                                  jiffies + (HZ/10));
 275                        break;
 276                }
 277
 278                __skb_fill_page_desc(skb, 0, page, 0, 0);
 279                skb_shinfo(skb)->nr_frags = 1;
 280                __skb_queue_tail(&np->rx_batch, skb);
 281        }
 282
 283        /* Is the batch large enough to be worthwhile? */
 284        if (i < (np->rx_target/2)) {
 285                if (req_prod > np->rx.sring->req_prod)
 286                        goto push;
 287                return;
 288        }
 289
 290        /* Adjust our fill target if we risked running out of buffers. */
 291        if (((req_prod - np->rx.sring->rsp_prod) < (np->rx_target / 4)) &&
 292            ((np->rx_target *= 2) > np->rx_max_target))
 293                np->rx_target = np->rx_max_target;
 294
 295 refill:
 296        for (i = 0; ; i++) {
 297                skb = __skb_dequeue(&np->rx_batch);
 298                if (skb == NULL)
 299                        break;
 300
 301                skb->dev = dev;
 302
 303                id = xennet_rxidx(req_prod + i);
 304
 305                BUG_ON(np->rx_skbs[id]);
 306                np->rx_skbs[id] = skb;
 307
 308                ref = gnttab_claim_grant_reference(&np->gref_rx_head);
 309                BUG_ON((signed short)ref < 0);
 310                np->grant_rx_ref[id] = ref;
 311
 312                pfn = page_to_pfn(skb_frag_page(&skb_shinfo(skb)->frags[0]));
 313                vaddr = page_address(skb_frag_page(&skb_shinfo(skb)->frags[0]));
 314
 315                req = RING_GET_REQUEST(&np->rx, req_prod + i);
 316                gnttab_grant_foreign_access_ref(ref,
 317                                                np->xbdev->otherend_id,
 318                                                pfn_to_mfn(pfn),
 319                                                0);
 320
 321                req->id = id;
 322                req->gref = ref;
 323        }
 324
 325        wmb();          /* barrier so backend seens requests */
 326
 327        /* Above is a suitable barrier to ensure backend will see requests. */
 328        np->rx.req_prod_pvt = req_prod + i;
 329 push:
 330        RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify);
 331        if (notify)
 332                notify_remote_via_irq(np->netdev->irq);
 333}
 334
 335static int xennet_open(struct net_device *dev)
 336{
 337        struct netfront_info *np = netdev_priv(dev);
 338
 339        napi_enable(&np->napi);
 340
 341        spin_lock_bh(&np->rx_lock);
 342        if (netif_carrier_ok(dev)) {
 343                xennet_alloc_rx_buffers(dev);
 344                np->rx.sring->rsp_event = np->rx.rsp_cons + 1;
 345                if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
 346                        napi_schedule(&np->napi);
 347        }
 348        spin_unlock_bh(&np->rx_lock);
 349
 350        netif_start_queue(dev);
 351
 352        return 0;
 353}
 354
 355static void xennet_tx_buf_gc(struct net_device *dev)
 356{
 357        RING_IDX cons, prod;
 358        unsigned short id;
 359        struct netfront_info *np = netdev_priv(dev);
 360        struct sk_buff *skb;
 361
 362        BUG_ON(!netif_carrier_ok(dev));
 363
 364        do {
 365                prod = np->tx.sring->rsp_prod;
 366                rmb(); /* Ensure we see responses up to 'rp'. */
 367
 368                for (cons = np->tx.rsp_cons; cons != prod; cons++) {
 369                        struct xen_netif_tx_response *txrsp;
 370
 371                        txrsp = RING_GET_RESPONSE(&np->tx, cons);
 372                        if (txrsp->status == XEN_NETIF_RSP_NULL)
 373                                continue;
 374
 375                        id  = txrsp->id;
 376                        skb = np->tx_skbs[id].skb;
 377                        if (unlikely(gnttab_query_foreign_access(
 378                                np->grant_tx_ref[id]) != 0)) {
 379                                printk(KERN_ALERT "xennet_tx_buf_gc: warning "
 380                                       "-- grant still in use by backend "
 381                                       "domain.\n");
 382                                BUG();
 383                        }
 384                        gnttab_end_foreign_access_ref(
 385                                np->grant_tx_ref[id], GNTMAP_readonly);
 386                        gnttab_release_grant_reference(
 387                                &np->gref_tx_head, np->grant_tx_ref[id]);
 388                        np->grant_tx_ref[id] = GRANT_INVALID_REF;
 389                        add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, id);
 390                        dev_kfree_skb_irq(skb);
 391                }
 392
 393                np->tx.rsp_cons = prod;
 394
 395                /*
 396                 * Set a new event, then check for race with update of tx_cons.
 397                 * Note that it is essential to schedule a callback, no matter
 398                 * how few buffers are pending. Even if there is space in the
 399                 * transmit ring, higher layers may be blocked because too much
 400                 * data is outstanding: in such cases notification from Xen is
 401                 * likely to be the only kick that we'll get.
 402                 */
 403                np->tx.sring->rsp_event =
 404                        prod + ((np->tx.sring->req_prod - prod) >> 1) + 1;
 405                mb();           /* update shared area */
 406        } while ((cons == prod) && (prod != np->tx.sring->rsp_prod));
 407
 408        xennet_maybe_wake_tx(dev);
 409}
 410
 411static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
 412                              struct xen_netif_tx_request *tx)
 413{
 414        struct netfront_info *np = netdev_priv(dev);
 415        char *data = skb->data;
 416        unsigned long mfn;
 417        RING_IDX prod = np->tx.req_prod_pvt;
 418        int frags = skb_shinfo(skb)->nr_frags;
 419        unsigned int offset = offset_in_page(data);
 420        unsigned int len = skb_headlen(skb);
 421        unsigned int id;
 422        grant_ref_t ref;
 423        int i;
 424
 425        /* While the header overlaps a page boundary (including being
 426           larger than a page), split it it into page-sized chunks. */
 427        while (len > PAGE_SIZE - offset) {
 428                tx->size = PAGE_SIZE - offset;
 429                tx->flags |= XEN_NETTXF_more_data;
 430                len -= tx->size;
 431                data += tx->size;
 432                offset = 0;
 433
 434                id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
 435                np->tx_skbs[id].skb = skb_get(skb);
 436                tx = RING_GET_REQUEST(&np->tx, prod++);
 437                tx->id = id;
 438                ref = gnttab_claim_grant_reference(&np->gref_tx_head);
 439                BUG_ON((signed short)ref < 0);
 440
 441                mfn = virt_to_mfn(data);
 442                gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
 443                                                mfn, GNTMAP_readonly);
 444
 445                tx->gref = np->grant_tx_ref[id] = ref;
 446                tx->offset = offset;
 447                tx->size = len;
 448                tx->flags = 0;
 449        }
 450
 451        /* Grant backend access to each skb fragment page. */
 452        for (i = 0; i < frags; i++) {
 453                skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 454
 455                tx->flags |= XEN_NETTXF_more_data;
 456
 457                id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
 458                np->tx_skbs[id].skb = skb_get(skb);
 459                tx = RING_GET_REQUEST(&np->tx, prod++);
 460                tx->id = id;
 461                ref = gnttab_claim_grant_reference(&np->gref_tx_head);
 462                BUG_ON((signed short)ref < 0);
 463
 464                mfn = pfn_to_mfn(page_to_pfn(skb_frag_page(frag)));
 465                gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
 466                                                mfn, GNTMAP_readonly);
 467
 468                tx->gref = np->grant_tx_ref[id] = ref;
 469                tx->offset = frag->page_offset;
