linux/drivers/net/xen-netback/interface.c
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   1/*
   2 * Network-device interface management.
   3 *
   4 * Copyright (c) 2004-2005, Keir Fraser
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License version 2
   8 * as published by the Free Software Foundation; or, when distributed
   9 * separately from the Linux kernel or incorporated into other
  10 * software packages, subject to the following license:
  11 *
  12 * Permission is hereby granted, free of charge, to any person obtaining a copy
  13 * of this source file (the "Software"), to deal in the Software without
  14 * restriction, including without limitation the rights to use, copy, modify,
  15 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  16 * and to permit persons to whom the Software is furnished to do so, subject to
  17 * the following conditions:
  18 *
  19 * The above copyright notice and this permission notice shall be included in
  20 * all copies or substantial portions of the Software.
  21 *
  22 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  25 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  26 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  27 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  28 * IN THE SOFTWARE.
  29 */
  30
  31#include "common.h"
  32
  33#include <linux/kthread.h>
  34#include <linux/sched/task.h>
  35#include <linux/ethtool.h>
  36#include <linux/rtnetlink.h>
  37#include <linux/if_vlan.h>
  38#include <linux/vmalloc.h>
  39
  40#include <xen/events.h>
  41#include <asm/xen/hypercall.h>
  42#include <xen/balloon.h>
  43
  44#define XENVIF_QUEUE_LENGTH 32
  45#define XENVIF_NAPI_WEIGHT  64
  46
  47/* Number of bytes allowed on the internal guest Rx queue. */
  48#define XENVIF_RX_QUEUE_BYTES (XEN_NETIF_RX_RING_SIZE/2 * PAGE_SIZE)
  49
  50/* This function is used to set SKBFL_ZEROCOPY_ENABLE as well as
  51 * increasing the inflight counter. We need to increase the inflight
  52 * counter because core driver calls into xenvif_zerocopy_callback
  53 * which calls xenvif_skb_zerocopy_complete.
  54 */
  55void xenvif_skb_zerocopy_prepare(struct xenvif_queue *queue,
  56                                 struct sk_buff *skb)
  57{
  58        skb_shinfo(skb)->flags |= SKBFL_ZEROCOPY_ENABLE;
  59        atomic_inc(&queue->inflight_packets);
  60}
  61
  62void xenvif_skb_zerocopy_complete(struct xenvif_queue *queue)
  63{
  64        atomic_dec(&queue->inflight_packets);
  65
  66        /* Wake the dealloc thread _after_ decrementing inflight_packets so
  67         * that if kthread_stop() has already been called, the dealloc thread
  68         * does not wait forever with nothing to wake it.
  69         */
  70        wake_up(&queue->dealloc_wq);
  71}
  72
  73int xenvif_schedulable(struct xenvif *vif)
  74{
  75        return netif_running(vif->dev) &&
  76                test_bit(VIF_STATUS_CONNECTED, &vif->status) &&
  77                !vif->disabled;
  78}
  79
  80static bool xenvif_handle_tx_interrupt(struct xenvif_queue *queue)
  81{
  82        bool rc;
  83
  84        rc = RING_HAS_UNCONSUMED_REQUESTS(&queue->tx);
  85        if (rc)
  86                napi_schedule(&queue->napi);
  87        return rc;
  88}
  89
  90static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
  91{
  92        struct xenvif_queue *queue = dev_id;
  93        int old;
  94
  95        old = atomic_fetch_or(NETBK_TX_EOI, &queue->eoi_pending);
  96        WARN(old & NETBK_TX_EOI, "Interrupt while EOI pending\n");
  97
  98        if (!xenvif_handle_tx_interrupt(queue)) {
  99                atomic_andnot(NETBK_TX_EOI, &queue->eoi_pending);
 100                xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
 101        }
 102
 103        return IRQ_HANDLED;
 104}
 105
 106static int xenvif_poll(struct napi_struct *napi, int budget)
 107{
 108        struct xenvif_queue *queue =
 109                container_of(napi, struct xenvif_queue, napi);
 110        int work_done;
 111
 112        /* This vif is rogue, we pretend we've there is nothing to do
 113         * for this vif to deschedule it from NAPI. But this interface
 114         * will be turned off in thread context later.
