drivers/net/hyperv/netvsc.c

   1 /*
   2  * Copyright (c) 2009, Microsoft Corporation.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along with
  14  * this program; if not, see <http://www.gnu.org/licenses/>.
  15  *
  16  * Authors:
  17  *   Haiyang Zhang <haiyangz@microsoft.com>
  18  *   Hank Janssen  <hjanssen@microsoft.com>
  19  */
  20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22 #include <linux/kernel.h>
  23 #include <linux/sched.h>
  24 #include <linux/wait.h>
  25 #include <linux/mm.h>
  26 #include <linux/delay.h>
  27 #include <linux/io.h>
  28 #include <linux/slab.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/if_ether.h>
  31 #include <linux/vmalloc.h>
  32 #include <linux/rtnetlink.h>
  33 #include <linux/prefetch.h>
  34
  35 #include <asm/sync_bitops.h>
  36
  37 #include "hyperv_net.h"
  38
  39 /*
  40  * Switch the data path from the synthetic interface to the VF
  41  * interface.
  42  */
  43 void netvsc_switch_datapath(struct net_device *ndev, bool vf)
  44 {
  45         struct net_device_context *net_device_ctx = netdev_priv(ndev);
  46         struct hv_device *dev = net_device_ctx->device_ctx;
  47         struct netvsc_device *nv_dev = rtnl_dereference(net_device_ctx->nvdev);
  48         struct nvsp_message *init_pkt = &nv_dev->channel_init_pkt;
  49
  50         memset(init_pkt, 0, sizeof(struct nvsp_message));
  51         init_pkt->hdr.msg_type = NVSP_MSG4_TYPE_SWITCH_DATA_PATH;
  52         if (vf)
  53                 init_pkt->msg.v4_msg.active_dp.active_datapath =
  54                         NVSP_DATAPATH_VF;
  55         else
  56                 init_pkt->msg.v4_msg.active_dp.active_datapath =
  57                         NVSP_DATAPATH_SYNTHETIC;
  58
  59         vmbus_sendpacket(dev->channel, init_pkt,
  60                                sizeof(struct nvsp_message),
  61                                (unsigned long)init_pkt,
  62                                VM_PKT_DATA_INBAND, 0);
  63 }
  64
  65 static struct netvsc_device *alloc_net_device(void)
  66 {
  67         struct netvsc_device *net_device;
  68
  69         net_device = kzalloc(sizeof(struct netvsc_device), GFP_KERNEL);
  70         if (!net_device)
  71                 return NULL;
  72
  73         init_waitqueue_head(&net_device->wait_drain);
  74         net_device->destroy = false;
  75         atomic_set(&net_device->open_cnt, 0);
  76         net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
  77         net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;
  78
  79         init_completion(&net_device->channel_init_wait);
  80         init_waitqueue_head(&net_device->subchan_open);
  81         INIT_WORK(&net_device->subchan_work, rndis_set_subchannel);
  82
  83         return net_device;
  84 }
  85
  86 static void free_netvsc_device(struct rcu_head *head)
  87 {
  88         struct netvsc_device *nvdev
  89                 = container_of(head, struct netvsc_device, rcu);
  90         int i;
  91
  92         for (i = 0; i < VRSS_CHANNEL_MAX; i++)
  93                 vfree(nvdev->chan_table[i].mrc.slots);
  94
  95         kfree(nvdev);
  96 }
  97
  98 static void free_netvsc_device_rcu(struct netvsc_device *nvdev)
  99 {
 100         call_rcu(&nvdev->rcu, free_netvsc_device);
 101 }
 102
 103 static void netvsc_destroy_buf(struct hv_device *device)
 104 {
 105         struct nvsp_message *revoke_packet;
 106         struct net_device *ndev = hv_get_drvdata(device);
 107         struct net_device_context *ndc = netdev_priv(ndev);
 108         struct netvsc_device *net_device = rtnl_dereference(ndc->nvdev);
 109         int ret;
 110
 111         /*
 112          * If we got a section count, it means we received a
 113          * SendReceiveBufferComplete msg (ie sent
 114          * NvspMessage1TypeSendReceiveBuffer msg) therefore, we need
 115          * to send a revoke msg here
 116          */
 117         if (net_device->recv_section_cnt) {
 118                 /* Send the revoke receive buffer */
 119                 revoke_packet = &net_device->revoke_packet;
 120                 memset(revoke_packet, 0, sizeof(struct nvsp_message));
 121
 122                 revoke_packet->hdr.msg_type =
 123                         NVSP_MSG1_TYPE_REVOKE_RECV_BUF;
 124                 revoke_packet->msg.v1_msg.
 125                 revoke_recv_buf.id = NETVSC_RECEIVE_BUFFER_ID;
 126
 127                 ret = vmbus_sendpacket(device->channel,
 128                                        revoke_packet,
 129                                        sizeof(struct nvsp_message),
 130                                        (unsigned long)revoke_packet,
 131                                        VM_PKT_DATA_INBAND, 0);
 132                 /* If the failure is because the channel is rescinded;
 133                  * ignore the failure since we cannot send on a rescinded
 134                  * channel. This would allow us to properly cleanup
 135                  * even when the channel is rescinded.