 470                tx->size = skb_frag_size(frag);
 471                tx->flags = 0;
 472        }
 473
 474        np->tx.req_prod_pvt = prod;
 475}
 476
 477static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 478{
 479        unsigned short id;
 480        struct netfront_info *np = netdev_priv(dev);
 481        struct netfront_stats *stats = this_cpu_ptr(np->stats);
 482        struct xen_netif_tx_request *tx;
 483        struct xen_netif_extra_info *extra;
 484        char *data = skb->data;
 485        RING_IDX i;
 486        grant_ref_t ref;
 487        unsigned long mfn;
 488        int notify;
 489        int frags = skb_shinfo(skb)->nr_frags;
 490        unsigned int offset = offset_in_page(data);
 491        unsigned int len = skb_headlen(skb);
 492        unsigned long flags;
 493
 494        frags += DIV_ROUND_UP(offset + len, PAGE_SIZE);
 495        if (unlikely(frags > MAX_SKB_FRAGS + 1)) {
 496                printk(KERN_ALERT "xennet: skb rides the rocket: %d frags\n",
 497                       frags);
 498                dump_stack();
 499                goto drop;
 500        }
 501
 502        spin_lock_irqsave(&np->tx_lock, flags);
 503
 504        if (unlikely(!netif_carrier_ok(dev) ||
 505                     (frags > 1 && !xennet_can_sg(dev)) ||
 506                     netif_needs_gso(skb, netif_skb_features(skb)))) {
 507                spin_unlock_irqrestore(&np->tx_lock, flags);
 508                goto drop;
 509        }
 510
 511        i = np->tx.req_prod_pvt;
 512
 513        id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
 514        np->tx_skbs[id].skb = skb;
 515
 516        tx = RING_GET_REQUEST(&np->tx, i);
 517
 518        tx->id   = id;
 519        ref = gnttab_claim_grant_reference(&np->gref_tx_head);
 520        BUG_ON((signed short)ref < 0);
 521        mfn = virt_to_mfn(data);
 522        gnttab_grant_foreign_access_ref(
 523                ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
 524        tx->gref = np->grant_tx_ref[id] = ref;
 525        tx->offset = offset;
 526        tx->size = len;
 527        extra = NULL;
 528
 529        tx->flags = 0;
 530        if (skb->ip_summed == CHECKSUM_PARTIAL)
 531                /* local packet? */
 532                tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
 533        else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 534                /* remote but checksummed. */
 535                tx->flags |= XEN_NETTXF_data_validated;
 536
 537        if (skb_shinfo(skb)->gso_size) {
 538                struct xen_netif_extra_info *gso;
 539
 540                gso = (struct xen_netif_extra_info *)
 541                        RING_GET_REQUEST(&np->tx, ++i);
 542
 543                if (extra)
 544                        extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
 545                else
 546                        tx->flags |= XEN_NETTXF_extra_info;
 547
 548                gso->u.gso.size = skb_shinfo(skb)->gso_size;
 549                gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
 550                gso->u.gso.pad = 0;
 551                gso->u.gso.features = 0;
 552
 553                gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 554                gso->flags = 0;
 555                extra = gso;
 556        }
 557
 558        np->tx.req_prod_pvt = i + 1;
 559
 560        xennet_make_frags(skb, dev, tx);
 561        tx->size = skb->len;
 562
 563        RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
 564        if (notify)
 565                notify_remote_via_irq(np->netdev->irq);
 566
 567        u64_stats_update_begin(&stats->syncp);
 568        stats->tx_bytes += skb->len;
 569        stats->tx_packets++;
 570        u64_stats_update_end(&stats->syncp);
 571
 572        /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
 573        xennet_tx_buf_gc(dev);
 574
 575        if (!netfront_tx_slot_available(np))
 576                netif_stop_queue(dev);
 577
 578        spin_unlock_irqrestore(&np->tx_lock, flags);
 579
 580        return NETDEV_TX_OK;
 581
 582 drop:
 583        dev->stats.tx_dropped++;
 584        dev_kfree_skb(skb);
 585        return NETDEV_TX_OK;
 586}
 587
 588static int xennet_close(struct net_device *dev)
 589{
 590        struct netfront_info *np = netdev_priv(dev);
 591        netif_stop_queue(np->netdev);
 592        napi_disable(&np->napi);
 593        return 0;
 594}
 595
 596static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb,
 597                                grant_ref_t ref)
 598{
 599        int new = xennet_rxidx(np->rx.req_prod_pvt);
 600
 601        BUG_ON(np->rx_skbs[new]);
 602        np->rx_skbs[new] = skb;
 603        np->grant_rx_ref[new] = ref;
 604        RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
 605        RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
 606        np->rx.req_prod_pvt++;
 607}
 608
 609static int xennet_get_extras(struct netfront_info *np,
 610                             struct xen_netif_extra_info *extras,
 611                             RING_IDX rp)
 612
 613{
 614        struct xen_netif_extra_info *extra;
 615        struct device *dev = &np->netdev->dev;
 616        RING_IDX cons = np->rx.rsp_cons;
 617        int err = 0;
 618
 619        do {
 620                struct sk_buff *skb;
 621                grant_ref_t ref;
 622
 623                if (unlikely(cons + 1 == rp)) {
 624                        if (net_ratelimit())
 625                                dev_warn(dev, "Missing extra info\n");
 626                        err = -EBADR;
 627                        break;
 628                }
 629
 630                extra = (struct xen_netif_extra_info *)
 631                        RING_GET_RESPONSE(&np->rx, ++cons);
 632
 633                if (unlikely(!extra->type ||
 634                             extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 635                        if (net_ratelimit())
 636                                dev_warn(dev, "Invalid extra type: %d\n",
 637                                        extra->type);
 638                        err = -EINVAL;
 639                } else {
 640                        memcpy(&extras[extra->type - 1], extra,
 641                               sizeof(*extra));
 642                }
 643
 644                skb = xennet_get_rx_skb(np, cons);
 645                ref = xennet_get_rx_ref(np, cons);
 646                xennet_move_rx_slot(np, skb, ref);
 647        } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
 648
 649        np->rx.rsp_cons = cons;
 650        return err;
 651}
 652
 653static int xennet_get_responses(struct netfront_info *np,
 654                                struct netfront_rx_info *rinfo, RING_IDX rp,
 655                                struct sk_buff_head *list)
 656{
 657        struct xen_netif_rx_response *rx = &rinfo->rx;
 658        struct xen_netif_extra_info *extras = rinfo->extras;
 659        struct device *dev = &np->netdev->dev;
 660        RING_IDX cons = np->rx.rsp_cons;
 661        struct sk_buff *skb = xennet_get_rx_skb(np, cons);
 662        grant_ref_t ref = xennet_get_rx_ref(np, cons);
 663        int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
 664        int frags = 1;
 665        int err = 0;
 666        unsigned long ret;
 667
 668        if (rx->flags & XEN_NETRXF_extra_info) {
 669                err = xennet_get_extras(np, extras, rp);
 670                cons = np->rx.rsp_cons;
 671        }
 672
 673        for (;;) {
 674                if (unlikely(rx->status < 0 ||
 675                             rx->offset + rx->status > PAGE_SIZE)) {
 676                        if (net_ratelimit())
 677                                dev_warn(dev, "rx->offset: %x, size: %u\n",
 678                                         rx->offset, rx->status);
 679                        xennet_move_rx_slot(np, skb, ref);
 680                        err = -EINVAL;
 681                        goto next;
 682                }
 683
 684                /*
 685                 * This definitely indicates a bug, either in this driver or in
 686                 * the backend driver. In future this should flag the bad
 687                 * situation to the system controller to reboot the backed.
