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#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 <asm/xen/page.h>
  49#include <xen/xen.h>
  50#include <xen/xenbus.h>
  51#include <xen/events.h>
  52#include <xen/page.h>
  53#include <xen/platform_pci.h>
  54#include <xen/grant_table.h>
  55
  56#include <xen/interface/io/netif.h>
  57#include <xen/interface/memory.h>
  58#include <xen/interface/grant_table.h>
  59
  60static const struct ethtool_ops xennet_ethtool_ops;
  61
  62struct netfront_cb {
  63        int pull_to;
  64};
  65
  66#define NETFRONT_SKB_CB(skb)    ((struct netfront_cb *)((skb)->cb))
  67
  68#define RX_COPY_THRESHOLD 256
  69
  70#define GRANT_INVALID_REF       0
  71
  72#define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
  73#define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
  74#define TX_MAX_TARGET min_t(int, NET_TX_RING_SIZE, 256)
  75
  76struct netfront_stats {
  77        u64                     rx_packets;
  78        u64                     tx_packets;
  79        u64                     rx_bytes;
  80        u64                     tx_bytes;
  81        struct u64_stats_sync   syncp;
  82};
  83
  84struct netfront_info {
  85        struct list_head list;
  86        struct net_device *netdev;
  87
  88        struct napi_struct napi;
  89
  90        /* Split event channels support, tx_* == rx_* when using
  91         * single event channel.
  92         */
  93        unsigned int tx_evtchn, rx_evtchn;
  94        unsigned int tx_irq, rx_irq;
  95        /* Only used when split event channels support is enabled */
  96        char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
  97        char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
  98
  99        struct xenbus_device *xbdev;
 100
 101        spinlock_t   tx_lock;
 102        struct xen_netif_tx_front_ring tx;
 103        int tx_ring_ref;
 104
 105        /*
 106         * {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
 107         * are linked from tx_skb_freelist through skb_entry.link.
 108         *
 109         *  NB. Freelist index entries are always going to be less than
 110         *  PAGE_OFFSET, whereas pointers to skbs will always be equal or
 111         *  greater than PAGE_OFFSET: we use this property to distinguish
 112         *  them.
 113         */
 114        union skb_entry {
 115                struct sk_buff *skb;
 116                unsigned long link;
 117        } tx_skbs[NET_TX_RING_SIZE];
 118        grant_ref_t gref_tx_head;
 119        grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
 120        unsigned tx_skb_freelist;
 121
 122        spinlock_t   rx_lock ____cacheline_aligned_in_smp;
 123        struct xen_netif_rx_front_ring rx;
 124        int rx_ring_ref;
 125
 126        /* Receive-ring batched refills. */
 127#define RX_MIN_TARGET 8
 128#define RX_DFL_MIN_TARGET 64
 129#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
 130        unsigned rx_min_target, rx_max_target, rx_target;
 131        struct sk_buff_head rx_batch;
 132
 133        struct timer_list rx_refill_timer;
 134
 135        struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
 136        grant_ref_t gref_rx_head;
 137        grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
 138
 139        unsigned long rx_pfn_array[NET_RX_RING_SIZE];
 140        struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
 141        struct mmu_update rx_mmu[NET_RX_RING_SIZE];
 142
 143        /* Statistics */
 144        struct netfront_stats __percpu *stats;
 145
 146        unsigned long rx_gso_checksum_fixup;
 147};
 148
 149struct netfront_rx_info {
 150        struct xen_netif_rx_response rx;
 151        struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];
 152};
 153
 154static void skb_entry_set_link(union skb_entry *list, unsigned short id)
 155{
 156        list->link = id;
 157}
 158
 159static int skb_entry_is_link(const union skb_entry *list)
 160{
 161        BUILD_BUG_ON(sizeof(list->skb) != sizeof(list->link));
 162        return (unsigned long)list->skb < PAGE_OFFSET;
 163}
 164
 165/*
 166 * Access macros for acquiring freeing slots in tx_skbs[].
 167 */
 168
 169static void add_id_to_freelist(unsigned *head, union skb_entry *list,
 170                               unsigned short id)
 171{
 172        skb_entry_set_link(&list[id], *head);
 173        *head = id;
 174}
 175
 176static unsigned short get_id_from_freelist(unsigned *head,
 177                                           union skb_entry *list)
 178{
 179        unsigned int id = *head;
 180        *head = list[id].link;
 181        return id;
 182}
 183
 184static int xennet_rxidx(RING_IDX idx)
 185{
 186        return idx & (NET_RX_RING_SIZE - 1);
 187}
 188
 189static struct sk_buff *xennet_get_rx_skb(struct netfront_info *np,
 190                                         RING_IDX ri)
 191{
 192        int i = xennet_rxidx(ri);
 193        struct sk_buff *skb = np->rx_skbs[i];
 194        np->rx_skbs[i] = NULL;
 195        return skb;
 196}
 197
 198static grant_ref_t xennet_get_rx_ref(struct netfront_info *np,
 199                                            RING_IDX ri)
 200{
 201        int i = xennet_rxidx(ri);
 202        grant_ref_t ref = np->grant_rx_ref[i];
 203        np->grant_rx_ref[i] = GRANT_INVALID_REF;
 204        return ref;
 205}
 206
 207#ifdef CONFIG_SYSFS
 208static int xennet_sysfs_addif(struct net_device *netdev);
 209static void xennet_sysfs_delif(struct net_device *netdev);
 210#else /* !CONFIG_SYSFS */
 211#define xennet_sysfs_addif(dev) (0)
 212#define xennet_sysfs_delif(dev) do { } while (0)
 213#endif
 214
 215static bool xennet_can_sg(struct net_device *dev)
 216{
 217        return dev->features & NETIF_F_SG;
 218}
 219
 220
 221static void rx_refill_timeout(unsigned long data)
 222{
 223        struct net_device *dev = (struct net_device *)data;
 224        struct netfront_info *np = netdev_priv(dev);
 225        napi_schedule(&np->napi);
 226}
 227
 228static int netfront_tx_slot_available(struct netfront_info *np)
 229{
 230        return (np->tx.req_prod_pvt - np->tx.rsp_cons) <
 231                (TX_MAX_TARGET - MAX_SKB_FRAGS - 2);
 232}
 233
 234static void xennet_maybe_wake_tx(struct net_device *dev)
 235{
 236        struct netfront_info *np = netdev_priv(dev);
 237
 238        if (unlikely(netif_queue_stopped(dev)) &&
 239            netfront_tx_slot_available(np) &&
 240            likely(netif_running(dev)))
 241                netif_wake_queue(dev);
 242}
 243
 244static void xennet_alloc_rx_buffers(struct net_device *dev)
 245{
 246        unsigned short id;
 247        struct netfront_info *np = netdev_priv(dev);
 248        struct sk_buff *skb;
 249        struct page *page;
 250        int i, batch_target, notify;
 251        RING_IDX req_prod = np->rx.req_prod_pvt;
 252        grant_ref_t ref;
 253        unsigned long pfn;
 254        void *vaddr;
 255        struct xen_netif_rx_request *req;
 256
 257        if (unlikely(!netif_carrier_ok(dev)))
 258                return;
 259
 260        /*
 261         * Allocate skbuffs greedily, even though we batch updates to the
 262         * receive ring. This creates a less bursty demand on the memory
 263         * allocator, so should reduce the chance of failed allocation requests
 264         * both for ourself and for other kernel subsystems.