 136                  */
 137                 if (device->channel->rescind)
 138                         ret = 0;
 139                 /*
 140                  * If we failed here, we might as well return and
 141                  * have a leak rather than continue and a bugchk
 142                  */
 143                 if (ret != 0) {
 144                         netdev_err(ndev, "unable to send "
 145                                 "revoke receive buffer to netvsp\n");
 146                         return;
 147                 }
 148                 net_device->recv_section_cnt = 0;
 149         }
 150
 151         /* Teardown the gpadl on the vsp end */
 152         if (net_device->recv_buf_gpadl_handle) {
 153                 ret = vmbus_teardown_gpadl(device->channel,
 154                                            net_device->recv_buf_gpadl_handle);
 155
 156                 /* If we failed here, we might as well return and have a leak
 157                  * rather than continue and a bugchk
 158                  */
 159                 if (ret != 0) {
 160                         netdev_err(ndev,
 161                                    "unable to teardown receive buffer's gpadl\n");
 162                         return;
 163                 }
 164                 net_device->recv_buf_gpadl_handle = 0;
 165         }
 166
 167         if (net_device->recv_buf) {
 168                 /* Free up the receive buffer */
 169                 vfree(net_device->recv_buf);
 170                 net_device->recv_buf = NULL;
 171         }
 172
 173         /* Deal with the send buffer we may have setup.
 174          * If we got a  send section size, it means we received a
 175          * NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE msg (ie sent
 176          * NVSP_MSG1_TYPE_SEND_SEND_BUF msg) therefore, we need
 177          * to send a revoke msg here
 178          */
 179         if (net_device->send_section_cnt) {
 180                 /* Send the revoke receive buffer */
 181                 revoke_packet = &net_device->revoke_packet;
 182                 memset(revoke_packet, 0, sizeof(struct nvsp_message));
 183
 184                 revoke_packet->hdr.msg_type =
 185                         NVSP_MSG1_TYPE_REVOKE_SEND_BUF;
 186                 revoke_packet->msg.v1_msg.revoke_send_buf.id =
 187                         NETVSC_SEND_BUFFER_ID;
 188
 189                 ret = vmbus_sendpacket(device->channel,
 190                                        revoke_packet,
 191                                        sizeof(struct nvsp_message),
 192                                        (unsigned long)revoke_packet,
 193                                        VM_PKT_DATA_INBAND, 0);
 194
 195                 /* If the failure is because the channel is rescinded;
 196                  * ignore the failure since we cannot send on a rescinded
 197                  * channel. This would allow us to properly cleanup
 198                  * even when the channel is rescinded.
 199                  */
 200                 if (device->channel->rescind)
 201                         ret = 0;
 202
 203                 /* If we failed here, we might as well return and
 204                  * have a leak rather than continue and a bugchk
 205                  */
 206                 if (ret != 0) {
 207                         netdev_err(ndev, "unable to send "
 208                                    "revoke send buffer to netvsp\n");
 209                         return;
 210                 }
 211                 net_device->send_section_cnt = 0;
 212         }
 213         /* Teardown the gpadl on the vsp end */
 214         if (net_device->send_buf_gpadl_handle) {
 215                 ret = vmbus_teardown_gpadl(device->channel,
 216                                            net_device->send_buf_gpadl_handle);
 217
 218                 /* If we failed here, we might as well return and have a leak
 219                  * rather than continue and a bugchk
 220                  */
 221                 if (ret != 0) {
 222                         netdev_err(ndev,
 223                                    "unable to teardown send buffer's gpadl\n");
 224                         return;
 225                 }
 226                 net_device->send_buf_gpadl_handle = 0;
 227         }
 228         if (net_device->send_buf) {
 229                 /* Free up the send buffer */
 230                 vfree(net_device->send_buf);
 231                 net_device->send_buf = NULL;
 232         }
 233         kfree(net_device->send_section_map);
 234 }
 235
 236 int netvsc_alloc_recv_comp_ring(struct netvsc_device *net_device, u32 q_idx)
 237 {
 238         struct netvsc_channel *nvchan = &net_device->chan_table[q_idx];
 239         int node = cpu_to_node(nvchan->channel->target_cpu);
 240         size_t size;
 241
 242         size = net_device->recv_completion_cnt * sizeof(struct recv_comp_data);
 243         nvchan->mrc.slots = vzalloc_node(size, node);
 244         if (!nvchan->mrc.slots)
 245                 nvchan->mrc.slots = vzalloc(size);
 246
 247         return nvchan->mrc.slots ? 0 : -ENOMEM;
 248 }
 249
 250 static int netvsc_init_buf(struct hv_device *device,
 251                            struct netvsc_device *net_device,
 252                            const struct netvsc_device_info *device_info)
 253 {
 254         struct nvsp_1_message_send_receive_buffer_complete *resp;
 255         struct net_device *ndev = hv_get_drvdata(device);
 256         struct nvsp_message *init_packet;
 257         unsigned int buf_size;
 258         size_t map_words;
 259         int ret = 0;
 260
 261         /* Get receive buffer area. */
 262         buf_size = device_info->recv_sections * device_info->recv_section_size;
 263         buf_size = roundup(buf_size, PAGE_SIZE);
 264
 265         /* Legacy hosts only allow smaller receive buffer */
 266         if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_2)
 267                 buf_size = min_t(unsigned int, buf_size,
 268                                  NETVSC_RECEIVE_BUFFER_SIZE_LEGACY);
 269
 270         net_device->recv_buf = vzalloc(buf_size);
 271         if (!net_device->recv_buf) {
 272                 netdev_err(ndev,
 273                            "unable to allocate receive buffer of size %u\n",
 274                            buf_size);
 275                 ret = -ENOMEM;
 276                 goto cleanup;
 277         }
 278
 279         /*
 280          * Establish the gpadl handle for this buffer on this
 281          * channel.  Note: This call uses the vmbus connection rather
 282          * than the channel to establish the gpadl handle.