 688                 */
 689                if (ref == GRANT_INVALID_REF) {
 690                        if (net_ratelimit())
 691                                dev_warn(dev, "Bad rx response id %d.\n",
 692                                         rx->id);
 693                        err = -EINVAL;
 694                        goto next;
 695                }
 696
 697                ret = gnttab_end_foreign_access_ref(ref, 0);
 698                BUG_ON(!ret);
 699
 700                gnttab_release_grant_reference(&np->gref_rx_head, ref);
 701
 702                __skb_queue_tail(list, skb);
 703
 704next:
 705                if (!(rx->flags & XEN_NETRXF_more_data))
 706                        break;
 707
 708                if (cons + frags == rp) {
 709                        if (net_ratelimit())
 710                                dev_warn(dev, "Need more frags\n");
 711                        err = -ENOENT;
 712                        break;
 713                }
 714
 715                rx = RING_GET_RESPONSE(&np->rx, cons + frags);
 716                skb = xennet_get_rx_skb(np, cons + frags);
 717                ref = xennet_get_rx_ref(np, cons + frags);
 718                frags++;
 719        }
 720
 721        if (unlikely(frags > max)) {
 722                if (net_ratelimit())
 723                        dev_warn(dev, "Too many frags\n");
 724                err = -E2BIG;
 725        }
 726
 727        if (unlikely(err))
 728                np->rx.rsp_cons = cons + frags;
 729
 730        return err;
 731}
 732
 733static int xennet_set_skb_gso(struct sk_buff *skb,
 734                              struct xen_netif_extra_info *gso)
 735{
 736        if (!gso->u.gso.size) {
 737                if (net_ratelimit())
 738                        printk(KERN_WARNING "GSO size must not be zero.\n");
 739                return -EINVAL;
 740        }
 741
 742        /* Currently only TCPv4 S.O. is supported. */
 743        if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
 744                if (net_ratelimit())
 745                        printk(KERN_WARNING "Bad GSO type %d.\n", gso->u.gso.type);
 746                return -EINVAL;
 747        }
 748
 749        skb_shinfo(skb)->gso_size = gso->u.gso.size;
 750        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 751
 752        /* Header must be checked, and gso_segs computed. */
 753        skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 754        skb_shinfo(skb)->gso_segs = 0;
 755
 756        return 0;
 757}
 758
 759static RING_IDX xennet_fill_frags(struct netfront_info *np,
 760                                  struct sk_buff *skb,
 761                                  struct sk_buff_head *list)
 762{
 763        struct skb_shared_info *shinfo = skb_shinfo(skb);
 764        int nr_frags = shinfo->nr_frags;
 765        RING_IDX cons = np->rx.rsp_cons;
 766        struct sk_buff *nskb;
 767
 768        while ((nskb = __skb_dequeue(list))) {
 769                struct xen_netif_rx_response *rx =
 770                        RING_GET_RESPONSE(&np->rx, ++cons);
 771                skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
 772
 773                __skb_fill_page_desc(skb, nr_frags,
 774                                     skb_frag_page(nfrag),
 775                                     rx->offset, rx->status);
 776
 777                skb->data_len += rx->status;
 778
 779                skb_shinfo(nskb)->nr_frags = 0;
 780                kfree_skb(nskb);
 781
 782                nr_frags++;
 783        }
 784
 785        shinfo->nr_frags = nr_frags;
 786        return cons;
 787}
 788
 789static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 790{
 791        struct iphdr *iph;
 792        unsigned char *th;
 793        int err = -EPROTO;
 794        int recalculate_partial_csum = 0;
 795
 796        /*
 797         * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 798         * peers can fail to set NETRXF_csum_blank when sending a GSO
 799         * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 800         * recalculate the partial checksum.
 801         */
 802        if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 803                struct netfront_info *np = netdev_priv(dev);
 804                np->rx_gso_checksum_fixup++;
 805                skb->ip_summed = CHECKSUM_PARTIAL;
 806                recalculate_partial_csum = 1;
 807        }
 808
 809        /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 810        if (skb->ip_summed != CHECKSUM_PARTIAL)
 811                return 0;
 812
 813        if (skb->protocol != htons(ETH_P_IP))
 814                goto out;
 815
 816        iph = (void *)skb->data;
 817        th = skb->data + 4 * iph->ihl;
 818        if (th >= skb_tail_pointer(skb))
 819                goto out;
 820
 821        skb->csum_start = th - skb->head;
 822        switch (iph->protocol) {
 823        case IPPROTO_TCP:
 824                skb->csum_offset = offsetof(struct tcphdr, check);
 825
 826                if (recalculate_partial_csum) {
 827                        struct tcphdr *tcph = (struct tcphdr *)th;
 828                        tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
 829                                                         skb->len - iph->ihl*4,
 830                                                         IPPROTO_TCP, 0);
 831                }
 832                break;
 833        case IPPROTO_UDP:
 834                skb->csum_offset = offsetof(struct udphdr, check);
 835
 836                if (recalculate_partial_csum) {
 837                        struct udphdr *udph = (struct udphdr *)th;
 838                        udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
 839                                                         skb->len - iph->ihl*4,
 840                                                         IPPROTO_UDP, 0);
 841                }
 842                break;
 843        default:
 844                if (net_ratelimit())
 845                        printk(KERN_ERR "Attempting to checksum a non-"
 846                               "TCP/UDP packet, dropping a protocol"
 847                               " %d packet", iph->protocol);
 848                goto out;
 849        }
 850
 851        if ((th + skb->csum_offset + 2) > skb_tail_pointer(skb))
 852                goto out;
 853
 854        err = 0;
 855
 856out:
 857        return err;
 858}
 859
 860static int handle_incoming_queue(struct net_device *dev,
 861                                 struct sk_buff_head *rxq)
 862{
 863        struct netfront_info *np = netdev_priv(dev);
 864        struct netfront_stats *stats = this_cpu_ptr(np->stats);
 865        int packets_dropped = 0;
 866        struct sk_buff *skb;
 867
 868        while ((skb = __skb_dequeue(rxq)) != NULL) {
 869                int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 870
 871                __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 872
 873                /* Ethernet work: Delayed to here as it peeks the header. */
 874                skb->protocol = eth_type_trans(skb, dev);
 875
 876                if (checksum_setup(dev, skb)) {
 877                        kfree_skb(skb);
 878                        packets_dropped++;
 879                        dev->stats.rx_errors++;
 880                        continue;
 881                }
 882
 883                u64_stats_update_begin(&stats->syncp);
 884                stats->rx_packets++;
 885                stats->rx_bytes += skb->len;
 886                u64_stats_update_end(&stats->syncp);
 887
 888                /* Pass it up. */
 889                netif_receive_skb(skb);
 890        }
 891
 892        return packets_dropped;
 893}
 894
 895static int xennet_poll(struct napi_struct *napi, int budget)
 896{
 897        struct netfront_info *np = container_of(napi, struct netfront_info, napi);
 898        struct net_device *dev = np->netdev;
 899        struct sk_buff *skb;
 900        struct netfront_rx_info rinfo;
 901        struct xen_netif_rx_response *rx = &rinfo.rx;
 902        struct xen_netif_extra_info *extras = rinfo.extras;
 903        RING_IDX i, rp;
 904        int work_done;
 905        struct sk_buff_head rxq;
 906        struct sk_buff_head errq;