 115         */
 116        if (unlikely(queue->vif->disabled)) {
 117                napi_complete(napi);
 118                return 0;
 119        }
 120
 121        work_done = xenvif_tx_action(queue, budget);
 122
 123        if (work_done < budget) {
 124                napi_complete_done(napi, work_done);
 125                /* If the queue is rate-limited, it shall be
 126                 * rescheduled in the timer callback.
 127                 */
 128                if (likely(!queue->rate_limited))
 129                        xenvif_napi_schedule_or_enable_events(queue);
 130        }
 131
 132        return work_done;
 133}
 134
 135static bool xenvif_handle_rx_interrupt(struct xenvif_queue *queue)
 136{
 137        bool rc;
 138
 139        rc = xenvif_have_rx_work(queue, false);
 140        if (rc)
 141                xenvif_kick_thread(queue);
 142        return rc;
 143}
 144
 145static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
 146{
 147        struct xenvif_queue *queue = dev_id;
 148        int old;
 149
 150        old = atomic_fetch_or(NETBK_RX_EOI, &queue->eoi_pending);
 151        WARN(old & NETBK_RX_EOI, "Interrupt while EOI pending\n");
 152
 153        if (!xenvif_handle_rx_interrupt(queue)) {
 154                atomic_andnot(NETBK_RX_EOI, &queue->eoi_pending);
 155                xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
 156        }
 157
 158        return IRQ_HANDLED;
 159}
 160
 161irqreturn_t xenvif_interrupt(int irq, void *dev_id)
 162{
 163        struct xenvif_queue *queue = dev_id;
 164        int old;
 165        bool has_rx, has_tx;
 166
 167        old = atomic_fetch_or(NETBK_COMMON_EOI, &queue->eoi_pending);
 168        WARN(old, "Interrupt while EOI pending\n");
 169
 170        has_tx = xenvif_handle_tx_interrupt(queue);
 171        has_rx = xenvif_handle_rx_interrupt(queue);
 172
 173        if (!has_rx && !has_tx) {
 174                atomic_andnot(NETBK_COMMON_EOI, &queue->eoi_pending);
 175                xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
 176        }
 177
 178        return IRQ_HANDLED;
 179}
 180
 181int xenvif_queue_stopped(struct xenvif_queue *queue)
 182{
 183        struct net_device *dev = queue->vif->dev;
 184        unsigned int id = queue->id;
 185        return netif_tx_queue_stopped(netdev_get_tx_queue(dev, id));
 186}
 187
 188void xenvif_wake_queue(struct xenvif_queue *queue)
 189{
 190        struct net_device *dev = queue->vif->dev;
 191        unsigned int id = queue->id;
 192        netif_tx_wake_queue(netdev_get_tx_queue(dev, id));
 193}
 194
 195static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
 196                               struct net_device *sb_dev)
 197{
 198        struct xenvif *vif = netdev_priv(dev);
 199        unsigned int size = vif->hash.size;
 200        unsigned int num_queues;
 201
 202        /* If queues are not set up internally - always return 0
 203         * as the packet going to be dropped anyway */
 204        num_queues = READ_ONCE(vif->num_queues);
 205        if (num_queues < 1)
 206                return 0;
 207
 208        if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
 209                return netdev_pick_tx(dev, skb, NULL) %
 210                       dev->real_num_tx_queues;
 211
 212        xenvif_set_skb_hash(vif, skb);
 213
 214        if (size == 0)
 215                return skb_get_hash_raw(skb) % dev->real_num_tx_queues;
 216
 217        return vif->hash.mapping[vif->hash.mapping_sel]
 218                                [skb_get_hash_raw(skb) % size];
 219}
 220
 221static netdev_tx_t
 222xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
 223{
 224        struct xenvif *vif = netdev_priv(dev);
 225        struct xenvif_queue *queue = NULL;
 226        unsigned int num_queues;
 227        u16 index;
 228        struct xenvif_rx_cb *cb;
 229
 230        BUG_ON(skb->dev != dev);
 231
 232        /* Drop the packet if queues are not set up.