 283          */
 284         ret = vmbus_establish_gpadl(device->channel, net_device->recv_buf,
 285                                     buf_size,
 286                                     &net_device->recv_buf_gpadl_handle);
 287         if (ret != 0) {
 288                 netdev_err(ndev,
 289                         "unable to establish receive buffer's gpadl\n");
 290                 goto cleanup;
 291         }
 292
 293         /* Notify the NetVsp of the gpadl handle */
 294         init_packet = &net_device->channel_init_pkt;
 295         memset(init_packet, 0, sizeof(struct nvsp_message));
 296         init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_RECV_BUF;
 297         init_packet->msg.v1_msg.send_recv_buf.
 298                 gpadl_handle = net_device->recv_buf_gpadl_handle;
 299         init_packet->msg.v1_msg.
 300                 send_recv_buf.id = NETVSC_RECEIVE_BUFFER_ID;
 301
 302         /* Send the gpadl notification request */
 303         ret = vmbus_sendpacket(device->channel, init_packet,
 304                                sizeof(struct nvsp_message),
 305                                (unsigned long)init_packet,
 306                                VM_PKT_DATA_INBAND,
 307                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 308         if (ret != 0) {
 309                 netdev_err(ndev,
 310                         "unable to send receive buffer's gpadl to netvsp\n");
 311                 goto cleanup;
 312         }
 313
 314         wait_for_completion(&net_device->channel_init_wait);
 315
 316         /* Check the response */
 317         resp = &init_packet->msg.v1_msg.send_recv_buf_complete;
 318         if (resp->status != NVSP_STAT_SUCCESS) {
 319                 netdev_err(ndev,
 320                            "Unable to complete receive buffer initialization with NetVsp - status %d\n",
 321                            resp->status);
 322                 ret = -EINVAL;
 323                 goto cleanup;
 324         }
 325
 326         /* Parse the response */
 327         netdev_dbg(ndev, "Receive sections: %u sub_allocs: size %u count: %u\n",
 328                    resp->num_sections, resp->sections[0].sub_alloc_size,
 329                    resp->sections[0].num_sub_allocs);
 330
 331         /* There should only be one section for the entire receive buffer */
 332         if (resp->num_sections != 1 || resp->sections[0].offset != 0) {
 333                 ret = -EINVAL;
 334                 goto cleanup;
 335         }
 336
 337         net_device->recv_section_size = resp->sections[0].sub_alloc_size;
 338         net_device->recv_section_cnt = resp->sections[0].num_sub_allocs;
 339
 340         /* Setup receive completion ring */
 341         net_device->recv_completion_cnt
 342                 = round_up(net_device->recv_section_cnt + 1,
 343                            PAGE_SIZE / sizeof(u64));
 344         ret = netvsc_alloc_recv_comp_ring(net_device, 0);
 345         if (ret)
 346                 goto cleanup;
 347
 348         /* Now setup the send buffer. */
 349         buf_size = device_info->send_sections * device_info->send_section_size;
 350         buf_size = round_up(buf_size, PAGE_SIZE);
 351
 352         net_device->send_buf = vzalloc(buf_size);
 353         if (!net_device->send_buf) {
 354                 netdev_err(ndev, "unable to allocate send buffer of size %u\n",
 355                            buf_size);
 356                 ret = -ENOMEM;
 357                 goto cleanup;
 358         }
 359
 360         /* Establish the gpadl handle for this buffer on this
 361          * channel.  Note: This call uses the vmbus connection rather
 362          * than the channel to establish the gpadl handle.
 363          */
 364         ret = vmbus_establish_gpadl(device->channel, net_device->send_buf,
 365                                     buf_size,
 366                                     &net_device->send_buf_gpadl_handle);
 367         if (ret != 0) {
 368                 netdev_err(ndev,
 369                            "unable to establish send buffer's gpadl\n");
 370                 goto cleanup;
 371         }
 372
 373         /* Notify the NetVsp of the gpadl handle */
 374         init_packet = &net_device->channel_init_pkt;
 375         memset(init_packet, 0, sizeof(struct nvsp_message));
 376         init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_SEND_BUF;
 377         init_packet->msg.v1_msg.send_send_buf.gpadl_handle =
 378                 net_device->send_buf_gpadl_handle;
 379         init_packet->msg.v1_msg.send_send_buf.id = NETVSC_SEND_BUFFER_ID;
 380
 381         /* Send the gpadl notification request */
 382         ret = vmbus_sendpacket(device->channel, init_packet,
 383                                sizeof(struct nvsp_message),
 384                                (unsigned long)init_packet,
 385                                VM_PKT_DATA_INBAND,
 386                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 387         if (ret != 0) {
 388                 netdev_err(ndev,
 389                            "unable to send send buffer's gpadl to netvsp\n");
 390                 goto cleanup;
 391         }
 392
 393         wait_for_completion(&net_device->channel_init_wait);
 394
 395         /* Check the response */
 396         if (init_packet->msg.v1_msg.
 397             send_send_buf_complete.status != NVSP_STAT_SUCCESS) {
 398                 netdev_err(ndev, "Unable to complete send buffer "
 399                            "initialization with NetVsp - status %d\n",
 400                            init_packet->msg.v1_msg.