 907        struct sk_buff_head tmpq;
 908        unsigned long flags;
 909        int err;
 910
 911        spin_lock(&np->rx_lock);
 912
 913        skb_queue_head_init(&rxq);
 914        skb_queue_head_init(&errq);
 915        skb_queue_head_init(&tmpq);
 916
 917        rp = np->rx.sring->rsp_prod;
 918        rmb(); /* Ensure we see queued responses up to 'rp'. */
 919
 920        i = np->rx.rsp_cons;
 921        work_done = 0;
 922        while ((i != rp) && (work_done < budget)) {
 923                memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx));
 924                memset(extras, 0, sizeof(rinfo.extras));
 925
 926                err = xennet_get_responses(np, &rinfo, rp, &tmpq);
 927
 928                if (unlikely(err)) {
 929err:
 930                        while ((skb = __skb_dequeue(&tmpq)))
 931                                __skb_queue_tail(&errq, skb);
 932                        dev->stats.rx_errors++;
 933                        i = np->rx.rsp_cons;
 934                        continue;
 935                }
 936
 937                skb = __skb_dequeue(&tmpq);
 938
 939                if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
 940                        struct xen_netif_extra_info *gso;
 941                        gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
 942
 943                        if (unlikely(xennet_set_skb_gso(skb, gso))) {
 944                                __skb_queue_head(&tmpq, skb);
 945                                np->rx.rsp_cons += skb_queue_len(&tmpq);
 946                                goto err;
 947                        }
 948                }
 949
 950                NETFRONT_SKB_CB(skb)->pull_to = rx->status;
 951                if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
 952                        NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
 953
 954                skb_shinfo(skb)->frags[0].page_offset = rx->offset;
 955                skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
 956                skb->data_len = rx->status;
 957
 958                i = xennet_fill_frags(np, skb, &tmpq);
 959
 960                /*
 961                 * Truesize approximates the size of true data plus
 962                 * any supervisor overheads. Adding hypervisor
 963                 * overheads has been shown to significantly reduce
 964                 * achievable bandwidth with the default receive
 965                 * buffer size. It is therefore not wise to account
 966                 * for it here.
 967                 *
 968                 * After alloc_skb(RX_COPY_THRESHOLD), truesize is set
 969                 * to RX_COPY_THRESHOLD + the supervisor
 970                 * overheads. Here, we add the size of the data pulled
 971                 * in xennet_fill_frags().
 972                 *
 973                 * We also adjust for any unused space in the main
 974                 * data area by subtracting (RX_COPY_THRESHOLD -
 975                 * len). This is especially important with drivers
 976                 * which split incoming packets into header and data,
 977                 * using only 66 bytes of the main data area (see the
 978                 * e1000 driver for example.)  On such systems,
 979                 * without this last adjustement, our achievable
 980                 * receive throughout using the standard receive
 981                 * buffer size was cut by 25%(!!!).
 982                 */
 983                skb->truesize += skb->data_len - RX_COPY_THRESHOLD;
 984                skb->len += skb->data_len;
 985
 986                if (rx->flags & XEN_NETRXF_csum_blank)
 987                        skb->ip_summed = CHECKSUM_PARTIAL;
 988                else if (rx->flags & XEN_NETRXF_data_validated)
 989                        skb->ip_summed = CHECKSUM_UNNECESSARY;
 990
 991                __skb_queue_tail(&rxq, skb);
 992
 993                np->rx.rsp_cons = ++i;
 994                work_done++;
 995        }
 996
 997        __skb_queue_purge(&errq);
 998
 999        work_done -= handle_incoming_queue(dev, &rxq);
1000
1001        /* If we get a callback with very few responses, reduce fill target. */
1002        /* NB. Note exponential increase, linear decrease. */
1003        if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) >
1004             ((3*np->rx_target) / 4)) &&
1005            (--np->rx_target < np->rx_min_target))
1006                np->rx_target = np->rx_min_target;
1007
1008        xennet_alloc_rx_buffers(dev);
1009
1010        if (work_done < budget) {
1011                int more_to_do = 0;
1012
1013                local_irq_save(flags);
1014
1015                RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do);
1016                if (!more_to_do)
1017                        __napi_complete(napi);
1018
1019                local_irq_restore(flags);
1020        }
1021
1022        spin_unlock(&np->rx_lock);
1023
1024        return work_done;
1025}
1026
1027static int xennet_change_mtu(struct net_device *dev, int mtu)
1028{
1029        int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN;
1030
1031        if (mtu > max)
1032                return -EINVAL;
1033        dev->mtu = mtu;
1034        return 0;
1035}
1036
1037static struct rtnl_link_stats64 *xennet_get_stats64(struct net_device *dev,
1038                                                    struct rtnl_link_stats64 *tot)
1039{
1040        struct netfront_info *np = netdev_priv(dev);
1041        int cpu;
1042
1043        for_each_possible_cpu(cpu) {
1044                struct netfront_stats *stats = per_cpu_ptr(np->stats, cpu);
1045                u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1046                unsigned int start;
1047
1048                do {
1049                        start = u64_stats_fetch_begin_bh(&stats->syncp);
1050
1051                        rx_packets = stats->rx_packets;
1052                        tx_packets = stats->tx_packets;
1053                        rx_bytes = stats->rx_bytes;
1054                        tx_bytes = stats->tx_bytes;
1055                } while (u64_stats_fetch_retry_bh(&stats->syncp, start));
1056
1057                tot->rx_packets += rx_packets;
1058                tot->tx_packets += tx_packets;
1059                tot->rx_bytes   += rx_bytes;
1060                tot->tx_bytes   += tx_bytes;
1061        }
1062
1063        tot->rx_errors  = dev->stats.rx_errors;
1064        tot->tx_dropped = dev->stats.tx_dropped;
1065
1066        return tot;
1067}
1068
1069static void xennet_release_tx_bufs(struct netfront_info *np)
1070{
1071        struct sk_buff *skb;
1072        int i;
1073
1074        for (i = 0; i < NET_TX_RING_SIZE; i++) {
1075                /* Skip over entries which are actually freelist references */
1076                if (skb_entry_is_link(&np->tx_skbs[i]))
1077                        continue;
1078
1079                skb = np->tx_skbs[i].skb;
1080                gnttab_end_foreign_access_ref(np->grant_tx_ref[i],
1081                                              GNTMAP_readonly);
1082                gnttab_release_grant_reference(&np->gref_tx_head,
1083                                               np->grant_tx_ref[i]);
1084                np->grant_tx_ref[i] = GRANT_INVALID_REF;
1085                add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, i);
1086                dev_kfree_skb_irq(skb);
1087        }
1088}
1089
1090static void xennet_release_rx_bufs(struct netfront_info *np)
1091{
1092        struct mmu_update      *mmu = np->rx_mmu;
1093        struct multicall_entry *mcl = np->rx_mcl;
1094        struct sk_buff_head free_list;
1095        struct sk_buff *skb;
1096        unsigned long mfn;
1097        int xfer = 0, noxfer = 0, unused = 0;
1098        int id, ref;
1099
1100        dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n",
1101                         __func__);
1102        return;
1103
1104        skb_queue_head_init(&free_list);
1105
1106        spin_lock_bh(&np->rx_lock);
1107
1108        for (id = 0; id < NET_RX_RING_SIZE; id++) {
1109                ref = np->grant_rx_ref[id];
1110                if (ref == GRANT_INVALID_REF) {
1111                        unused++;
1112                        continue;
1113                }
1114