 233         * This handler should be called inside an RCU read section
 234         * so we don't need to enter it here explicitly.
 235         */
 236        num_queues = READ_ONCE(vif->num_queues);
 237        if (num_queues < 1)
 238                goto drop;
 239
 240        /* Obtain the queue to be used to transmit this packet */
 241        index = skb_get_queue_mapping(skb);
 242        if (index >= num_queues) {
 243                pr_warn_ratelimited("Invalid queue %hu for packet on interface %s\n",
 244                                    index, vif->dev->name);
 245                index %= num_queues;
 246        }
 247        queue = &vif->queues[index];
 248
 249        /* Drop the packet if queue is not ready */
 250        if (queue->task == NULL ||
 251            queue->dealloc_task == NULL ||
 252            !xenvif_schedulable(vif))
 253                goto drop;
 254
 255        if (vif->multicast_control && skb->pkt_type == PACKET_MULTICAST) {
 256                struct ethhdr *eth = (struct ethhdr *)skb->data;
 257
 258                if (!xenvif_mcast_match(vif, eth->h_dest))
 259                        goto drop;
 260        }
 261
 262        cb = XENVIF_RX_CB(skb);
 263        cb->expires = jiffies + vif->drain_timeout;
 264
 265        /* If there is no hash algorithm configured then make sure there
 266         * is no hash information in the socket buffer otherwise it
 267         * would be incorrectly forwarded to the frontend.
 268         */
 269        if (vif->hash.alg == XEN_NETIF_CTRL_HASH_ALGORITHM_NONE)
 270                skb_clear_hash(skb);
 271
 272        xenvif_rx_queue_tail(queue, skb);
 273        xenvif_kick_thread(queue);
 274
 275        return NETDEV_TX_OK;
 276
 277 drop:
 278        vif->dev->stats.tx_dropped++;
 279        dev_kfree_skb(skb);
 280        return NETDEV_TX_OK;
 281}
 282
 283static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
 284{
 285        struct xenvif *vif = netdev_priv(dev);
 286        struct xenvif_queue *queue = NULL;
 287        unsigned int num_queues;
 288        u64 rx_bytes = 0;
 289        u64 rx_packets = 0;
 290        u64 tx_bytes = 0;
 291        u64 tx_packets = 0;
 292        unsigned int index;
 293
 294        rcu_read_lock();
 295        num_queues = READ_ONCE(vif->num_queues);
 296
 297        /* Aggregate tx and rx stats from each queue */
 298        for (index = 0; index < num_queues; ++index) {
 299                queue = &vif->queues[index];
 300                rx_bytes += queue->stats.rx_bytes;
 301                rx_packets += queue->stats.rx_packets;
 302                tx_bytes += queue->stats.tx_bytes;
 303                tx_packets += queue->stats.tx_packets;
 304        }
 305
 306        rcu_read_unlock();
 307
 308        vif->dev->stats.rx_bytes = rx_bytes;
 309        vif->dev->stats.rx_packets = rx_packets;
 310        vif->dev->stats.tx_bytes = tx_bytes;
 311        vif->dev->stats.tx_packets = tx_packets;
 312
 313        return &vif->dev->stats;
 314}
 315
 316static void xenvif_up(struct xenvif *vif)
 317{
 318        struct xenvif_queue *queue = NULL;
 319        unsigned int num_queues = vif->num_queues;
 320        unsigned int queue_index;
 321
 322        for (queue_index = 0; queue_index < num_queues; ++queue_index) {
 323                queue = &vif->queues[queue_index];
 324                napi_enable(&queue->napi);
 325                enable_irq(queue->tx_irq);
 326                if (queue->tx_irq != queue->rx_irq)
 327                        enable_irq(queue->rx_irq);
 328                xenvif_napi_schedule_or_enable_events(queue);
 329        }
 330}
 331
 332static void xenvif_down(struct xenvif *vif)
 333{
 334        struct xenvif_queue *queue = NULL;
 335        unsigned int num_queues = vif->num_queues;
 336        unsigned int queue_index;
 337