 265         */
 266        batch_target = np->rx_target - (req_prod - np->rx.rsp_cons);
 267        for (i = skb_queue_len(&np->rx_batch); i < batch_target; i++) {
 268                skb = __netdev_alloc_skb(dev, RX_COPY_THRESHOLD + NET_IP_ALIGN,
 269                                         GFP_ATOMIC | __GFP_NOWARN);
 270                if (unlikely(!skb))
 271                        goto no_skb;
 272
 273                /* Align ip header to a 16 bytes boundary */
 274                skb_reserve(skb, NET_IP_ALIGN);
 275
 276                page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
 277                if (!page) {
 278                        kfree_skb(skb);
 279no_skb:
 280                        /* Any skbuffs queued for refill? Force them out. */
 281                        if (i != 0)
 282                                goto refill;
 283                        /* Could not allocate any skbuffs. Try again later. */
 284                        mod_timer(&np->rx_refill_timer,
 285                                  jiffies + (HZ/10));
 286                        break;
 287                }
 288
 289                skb_add_rx_frag(skb, 0, page, 0, 0, PAGE_SIZE);
 290                __skb_queue_tail(&np->rx_batch, skb);
 291        }
 292
 293        /* Is the batch large enough to be worthwhile? */
 294        if (i < (np->rx_target/2)) {
 295                if (req_prod > np->rx.sring->req_prod)
 296                        goto push;
 297                return;
 298        }
 299
 300        /* Adjust our fill target if we risked running out of buffers. */
 301        if (((req_prod - np->rx.sring->rsp_prod) < (np->rx_target / 4)) &&
 302            ((np->rx_target *= 2) > np->rx_max_target))
 303                np->rx_target = np->rx_max_target;
 304
 305 refill:
 306        for (i = 0; ; i++) {
 307                skb = __skb_dequeue(&np->rx_batch);
 308                if (skb == NULL)
 309                        break;
 310
 311                skb->dev = dev;
 312
 313                id = xennet_rxidx(req_prod + i);
 314
 315                BUG_ON(np->rx_skbs[id]);
 316                np->rx_skbs[id] = skb;
 317
 318                ref = gnttab_claim_grant_reference(&np->gref_rx_head);
 319                BUG_ON((signed short)ref < 0);
 320                np->grant_rx_ref[id] = ref;
 321
 322                pfn = page_to_pfn(skb_frag_page(&skb_shinfo(skb)->frags[0]));
 323                vaddr = page_address(skb_frag_page(&skb_shinfo(skb)->frags[0]));
 324
 325                req = RING_GET_REQUEST(&np->rx, req_prod + i);
 326                gnttab_grant_foreign_access_ref(ref,
 327                                                np->xbdev->otherend_id,
 328                                                pfn_to_mfn(pfn),
 329                                                0);
 330
 331                req->id = id;
 332                req->gref = ref;
 333        }
 334
 335        wmb();          /* barrier so backend seens requests */
 336
 337        /* Above is a suitable barrier to ensure backend will see requests. */
 338        np->rx.req_prod_pvt = req_prod + i;
 339 push:
 340        RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->rx, notify);
 341        if (notify)
 342                notify_remote_via_irq(np->rx_irq);
 343}
 344
 345static int xennet_open(struct net_device *dev)
 346{
 347        struct netfront_info *np = netdev_priv(dev);
 348
 349        napi_enable(&np->napi);
 350
 351        spin_lock_bh(&np->rx_lock);
 352        if (netif_carrier_ok(dev)) {
 353                xennet_alloc_rx_buffers(dev);
 354                np->rx.sring->rsp_event = np->rx.rsp_cons + 1;
 355                if (RING_HAS_UNCONSUMED_RESPONSES(&np->rx))
 356                        napi_schedule(&np->napi);
 357        }
 358        spin_unlock_bh(&np->rx_lock);
 359
 360        netif_start_queue(dev);
 361
 362        return 0;
 363}
 364
 365static void xennet_tx_buf_gc(struct net_device *dev)
 366{
 367        RING_IDX cons, prod;
 368        unsigned short id;
 369        struct netfront_info *np = netdev_priv(dev);
 370        struct sk_buff *skb;
 371
 372        BUG_ON(!netif_carrier_ok(dev));
 373
 374        do {
 375                prod = np->tx.sring->rsp_prod;
 376                rmb(); /* Ensure we see responses up to 'rp'. */
 377
 378                for (cons = np->tx.rsp_cons; cons != prod; cons++) {
 379                        struct xen_netif_tx_response *txrsp;
 380
 381                        txrsp = RING_GET_RESPONSE(&np->tx, cons);
 382                        if (txrsp->status == XEN_NETIF_RSP_NULL)
 383                                continue;
 384
 385                        id  = txrsp->id;
 386                        skb = np->tx_skbs[id].skb;
 387                        if (unlikely(gnttab_query_foreign_access(
 388                                np->grant_tx_ref[id]) != 0)) {
 389                                pr_alert("%s: warning -- grant still in use by backend domain\n",
 390                                         __func__);
 391                                BUG();
 392                        }
 393                        gnttab_end_foreign_access_ref(
 394                                np->grant_tx_ref[id], GNTMAP_readonly);
 395                        gnttab_release_grant_reference(
 396                                &np->gref_tx_head, np->grant_tx_ref[id]);
 397                        np->grant_tx_ref[id] = GRANT_INVALID_REF;
 398                        add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, id);
 399                        dev_kfree_skb_irq(skb);
 400                }
 401
 402                np->tx.rsp_cons = prod;
 403
 404                /*
 405                 * Set a new event, then check for race with update of tx_cons.
 406                 * Note that it is essential to schedule a callback, no matter
 407                 * how few buffers are pending. Even if there is space in the
 408                 * transmit ring, higher layers may be blocked because too much
 409                 * data is outstanding: in such cases notification from Xen is
 410                 * likely to be the only kick that we'll get.
 411                 */
 412                np->tx.sring->rsp_event =
 413                        prod + ((np->tx.sring->req_prod - prod) >> 1) + 1;
 414                mb();           /* update shared area */
 415        } while ((cons == prod) && (prod != np->tx.sring->rsp_prod));
 416
 417        xennet_maybe_wake_tx(dev);
 418}
 419
 420static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
 421                              struct xen_netif_tx_request *tx)
 422{
 423        struct netfront_info *np = netdev_priv(dev);
 424        char *data = skb->data;
 425        unsigned long mfn;
 426        RING_IDX prod = np->tx.req_prod_pvt;
 427        int frags = skb_shinfo(skb)->nr_frags;
 428        unsigned int offset = offset_in_page(data);
 429        unsigned int len = skb_headlen(skb);
 430        unsigned int id;
 431        grant_ref_t ref;
 432        int i;
 433
 434        /* While the header overlaps a page boundary (including being
 435           larger than a page), split it it into page-sized chunks. */
 436        while (len > PAGE_SIZE - offset) {
 437                tx->size = PAGE_SIZE - offset;
 438                tx->flags |= XEN_NETTXF_more_data;
 439                len -= tx->size;
 440                data += tx->size;
 441                offset = 0;
 442
 443                id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
 444                np->tx_skbs[id].skb = skb_get(skb);
 445                tx = RING_GET_REQUEST(&np->tx, prod++);
 446                tx->id = id;
 447                ref = gnttab_claim_grant_reference(&np->gref_tx_head);
 448                BUG_ON((signed short)ref < 0);
 449
 450                mfn = virt_to_mfn(data);
 451                gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
 452                                                mfn, GNTMAP_readonly);
 453
 454                tx->gref = np->grant_tx_ref[id] = ref;
 455                tx->offset = offset;
 456                tx->size = len;
 457                tx->flags = 0;
 458        }
 459
 460        /* Grant backend access to each skb fragment page. */
 461        for (i = 0; i < frags; i++) {
 462                skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 463                struct page *page = skb_frag_page(frag);
 464
 465                len = skb_frag_size(frag);
 466                offset = frag->page_offset;
 467
 468                /* Data must not cross a page boundary. */
 469                BUG_ON(len + offset > PAGE_SIZE<<compound_order(page));
 470
 471                /* Skip unused frames from start of page */
 472                page += offset >> PAGE_SHIFT;
 473                offset &= ~PAGE_MASK;
 474
 475                while (len > 0) {
 476                        unsigned long bytes;
 477
 478                        BUG_ON(offset >= PAGE_SIZE);
 479
 480                        bytes = PAGE_SIZE - offset;
 481                        if (bytes > len)
 482                                bytes = len;
 483
 484                        tx->flags |= XEN_NETTXF_more_data;
 485
 486                        id = get_id_from_freelist(&np->tx_skb_freelist,
 487                                                  np->tx_skbs);
 488                        np->tx_skbs[id].skb = skb_get(skb);
 489                        tx = RING_GET_REQUEST(&np->tx, prod++);
 490                        tx->id = id;
 491                        ref = gnttab_claim_grant_reference(&np->gref_tx_head);
 492                        BUG_ON((signed short)ref < 0);
 493
 494                        mfn = pfn_to_mfn(page_to_pfn(page));
 495                        gnttab_grant_foreign_access_ref(ref,
 496                                                        np->xbdev->otherend_id,
 497                                                        mfn, GNTMAP_readonly);
 498
 499                        tx->gref = np->grant_tx_ref[id] = ref;
 500                        tx->offset = offset;
 501                        tx->size = bytes;
 502                        tx->flags = 0;
 503
 504                        offset += bytes;
 505                        len -= bytes;
 506
 507                        /* Next frame */
 508                        if (offset == PAGE_SIZE && len) {
 509                                BUG_ON(!PageCompound(page));
 510                                page++;
 511                                offset = 0;
 512                        }
 513                }
 514        }
 515
 516        np->tx.req_prod_pvt = prod;
 517}
 518
 519/*
 520 * Count how many ring slots are required to send the frags of this
 521 * skb. Each frag might be a compound page.
 522 */
 523static int xennet_count_skb_frag_slots(struct sk_buff *skb)
 524{
 525        int i, frags = skb_shinfo(skb)->nr_frags;
 526        int pages = 0;
 527
 528        for (i = 0; i < frags; i++) {
 529                skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 530                unsigned long size = skb_frag_size(frag);
 531                unsigned long offset = frag->page_offset;
 532
 533                /* Skip unused frames from start of page */
 534                offset &= ~PAGE_MASK;
 535
 536                pages += PFN_UP(offset + size);
 537        }
 538
 539        return pages;
 540}
 541
 542static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 543{
 544        unsigned short id;
 545        struct netfront_info *np = netdev_priv(dev);
 546        struct netfront_stats *stats = this_cpu_ptr(np->stats);
 547        struct xen_netif_tx_request *tx;
 548        char *data = skb->data;
 549        RING_IDX i;
 550        grant_ref_t ref;
 551        unsigned long mfn;
 552        int notify;
 553        int slots;
 554        unsigned int offset = offset_in_page(data);
 555        unsigned int len = skb_headlen(skb);
 556        unsigned long flags;
 557
 558        /* If skb->len is too big for wire format, drop skb and alert
 559         * user about misconfiguration.