1115                skb = np->rx_skbs[id];
1116                mfn = gnttab_end_foreign_transfer_ref(ref);
1117                gnttab_release_grant_reference(&np->gref_rx_head, ref);
1118                np->grant_rx_ref[id] = GRANT_INVALID_REF;
1119
1120                if (0 == mfn) {
1121                        skb_shinfo(skb)->nr_frags = 0;
1122                        dev_kfree_skb(skb);
1123                        noxfer++;
1124                        continue;
1125                }
1126
1127                if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1128                        /* Remap the page. */
1129                        const struct page *page =
1130                                skb_frag_page(&skb_shinfo(skb)->frags[0]);
1131                        unsigned long pfn = page_to_pfn(page);
1132                        void *vaddr = page_address(page);
1133
1134                        MULTI_update_va_mapping(mcl, (unsigned long)vaddr,
1135                                                mfn_pte(mfn, PAGE_KERNEL),
1136                                                0);
1137                        mcl++;
1138                        mmu->ptr = ((u64)mfn << PAGE_SHIFT)
1139                                | MMU_MACHPHYS_UPDATE;
1140                        mmu->val = pfn;
1141                        mmu++;
1142
1143                        set_phys_to_machine(pfn, mfn);
1144                }
1145                __skb_queue_tail(&free_list, skb);
1146                xfer++;
1147        }
1148
1149        dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n",
1150                 __func__, xfer, noxfer, unused);
1151
1152        if (xfer) {
1153                if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1154                        /* Do all the remapping work and M2P updates. */
1155                        MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu,
1156                                         NULL, DOMID_SELF);
1157                        mcl++;
1158                        HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl);
1159                }
1160        }
1161
1162        __skb_queue_purge(&free_list);
1163
1164        spin_unlock_bh(&np->rx_lock);
1165}
1166
1167static void xennet_uninit(struct net_device *dev)
1168{
1169        struct netfront_info *np = netdev_priv(dev);
1170        xennet_release_tx_bufs(np);
1171        xennet_release_rx_bufs(np);
1172        gnttab_free_grant_references(np->gref_tx_head);
1173        gnttab_free_grant_references(np->gref_rx_head);
1174}
1175
1176static netdev_features_t xennet_fix_features(struct net_device *dev,
1177        netdev_features_t features)
1178{
1179        struct netfront_info *np = netdev_priv(dev);
1180        int val;
1181
1182        if (features & NETIF_F_SG) {
1183                if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg",
1184                                 "%d", &val) < 0)
1185                        val = 0;
1186
1187                if (!val)
1188                        features &= ~NETIF_F_SG;
1189        }
1190
1191        if (features & NETIF_F_TSO) {
1192                if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1193                                 "feature-gso-tcpv4", "%d", &val) < 0)
1194                        val = 0;
1195
1196                if (!val)
1197                        features &= ~NETIF_F_TSO;
1198        }
1199
1200        return features;
1201}
1202
1203static int xennet_set_features(struct net_device *dev,
1204        netdev_features_t features)
1205{
1206        if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1207                netdev_info(dev, "Reducing MTU because no SG offload");
1208                dev->mtu = ETH_DATA_LEN;
1209        }
1210
1211        return 0;
1212}
1213
1214static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1215{
1216        struct net_device *dev = dev_id;
1217        struct netfront_info *np = netdev_priv(dev);
1218        unsigned long flags;
1219
1220        spin_lock_irqsave(&np->tx_lock, flags);
1221
1222        if (likely(netif_carrier_ok(dev))) {
1223                xennet_tx_buf_gc(dev);
1224                /* Under tx_lock: protects access to rx shared-ring indexes. */
1225                if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
1226                        napi_schedule(&np->napi);
1227        }
1228
1229        spin_unlock_irqrestore(&np->tx_lock, flags);
1230
1231        return IRQ_HANDLED;
1232}
1233
1234#ifdef CONFIG_NET_POLL_CONTROLLER
1235static void xennet_poll_controller(struct net_device *dev)
1236{
1237        xennet_interrupt(0, dev);
1238}
1239#endif
1240
1241static const struct net_device_ops xennet_netdev_ops = {
1242        .ndo_open            = xennet_open,
1243        .ndo_uninit          = xennet_uninit,
1244        .ndo_stop            = xennet_close,
1245        .ndo_start_xmit      = xennet_start_xmit,
1246        .ndo_change_mtu      = xennet_change_mtu,
1247        .ndo_get_stats64     = xennet_get_stats64,
1248        .ndo_set_mac_address = eth_mac_addr,
1249        .ndo_validate_addr   = eth_validate_addr,
1250        .ndo_fix_features    = xennet_fix_features,
1251        .ndo_set_features    = xennet_set_features,
1252#ifdef CONFIG_NET_POLL_CONTROLLER
1253        .ndo_poll_controller = xennet_poll_controller,
1254#endif
1255};
1256
1257static struct net_device * __devinit xennet_create_dev(struct xenbus_device *dev)
1258{
1259        int i, err;
1260        struct net_device *netdev;
1261        struct netfront_info *np;
1262
1263        netdev = alloc_etherdev(sizeof(struct netfront_info));
1264        if (!netdev)
1265                return ERR_PTR(-ENOMEM);
1266
1267        np                   = netdev_priv(netdev);
1268        np->xbdev            = dev;
1269
1270        spin_lock_init(&np->tx_lock);
1271        spin_lock_init(&np->rx_lock);
1272
1273        skb_queue_head_init(&np->rx_batch);
1274        np->rx_target     = RX_DFL_MIN_TARGET;
1275        np->rx_min_target = RX_DFL_MIN_TARGET;
1276        np->rx_max_target = RX_MAX_TARGET;
1277
1278        init_timer(&np->rx_refill_timer);
1279        np->rx_refill_timer.data = (unsigned long)netdev;
1280        np->rx_refill_timer.function = rx_refill_timeout;
1281
1282        err = -ENOMEM;
1283        np->stats = alloc_percpu(struct netfront_stats);
1284        if (np->stats == NULL)
1285                goto exit;
1286
1287        /* Initialise tx_skbs as a free chain containing every entry. */
1288        np->tx_skb_freelist = 0;
1289        for (i = 0; i < NET_TX_RING_SIZE; i++) {
1290                skb_entry_set_link(&np->tx_skbs[i], i+1);
1291                np->grant_tx_ref[i] = GRANT_INVALID_REF;
1292        }
1293
1294        /* Clear out rx_skbs */
1295        for (i = 0; i < NET_RX_RING_SIZE; i++) {
1296                np->rx_skbs[i] = NULL;
1297                np->grant_rx_ref[i] = GRANT_INVALID_REF;
1298        }
1299
1300        /* A grant for every tx ring slot */
1301        if (gnttab_alloc_grant_references(TX_MAX_TARGET,
1302                                          &np->gref_tx_head) < 0) {
1303                printk(KERN_ALERT "#### netfront can't alloc tx grant refs\n");
1304                err = -ENOMEM;
1305                goto exit_free_stats;
1306        }
1307        /* A grant for every rx ring slot */
1308        if (gnttab_alloc_grant_references(RX_MAX_TARGET,
1309                                          &np->gref_rx_head) < 0) {
1310                printk(KERN_ALERT "#### netfront can't alloc rx grant refs\n");
1311                err = -ENOMEM;
1312                goto exit_free_tx;
1313        }
1314
1315        netdev->netdev_ops      = &xennet_netdev_ops;
1316
1317        netif_napi_add(netdev, &np->napi, xennet_poll, 64);
1318        netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1319                                  NETIF_F_GSO_ROBUST;
1320        netdev->hw_features     = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO;
1321
1322        /*
1323         * Assume that all hw features are available for now. This set
1324         * will be adjusted by the call to netdev_update_features() in
1325         * xennet_connect() which is the earliest point where we can
1326         * negotiate with the backend regarding supported features.