 338        for (queue_index = 0; queue_index < num_queues; ++queue_index) {
 339                queue = &vif->queues[queue_index];
 340                disable_irq(queue->tx_irq);
 341                if (queue->tx_irq != queue->rx_irq)
 342                        disable_irq(queue->rx_irq);
 343                napi_disable(&queue->napi);
 344                del_timer_sync(&queue->credit_timeout);
 345        }
 346}
 347
 348static int xenvif_open(struct net_device *dev)
 349{
 350        struct xenvif *vif = netdev_priv(dev);
 351        if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
 352                xenvif_up(vif);
 353        netif_tx_start_all_queues(dev);
 354        return 0;
 355}
 356
 357static int xenvif_close(struct net_device *dev)
 358{
 359        struct xenvif *vif = netdev_priv(dev);
 360        if (test_bit(VIF_STATUS_CONNECTED, &vif->status))
 361                xenvif_down(vif);
 362        netif_tx_stop_all_queues(dev);
 363        return 0;
 364}
 365
 366static int xenvif_change_mtu(struct net_device *dev, int mtu)
 367{
 368        struct xenvif *vif = netdev_priv(dev);
 369        int max = vif->can_sg ? ETH_MAX_MTU - VLAN_ETH_HLEN : ETH_DATA_LEN;
 370
 371        if (mtu > max)
 372                return -EINVAL;
 373        dev->mtu = mtu;
 374        return 0;
 375}
 376
 377static netdev_features_t xenvif_fix_features(struct net_device *dev,
 378        netdev_features_t features)
 379{
 380        struct xenvif *vif = netdev_priv(dev);
 381
 382        if (!vif->can_sg)
 383                features &= ~NETIF_F_SG;
 384        if (~(vif->gso_mask) & GSO_BIT(TCPV4))
 385                features &= ~NETIF_F_TSO;
 386        if (~(vif->gso_mask) & GSO_BIT(TCPV6))
 387                features &= ~NETIF_F_TSO6;
 388        if (!vif->ip_csum)
 389                features &= ~NETIF_F_IP_CSUM;
 390        if (!vif->ipv6_csum)
 391                features &= ~NETIF_F_IPV6_CSUM;
 392
 393        return features;
 394}
 395
 396static const struct xenvif_stat {
 397        char name[ETH_GSTRING_LEN];
 398        u16 offset;
 399} xenvif_stats[] = {
 400        {
 401                "rx_gso_checksum_fixup",
 402                offsetof(struct xenvif_stats, rx_gso_checksum_fixup)
 403        },
 404        /* If (sent != success + fail), there are probably packets never
 405         * freed up properly!
 406         */
 407        {
 408                "tx_zerocopy_sent",
 409                offsetof(struct xenvif_stats, tx_zerocopy_sent),
 410        },
 411        {
 412                "tx_zerocopy_success",
 413                offsetof(struct xenvif_stats, tx_zerocopy_success),
 414        },
 415        {
 416                "tx_zerocopy_fail",
 417                offsetof(struct xenvif_stats, tx_zerocopy_fail)
 418        },
 419        /* Number of packets exceeding MAX_SKB_FRAG slots. You should use
 420         * a guest with the same MAX_SKB_FRAG
 421         */
 422        {
 423                "tx_frag_overflow",
 424                offsetof(struct xenvif_stats, tx_frag_overflow)
 425        },
 426};
 427
 428static int xenvif_get_sset_count(struct net_device *dev, int string_set)
 429{
 430        switch (string_set) {
 431        case ETH_SS_STATS:
 432                return ARRAY_SIZE(xenvif_stats);
 433        default:
 434                return -EINVAL;
 435        }
 436}
 437
 438static void xenvif_get_ethtool_stats(struct net_device *dev,
 439                                     struct ethtool_stats *stats, u64 * data)
 440{
 441        struct xenvif *vif = netdev_priv(dev);
 442        unsigned int num_queues;
 443        int i;
 444        unsigned int queue_index;
 445
 446        rcu_read_lock();
 447        num_queues = READ_ONCE(vif->num_queues);
 448
 449        for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
 450                unsigned long accum = 0;