 560         */
 561        if (unlikely(skb->len > XEN_NETIF_MAX_TX_SIZE)) {
 562                net_alert_ratelimited(
 563                        "xennet: skb->len = %u, too big for wire format\n",
 564                        skb->len);
 565                goto drop;
 566        }
 567
 568        slots = DIV_ROUND_UP(offset + len, PAGE_SIZE) +
 569                xennet_count_skb_frag_slots(skb);
 570        if (unlikely(slots > MAX_SKB_FRAGS + 1)) {
 571                net_alert_ratelimited(
 572                        "xennet: skb rides the rocket: %d slots\n", slots);
 573                goto drop;
 574        }
 575
 576        spin_lock_irqsave(&np->tx_lock, flags);
 577
 578        if (unlikely(!netif_carrier_ok(dev) ||
 579                     (slots > 1 && !xennet_can_sg(dev)) ||
 580                     netif_needs_gso(skb, netif_skb_features(skb)))) {
 581                spin_unlock_irqrestore(&np->tx_lock, flags);
 582                goto drop;
 583        }
 584
 585        i = np->tx.req_prod_pvt;
 586
 587        id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
 588        np->tx_skbs[id].skb = skb;
 589
 590        tx = RING_GET_REQUEST(&np->tx, i);
 591
 592        tx->id   = id;
 593        ref = gnttab_claim_grant_reference(&np->gref_tx_head);
 594        BUG_ON((signed short)ref < 0);
 595        mfn = virt_to_mfn(data);
 596        gnttab_grant_foreign_access_ref(
 597                ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
 598        tx->gref = np->grant_tx_ref[id] = ref;
 599        tx->offset = offset;
 600        tx->size = len;
 601
 602        tx->flags = 0;
 603        if (skb->ip_summed == CHECKSUM_PARTIAL)
 604                /* local packet? */
 605                tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
 606        else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 607                /* remote but checksummed. */
 608                tx->flags |= XEN_NETTXF_data_validated;
 609
 610        if (skb_shinfo(skb)->gso_size) {
 611                struct xen_netif_extra_info *gso;
 612
 613                gso = (struct xen_netif_extra_info *)
 614                        RING_GET_REQUEST(&np->tx, ++i);
 615
 616                tx->flags |= XEN_NETTXF_extra_info;
 617
 618                gso->u.gso.size = skb_shinfo(skb)->gso_size;
 619                gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
 620                gso->u.gso.pad = 0;
 621                gso->u.gso.features = 0;
 622
 623                gso->type = XEN_NETIF_EXTRA_TYPE_GSO;
 624                gso->flags = 0;
 625        }
 626
 627        np->tx.req_prod_pvt = i + 1;
 628
 629        xennet_make_frags(skb, dev, tx);
 630        tx->size = skb->len;
 631
 632        RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&np->tx, notify);
 633        if (notify)
 634                notify_remote_via_irq(np->tx_irq);
 635
 636        u64_stats_update_begin(&stats->syncp);
 637        stats->tx_bytes += skb->len;
 638        stats->tx_packets++;
 639        u64_stats_update_end(&stats->syncp);
 640
 641        /* Note: It is not safe to access skb after xennet_tx_buf_gc()! */
 642        xennet_tx_buf_gc(dev);
 643
 644        if (!netfront_tx_slot_available(np))
 645                netif_stop_queue(dev);
 646
 647        spin_unlock_irqrestore(&np->tx_lock, flags);
 648
 649        return NETDEV_TX_OK;
 650
 651 drop:
 652        dev->stats.tx_dropped++;
 653        dev_kfree_skb(skb);
 654        return NETDEV_TX_OK;
 655}
 656
 657static int xennet_close(struct net_device *dev)
 658{
 659        struct netfront_info *np = netdev_priv(dev);
 660        netif_stop_queue(np->netdev);
 661        napi_disable(&np->napi);
 662        return 0;
 663}
 664
 665static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb,
 666                                grant_ref_t ref)
 667{
 668        int new = xennet_rxidx(np->rx.req_prod_pvt);
 669
 670        BUG_ON(np->rx_skbs[new]);
 671        np->rx_skbs[new] = skb;
 672        np->grant_rx_ref[new] = ref;
 673        RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->id = new;
 674        RING_GET_REQUEST(&np->rx, np->rx.req_prod_pvt)->gref = ref;
 675        np->rx.req_prod_pvt++;
 676}
 677
 678static int xennet_get_extras(struct netfront_info *np,
 679                             struct xen_netif_extra_info *extras,
 680                             RING_IDX rp)
 681
 682{
 683        struct xen_netif_extra_info *extra;
 684        struct device *dev = &np->netdev->dev;
 685        RING_IDX cons = np->rx.rsp_cons;
 686        int err = 0;
 687
 688        do {
 689                struct sk_buff *skb;
 690                grant_ref_t ref;
 691
 692                if (unlikely(cons + 1 == rp)) {
 693                        if (net_ratelimit())
 694                                dev_warn(dev, "Missing extra info\n");
 695                        err = -EBADR;
 696                        break;
 697                }
 698
 699                extra = (struct xen_netif_extra_info *)
 700                        RING_GET_RESPONSE(&np->rx, ++cons);
 701
 702                if (unlikely(!extra->type ||
 703                             extra->type >= XEN_NETIF_EXTRA_TYPE_MAX)) {
 704                        if (net_ratelimit())
 705                                dev_warn(dev, "Invalid extra type: %d\n",
 706                                        extra->type);
 707                        err = -EINVAL;
 708                } else {
 709                        memcpy(&extras[extra->type - 1], extra,
 710                               sizeof(*extra));
 711                }
 712
 713                skb = xennet_get_rx_skb(np, cons);
 714                ref = xennet_get_rx_ref(np, cons);
 715                xennet_move_rx_slot(np, skb, ref);
 716        } while (extra->flags & XEN_NETIF_EXTRA_FLAG_MORE);
 717
 718        np->rx.rsp_cons = cons;
 719        return err;
 720}
 721
 722static int xennet_get_responses(struct netfront_info *np,
 723                                struct netfront_rx_info *rinfo, RING_IDX rp,
 724                                struct sk_buff_head *list)
 725{
 726        struct xen_netif_rx_response *rx = &rinfo->rx;
 727        struct xen_netif_extra_info *extras = rinfo->extras;
 728        struct device *dev = &np->netdev->dev;
 729        RING_IDX cons = np->rx.rsp_cons;
 730        struct sk_buff *skb = xennet_get_rx_skb(np, cons);
 731        grant_ref_t ref = xennet_get_rx_ref(np, cons);
 732        int max = MAX_SKB_FRAGS + (rx->status <= RX_COPY_THRESHOLD);
 733        int slots = 1;
 734        int err = 0;
 735        unsigned long ret;
 736
 737        if (rx->flags & XEN_NETRXF_extra_info) {
 738                err = xennet_get_extras(np, extras, rp);
 739                cons = np->rx.rsp_cons;
 740        }
 741
 742        for (;;) {
 743                if (unlikely(rx->status < 0 ||
 744                             rx->offset + rx->status > PAGE_SIZE)) {
 745                        if (net_ratelimit())
 746                                dev_warn(dev, "rx->offset: %x, size: %u\n",
 747                                         rx->offset, rx->status);
 748                        xennet_move_rx_slot(np, skb, ref);
 749                        err = -EINVAL;
 750                        goto next;
 751                }
 752
 753                /*
 754                 * This definitely indicates a bug, either in this driver or in
 755                 * the backend driver. In future this should flag the bad
 756                 * situation to the system controller to reboot the backend.
 757                 */
 758                if (ref == GRANT_INVALID_REF) {
 759                        if (net_ratelimit())
 760                                dev_warn(dev, "Bad rx response id %d.\n",
 761                                         rx->id);
 762                        err = -EINVAL;
 763                        goto next;
 764                }
 765
 766                ret = gnttab_end_foreign_access_ref(ref, 0);
 767                BUG_ON(!ret);
 768
 769                gnttab_release_grant_reference(&np->gref_rx_head, ref);
 770
 771                __skb_queue_tail(list, skb);
 772
 773next:
 774                if (!(rx->flags & XEN_NETRXF_more_data))
 775                        break;
 776
 777                if (cons + slots == rp) {
 778                        if (net_ratelimit())
 779                                dev_warn(dev, "Need more slots\n");
 780                        err = -ENOENT;
 781                        break;
 782                }
 783
 784                rx = RING_GET_RESPONSE(&np->rx, cons + slots);
 785                skb = xennet_get_rx_skb(np, cons + slots);
 786                ref = xennet_get_rx_ref(np, cons + slots);
 787                slots++;
 788        }
 789
 790        if (unlikely(slots > max)) {
 791                if (net_ratelimit())
 792                        dev_warn(dev, "Too many slots\n");
 793                err = -E2BIG;
 794        }
 795
 796        if (unlikely(err))
 797                np->rx.rsp_cons = cons + slots;
 798
 799        return err;
 800}
 801
 802static int xennet_set_skb_gso(struct sk_buff *skb,
 803                              struct xen_netif_extra_info *gso)
 804{
 805        if (!gso->u.gso.size) {
 806                if (net_ratelimit())
 807                        pr_warn("GSO size must not be zero\n");
 808                return -EINVAL;
 809        }
 810
 811        /* Currently only TCPv4 S.O. is supported. */
 812        if (gso->u.gso.type != XEN_NETIF_GSO_TYPE_TCPV4) {
 813                if (net_ratelimit())
 814                        pr_warn("Bad GSO type %d\n", gso->u.gso.type);
 815                return -EINVAL;
 816        }
 817
 818        skb_shinfo(skb)->gso_size = gso->u.gso.size;
 819        skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 820
 821        /* Header must be checked, and gso_segs computed. */
 822        skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 823        skb_shinfo(skb)->gso_segs = 0;
 824
 825        return 0;
 826}
 827
 828static RING_IDX xennet_fill_frags(struct netfront_info *np,
 829                                  struct sk_buff *skb,
 830                                  struct sk_buff_head *list)
 831{
 832        struct skb_shared_info *shinfo = skb_shinfo(skb);
 833        RING_IDX cons = np->rx.rsp_cons;
 834        struct sk_buff *nskb;
 835
 836        while ((nskb = __skb_dequeue(list))) {
 837                struct xen_netif_rx_response *rx =
 838                        RING_GET_RESPONSE(&np->rx, ++cons);
 839                skb_frag_t *nfrag = &skb_shinfo(nskb)->frags[0];
 840
 841                if (shinfo->nr_frags == MAX_SKB_FRAGS) {
 842                        unsigned int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 843
 844                        BUG_ON(pull_to <= skb_headlen(skb));
 845                        __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 846                }
 847                BUG_ON(shinfo->nr_frags >= MAX_SKB_FRAGS);
 848
 849                skb_add_rx_frag(skb, shinfo->nr_frags, skb_frag_page(nfrag),
 850                                rx->offset, rx->status, PAGE_SIZE);
 851
 852                skb_shinfo(nskb)->nr_frags = 0;
 853                kfree_skb(nskb);
 854        }
 855
 856        return cons;
 857}
 858
 859static int checksum_setup(struct net_device *dev, struct sk_buff *skb)
 860{
 861        struct iphdr *iph;
 862        int err = -EPROTO;
 863        int recalculate_partial_csum = 0;
 864
 865        /*
 866         * A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
 867         * peers can fail to set NETRXF_csum_blank when sending a GSO
 868         * frame. In this case force the SKB to CHECKSUM_PARTIAL and
 869         * recalculate the partial checksum.