 401                            send_send_buf_complete.status);
 402                 ret = -EINVAL;
 403                 goto cleanup;
 404         }
 405
 406         /* Parse the response */
 407         net_device->send_section_size = init_packet->msg.
 408                                 v1_msg.send_send_buf_complete.section_size;
 409
 410         /* Section count is simply the size divided by the section size. */
 411         net_device->send_section_cnt = buf_size / net_device->send_section_size;
 412
 413         netdev_dbg(ndev, "Send section size: %d, Section count:%d\n",
 414                    net_device->send_section_size, net_device->send_section_cnt);
 415
 416         /* Setup state for managing the send buffer. */
 417         map_words = DIV_ROUND_UP(net_device->send_section_cnt, BITS_PER_LONG);
 418
 419         net_device->send_section_map = kcalloc(map_words, sizeof(ulong), GFP_KERNEL);
 420         if (net_device->send_section_map == NULL) {
 421                 ret = -ENOMEM;
 422                 goto cleanup;
 423         }
 424
 425         goto exit;
 426
 427 cleanup:
 428         netvsc_destroy_buf(device);
 429
 430 exit:
 431         return ret;
 432 }
 433
 434 /* Negotiate NVSP protocol version */
 435 static int negotiate_nvsp_ver(struct hv_device *device,
 436                               struct netvsc_device *net_device,
 437                               struct nvsp_message *init_packet,
 438                               u32 nvsp_ver)
 439 {
 440         struct net_device *ndev = hv_get_drvdata(device);
 441         int ret;
 442
 443         memset(init_packet, 0, sizeof(struct nvsp_message));
 444         init_packet->hdr.msg_type = NVSP_MSG_TYPE_INIT;
 445         init_packet->msg.init_msg.init.min_protocol_ver = nvsp_ver;
 446         init_packet->msg.init_msg.init.max_protocol_ver = nvsp_ver;
 447
 448         /* Send the init request */
 449         ret = vmbus_sendpacket(device->channel, init_packet,
 450                                sizeof(struct nvsp_message),
 451                                (unsigned long)init_packet,
 452                                VM_PKT_DATA_INBAND,
 453                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 454
 455         if (ret != 0)
 456                 return ret;
 457
 458         wait_for_completion(&net_device->channel_init_wait);
 459
 460         if (init_packet->msg.init_msg.init_complete.status !=
 461             NVSP_STAT_SUCCESS)
 462                 return -EINVAL;
 463
 464         if (nvsp_ver == NVSP_PROTOCOL_VERSION_1)
 465                 return 0;
 466
 467         /* NVSPv2 or later: Send NDIS config */
 468         memset(init_packet, 0, sizeof(struct nvsp_message));
 469         init_packet->hdr.msg_type = NVSP_MSG2_TYPE_SEND_NDIS_CONFIG;
 470         init_packet->msg.v2_msg.send_ndis_config.mtu = ndev->mtu + ETH_HLEN;
 471         init_packet->msg.v2_msg.send_ndis_config.capability.ieee8021q = 1;
 472
 473         if (nvsp_ver >= NVSP_PROTOCOL_VERSION_5) {
 474                 init_packet->msg.v2_msg.send_ndis_config.capability.sriov = 1;
 475
 476                 /* Teaming bit is needed to receive link speed updates */
 477                 init_packet->msg.v2_msg.send_ndis_config.capability.teaming = 1;
 478         }
 479
 480         ret = vmbus_sendpacket(device->channel, init_packet,
 481                                 sizeof(struct nvsp_message),
 482                                 (unsigned long)init_packet,
 483                                 VM_PKT_DATA_INBAND, 0);
 484
 485         return ret;
 486 }
 487
 488 static int netvsc_connect_vsp(struct hv_device *device,
 489                               struct netvsc_device *net_device,
 490                               const struct netvsc_device_info *device_info)
 491 {
 492         const u32 ver_list[] = {
 493                 NVSP_PROTOCOL_VERSION_1, NVSP_PROTOCOL_VERSION_2,
 494                 NVSP_PROTOCOL_VERSION_4, NVSP_PROTOCOL_VERSION_5
 495         };
 496         struct nvsp_message *init_packet;
 497         int ndis_version, i, ret;
 498
 499         init_packet = &net_device->channel_init_pkt;
 500
 501         /* Negotiate the latest NVSP protocol supported */
 502         for (i = ARRAY_SIZE(ver_list) - 1; i >= 0; i--)
 503                 if (negotiate_nvsp_ver(device, net_device, init_packet,
 504                                        ver_list[i])  == 0) {
 505                         net_device->nvsp_version = ver_list[i];
 506                         break;
 507                 }
 508
 509         if (i < 0) {
 510                 ret = -EPROTO;
 511                 goto cleanup;
 512         }
 513
 514         pr_debug("Negotiated NVSP version:%x\n", net_device->nvsp_version);
 515
 516         /* Send the ndis version */
 517         memset(init_packet, 0, sizeof(struct nvsp_message));
 518
 519         if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_4)
 520                 ndis_version = 0x00060001;
 521         else
 522                 ndis_version = 0x0006001e;
 523
 524         init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_NDIS_VER;
 525         init_packet->msg.v1_msg.
 526                 send_ndis_ver.ndis_major_ver =
 527                                 (ndis_version & 0xFFFF0000) >> 16;
 528         init_packet->msg.v1_msg.