1327         */
1328        netdev->features |= netdev->hw_features;
1329
1330        SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops);
1331        SET_NETDEV_DEV(netdev, &dev->dev);
1332
1333        np->netdev = netdev;
1334
1335        netif_carrier_off(netdev);
1336
1337        return netdev;
1338
1339 exit_free_tx:
1340        gnttab_free_grant_references(np->gref_tx_head);
1341 exit_free_stats:
1342        free_percpu(np->stats);
1343 exit:
1344        free_netdev(netdev);
1345        return ERR_PTR(err);
1346}
1347
1348/**
1349 * Entry point to this code when a new device is created.  Allocate the basic
1350 * structures and the ring buffers for communication with the backend, and
1351 * inform the backend of the appropriate details for those.
1352 */
1353static int __devinit netfront_probe(struct xenbus_device *dev,
1354                                    const struct xenbus_device_id *id)
1355{
1356        int err;
1357        struct net_device *netdev;
1358        struct netfront_info *info;
1359
1360        netdev = xennet_create_dev(dev);
1361        if (IS_ERR(netdev)) {
1362                err = PTR_ERR(netdev);
1363                xenbus_dev_fatal(dev, err, "creating netdev");
1364                return err;
1365        }
1366
1367        info = netdev_priv(netdev);
1368        dev_set_drvdata(&dev->dev, info);
1369
1370        err = register_netdev(info->netdev);
1371        if (err) {
1372                printk(KERN_WARNING "%s: register_netdev err=%d\n",
1373                       __func__, err);
1374                goto fail;
1375        }
1376
1377        err = xennet_sysfs_addif(info->netdev);
1378        if (err) {
1379                unregister_netdev(info->netdev);
1380                printk(KERN_WARNING "%s: add sysfs failed err=%d\n",
1381                       __func__, err);
1382                goto fail;
1383        }
1384
1385        return 0;
1386
1387 fail:
1388        free_netdev(netdev);
1389        dev_set_drvdata(&dev->dev, NULL);
1390        return err;
1391}
1392
1393static void xennet_end_access(int ref, void *page)
1394{
1395        /* This frees the page as a side-effect */
1396        if (ref != GRANT_INVALID_REF)
1397                gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1398}
1399
1400static void xennet_disconnect_backend(struct netfront_info *info)
1401{
1402        /* Stop old i/f to prevent errors whilst we rebuild the state. */
1403        spin_lock_bh(&info->rx_lock);
1404        spin_lock_irq(&info->tx_lock);
1405        netif_carrier_off(info->netdev);
1406        spin_unlock_irq(&info->tx_lock);
1407        spin_unlock_bh(&info->rx_lock);
1408
1409        if (info->netdev->irq)
1410                unbind_from_irqhandler(info->netdev->irq, info->netdev);
1411        info->evtchn = info->netdev->irq = 0;
1412
1413        /* End access and free the pages */
1414        xennet_end_access(info->tx_ring_ref, info->tx.sring);
1415        xennet_end_access(info->rx_ring_ref, info->rx.sring);
1416
1417        info->tx_ring_ref = GRANT_INVALID_REF;
1418        info->rx_ring_ref = GRANT_INVALID_REF;
1419        info->tx.sring = NULL;
1420        info->rx.sring = NULL;
1421}
1422
1423/**
1424 * We are reconnecting to the backend, due to a suspend/resume, or a backend
1425 * driver restart.  We tear down our netif structure and recreate it, but
1426 * leave the device-layer structures intact so that this is transparent to the
1427 * rest of the kernel.