 870         */
 871        if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
 872                struct netfront_info *np = netdev_priv(dev);
 873                np->rx_gso_checksum_fixup++;
 874                skb->ip_summed = CHECKSUM_PARTIAL;
 875                recalculate_partial_csum = 1;
 876        }
 877
 878        /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
 879        if (skb->ip_summed != CHECKSUM_PARTIAL)
 880                return 0;
 881
 882        if (skb->protocol != htons(ETH_P_IP))
 883                goto out;
 884
 885        iph = (void *)skb->data;
 886
 887        switch (iph->protocol) {
 888        case IPPROTO_TCP:
 889                if (!skb_partial_csum_set(skb, 4 * iph->ihl,
 890                                          offsetof(struct tcphdr, check)))
 891                        goto out;
 892
 893                if (recalculate_partial_csum) {
 894                        struct tcphdr *tcph = tcp_hdr(skb);
 895                        tcph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
 896                                                         skb->len - iph->ihl*4,
 897                                                         IPPROTO_TCP, 0);
 898                }
 899                break;
 900        case IPPROTO_UDP:
 901                if (!skb_partial_csum_set(skb, 4 * iph->ihl,
 902                                          offsetof(struct udphdr, check)))
 903                        goto out;
 904
 905                if (recalculate_partial_csum) {
 906                        struct udphdr *udph = udp_hdr(skb);
 907                        udph->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr,
 908                                                         skb->len - iph->ihl*4,
 909                                                         IPPROTO_UDP, 0);
 910                }
 911                break;
 912        default:
 913                if (net_ratelimit())
 914                        pr_err("Attempting to checksum a non-TCP/UDP packet, dropping a protocol %d packet\n",
 915                               iph->protocol);
 916                goto out;
 917        }
 918
 919        err = 0;
 920
 921out:
 922        return err;
 923}
 924
 925static int handle_incoming_queue(struct net_device *dev,
 926                                 struct sk_buff_head *rxq)
 927{
 928        struct netfront_info *np = netdev_priv(dev);
 929        struct netfront_stats *stats = this_cpu_ptr(np->stats);
 930        int packets_dropped = 0;
 931        struct sk_buff *skb;
 932
 933        while ((skb = __skb_dequeue(rxq)) != NULL) {
 934                int pull_to = NETFRONT_SKB_CB(skb)->pull_to;
 935
 936                if (pull_to > skb_headlen(skb))
 937                        __pskb_pull_tail(skb, pull_to - skb_headlen(skb));
 938
 939                /* Ethernet work: Delayed to here as it peeks the header. */
 940                skb->protocol = eth_type_trans(skb, dev);
 941
 942                if (checksum_setup(dev, skb)) {
 943                        kfree_skb(skb);
 944                        packets_dropped++;
 945                        dev->stats.rx_errors++;
 946                        continue;
 947                }
 948
 949                u64_stats_update_begin(&stats->syncp);
 950                stats->rx_packets++;
 951                stats->rx_bytes += skb->len;
 952                u64_stats_update_end(&stats->syncp);
 953
 954                /* Pass it up. */
 955                netif_receive_skb(skb);
 956        }
 957
 958        return packets_dropped;
 959}
 960
 961static int xennet_poll(struct napi_struct *napi, int budget)
 962{
 963        struct netfront_info *np = container_of(napi, struct netfront_info, napi);
 964        struct net_device *dev = np->netdev;
 965        struct sk_buff *skb;
 966        struct netfront_rx_info rinfo;
 967        struct xen_netif_rx_response *rx = &rinfo.rx;
 968        struct xen_netif_extra_info *extras = rinfo.extras;
 969        RING_IDX i, rp;
 970        int work_done;
 971        struct sk_buff_head rxq;
 972        struct sk_buff_head errq;
 973        struct sk_buff_head tmpq;
 974        unsigned long flags;
 975        int err;
 976
 977        spin_lock(&np->rx_lock);
 978
 979        skb_queue_head_init(&rxq);
 980        skb_queue_head_init(&errq);
 981        skb_queue_head_init(&tmpq);
 982
 983        rp = np->rx.sring->rsp_prod;
 984        rmb(); /* Ensure we see queued responses up to 'rp'. */
 985
 986        i = np->rx.rsp_cons;
 987        work_done = 0;
 988        while ((i != rp) && (work_done < budget)) {
 989                memcpy(rx, RING_GET_RESPONSE(&np->rx, i), sizeof(*rx));
 990                memset(extras, 0, sizeof(rinfo.extras));
 991
 992                err = xennet_get_responses(np, &rinfo, rp, &tmpq);
 993
 994                if (unlikely(err)) {
 995err:
 996                        while ((skb = __skb_dequeue(&tmpq)))
 997                                __skb_queue_tail(&errq, skb);
 998                        dev->stats.rx_errors++;
 999                        i = np->rx.rsp_cons;
1000                        continue;
1001                }
1002
1003                skb = __skb_dequeue(&tmpq);
1004
1005                if (extras[XEN_NETIF_EXTRA_TYPE_GSO - 1].type) {
1006                        struct xen_netif_extra_info *gso;
1007                        gso = &extras[XEN_NETIF_EXTRA_TYPE_GSO - 1];
1008
1009                        if (unlikely(xennet_set_skb_gso(skb, gso))) {
1010                                __skb_queue_head(&tmpq, skb);
1011                                np->rx.rsp_cons += skb_queue_len(&tmpq);
1012                                goto err;
1013                        }
1014                }
1015
1016                NETFRONT_SKB_CB(skb)->pull_to = rx->status;
1017                if (NETFRONT_SKB_CB(skb)->pull_to > RX_COPY_THRESHOLD)
1018                        NETFRONT_SKB_CB(skb)->pull_to = RX_COPY_THRESHOLD;
1019
1020                skb_shinfo(skb)->frags[0].page_offset = rx->offset;
1021                skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status);
1022                skb->data_len = rx->status;
1023                skb->len += rx->status;
1024
1025                i = xennet_fill_frags(np, skb, &tmpq);
1026
1027                if (rx->flags & XEN_NETRXF_csum_blank)
1028                        skb->ip_summed = CHECKSUM_PARTIAL;
1029                else if (rx->flags & XEN_NETRXF_data_validated)
1030                        skb->ip_summed = CHECKSUM_UNNECESSARY;
1031
1032                __skb_queue_tail(&rxq, skb);
1033
1034                np->rx.rsp_cons = ++i;
1035                work_done++;
1036        }
1037
1038        __skb_queue_purge(&errq);
1039
1040        work_done -= handle_incoming_queue(dev, &rxq);
1041
1042        /* If we get a callback with very few responses, reduce fill target. */
1043        /* NB. Note exponential increase, linear decrease. */
1044        if (((np->rx.req_prod_pvt - np->rx.sring->rsp_prod) >
1045             ((3*np->rx_target) / 4)) &&
1046            (--np->rx_target < np->rx_min_target))
1047                np->rx_target = np->rx_min_target;
1048
1049        xennet_alloc_rx_buffers(dev);
1050
1051        if (work_done < budget) {
1052                int more_to_do = 0;
1053
1054                local_irq_save(flags);
1055
1056                RING_FINAL_CHECK_FOR_RESPONSES(&np->rx, more_to_do);
1057                if (!more_to_do)
1058                        __napi_complete(napi);
1059
1060                local_irq_restore(flags);
1061        }
1062
1063        spin_unlock(&np->rx_lock);
1064
1065        return work_done;
1066}
1067
1068static int xennet_change_mtu(struct net_device *dev, int mtu)
1069{
1070        int max = xennet_can_sg(dev) ?