 451                for (queue_index = 0; queue_index < num_queues; ++queue_index) {
 452                        void *vif_stats = &vif->queues[queue_index].stats;
 453                        accum += *(unsigned long *)(vif_stats + xenvif_stats[i].offset);
 454                }
 455                data[i] = accum;
 456        }
 457
 458        rcu_read_unlock();
 459}
 460
 461static void xenvif_get_strings(struct net_device *dev, u32 stringset, u8 * data)
 462{
 463        int i;
 464
 465        switch (stringset) {
 466        case ETH_SS_STATS:
 467                for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++)
 468                        memcpy(data + i * ETH_GSTRING_LEN,
 469                               xenvif_stats[i].name, ETH_GSTRING_LEN);
 470                break;
 471        }
 472}
 473
 474static const struct ethtool_ops xenvif_ethtool_ops = {
 475        .get_link       = ethtool_op_get_link,
 476
 477        .get_sset_count = xenvif_get_sset_count,
 478        .get_ethtool_stats = xenvif_get_ethtool_stats,
 479        .get_strings = xenvif_get_strings,
 480};
 481
 482static const struct net_device_ops xenvif_netdev_ops = {
 483        .ndo_select_queue = xenvif_select_queue,
 484        .ndo_start_xmit = xenvif_start_xmit,
 485        .ndo_get_stats  = xenvif_get_stats,
 486        .ndo_open       = xenvif_open,
 487        .ndo_stop       = xenvif_close,
 488        .ndo_change_mtu = xenvif_change_mtu,
 489        .ndo_fix_features = xenvif_fix_features,
 490        .ndo_set_mac_address = eth_mac_addr,
 491        .ndo_validate_addr   = eth_validate_addr,
 492};
 493
 494struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 495                            unsigned int handle)
 496{
 497        int err;
 498        struct net_device *dev;
 499        struct xenvif *vif;
 500        char name[IFNAMSIZ] = {};
 501
 502        snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle);
 503        /* Allocate a netdev with the max. supported number of queues.
 504         * When the guest selects the desired number, it will be updated
 505         * via netif_set_real_num_*_queues().
 506         */
 507        dev = alloc_netdev_mq(sizeof(struct xenvif), name, NET_NAME_UNKNOWN,
 508                              ether_setup, xenvif_max_queues);
 509        if (dev == NULL) {
 510                pr_warn("Could not allocate netdev for %s\n", name);
 511                return ERR_PTR(-ENOMEM);
 512        }
 513
 514        SET_NETDEV_DEV(dev, parent);
 515
 516        vif = netdev_priv(dev);
 517
 518        vif->domid  = domid;
 519        vif->handle = handle;
 520        vif->can_sg = 1;
 521        vif->ip_csum = 1;
 522        vif->dev = dev;
 523        vif->disabled = false;
 524        vif->drain_timeout = msecs_to_jiffies(rx_drain_timeout_msecs);
 525        vif->stall_timeout = msecs_to_jiffies(rx_stall_timeout_msecs);
 526
 527        /* Start out with no queues. */
 528        vif->queues = NULL;
 529        vif->num_queues = 0;
 530
 531        vif->xdp_headroom = 0;
 532
 533        spin_lock_init(&vif->lock);
 534        INIT_LIST_HEAD(&vif->fe_mcast_addr);
 535
 536        dev->netdev_ops = &xenvif_netdev_ops;
 537        dev->hw_features = NETIF_F_SG |
 538                NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
 539                NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_FRAGLIST;
 540        dev->features = dev->hw_features | NETIF_F_RXCSUM;
 541        dev->ethtool_ops = &xenvif_ethtool_ops;
 542
 543        dev->tx_queue_len = XENVIF_QUEUE_LENGTH;
 544
 545        dev->min_mtu = ETH_MIN_MTU;
 546        dev->max_mtu = ETH_MAX_MTU - VLAN_ETH_HLEN;
 547
 548        /*
 549         * Initialise a dummy MAC address. We choose the numerically
 550         * largest non-broadcast address to prevent the address getting
 551         * stolen by an Ethernet bridge for STP purposes.