 529                 send_ndis_ver.ndis_minor_ver =
 530                                 ndis_version & 0xFFFF;
 531
 532         /* Send the init request */
 533         ret = vmbus_sendpacket(device->channel, init_packet,
 534                                 sizeof(struct nvsp_message),
 535                                 (unsigned long)init_packet,
 536                                 VM_PKT_DATA_INBAND, 0);
 537         if (ret != 0)
 538                 goto cleanup;
 539
 540
 541         ret = netvsc_init_buf(device, net_device, device_info);
 542
 543 cleanup:
 544         return ret;
 545 }
 546
 547 static void netvsc_disconnect_vsp(struct hv_device *device)
 548 {
 549         netvsc_destroy_buf(device);
 550 }
 551
 552 /*
 553  * netvsc_device_remove - Callback when the root bus device is removed
 554  */
 555 void netvsc_device_remove(struct hv_device *device)
 556 {
 557         struct net_device *ndev = hv_get_drvdata(device);
 558         struct net_device_context *net_device_ctx = netdev_priv(ndev);
 559         struct netvsc_device *net_device
 560                 = rtnl_dereference(net_device_ctx->nvdev);
 561         int i;
 562
 563         cancel_work_sync(&net_device->subchan_work);
 564
 565         netvsc_disconnect_vsp(device);
 566
 567         RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
 568
 569         /*
 570          * At this point, no one should be accessing net_device
 571          * except in here
 572          */
 573         netdev_dbg(ndev, "net device safe to remove\n");
 574
 575         /* Now, we can close the channel safely */
 576         vmbus_close(device->channel);
 577
 578         /* And dissassociate NAPI context from device */
 579         for (i = 0; i < net_device->num_chn; i++)
 580                 netif_napi_del(&net_device->chan_table[i].napi);
 581
 582         /* Release all resources */
 583         free_netvsc_device_rcu(net_device);
 584 }
 585
 586 #define RING_AVAIL_PERCENT_HIWATER 20
 587 #define RING_AVAIL_PERCENT_LOWATER 10
 588
 589 /*
 590  * Get the percentage of available bytes to write in the ring.
 591  * The return value is in range from 0 to 100.
 592  */
 593 static inline u32 hv_ringbuf_avail_percent(
 594                 struct hv_ring_buffer_info *ring_info)
 595 {
 596         u32 avail_read, avail_write;
 597
 598         hv_get_ringbuffer_availbytes(ring_info, &avail_read, &avail_write);
 599
 600         return avail_write * 100 / ring_info->ring_datasize;
 601 }
 602
 603 static inline void netvsc_free_send_slot(struct netvsc_device *net_device,
 604                                          u32 index)
 605 {
 606         sync_change_bit(index, net_device->send_section_map);
 607 }
 608
 609 static void netvsc_send_tx_complete(struct netvsc_device *net_device,
 610                                     struct vmbus_channel *incoming_channel,
 611                                     struct hv_device *device,
 612                                     const struct vmpacket_descriptor *desc,
 613                                     int budget)
 614 {
 615         struct sk_buff *skb = (struct sk_buff *)(unsigned long)desc->trans_id;
 616         struct net_device *ndev = hv_get_drvdata(device);
 617         struct vmbus_channel *channel = device->channel;
 618         u16 q_idx = 0;
 619         int queue_sends;
 620
 621         /* Notify the layer above us */
 622         if (likely(skb)) {
 623                 const struct hv_netvsc_packet *packet
 624                         = (struct hv_netvsc_packet *)skb->cb;
 625                 u32 send_index = packet->send_buf_index;
 626                 struct netvsc_stats *tx_stats;
 627
 628                 if (send_index != NETVSC_INVALID_INDEX)
 629                         netvsc_free_send_slot(net_device, send_index);
 630                 q_idx = packet->q_idx;
 631                 channel = incoming_channel;
 632
 633                 tx_stats = &net_device->chan_table[q_idx].tx_stats;
 634
 635                 u64_stats_update_begin(&tx_stats->syncp);
 636                 tx_stats->packets += packet->total_packets;
 637                 tx_stats->bytes += packet->total_bytes;
 638                 u64_stats_update_end(&tx_stats->syncp);
 639
 640                 napi_consume_skb(skb, budget);
 641         }
 642
 643         queue_sends =
 644                 atomic_dec_return(&net_device->chan_table[q_idx].queue_sends);
 645
 646         if (net_device->destroy && queue_sends == 0)
 647                 wake_up(&net_device->wait_drain);
 648
 649         if (netif_tx_queue_stopped(netdev_get_tx_queue(ndev, q_idx)) &&
 650             (hv_ringbuf_avail_percent(&channel->outbound) > RING_AVAIL_PERCENT_HIWATER ||
 651              queue_sends < 1))
 652                 netif_tx_wake_queue(netdev_get_tx_queue(ndev, q_idx));
 653 }
 654
 655 static void netvsc_send_completion(struct netvsc_device *net_device,
 656                                    struct vmbus_channel *incoming_channel,
 657                                    struct hv_device *device,
 658                                    const struct vmpacket_descriptor *desc,
 659                                    int budget)
 660 {
 661         struct nvsp_message *nvsp_packet = hv_pkt_data(desc);
 662         struct net_device *ndev = hv_get_drvdata(device);
 663
 664         switch (nvsp_packet->hdr.msg_type) {
 665         case NVSP_MSG_TYPE_INIT_COMPLETE:
 666         case NVSP_MSG1_TYPE_SEND_RECV_BUF_COMPLETE:
 667         case NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE:
 668         case NVSP_MSG5_TYPE_SUBCHANNEL:
 669                 /* Copy the response back */