1071                XEN_NETIF_MAX_TX_SIZE - MAX_TCP_HEADER : ETH_DATA_LEN;
1072
1073        if (mtu > max)
1074                return -EINVAL;
1075        dev->mtu = mtu;
1076        return 0;
1077}
1078
1079static struct rtnl_link_stats64 *xennet_get_stats64(struct net_device *dev,
1080                                                    struct rtnl_link_stats64 *tot)
1081{
1082        struct netfront_info *np = netdev_priv(dev);
1083        int cpu;
1084
1085        for_each_possible_cpu(cpu) {
1086                struct netfront_stats *stats = per_cpu_ptr(np->stats, cpu);
1087                u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
1088                unsigned int start;
1089
1090                do {
1091                        start = u64_stats_fetch_begin_bh(&stats->syncp);
1092
1093                        rx_packets = stats->rx_packets;
1094                        tx_packets = stats->tx_packets;
1095                        rx_bytes = stats->rx_bytes;
1096                        tx_bytes = stats->tx_bytes;
1097                } while (u64_stats_fetch_retry_bh(&stats->syncp, start));
1098
1099                tot->rx_packets += rx_packets;
1100                tot->tx_packets += tx_packets;
1101                tot->rx_bytes   += rx_bytes;
1102                tot->tx_bytes   += tx_bytes;
1103        }
1104
1105        tot->rx_errors  = dev->stats.rx_errors;
1106        tot->tx_dropped = dev->stats.tx_dropped;
1107
1108        return tot;
1109}
1110
1111static void xennet_release_tx_bufs(struct netfront_info *np)
1112{
1113        struct sk_buff *skb;
1114        int i;
1115
1116        for (i = 0; i < NET_TX_RING_SIZE; i++) {
1117                /* Skip over entries which are actually freelist references */
1118                if (skb_entry_is_link(&np->tx_skbs[i]))
1119                        continue;
1120
1121                skb = np->tx_skbs[i].skb;
1122                gnttab_end_foreign_access_ref(np->grant_tx_ref[i],
1123                                              GNTMAP_readonly);
1124                gnttab_release_grant_reference(&np->gref_tx_head,
1125                                               np->grant_tx_ref[i]);
1126                np->grant_tx_ref[i] = GRANT_INVALID_REF;
1127                add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, i);
1128                dev_kfree_skb_irq(skb);
1129        }
1130}
1131
1132static void xennet_release_rx_bufs(struct netfront_info *np)
1133{
1134        struct mmu_update      *mmu = np->rx_mmu;
1135        struct multicall_entry *mcl = np->rx_mcl;
1136        struct sk_buff_head free_list;
1137        struct sk_buff *skb;
1138        unsigned long mfn;
1139        int xfer = 0, noxfer = 0, unused = 0;
1140        int id, ref;
1141
1142        dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n",
1143                         __func__);
1144        return;
1145
1146        skb_queue_head_init(&free_list);
1147
1148        spin_lock_bh(&np->rx_lock);
1149
1150        for (id = 0; id < NET_RX_RING_SIZE; id++) {
1151                ref = np->grant_rx_ref[id];
1152                if (ref == GRANT_INVALID_REF) {
1153                        unused++;
1154                        continue;
1155                }
1156
1157                skb = np->rx_skbs[id];
1158                mfn = gnttab_end_foreign_transfer_ref(ref);
1159                gnttab_release_grant_reference(&np->gref_rx_head, ref);
1160                np->grant_rx_ref[id] = GRANT_INVALID_REF;
1161
1162                if (0 == mfn) {
1163                        skb_shinfo(skb)->nr_frags = 0;
1164                        dev_kfree_skb(skb);
1165                        noxfer++;
1166                        continue;
1167                }
1168
1169                if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1170                        /* Remap the page. */
1171                        const struct page *page =
1172                                skb_frag_page(&skb_shinfo(skb)->frags[0]);
1173                        unsigned long pfn = page_to_pfn(page);
1174                        void *vaddr = page_address(page);
1175
1176                        MULTI_update_va_mapping(mcl, (unsigned long)vaddr,
1177                                                mfn_pte(mfn, PAGE_KERNEL),
1178                                                0);
1179                        mcl++;
1180                        mmu->ptr = ((u64)mfn << PAGE_SHIFT)
1181                                | MMU_MACHPHYS_UPDATE;
1182                        mmu->val = pfn;
1183                        mmu++;
1184
1185                        set_phys_to_machine(pfn, mfn);
1186                }
1187                __skb_queue_tail(&free_list, skb);
1188                xfer++;
1189        }
1190
1191        dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n",
1192                 __func__, xfer, noxfer, unused);
1193
1194        if (xfer) {
1195                if (!xen_feature(XENFEAT_auto_translated_physmap)) {
1196                        /* Do all the remapping work and M2P updates. */
1197                        MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu,
1198                                         NULL, DOMID_SELF);
1199                        mcl++;
1200                        HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl);
1201                }
1202        }
1203
1204        __skb_queue_purge(&free_list);
1205
1206        spin_unlock_bh(&np->rx_lock);
1207}
1208
1209static void xennet_uninit(struct net_device *dev)
1210{
1211        struct netfront_info *np = netdev_priv(dev);
1212        xennet_release_tx_bufs(np);
1213        xennet_release_rx_bufs(np);
1214        gnttab_free_grant_references(np->gref_tx_head);
1215        gnttab_free_grant_references(np->gref_rx_head);
1216}
1217
1218static netdev_features_t xennet_fix_features(struct net_device *dev,
1219        netdev_features_t features)
1220{
1221        struct netfront_info *np = netdev_priv(dev);
1222        int val;
1223
1224        if (features & NETIF_F_SG) {
1225                if (xenbus_scanf(XBT_NIL, np->xbdev->otherend, "feature-sg",
1226                                 "%d", &val) < 0)
1227                        val = 0;
1228
1229                if (!val)
1230                        features &= ~NETIF_F_SG;
1231        }
1232
1233        if (features & NETIF_F_TSO) {
1234                if (xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1235                                 "feature-gso-tcpv4", "%d", &val) < 0)
1236                        val = 0;
1237
1238                if (!val)
1239                        features &= ~NETIF_F_TSO;
1240        }
1241
1242        return features;
1243}
1244
1245static int xennet_set_features(struct net_device *dev,
1246        netdev_features_t features)
1247{
1248        if (!(features & NETIF_F_SG) && dev->mtu > ETH_DATA_LEN) {
1249                netdev_info(dev, "Reducing MTU because no SG offload");
1250                dev->mtu = ETH_DATA_LEN;
1251        }
1252
1253        return 0;
1254}
1255
1256static irqreturn_t xennet_tx_interrupt(int irq, void *dev_id)
1257{
1258        struct netfront_info *np = dev_id;
1259        struct net_device *dev = np->netdev;
1260        unsigned long flags;
1261
1262        spin_lock_irqsave(&np->tx_lock, flags);
1263        xennet_tx_buf_gc(dev);
1264        spin_unlock_irqrestore(&np->tx_lock, flags);
1265
1266        return IRQ_HANDLED;
1267}
1268
1269static irqreturn_t xennet_rx_interrupt(int irq, void *dev_id)
1270{
1271        struct netfront_info *np = dev_id;
1272        struct net_device *dev = np->netdev;
1273
1274        if (likely(netif_carrier_ok(dev) &&
1275                   RING_HAS_UNCONSUMED_RESPONSES(&np->rx)))
1276                        napi_schedule(&np->napi);
1277
1278        return IRQ_HANDLED;
1279}
1280
1281static irqreturn_t xennet_interrupt(int irq, void *dev_id)
1282{
1283        xennet_tx_interrupt(irq, dev_id);
1284        xennet_rx_interrupt(irq, dev_id);
1285        return IRQ_HANDLED;
1286}
1287
1288#ifdef CONFIG_NET_POLL_CONTROLLER
1289static void xennet_poll_controller(struct net_device *dev)
1290{
1291        xennet_interrupt(0, dev);
1292}
1293#endif
1294
1295static const struct net_device_ops xennet_netdev_ops = {
1296        .ndo_open            = xennet_open,
1297        .ndo_uninit          = xennet_uninit,
1298        .ndo_stop            = xennet_close,
1299        .ndo_start_xmit      = xennet_start_xmit,
1300        .ndo_change_mtu      = xennet_change_mtu,
1301        .ndo_get_stats64     = xennet_get_stats64,
1302        .ndo_set_mac_address = eth_mac_addr,
1303        .ndo_validate_addr   = eth_validate_addr,
1304        .ndo_fix_features    = xennet_fix_features,
1305        .ndo_set_features    = xennet_set_features,
1306#ifdef CONFIG_NET_POLL_CONTROLLER
1307        .ndo_poll_controller = xennet_poll_controller,
1308#endif
1309};
1310
1311static struct net_device *xennet_create_dev(struct xenbus_device *dev)
1312{
1313        int i, err;
1314        struct net_device *netdev;
1315        struct netfront_info *np;
1316
1317        netdev = alloc_etherdev(sizeof(struct netfront_info));
1318        if (!netdev)
1319                return ERR_PTR(-ENOMEM);
1320
1321        np                   = netdev_priv(netdev);
1322        np->xbdev            = dev;
1323
1324        spin_lock_init(&np->tx_lock);
1325        spin_lock_init(&np->rx_lock);
1326
1327        skb_queue_head_init(&np->rx_batch);
1328        np->rx_target     = RX_DFL_MIN_TARGET;
1329        np->rx_min_target = RX_DFL_MIN_TARGET;
1330        np->rx_max_target = RX_MAX_TARGET;
1331
1332        init_timer(&np->rx_refill_timer);
1333        np->rx_refill_timer.data = (unsigned long)netdev;
1334        np->rx_refill_timer.function = rx_refill_timeout;
1335
1336        err = -ENOMEM;
1337        np->stats = alloc_percpu(struct netfront_stats);
1338        if (np->stats == NULL)
1339                goto exit;
1340
1341        /* Initialise tx_skbs as a free chain containing every entry. */
1342        np->tx_skb_freelist = 0;
1343        for (i = 0; i < NET_TX_RING_SIZE; i++) {
1344                skb_entry_set_link(&np->tx_skbs[i], i+1);
1345                np->grant_tx_ref[i] = GRANT_INVALID_REF;
1346        }
1347
1348        /* Clear out rx_skbs */
1349        for (i = 0; i < NET_RX_RING_SIZE; i++) {
1350                np->rx_skbs[i] = NULL;
1351                np->grant_rx_ref[i] = GRANT_INVALID_REF;
1352        }
1353
1354        /* A grant for every tx ring slot */
1355        if (gnttab_alloc_grant_references(TX_MAX_TARGET,
1356                                          &np->gref_tx_head) < 0) {
1357                pr_alert("can't alloc tx grant refs\n");
1358                err = -ENOMEM;
1359                goto exit_free_stats;
1360        }
1361        /* A grant for every rx ring slot */
1362        if (gnttab_alloc_grant_references(RX_MAX_TARGET,
1363                                          &np->gref_rx_head) < 0) {
1364                pr_alert("can't alloc rx grant refs\n");
1365                err = -ENOMEM;
1366                goto exit_free_tx;
1367        }
1368
1369        netdev->netdev_ops      = &xennet_netdev_ops;
1370
1371        netif_napi_add(netdev, &np->napi, xennet_poll, 64);
1372        netdev->features        = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
1373                                  NETIF_F_GSO_ROBUST;
1374        netdev->hw_features     = NETIF_F_IP_CSUM | NETIF_F_SG | NETIF_F_TSO;
1375
1376        /*
1377         * Assume that all hw features are available for now. This set
1378         * will be adjusted by the call to netdev_update_features() in
1379         * xennet_connect() which is the earliest point where we can
1380         * negotiate with the backend regarding supported features.