1428 */
1429static int netfront_resume(struct xenbus_device *dev)
1430{
1431        struct netfront_info *info = dev_get_drvdata(&dev->dev);
1432
1433        dev_dbg(&dev->dev, "%s\n", dev->nodename);
1434
1435        xennet_disconnect_backend(info);
1436        return 0;
1437}
1438
1439static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1440{
1441        char *s, *e, *macstr;
1442        int i;
1443
1444        macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1445        if (IS_ERR(macstr))
1446                return PTR_ERR(macstr);
1447
1448        for (i = 0; i < ETH_ALEN; i++) {
1449                mac[i] = simple_strtoul(s, &e, 16);
1450                if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1451                        kfree(macstr);
1452                        return -ENOENT;
1453                }
1454                s = e+1;
1455        }
1456
1457        kfree(macstr);
1458        return 0;
1459}
1460
1461static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
1462{
1463        struct xen_netif_tx_sring *txs;
1464        struct xen_netif_rx_sring *rxs;
1465        int err;
1466        struct net_device *netdev = info->netdev;
1467
1468        info->tx_ring_ref = GRANT_INVALID_REF;
1469        info->rx_ring_ref = GRANT_INVALID_REF;
1470        info->rx.sring = NULL;
1471        info->tx.sring = NULL;
1472        netdev->irq = 0;
1473
1474        err = xen_net_read_mac(dev, netdev->dev_addr);
1475        if (err) {
1476                xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1477                goto fail;
1478        }
1479
1480        txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1481        if (!txs) {
1482                err = -ENOMEM;
1483                xenbus_dev_fatal(dev, err, "allocating tx ring page");
1484                goto fail;
1485        }
1486        SHARED_RING_INIT(txs);
1487        FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
1488
1489        err = xenbus_grant_ring(dev, virt_to_mfn(txs));
1490        if (err < 0) {
1491                free_page((unsigned long)txs);
1492                goto fail;
1493        }
1494
1495        info->tx_ring_ref = err;
1496        rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1497        if (!rxs) {
1498                err = -ENOMEM;
1499                xenbus_dev_fatal(dev, err, "allocating rx ring page");
1500                goto fail;
1501        }
1502        SHARED_RING_INIT(rxs);
1503        FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);
1504
1505        err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
1506        if (err < 0) {
1507                free_page((unsigned long)rxs);
1508                goto fail;
1509        }
1510        info->rx_ring_ref = err;
1511
1512        err = xenbus_alloc_evtchn(dev, &info->evtchn);
1513        if (err)
1514                goto fail;
1515
1516        err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt,
1517                                        0, netdev->name, netdev);
1518        if (err < 0)
1519                goto fail;
1520        netdev->irq = err;
1521        return 0;
1522
1523 fail:
1524        return err;
1525}
1526
1527/* Common code used when first setting up, and when resuming. */
1528static int talk_to_netback(struct xenbus_device *dev,
1529                           struct netfront_info *info)
1530{
1531        const char *message;
1532        struct xenbus_transaction xbt;
1533        int err;
1534
1535        /* Create shared ring, alloc event channel. */
1536        err = setup_netfront(dev, info);
1537        if (err)
1538                goto out;
1539
1540again:
1541        err = xenbus_transaction_start(&xbt);
1542        if (err) {
1543                xenbus_dev_fatal(dev, err, "starting transaction");
1544                goto destroy_ring;
1545        }
1546
1547        err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u",
1548                            info->tx_ring_ref);
1549        if (err) {
1550                message = "writing tx ring-ref";
1551                goto abort_transaction;
1552        }
1553        err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u",
1554                            info->rx_ring_ref);
1555        if (err) {
1556                message = "writing rx ring-ref";
1557                goto abort_transaction;
1558        }
1559        err = xenbus_printf(xbt, dev->nodename,
1560                            "event-channel", "%u", info->evtchn);
1561        if (err) {
1562                message = "writing event-channel";
1563                goto abort_transaction;
1564        }
1565
1566        err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1567                            1);
1568        if (err) {
1569                message = "writing request-rx-copy";
1570                goto abort_transaction;
1571        }
1572
1573        err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1574        if (err) {
1575                message = "writing feature-rx-notify";
1576                goto abort_transaction;
1577        }
1578
1579        err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1580        if (err) {
1581                message = "writing feature-sg";
1582                goto abort_transaction;
1583        }
1584
1585        err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1586        if (err) {
1587                message = "writing feature-gso-tcpv4";
1588                goto abort_transaction;
1589        }
1590
1591        err = xenbus_transaction_end(xbt, 0);
1592        if (err) {
1593                if (err == -EAGAIN)
1594                        goto again;
1595                xenbus_dev_fatal(dev, err, "completing transaction");
1596                goto destroy_ring;
1597        }
1598
1599        return 0;
1600
1601 abort_transaction:
1602        xenbus_transaction_end(xbt, 1);
1603        xenbus_dev_fatal(dev, err, "%s", message);
1604 destroy_ring:
1605        xennet_disconnect_backend(info);
1606 out:
1607        return err;
1608}
1609
1610static int xennet_connect(struct net_device *dev)
1611{
1612        struct netfront_info *np = netdev_priv(dev);
1613        int i, requeue_idx, err;
1614        struct sk_buff *skb;
1615        grant_ref_t ref;
1616        struct xen_netif_rx_request *req;
1617        unsigned int feature_rx_copy;
1618
1619        err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1620                           "feature-rx-copy", "%u", &feature_rx_copy);
1621        if (err != 1)
1622                feature_rx_copy = 0;
1623
1624        if (!feature_rx_copy) {
1625                dev_info(&dev->dev,
1626                         "backend does not support copying receive path\n");
1627                return -ENODEV;
1628        }
1629
1630        err = talk_to_netback(np->xbdev, np);
1631        if (err)
1632                return err;
1633
1634        rtnl_lock();
1635        netdev_update_features(dev);
1636        rtnl_unlock();
1637
1638        spin_lock_bh(&np->rx_lock);
1639        spin_lock_irq(&np->tx_lock);
1640
1641        /* Step 1: Discard all pending TX packet fragments. */
1642        xennet_release_tx_bufs(np);
1643
1644        /* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
1645        for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) {
1646                skb_frag_t *frag;
1647                const struct page *page;
1648                if (!np->rx_skbs[i])
1649                        continue;
1650
1651                skb = np->rx_skbs[requeue_idx] = xennet_get_rx_skb(np, i);
1652                ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i);
1653                req = RING_GET_REQUEST(&np->rx, requeue_idx);
1654
1655                frag = &skb_shinfo(skb)->frags[0];
1656                page = skb_frag_page(frag);
1657                gnttab_grant_foreign_access_ref(
1658                        ref, np->xbdev->otherend_id,
1659                        pfn_to_mfn(page_to_pfn(page)),
1660                        0);
1661                req->gref = ref;
1662                req->id   = requeue_idx;
1663
1664                requeue_idx++;
1665        }
1666
1667        np->rx.req_prod_pvt = requeue_idx;
1668
1669        /*
1670         * Step 3: All public and private state should now be sane.  Get
1671         * ready to start sending and receiving packets and give the driver
1672         * domain a kick because we've probably just requeued some
1673         * packets.
1674         */
1675        netif_carrier_on(np->netdev);
1676        notify_remote_via_irq(np->netdev->irq);
1677        xennet_tx_buf_gc(dev);
1678        xennet_alloc_rx_buffers(dev);
1679
1680        spin_unlock_irq(&np->tx_lock);
1681        spin_unlock_bh(&np->rx_lock);
1682
1683        return 0;
1684}
1685
1686/**
1687 * Callback received when the backend's state changes.