 552         * (FE:FF:FF:FF:FF:FF)
 553         */
 554        eth_broadcast_addr(dev->dev_addr);
 555        dev->dev_addr[0] &= ~0x01;
 556
 557        netif_carrier_off(dev);
 558
 559        err = register_netdev(dev);
 560        if (err) {
 561                netdev_warn(dev, "Could not register device: err=%d\n", err);
 562                free_netdev(dev);
 563                return ERR_PTR(err);
 564        }
 565
 566        netdev_dbg(dev, "Successfully created xenvif\n");
 567
 568        __module_get(THIS_MODULE);
 569
 570        return vif;
 571}
 572
 573int xenvif_init_queue(struct xenvif_queue *queue)
 574{
 575        int err, i;
 576
 577        queue->credit_bytes = queue->remaining_credit = ~0UL;
 578        queue->credit_usec  = 0UL;
 579        timer_setup(&queue->credit_timeout, xenvif_tx_credit_callback, 0);
 580        queue->credit_window_start = get_jiffies_64();
 581
 582        queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES;
 583
 584        skb_queue_head_init(&queue->rx_queue);
 585        skb_queue_head_init(&queue->tx_queue);
 586
 587        queue->pending_cons = 0;
 588        queue->pending_prod = MAX_PENDING_REQS;
 589        for (i = 0; i < MAX_PENDING_REQS; ++i)
 590                queue->pending_ring[i] = i;
 591
 592        spin_lock_init(&queue->callback_lock);
 593        spin_lock_init(&queue->response_lock);
 594
 595        /* If ballooning is disabled, this will consume real memory, so you
 596         * better enable it. The long term solution would be to use just a
 597         * bunch of valid page descriptors, without dependency on ballooning
 598         */
 599        err = gnttab_alloc_pages(MAX_PENDING_REQS,
 600                                 queue->mmap_pages);
 601        if (err) {
 602                netdev_err(queue->vif->dev, "Could not reserve mmap_pages\n");
 603                return -ENOMEM;
 604        }
 605
 606        for (i = 0; i < MAX_PENDING_REQS; i++) {
 607                queue->pending_tx_info[i].callback_struct = (struct ubuf_info)
 608                        { .callback = xenvif_zerocopy_callback,
 609                          { { .ctx = NULL,
 610                              .desc = i } } };
 611                queue->grant_tx_handle[i] = NETBACK_INVALID_HANDLE;
 612        }
 613
 614        return 0;
 615}
 616
 617void xenvif_carrier_on(struct xenvif *vif)
 618{
 619        rtnl_lock();
 620        if (!vif->can_sg && vif->dev->mtu > ETH_DATA_LEN)
 621                dev_set_mtu(vif->dev, ETH_DATA_LEN);
 622        netdev_update_features(vif->dev);
 623        set_bit(VIF_STATUS_CONNECTED, &vif->status);
 624        if (netif_running(vif->dev))
 625                xenvif_up(vif);
 626        rtnl_unlock();
 627}
 628
 629int xenvif_connect_ctrl(struct xenvif *vif, grant_ref_t ring_ref,
 630                        unsigned int evtchn)
 631{
 632        struct net_device *dev = vif->dev;
 633        struct xenbus_device *xendev = xenvif_to_xenbus_device(vif);
 634        void *addr;
 635        struct xen_netif_ctrl_sring *shared;
 636        RING_IDX rsp_prod, req_prod;
 637        int err;
 638
 639        err = xenbus_map_ring_valloc(xendev, &ring_ref, 1, &addr);
 640        if (err)
 641                goto err;
 642
 643        shared = (struct xen_netif_ctrl_sring *)addr;
 644        rsp_prod = READ_ONCE(shared->rsp_prod);
 645        req_prod = READ_ONCE(shared->req_prod);
 646
 647        BACK_RING_ATTACH(&vif->ctrl, shared, rsp_prod, XEN_PAGE_SIZE);