1381         */
1382        netdev->features |= netdev->hw_features;
1383
1384        SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops);
1385        SET_NETDEV_DEV(netdev, &dev->dev);
1386
1387        netif_set_gso_max_size(netdev, XEN_NETIF_MAX_TX_SIZE - MAX_TCP_HEADER);
1388
1389        np->netdev = netdev;
1390
1391        netif_carrier_off(netdev);
1392
1393        return netdev;
1394
1395 exit_free_tx:
1396        gnttab_free_grant_references(np->gref_tx_head);
1397 exit_free_stats:
1398        free_percpu(np->stats);
1399 exit:
1400        free_netdev(netdev);
1401        return ERR_PTR(err);
1402}
1403
1404/**
1405 * Entry point to this code when a new device is created.  Allocate the basic
1406 * structures and the ring buffers for communication with the backend, and
1407 * inform the backend of the appropriate details for those.
1408 */
1409static int netfront_probe(struct xenbus_device *dev,
1410                          const struct xenbus_device_id *id)
1411{
1412        int err;
1413        struct net_device *netdev;
1414        struct netfront_info *info;
1415
1416        netdev = xennet_create_dev(dev);
1417        if (IS_ERR(netdev)) {
1418                err = PTR_ERR(netdev);
1419                xenbus_dev_fatal(dev, err, "creating netdev");
1420                return err;
1421        }
1422
1423        info = netdev_priv(netdev);
1424        dev_set_drvdata(&dev->dev, info);
1425
1426        err = register_netdev(info->netdev);
1427        if (err) {
1428                pr_warn("%s: register_netdev err=%d\n", __func__, err);
1429                goto fail;
1430        }
1431
1432        err = xennet_sysfs_addif(info->netdev);
1433        if (err) {
1434                unregister_netdev(info->netdev);
1435                pr_warn("%s: add sysfs failed err=%d\n", __func__, err);
1436                goto fail;
1437        }
1438
1439        return 0;
1440
1441 fail:
1442        free_netdev(netdev);
1443        dev_set_drvdata(&dev->dev, NULL);
1444        return err;
1445}
1446
1447static void xennet_end_access(int ref, void *page)
1448{
1449        /* This frees the page as a side-effect */
1450        if (ref != GRANT_INVALID_REF)
1451                gnttab_end_foreign_access(ref, 0, (unsigned long)page);
1452}
1453
1454static void xennet_disconnect_backend(struct netfront_info *info)
1455{
1456        /* Stop old i/f to prevent errors whilst we rebuild the state. */
1457        spin_lock_bh(&info->rx_lock);
1458        spin_lock_irq(&info->tx_lock);
1459        netif_carrier_off(info->netdev);
1460        spin_unlock_irq(&info->tx_lock);
1461        spin_unlock_bh(&info->rx_lock);
1462
1463        if (info->tx_irq && (info->tx_irq == info->rx_irq))
1464                unbind_from_irqhandler(info->tx_irq, info);
1465        if (info->tx_irq && (info->tx_irq != info->rx_irq)) {
1466                unbind_from_irqhandler(info->tx_irq, info);
1467                unbind_from_irqhandler(info->rx_irq, info);
1468        }
1469        info->tx_evtchn = info->rx_evtchn = 0;
1470        info->tx_irq = info->rx_irq = 0;
1471
1472        /* End access and free the pages */
1473        xennet_end_access(info->tx_ring_ref, info->tx.sring);
1474        xennet_end_access(info->rx_ring_ref, info->rx.sring);
1475
1476        info->tx_ring_ref = GRANT_INVALID_REF;
1477        info->rx_ring_ref = GRANT_INVALID_REF;
1478        info->tx.sring = NULL;
1479        info->rx.sring = NULL;
1480}
1481
1482/**
1483 * We are reconnecting to the backend, due to a suspend/resume, or a backend
1484 * driver restart.  We tear down our netif structure and recreate it, but
1485 * leave the device-layer structures intact so that this is transparent to the
1486 * rest of the kernel.
1487 */
1488static int netfront_resume(struct xenbus_device *dev)
1489{
1490        struct netfront_info *info = dev_get_drvdata(&dev->dev);
1491
1492        dev_dbg(&dev->dev, "%s\n", dev->nodename);
1493
1494        xennet_disconnect_backend(info);
1495        return 0;
1496}
1497
1498static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
1499{
1500        char *s, *e, *macstr;
1501        int i;
1502
1503        macstr = s = xenbus_read(XBT_NIL, dev->nodename, "mac", NULL);
1504        if (IS_ERR(macstr))
1505                return PTR_ERR(macstr);
1506
1507        for (i = 0; i < ETH_ALEN; i++) {
1508                mac[i] = simple_strtoul(s, &e, 16);
1509                if ((s == e) || (*e != ((i == ETH_ALEN-1) ? '\0' : ':'))) {
1510                        kfree(macstr);
1511                        return -ENOENT;
1512                }
1513                s = e+1;
1514        }
1515
1516        kfree(macstr);
1517        return 0;
1518}
1519
1520static int setup_netfront_single(struct netfront_info *info)
1521{
1522        int err;
1523
1524        err = xenbus_alloc_evtchn(info->xbdev, &info->tx_evtchn);
1525        if (err < 0)
1526                goto fail;
1527
1528        err = bind_evtchn_to_irqhandler(info->tx_evtchn,
1529                                        xennet_interrupt,
1530                                        0, info->netdev->name, info);
1531        if (err < 0)
1532                goto bind_fail;
1533        info->rx_evtchn = info->tx_evtchn;
1534        info->rx_irq = info->tx_irq = err;
1535
1536        return 0;
1537
1538bind_fail:
1539        xenbus_free_evtchn(info->xbdev, info->tx_evtchn);
1540        info->tx_evtchn = 0;
1541fail:
1542        return err;
1543}
1544
1545static int setup_netfront_split(struct netfront_info *info)
1546{
1547        int err;
1548
1549        err = xenbus_alloc_evtchn(info->xbdev, &info->tx_evtchn);
1550        if (err < 0)
1551                goto fail;
1552        err = xenbus_alloc_evtchn(info->xbdev, &info->rx_evtchn);
1553        if (err < 0)
1554                goto alloc_rx_evtchn_fail;
1555
1556        snprintf(info->tx_irq_name, sizeof(info->tx_irq_name),
1557                 "%s-tx", info->netdev->name);
1558        err = bind_evtchn_to_irqhandler(info->tx_evtchn,
1559                                        xennet_tx_interrupt,
1560                                        0, info->tx_irq_name, info);
1561        if (err < 0)
1562                goto bind_tx_fail;
1563        info->tx_irq = err;
1564
1565        snprintf(info->rx_irq_name, sizeof(info->rx_irq_name),
1566                 "%s-rx", info->netdev->name);
1567        err = bind_evtchn_to_irqhandler(info->rx_evtchn,
1568                                        xennet_rx_interrupt,
1569                                        0, info->rx_irq_name, info);
1570        if (err < 0)
1571                goto bind_rx_fail;
1572        info->rx_irq = err;
1573
1574        return 0;
1575
1576bind_rx_fail:
1577        unbind_from_irqhandler(info->tx_irq, info);
1578        info->tx_irq = 0;
1579bind_tx_fail:
1580        xenbus_free_evtchn(info->xbdev, info->rx_evtchn);
1581        info->rx_evtchn = 0;
1582alloc_rx_evtchn_fail:
1583        xenbus_free_evtchn(info->xbdev, info->tx_evtchn);
1584        info->tx_evtchn = 0;
1585fail:
1586        return err;
1587}
1588
1589static int setup_netfront(struct xenbus_device *dev, struct netfront_info *info)
1590{
1591        struct xen_netif_tx_sring *txs;
1592        struct xen_netif_rx_sring *rxs;
1593        int err;
1594        struct net_device *netdev = info->netdev;
1595        unsigned int feature_split_evtchn;
1596
1597        info->tx_ring_ref = GRANT_INVALID_REF;
1598        info->rx_ring_ref = GRANT_INVALID_REF;
1599        info->rx.sring = NULL;
1600        info->tx.sring = NULL;
1601        netdev->irq = 0;
1602
1603        err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
1604                           "feature-split-event-channels", "%u",
1605                           &feature_split_evtchn);
1606        if (err < 0)
1607                feature_split_evtchn = 0;
1608
1609        err = xen_net_read_mac(dev, netdev->dev_addr);
1610        if (err) {
1611                xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
1612                goto fail;
1613        }
1614
1615        txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1616        if (!txs) {
1617                err = -ENOMEM;
1618                xenbus_dev_fatal(dev, err, "allocating tx ring page");
1619                goto fail;
1620        }
1621        SHARED_RING_INIT(txs);
1622        FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