 670                 memcpy(&net_device->channel_init_pkt, nvsp_packet,
 671                        sizeof(struct nvsp_message));
 672                 complete(&net_device->channel_init_wait);
 673                 break;
 674
 675         case NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE:
 676                 netvsc_send_tx_complete(net_device, incoming_channel,
 677                                         device, desc, budget);
 678                 break;
 679
 680         default:
 681                 netdev_err(ndev,
 682                            "Unknown send completion type %d received!!\n",
 683                            nvsp_packet->hdr.msg_type);
 684         }
 685 }
 686
 687 static u32 netvsc_get_next_send_section(struct netvsc_device *net_device)
 688 {
 689         unsigned long *map_addr = net_device->send_section_map;
 690         unsigned int i;
 691
 692         for_each_clear_bit(i, map_addr, net_device->send_section_cnt) {
 693                 if (sync_test_and_set_bit(i, map_addr) == 0)
 694                         return i;
 695         }
 696
 697         return NETVSC_INVALID_INDEX;
 698 }
 699
 700 static u32 netvsc_copy_to_send_buf(struct netvsc_device *net_device,
 701                                    unsigned int section_index,
 702                                    u32 pend_size,
 703                                    struct hv_netvsc_packet *packet,
 704                                    struct rndis_message *rndis_msg,
 705                                    struct hv_page_buffer *pb,
 706                                    struct sk_buff *skb)
 707 {
 708         char *start = net_device->send_buf;
 709         char *dest = start + (section_index * net_device->send_section_size)
 710                      + pend_size;
 711         int i;
 712         u32 msg_size = 0;
 713         u32 padding = 0;
 714         u32 remain = packet->total_data_buflen % net_device->pkt_align;
 715         u32 page_count = packet->cp_partial ? packet->rmsg_pgcnt :
 716                 packet->page_buf_cnt;
 717
 718         /* Add padding */
 719         if (skb->xmit_more && remain && !packet->cp_partial) {
 720                 padding = net_device->pkt_align - remain;
 721                 rndis_msg->msg_len += padding;
 722                 packet->total_data_buflen += padding;
 723         }
 724
 725         for (i = 0; i < page_count; i++) {
 726                 char *src = phys_to_virt(pb[i].pfn << PAGE_SHIFT);
 727                 u32 offset = pb[i].offset;
 728                 u32 len = pb[i].len;
 729
 730                 memcpy(dest, (src + offset), len);
 731                 msg_size += len;
 732                 dest += len;
 733         }
 734
 735         if (padding) {
 736                 memset(dest, 0, padding);
 737                 msg_size += padding;
 738         }
 739
 740         return msg_size;
 741 }
 742
 743 static inline int netvsc_send_pkt(
 744         struct hv_device *device,
 745         struct hv_netvsc_packet *packet,
 746         struct netvsc_device *net_device,
 747         struct hv_page_buffer *pb,
 748         struct sk_buff *skb)
 749 {
 750         struct nvsp_message nvmsg;
 751         struct nvsp_1_message_send_rndis_packet * const rpkt =
 752                 &nvmsg.msg.v1_msg.send_rndis_pkt;
 753         struct netvsc_channel * const nvchan =
 754                 &net_device->chan_table[packet->q_idx];
 755         struct vmbus_channel *out_channel = nvchan->channel;
 756         struct net_device *ndev = hv_get_drvdata(device);
 757         struct netdev_queue *txq = netdev_get_tx_queue(ndev, packet->q_idx);
 758         u64 req_id;
 759         int ret;
 760         u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound);
 761
 762         nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
 763         if (skb)
 764                 rpkt->channel_type = 0;         /* 0 is RMC_DATA */
 765         else
 766                 rpkt->channel_type = 1;         /* 1 is RMC_CONTROL */
 767
 768         rpkt->send_buf_section_index = packet->send_buf_index;
 769         if (packet->send_buf_index == NETVSC_INVALID_INDEX)
 770                 rpkt->send_buf_section_size = 0;
 771         else
 772                 rpkt->send_buf_section_size = packet->total_data_buflen;
 773
 774         req_id = (ulong)skb;
 775
 776         if (out_channel->rescind)
 777                 return -ENODEV;
 778
 779         if (packet->page_buf_cnt) {
 780                 if (packet->cp_partial)
 781                         pb += packet->rmsg_pgcnt;
 782
 783                 ret = vmbus_sendpacket_pagebuffer(out_channel,
 784                                                   pb, packet->page_buf_cnt,
 785                                                   &nvmsg, sizeof(nvmsg),
 786                                                   req_id);
 787         } else {
 788                 ret = vmbus_sendpacket(out_channel,
 789                                        &nvmsg, sizeof(nvmsg),
 790                                        req_id, VM_PKT_DATA_INBAND,
 791                                        VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 792         }
 793
 794         if (ret == 0) {
 795                 atomic_inc_return(&nvchan->queue_sends);
 796
 797                 if (ring_avail < RING_AVAIL_PERCENT_LOWATER)
 798                         netif_tx_stop_queue(txq);
 799         } else if (ret == -EAGAIN) {
 800                 netif_tx_stop_queue(txq);
 801                 if (atomic_read(&nvchan->queue_sends) < 1) {
 802                         netif_tx_wake_queue(txq);
 803                         ret = -ENOSPC;