 648
 649        err = -EIO;
 650        if (req_prod - rsp_prod > RING_SIZE(&vif->ctrl))
 651                goto err_unmap;
 652
 653        err = bind_interdomain_evtchn_to_irq_lateeoi(xendev, evtchn);
 654        if (err < 0)
 655                goto err_unmap;
 656
 657        vif->ctrl_irq = err;
 658
 659        xenvif_init_hash(vif);
 660
 661        err = request_threaded_irq(vif->ctrl_irq, NULL, xenvif_ctrl_irq_fn,
 662                                   IRQF_ONESHOT, "xen-netback-ctrl", vif);
 663        if (err) {
 664                pr_warn("Could not setup irq handler for %s\n", dev->name);
 665                goto err_deinit;
 666        }
 667
 668        return 0;
 669
 670err_deinit:
 671        xenvif_deinit_hash(vif);
 672        unbind_from_irqhandler(vif->ctrl_irq, vif);
 673        vif->ctrl_irq = 0;
 674
 675err_unmap:
 676        xenbus_unmap_ring_vfree(xendev, vif->ctrl.sring);
 677        vif->ctrl.sring = NULL;
 678
 679err:
 680        return err;
 681}
 682
 683static void xenvif_disconnect_queue(struct xenvif_queue *queue)
 684{
 685        if (queue->task) {
 686                kthread_stop(queue->task);
 687                put_task_struct(queue->task);
 688                queue->task = NULL;
 689        }
 690
 691        if (queue->dealloc_task) {
 692                kthread_stop(queue->dealloc_task);
 693                queue->dealloc_task = NULL;
 694        }
 695
 696        if (queue->napi.poll) {
 697                netif_napi_del(&queue->napi);
 698                queue->napi.poll = NULL;
 699        }
 700
 701        if (queue->tx_irq) {
 702                unbind_from_irqhandler(queue->tx_irq, queue);
 703                if (queue->tx_irq == queue->rx_irq)
 704                        queue->rx_irq = 0;
 705                queue->tx_irq = 0;
 706        }
 707
 708        if (queue->rx_irq) {
 709                unbind_from_irqhandler(queue->rx_irq, queue);
 710                queue->rx_irq = 0;
 711        }
 712
 713        xenvif_unmap_frontend_data_rings(queue);
 714}
 715
 716int xenvif_connect_data(struct xenvif_queue *queue,
 717                        unsigned long tx_ring_ref,
 718                        unsigned long rx_ring_ref,
 719                        unsigned int tx_evtchn,
 720                        unsigned int rx_evtchn)
 721{
 722        struct xenbus_device *dev = xenvif_to_xenbus_device(queue->vif);
 723        struct task_struct *task;
 724        int err;
 725
 726        BUG_ON(queue->tx_irq);
 727        BUG_ON(queue->task);
 728        BUG_ON(queue->dealloc_task);
 729
 730        err = xenvif_map_frontend_data_rings(queue, tx_ring_ref,
 731                                             rx_ring_ref);
 732        if (err < 0)
 733                goto err;
 734
 735        init_waitqueue_head(&queue->wq);
 736        init_waitqueue_head(&queue->dealloc_wq);
 737        atomic_set(&queue->inflight_packets, 0);
 738
 739        netif_napi_add(queue->vif->dev, &queue->napi, xenvif_poll,
 740                        XENVIF_NAPI_WEIGHT);
 741
 742        queue->stalled = true;
 743
 744        task = kthread_run(xenvif_kthread_guest_rx, queue,
 745                           "%s-guest-rx", queue->name);
 746        if (IS_ERR(task))
 747                goto kthread_err;
 748        queue->task = task;
 749        /*
 750         * Take a reference to the task in order to prevent it from being freed
 751         * if the thread function returns before kthread_stop is called.