1688 */
1689static void netback_changed(struct xenbus_device *dev,
1690                            enum xenbus_state backend_state)
1691{
1692        struct netfront_info *np = dev_get_drvdata(&dev->dev);
1693        struct net_device *netdev = np->netdev;
1694
1695        dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
1696
1697        switch (backend_state) {
1698        case XenbusStateInitialising:
1699        case XenbusStateInitialised:
1700        case XenbusStateReconfiguring:
1701        case XenbusStateReconfigured:
1702        case XenbusStateUnknown:
1703        case XenbusStateClosed:
1704                break;
1705
1706        case XenbusStateInitWait:
1707                if (dev->state != XenbusStateInitialising)
1708                        break;
1709                if (xennet_connect(netdev) != 0)
1710                        break;
1711                xenbus_switch_state(dev, XenbusStateConnected);
1712                break;
1713
1714        case XenbusStateConnected:
1715                netif_notify_peers(netdev);
1716                break;
1717
1718        case XenbusStateClosing:
1719                xenbus_frontend_closed(dev);
1720                break;
1721        }
1722}
1723
1724static const struct xennet_stat {
1725        char name[ETH_GSTRING_LEN];
1726        u16 offset;
1727} xennet_stats[] = {
1728        {
1729                "rx_gso_checksum_fixup",
1730                offsetof(struct netfront_info, rx_gso_checksum_fixup)
1731        },
1732};
1733
1734static int xennet_get_sset_count(struct net_device *dev, int string_set)
1735{
1736        switch (string_set) {
1737        case ETH_SS_STATS:
1738                return ARRAY_SIZE(xennet_stats);
1739        default:
1740                return -EINVAL;
1741        }
1742}
1743
1744static void xennet_get_ethtool_stats(struct net_device *dev,
1745                                     struct ethtool_stats *stats, u64 * data)
1746{
1747        void *np = netdev_priv(dev);
1748        int i;
1749
1750        for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
1751                data[i] = *(unsigned long *)(np + xennet_stats[i].offset);
1752}
1753
1754static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
1755{
1756        int i;
1757
1758        switch (stringset) {
1759        case ETH_SS_STATS:
1760                for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
1761                        memcpy(data + i * ETH_GSTRING_LEN,
1762                               xennet_stats[i].name, ETH_GSTRING_LEN);
1763                break;
1764        }
1765}
1766
1767static const struct ethtool_ops xennet_ethtool_ops =
1768{
1769        .get_link = ethtool_op_get_link,
1770
1771        .get_sset_count = xennet_get_sset_count,
1772        .get_ethtool_stats = xennet_get_ethtool_stats,
1773        .get_strings = xennet_get_strings,
1774};
1775
1776#ifdef CONFIG_SYSFS
1777static ssize_t show_rxbuf_min(struct device *dev,
1778                              struct device_attribute *attr, char *buf)
1779{
1780        struct net_device *netdev = to_net_dev(dev);
1781        struct netfront_info *info = netdev_priv(netdev);
1782
1783        return sprintf(buf, "%u\n", info->rx_min_target);
1784}
1785
1786static ssize_t store_rxbuf_min(struct device *dev,
1787                               struct device_attribute *attr,
1788                               const char *buf, size_t len)
1789{
1790        struct net_device *netdev = to_net_dev(dev);
1791        struct netfront_info *np = netdev_priv(netdev);
1792        char *endp;
1793        unsigned long target;
1794
1795        if (!capable(CAP_NET_ADMIN))
1796                return -EPERM;
1797
1798        target = simple_strtoul(buf, &endp, 0);
1799        if (endp == buf)
1800                return -EBADMSG;
1801
1802        if (target < RX_MIN_TARGET)
1803                target = RX_MIN_TARGET;
1804        if (target > RX_MAX_TARGET)
1805                target = RX_MAX_TARGET;
1806
1807        spin_lock_bh(&np->rx_lock);
1808        if (target > np->rx_max_target)
1809                np->rx_max_target = target;
1810        np->rx_min_target = target;
1811        if (target > np->rx_target)
1812                np->rx_target = target;
1813
1814        xennet_alloc_rx_buffers(netdev);
1815
1816        spin_unlock_bh(&np->rx_lock);
1817        return len;
1818}
1819
1820static ssize_t show_rxbuf_max(struct device *dev,
1821                              struct device_attribute *attr, char *buf)
1822{
1823        struct net_device *netdev = to_net_dev(dev);
1824        struct netfront_info *info = netdev_priv(netdev);
1825
1826        return sprintf(buf, "%u\n", info->rx_max_target);
1827}
1828
1829static ssize_t store_rxbuf_max(struct device *dev,
1830                               struct device_attribute *attr,
1831                               const char *buf, size_t len)
1832{
1833        struct net_device *netdev = to_net_dev(dev);
1834        struct netfront_info *np = netdev_priv(netdev);
1835        char *endp;
1836        unsigned long target;
1837
1838        if (!capable(CAP_NET_ADMIN))
1839                return -EPERM;
1840
1841        target = simple_strtoul(buf, &endp, 0);
1842        if (endp == buf)
1843                return -EBADMSG;
1844
1845        if (target < RX_MIN_TARGET)
1846                target = RX_MIN_TARGET;
1847        if (target > RX_MAX_TARGET)
1848                target = RX_MAX_TARGET;
1849
1850        spin_lock_bh(&np->rx_lock);
1851        if (target < np->rx_min_target)
1852                np->rx_min_target = target;
1853        np->rx_max_target = target;
1854        if (target < np->rx_target)
1855                np->rx_target = target;
1856
1857        xennet_alloc_rx_buffers(netdev);
1858
1859        spin_unlock_bh(&np->rx_lock);
1860        return len;
1861}
1862
1863static ssize_t show_rxbuf_cur(struct device *dev,
1864                              struct device_attribute *attr, char *buf)
1865{
1866        struct net_device *netdev = to_net_dev(dev);
1867        struct netfront_info *info = netdev_priv(netdev);
1868
1869        return sprintf(buf, "%u\n", info->rx_target);
1870}
1871
1872static struct device_attribute xennet_attrs[] = {
1873        __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min),
1874        __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max),
1875        __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL),
1876};
1877
1878static int xennet_sysfs_addif(struct net_device *netdev)
1879{
1880        int i;
1881        int err;
1882
1883        for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) {
1884                err = device_create_file(&netdev->dev,
1885                                           &xennet_attrs[i]);
1886                if (err)
1887                        goto fail;
1888        }
1889        return 0;
1890
1891 fail:
1892        while (--i >= 0)
1893                device_remove_file(&netdev->dev, &xennet_attrs[i]);
1894        return err;
1895}
1896
1897static void xennet_sysfs_delif(struct net_device *netdev)
1898{
1899        int i;
1900
1901        for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++)
1902                device_remove_file(&netdev->dev, &xennet_attrs[i]);
1903}
1904
1905#endif /* CONFIG_SYSFS */
1906
1907static const struct xenbus_device_id netfront_ids[] = {
1908        { "vif" },
1909        { "" }
1910};
1911
1912
1913static int __devexit xennet_remove(struct xenbus_device *dev)
1914{
1915        struct netfront_info *info = dev_get_drvdata(&dev->dev);
1916
1917        dev_dbg(&dev->dev, "%s\n", dev->nodename);
1918
1919        xennet_disconnect_backend(info);
1920
1921        xennet_sysfs_delif(info->netdev);
1922
1923        unregister_netdev(info->netdev);
1924
1925        del_timer_sync(&info->rx_refill_timer);
1926
1927        free_percpu(info->stats);
1928
1929        free_netdev(info->netdev);
1930
1931        return 0;
1932}
1933
1934static DEFINE_XENBUS_DRIVER(netfront, ,
1935        .probe = netfront_probe,
1936        .remove = __devexit_p(xennet_remove),
1937        .resume = netfront_resume,
1938        .otherend_changed = netback_changed,
1939);
1940
1941static int __init netif_init(void)
1942{
1943        if (!xen_domain())
1944                return -ENODEV;
1945
1946        if (xen_hvm_domain() && !xen_platform_pci_unplug)
1947                return -ENODEV;
1948
1949        printk(KERN_INFO "Initialising Xen virtual ethernet driver.\n");
1950
1951        return xenbus_register_frontend(&netfront_driver);
1952}
1953module_init(netif_init);
1954
1955
1956static void __exit netif_exit(void)
1957{
1958        xenbus_unregister_driver(&netfront_driver);
1959}
1960module_exit(netif_exit);
1961
1962MODULE_DESCRIPTION("Xen virtual network device frontend");
1963MODULE_LICENSE("GPL");
1964MODULE_ALIAS("xen:vif");
1965MODULE_ALIAS("xennet");
1966
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