1623
1624        err = xenbus_grant_ring(dev, virt_to_mfn(txs));
1625        if (err < 0)
1626                goto grant_tx_ring_fail;
1627
1628        info->tx_ring_ref = err;
1629        rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO | __GFP_HIGH);
1630        if (!rxs) {
1631                err = -ENOMEM;
1632                xenbus_dev_fatal(dev, err, "allocating rx ring page");
1633                goto alloc_rx_ring_fail;
1634        }
1635        SHARED_RING_INIT(rxs);
1636        FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);
1637
1638        err = xenbus_grant_ring(dev, virt_to_mfn(rxs));
1639        if (err < 0)
1640                goto grant_rx_ring_fail;
1641        info->rx_ring_ref = err;
1642
1643        if (feature_split_evtchn)
1644                err = setup_netfront_split(info);
1645        /* setup single event channel if
1646         *  a) feature-split-event-channels == 0
1647         *  b) feature-split-event-channels == 1 but failed to setup
1648         */
1649        if (!feature_split_evtchn || (feature_split_evtchn && err))
1650                err = setup_netfront_single(info);
1651
1652        if (err)
1653                goto alloc_evtchn_fail;
1654
1655        return 0;
1656
1657        /* If we fail to setup netfront, it is safe to just revoke access to
1658         * granted pages because backend is not accessing it at this point.
1659         */
1660alloc_evtchn_fail:
1661        gnttab_end_foreign_access_ref(info->rx_ring_ref, 0);
1662grant_rx_ring_fail:
1663        free_page((unsigned long)rxs);
1664alloc_rx_ring_fail:
1665        gnttab_end_foreign_access_ref(info->tx_ring_ref, 0);
1666grant_tx_ring_fail:
1667        free_page((unsigned long)txs);
1668fail:
1669        return err;
1670}
1671
1672/* Common code used when first setting up, and when resuming. */
1673static int talk_to_netback(struct xenbus_device *dev,
1674                           struct netfront_info *info)
1675{
1676        const char *message;
1677        struct xenbus_transaction xbt;
1678        int err;
1679
1680        /* Create shared ring, alloc event channel. */
1681        err = setup_netfront(dev, info);
1682        if (err)
1683                goto out;
1684
1685again:
1686        err = xenbus_transaction_start(&xbt);
1687        if (err) {
1688                xenbus_dev_fatal(dev, err, "starting transaction");
1689                goto destroy_ring;
1690        }
1691
1692        err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u",
1693                            info->tx_ring_ref);
1694        if (err) {
1695                message = "writing tx ring-ref";
1696                goto abort_transaction;
1697        }
1698        err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u",
1699                            info->rx_ring_ref);
1700        if (err) {
1701                message = "writing rx ring-ref";
1702                goto abort_transaction;
1703        }
1704
1705        if (info->tx_evtchn == info->rx_evtchn) {
1706                err = xenbus_printf(xbt, dev->nodename,
1707                                    "event-channel", "%u", info->tx_evtchn);
1708                if (err) {
1709                        message = "writing event-channel";
1710                        goto abort_transaction;
1711                }
1712        } else {
1713                err = xenbus_printf(xbt, dev->nodename,
1714                                    "event-channel-tx", "%u", info->tx_evtchn);
1715                if (err) {
1716                        message = "writing event-channel-tx";
1717                        goto abort_transaction;
1718                }
1719                err = xenbus_printf(xbt, dev->nodename,
1720                                    "event-channel-rx", "%u", info->rx_evtchn);
1721                if (err) {
1722                        message = "writing event-channel-rx";
1723                        goto abort_transaction;
1724                }
1725        }
1726
1727        err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
1728                            1);
1729        if (err) {
1730                message = "writing request-rx-copy";
1731                goto abort_transaction;
1732        }
1733
1734        err = xenbus_printf(xbt, dev->nodename, "feature-rx-notify", "%d", 1);
1735        if (err) {
1736                message = "writing feature-rx-notify";
1737                goto abort_transaction;
1738        }
1739
1740        err = xenbus_printf(xbt, dev->nodename, "feature-sg", "%d", 1);
1741        if (err) {
1742                message = "writing feature-sg";
1743                goto abort_transaction;
1744        }
1745
1746        err = xenbus_printf(xbt, dev->nodename, "feature-gso-tcpv4", "%d", 1);
1747        if (err) {
1748                message = "writing feature-gso-tcpv4";
1749                goto abort_transaction;
1750        }
1751
1752        err = xenbus_transaction_end(xbt, 0);
1753        if (err) {
1754                if (err == -EAGAIN)
1755                        goto again;
1756                xenbus_dev_fatal(dev, err, "completing transaction");
1757                goto destroy_ring;
1758        }
1759
1760        return 0;
1761
1762 abort_transaction:
1763        xenbus_transaction_end(xbt, 1);
1764        xenbus_dev_fatal(dev, err, "%s", message);
1765 destroy_ring:
1766        xennet_disconnect_backend(info);
1767 out:
1768        return err;
1769}
1770
1771static int xennet_connect(struct net_device *dev)
1772{
1773        struct netfront_info *np = netdev_priv(dev);
1774        int i, requeue_idx, err;
1775        struct sk_buff *skb;
1776        grant_ref_t ref;
1777        struct xen_netif_rx_request *req;
1778        unsigned int feature_rx_copy;
1779
1780        err = xenbus_scanf(XBT_NIL, np->xbdev->otherend,
1781                           "feature-rx-copy", "%u", &feature_rx_copy);
1782        if (err != 1)
1783                feature_rx_copy = 0;
1784
1785        if (!feature_rx_copy) {
1786                dev_info(&dev->dev,
1787                         "backend does not support copying receive path\n");
1788                return -ENODEV;
1789        }
1790
1791        err = talk_to_netback(np->xbdev, np);
1792        if (err)
1793                return err;
1794
1795        rtnl_lock();
1796        netdev_update_features(dev);
1797        rtnl_unlock();
1798
1799        spin_lock_bh(&np->rx_lock);
1800        spin_lock_irq(&np->tx_lock);
1801
1802        /* Step 1: Discard all pending TX packet fragments. */
1803        xennet_release_tx_bufs(np);
1804
1805        /* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
1806        for (requeue_idx = 0, i = 0; i < NET_RX_RING_SIZE; i++) {
1807                skb_frag_t *frag;
1808                const struct page *page;
1809                if (!np->rx_skbs[i])
1810                        continue;
1811
1812                skb = np->rx_skbs[requeue_idx] = xennet_get_rx_skb(np, i);
1813                ref = np->grant_rx_ref[requeue_idx] = xennet_get_rx_ref(np, i);
1814                req = RING_GET_REQUEST(&np->rx, requeue_idx);
1815
1816                frag = &skb_shinfo(skb)->frags[0];
1817                page = skb_frag_page(frag);
1818                gnttab_grant_foreign_access_ref(
1819                        ref, np->xbdev->otherend_id,
1820                        pfn_to_mfn(page_to_pfn(page)),
1821                        0);
1822                req->gref = ref;
1823                req->id   = requeue_idx;
1824
1825                requeue_idx++;
1826        }
1827
1828        np->rx.req_prod_pvt = requeue_idx;
1829
1830        /*
1831         * Step 3: All public and private state should now be sane.  Get
1832         * ready to start sending and receiving packets and give the driver
1833         * domain a kick because we've probably just requeued some
1834         * packets.
1835         */
1836        netif_carrier_on(np->netdev);
1837        notify_remote_via_irq(np->tx_irq);
1838        if (np->tx_irq != np->rx_irq)
1839                notify_remote_via_irq(np->rx_irq);
1840        xennet_tx_buf_gc(dev);
1841        xennet_alloc_rx_buffers(dev);
1842
1843        spin_unlock_irq(&np->tx_lock);
1844        spin_unlock_bh(&np->rx_lock);
1845
1846        return 0;
1847}
1848
1849/**
1850 * Callback received when the backend's state changes.