 752         */
 753        get_task_struct(task);
 754
 755        task = kthread_run(xenvif_dealloc_kthread, queue,
 756                           "%s-dealloc", queue->name);
 757        if (IS_ERR(task))
 758                goto kthread_err;
 759        queue->dealloc_task = task;
 760
 761        if (tx_evtchn == rx_evtchn) {
 762                /* feature-split-event-channels == 0 */
 763                err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
 764                        dev, tx_evtchn, xenvif_interrupt, 0,
 765                        queue->name, queue);
 766                if (err < 0)
 767                        goto err;
 768                queue->tx_irq = queue->rx_irq = err;
 769                disable_irq(queue->tx_irq);
 770        } else {
 771                /* feature-split-event-channels == 1 */
 772                snprintf(queue->tx_irq_name, sizeof(queue->tx_irq_name),
 773                         "%s-tx", queue->name);
 774                err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
 775                        dev, tx_evtchn, xenvif_tx_interrupt, 0,
 776                        queue->tx_irq_name, queue);
 777                if (err < 0)
 778                        goto err;
 779                queue->tx_irq = err;
 780                disable_irq(queue->tx_irq);
 781
 782                snprintf(queue->rx_irq_name, sizeof(queue->rx_irq_name),
 783                         "%s-rx", queue->name);
 784                err = bind_interdomain_evtchn_to_irqhandler_lateeoi(
 785                        dev, rx_evtchn, xenvif_rx_interrupt, 0,
 786                        queue->rx_irq_name, queue);
 787                if (err < 0)
 788                        goto err;
 789                queue->rx_irq = err;
 790                disable_irq(queue->rx_irq);
 791        }
 792
 793        return 0;
 794
 795kthread_err:
 796        pr_warn("Could not allocate kthread for %s\n", queue->name);
 797        err = PTR_ERR(task);
 798err:
 799        xenvif_disconnect_queue(queue);
 800        return err;
 801}
 802
 803void xenvif_carrier_off(struct xenvif *vif)
 804{
 805        struct net_device *dev = vif->dev;
 806
 807        rtnl_lock();
 808        if (test_and_clear_bit(VIF_STATUS_CONNECTED, &vif->status)) {
 809                netif_carrier_off(dev); /* discard queued packets */
 810                if (netif_running(dev))
 811                        xenvif_down(vif);
 812        }
 813        rtnl_unlock();
 814}
 815
 816void xenvif_disconnect_data(struct xenvif *vif)
 817{
 818        struct xenvif_queue *queue = NULL;
 819        unsigned int num_queues = vif->num_queues;
 820        unsigned int queue_index;
 821
 822        xenvif_carrier_off(vif);
 823
 824        for (queue_index = 0; queue_index < num_queues; ++queue_index) {
 825                queue = &vif->queues[queue_index];
 826
 827                xenvif_disconnect_queue(queue);
 828        }
 829
 830        xenvif_mcast_addr_list_free(vif);
 831}
 832
 833void xenvif_disconnect_ctrl(struct xenvif *vif)
 834{
 835        if (vif->ctrl_irq) {
 836                xenvif_deinit_hash(vif);
 837                unbind_from_irqhandler(vif->ctrl_irq, vif);
 838                vif->ctrl_irq = 0;
 839        }
 840
 841        if (vif->ctrl.sring) {
 842                xenbus_unmap_ring_vfree(xenvif_to_xenbus_device(vif),
 843                                        vif->ctrl.sring);
 844                vif->ctrl.sring = NULL;
 845        }
 846}
 847
 848/* Reverse the relevant parts of xenvif_init_queue().
 849 * Used for queue teardown from xenvif_free(), and on the
 850 * error handling paths in xenbus.c:connect().
 851 */
 852void xenvif_deinit_queue(struct xenvif_queue *queue)
 853{
 854        gnttab_free_pages(MAX_PENDING_REQS, queue->mmap_pages);
 855}
 856
 857void xenvif_free(struct xenvif *vif)
 858{
 859        struct xenvif_queue *queues = vif->queues;
 860        unsigned int num_queues = vif->num_queues;
 861        unsigned int queue_index;
 862
 863        unregister_netdev(vif->dev);
 864        free_netdev(vif->dev);
 865
 866        for (queue_index = 0; queue_index < num_queues; ++queue_index)
 867                xenvif_deinit_queue(&queues[queue_index]);
 868        vfree(queues);
 869
 870        module_put(THIS_MODULE);
 871}
 872
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