 804                 }
 805         } else {
 806                 netdev_err(ndev,
 807                            "Unable to send packet pages %u len %u, ret %d\n",
 808                            packet->page_buf_cnt, packet->total_data_buflen,
 809                            ret);
 810         }
 811
 812         return ret;
 813 }
 814
 815 /* Move packet out of multi send data (msd), and clear msd */
 816 static inline void move_pkt_msd(struct hv_netvsc_packet **msd_send,
 817                                 struct sk_buff **msd_skb,
 818                                 struct multi_send_data *msdp)
 819 {
 820         *msd_skb = msdp->skb;
 821         *msd_send = msdp->pkt;
 822         msdp->skb = NULL;
 823         msdp->pkt = NULL;
 824         msdp->count = 0;
 825 }
 826
 827 /* RCU already held by caller */
 828 int netvsc_send(struct net_device_context *ndev_ctx,
 829                 struct hv_netvsc_packet *packet,
 830                 struct rndis_message *rndis_msg,
 831                 struct hv_page_buffer *pb,
 832                 struct sk_buff *skb)
 833 {
 834         struct netvsc_device *net_device
 835                 = rcu_dereference_bh(ndev_ctx->nvdev);
 836         struct hv_device *device = ndev_ctx->device_ctx;
 837         int ret = 0;
 838         struct netvsc_channel *nvchan;
 839         u32 pktlen = packet->total_data_buflen, msd_len = 0;
 840         unsigned int section_index = NETVSC_INVALID_INDEX;
 841         struct multi_send_data *msdp;
 842         struct hv_netvsc_packet *msd_send = NULL, *cur_send = NULL;
 843         struct sk_buff *msd_skb = NULL;
 844         bool try_batch;
 845         bool xmit_more = (skb != NULL) ? skb->xmit_more : false;
 846
 847         /* If device is rescinded, return error and packet will get dropped. */
 848         if (unlikely(!net_device || net_device->destroy))
 849                 return -ENODEV;
 850
 851         /* We may race with netvsc_connect_vsp()/netvsc_init_buf() and get
 852          * here before the negotiation with the host is finished and
 853          * send_section_map may not be allocated yet.
 854          */
 855         if (unlikely(!net_device->send_section_map))
 856                 return -EAGAIN;
 857
 858         nvchan = &net_device->chan_table[packet->q_idx];
 859         packet->send_buf_index = NETVSC_INVALID_INDEX;
 860         packet->cp_partial = false;
 861
 862         /* Send control message directly without accessing msd (Multi-Send
 863          * Data) field which may be changed during data packet processing.
 864          */
 865         if (!skb) {
 866                 cur_send = packet;
 867                 goto send_now;
 868         }
 869
 870         /* batch packets in send buffer if possible */
 871         msdp = &nvchan->msd;
 872         if (msdp->pkt)
 873                 msd_len = msdp->pkt->total_data_buflen;
 874
 875         try_batch =  msd_len > 0 && msdp->count < net_device->max_pkt;
 876         if (try_batch && msd_len + pktlen + net_device->pkt_align <
 877             net_device->send_section_size) {
 878                 section_index = msdp->pkt->send_buf_index;
 879
 880         } else if (try_batch && msd_len + packet->rmsg_size <
 881                    net_device->send_section_size) {
 882                 section_index = msdp->pkt->send_buf_index;
 883                 packet->cp_partial = true;
 884
 885         } else if (pktlen + net_device->pkt_align <
 886                    net_device->send_section_size) {
 887                 section_index = netvsc_get_next_send_section(net_device);
 888                 if (unlikely(section_index == NETVSC_INVALID_INDEX)) {
 889                         ++ndev_ctx->eth_stats.tx_send_full;
 890                 } else {
 891                         move_pkt_msd(&msd_send, &msd_skb, msdp);
 892                         msd_len = 0;
 893                 }
 894         }
 895
 896         if (section_index != NETVSC_INVALID_INDEX) {
 897                 netvsc_copy_to_send_buf(net_device,
 898                                         section_index, msd_len,
 899                                         packet, rndis_msg, pb, skb);
 900
 901                 packet->send_buf_index = section_index;
 902
 903                 if (packet->cp_partial) {
 904                         packet->page_buf_cnt -= packet->rmsg_pgcnt;
 905                         packet->total_data_buflen = msd_len + packet->rmsg_size;
 906                 } else {
 907                         packet->page_buf_cnt = 0;
 908                         packet->total_data_buflen += msd_len;
 909                 }
 910
 911                 if (msdp->pkt) {
 912                         packet->total_packets += msdp->pkt->total_packets;
 913                         packet->total_bytes += msdp->pkt->total_bytes;
 914                 }
 915
 916                 if (msdp->skb)
 917                         dev_consume_skb_any(msdp->skb);
 918
 919                 if (xmit_more && !packet->cp_partial) {
 920                         msdp->skb = skb;
 921                         msdp->pkt = packet;
 922                         msdp->count++;
 923                 } else {
 924                         cur_send = packet;
 925                         msdp->skb = NULL;
 926                         msdp->pkt = NULL;
 927                         msdp->count = 0;
 928                 }
 929         } else {
 930                 move_pkt_msd(&msd_send, &msd_skb, msdp);
 931                 cur_send = packet;
 932         }
 933
 934         if (msd_send) {
 935                 int m_ret = netvsc_send_pkt(device, msd_send, net_device,