1851 */
1852static void netback_changed(struct xenbus_device *dev,
1853                            enum xenbus_state backend_state)
1854{
1855        struct netfront_info *np = dev_get_drvdata(&dev->dev);
1856        struct net_device *netdev = np->netdev;
1857
1858        dev_dbg(&dev->dev, "%s\n", xenbus_strstate(backend_state));
1859
1860        switch (backend_state) {
1861        case XenbusStateInitialising:
1862        case XenbusStateInitialised:
1863        case XenbusStateReconfiguring:
1864        case XenbusStateReconfigured:
1865        case XenbusStateUnknown:
1866        case XenbusStateClosed:
1867                break;
1868
1869        case XenbusStateInitWait:
1870                if (dev->state != XenbusStateInitialising)
1871                        break;
1872                if (xennet_connect(netdev) != 0)
1873                        break;
1874                xenbus_switch_state(dev, XenbusStateConnected);
1875                break;
1876
1877        case XenbusStateConnected:
1878                netdev_notify_peers(netdev);
1879                break;
1880
1881        case XenbusStateClosing:
1882                xenbus_frontend_closed(dev);
1883                break;
1884        }
1885}
1886
1887static const struct xennet_stat {
1888        char name[ETH_GSTRING_LEN];
1889        u16 offset;
1890} xennet_stats[] = {
1891        {
1892                "rx_gso_checksum_fixup",
1893                offsetof(struct netfront_info, rx_gso_checksum_fixup)
1894        },
1895};
1896
1897static int xennet_get_sset_count(struct net_device *dev, int string_set)
1898{
1899        switch (string_set) {
1900        case ETH_SS_STATS:
1901                return ARRAY_SIZE(xennet_stats);
1902        default:
1903                return -EINVAL;
1904        }
1905}
1906
1907static void xennet_get_ethtool_stats(struct net_device *dev,
1908                                     struct ethtool_stats *stats, u64 * data)
1909{
1910        void *np = netdev_priv(dev);
1911        int i;
1912
1913        for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
1914                data[i] = *(unsigned long *)(np + xennet_stats[i].offset);
1915}
1916
1917static void xennet_get_strings(struct net_device *dev, u32 stringset, u8 * data)
1918{
1919        int i;
1920
1921        switch (stringset) {
1922        case ETH_SS_STATS:
1923                for (i = 0; i < ARRAY_SIZE(xennet_stats); i++)
1924                        memcpy(data + i * ETH_GSTRING_LEN,
1925                               xennet_stats[i].name, ETH_GSTRING_LEN);
1926                break;
1927        }
1928}
1929
1930static const struct ethtool_ops xennet_ethtool_ops =
1931{
1932        .get_link = ethtool_op_get_link,
1933
1934        .get_sset_count = xennet_get_sset_count,
1935        .get_ethtool_stats = xennet_get_ethtool_stats,
1936        .get_strings = xennet_get_strings,
1937};
1938
1939#ifdef CONFIG_SYSFS
1940static ssize_t show_rxbuf_min(struct device *dev,
1941                              struct device_attribute *attr, char *buf)
1942{
1943        struct net_device *netdev = to_net_dev(dev);
1944        struct netfront_info *info = netdev_priv(netdev);
1945
1946        return sprintf(buf, "%u\n", info->rx_min_target);
1947}
1948
1949static ssize_t store_rxbuf_min(struct device *dev,
1950                               struct device_attribute *attr,
1951                               const char *buf, size_t len)
1952{
1953        struct net_device *netdev = to_net_dev(dev);
1954        struct netfront_info *np = netdev_priv(netdev);
1955        char *endp;
1956        unsigned long target;
1957
1958        if (!capable(CAP_NET_ADMIN))
1959                return -EPERM;
1960
1961        target = simple_strtoul(buf, &endp, 0);
1962        if (endp == buf)
1963                return -EBADMSG;
1964
1965        if (target < RX_MIN_TARGET)
1966                target = RX_MIN_TARGET;
1967        if (target > RX_MAX_TARGET)
1968                target = RX_MAX_TARGET;
1969
1970        spin_lock_bh(&np->rx_lock);
1971        if (target > np->rx_max_target)
1972                np->rx_max_target = target;
1973        np->rx_min_target = target;
1974        if (target > np->rx_target)
1975                np->rx_target = target;
1976
1977        xennet_alloc_rx_buffers(netdev);
1978
1979        spin_unlock_bh(&np->rx_lock);
1980        return len;
1981}
1982
1983static ssize_t show_rxbuf_max(struct device *dev,
1984                              struct device_attribute *attr, char *buf)
1985{
1986        struct net_device *netdev = to_net_dev(dev);
1987        struct netfront_info *info = netdev_priv(netdev);
1988
1989        return sprintf(buf, "%u\n", info->rx_max_target);
1990}
1991
1992static ssize_t store_rxbuf_max(struct device *dev,
1993                               struct device_attribute *attr,
1994                               const char *buf, size_t len)
1995{
1996        struct net_device *netdev = to_net_dev(dev);
1997        struct netfront_info *np = netdev_priv(netdev);
1998        char *endp;
1999        unsigned long target;
2000
2001        if (!capable(CAP_NET_ADMIN))
2002                return -EPERM;
2003
2004        target = simple_strtoul(buf, &endp, 0);
2005        if (endp == buf)
2006                return -EBADMSG;
2007
2008        if (target < RX_MIN_TARGET)
2009                target = RX_MIN_TARGET;
2010        if (target > RX_MAX_TARGET)
2011                target = RX_MAX_TARGET;
2012
2013        spin_lock_bh(&np->rx_lock);
2014        if (target < np->rx_min_target)
2015                np->rx_min_target = target;
2016        np->rx_max_target = target;
2017        if (target < np->rx_target)
2018                np->rx_target = target;
2019
2020        xennet_alloc_rx_buffers(netdev);
2021
2022        spin_unlock_bh(&np->rx_lock);
2023        return len;
2024}
2025
2026static ssize_t show_rxbuf_cur(struct device *dev,
2027                              struct device_attribute *attr, char *buf)
2028{
2029        struct net_device *netdev = to_net_dev(dev);
2030        struct netfront_info *info = netdev_priv(netdev);
2031
2032        return sprintf(buf, "%u\n", info->rx_target);
2033}
2034
2035static struct device_attribute xennet_attrs[] = {
2036        __ATTR(rxbuf_min, S_IRUGO|S_IWUSR, show_rxbuf_min, store_rxbuf_min),
2037        __ATTR(rxbuf_max, S_IRUGO|S_IWUSR, show_rxbuf_max, store_rxbuf_max),
2038        __ATTR(rxbuf_cur, S_IRUGO, show_rxbuf_cur, NULL),
2039};
2040
2041static int xennet_sysfs_addif(struct net_device *netdev)
2042{
2043        int i;
2044        int err;
2045
2046        for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++) {
2047                err = device_create_file(&netdev->dev,
2048                                           &xennet_attrs[i]);
2049                if (err)
2050                        goto fail;
2051        }
2052        return 0;
2053
2054 fail:
2055        while (--i >= 0)
2056                device_remove_file(&netdev->dev, &xennet_attrs[i]);
2057        return err;
2058}
2059
2060static void xennet_sysfs_delif(struct net_device *netdev)
2061{
2062        int i;
2063
2064        for (i = 0; i < ARRAY_SIZE(xennet_attrs); i++)
2065                device_remove_file(&netdev->dev, &xennet_attrs[i]);
2066}
2067
2068#endif /* CONFIG_SYSFS */
2069
2070static const struct xenbus_device_id netfront_ids[] = {
2071        { "vif" },
2072        { "" }
2073};
2074
2075
2076static int xennet_remove(struct xenbus_device *dev)
2077{
2078        struct netfront_info *info = dev_get_drvdata(&dev->dev);
2079
2080        dev_dbg(&dev->dev, "%s\n", dev->nodename);
2081
2082        xennet_disconnect_backend(info);
2083
2084        xennet_sysfs_delif(info->netdev);
2085
2086        unregister_netdev(info->netdev);
2087
2088        del_timer_sync(&info->rx_refill_timer);
2089
2090        free_percpu(info->stats);
2091
2092        free_netdev(info->netdev);
2093
2094        return 0;
2095}
2096
2097static DEFINE_XENBUS_DRIVER(netfront, ,
2098        .probe = netfront_probe,
2099        .remove = xennet_remove,
2100        .resume = netfront_resume,
2101        .otherend_changed = netback_changed,
2102);
2103
2104static int __init netif_init(void)
2105{
2106        if (!xen_domain())
2107                return -ENODEV;
2108
2109        if (xen_hvm_domain() && !xen_platform_pci_unplug)
2110                return -ENODEV;
2111
2112        pr_info("Initialising Xen virtual ethernet driver\n");
2113
2114        return xenbus_register_frontend(&netfront_driver);
2115}
2116module_init(netif_init);
2117
2118
2119static void __exit netif_exit(void)
2120{
2121        xenbus_unregister_driver(&netfront_driver);
2122}
2123module_exit(netif_exit);
2124
2125MODULE_DESCRIPTION("Xen virtual network device frontend");
2126MODULE_LICENSE("GPL");
2127MODULE_ALIAS("xen:vif");
2128MODULE_ALIAS("xennet");
2129
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