 936                                             NULL, msd_skb);
 937
 938                 if (m_ret != 0) {
 939                         netvsc_free_send_slot(net_device,
 940                                               msd_send->send_buf_index);
 941                         dev_kfree_skb_any(msd_skb);
 942                 }
 943         }
 944
 945 send_now:
 946         if (cur_send)
 947                 ret = netvsc_send_pkt(device, cur_send, net_device, pb, skb);
 948
 949         if (ret != 0 && section_index != NETVSC_INVALID_INDEX)
 950                 netvsc_free_send_slot(net_device, section_index);
 951
 952         return ret;
 953 }
 954
 955 /* Send pending recv completions */
 956 static int send_recv_completions(struct net_device *ndev,
 957                                  struct netvsc_device *nvdev,
 958                                  struct netvsc_channel *nvchan)
 959 {
 960         struct multi_recv_comp *mrc = &nvchan->mrc;
 961         struct recv_comp_msg {
 962                 struct nvsp_message_header hdr;
 963                 u32 status;
 964         }  __packed;
 965         struct recv_comp_msg msg = {
 966                 .hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE,
 967         };
 968         int ret;
 969
 970         while (mrc->first != mrc->next) {
 971                 const struct recv_comp_data *rcd
 972                         = mrc->slots + mrc->first;
 973
 974                 msg.status = rcd->status;
 975                 ret = vmbus_sendpacket(nvchan->channel, &msg, sizeof(msg),
 976                                        rcd->tid, VM_PKT_COMP, 0);
 977                 if (unlikely(ret)) {
 978                         struct net_device_context *ndev_ctx = netdev_priv(ndev);
 979
 980                         ++ndev_ctx->eth_stats.rx_comp_busy;
 981                         return ret;
 982                 }
 983
 984                 if (++mrc->first == nvdev->recv_completion_cnt)
 985                         mrc->first = 0;
 986         }
 987
 988         /* receive completion ring has been emptied */
 989         if (unlikely(nvdev->destroy))
 990                 wake_up(&nvdev->wait_drain);
 991
 992         return 0;
 993 }
 994
 995 /* Count how many receive completions are outstanding */
 996 static void recv_comp_slot_avail(const struct netvsc_device *nvdev,
 997                                  const struct multi_recv_comp *mrc,
 998                                  u32 *filled, u32 *avail)
 999 {
1000         u32 count = nvdev->recv_completion_cnt;
1001
1002         if (mrc->next >= mrc->first)
1003                 *filled = mrc->next - mrc->first;
1004         else
1005                 *filled = (count - mrc->first) + mrc->next;
1006
1007         *avail = count - *filled - 1;
1008 }
1009
1010 /* Add receive complete to ring to send to host. */
1011 static void enq_receive_complete(struct net_device *ndev,
1012                                  struct netvsc_device *nvdev, u16 q_idx,
1013                                  u64 tid, u32 status)
1014 {
1015         struct netvsc_channel *nvchan = &nvdev->chan_table[q_idx];
1016         struct multi_recv_comp *mrc = &nvchan->mrc;
1017         struct recv_comp_data *rcd;
1018         u32 filled, avail;
1019
1020         recv_comp_slot_avail(nvdev, mrc, &filled, &avail);
1021
1022         if (unlikely(filled > NAPI_POLL_WEIGHT)) {
1023                 send_recv_completions(ndev, nvdev, nvchan);
1024                 recv_comp_slot_avail(nvdev, mrc, &filled, &avail);
1025         }
1026
1027         if (unlikely(!avail)) {
1028                 netdev_err(ndev, "Recv_comp full buf q:%hd, tid:%llx\n",
1029                            q_idx, tid);
1030                 return;
1031         }
1032
1033         rcd = mrc->slots + mrc->next;
1034         rcd->tid = tid;
1035         rcd->status = status;
1036
1037         if (++mrc->next == nvdev->recv_completion_cnt)
1038                 mrc->next = 0;
1039 }
1040
1041 static int netvsc_receive(struct net_device *ndev,
1042                           struct netvsc_device *net_device,
1043                           struct net_device_context *net_device_ctx,
1044                           struct hv_device *device,
1045                           struct vmbus_channel *channel,
1046                           const struct vmpacket_descriptor *desc,
1047                           struct nvsp_message *nvsp)
1048 {
1049         const struct vmtransfer_page_packet_header *vmxferpage_packet
1050                 = container_of(desc, const struct vmtransfer_page_packet_header, d);
1051         u16 q_idx = channel->offermsg.offer.sub_channel_index;
1052         char *recv_buf = net_device->recv_buf;
1053         u32 status = NVSP_STAT_SUCCESS;
1054         int i;
1055         int count = 0;
1056
1057         /* Make sure this is a valid nvsp packet */
1058         if (unlikely(nvsp->hdr.msg_type != NVSP_MSG1_TYPE_SEND_RNDIS_PKT)) {
1059                 netif_err(net_device_ctx, rx_err, ndev,
1060                           "Unknown nvsp packet type received %u\n",
1061                           nvsp->hdr.msg_type);
1062                 return 0;
1063         }
1064
1065         if (unlikely(vmxferpage_packet->xfer_pageset_id != NETVSC_RECEIVE_BUFFER_ID)) {
1066                 netif_err(net_device_ctx, rx_err, ndev,
1067                           "Invalid xfer page set id - expecting %x got %x\n",
1068                           NETVSC_RECEIVE_BUFFER_ID,
1069                           vmxferpage_packet->xfer_pageset_id);
1070                 return 0;
1071         }
1072
1073         count = vmxferpage_packet->range_cnt;
1074
1075         /* Each range represents 1 RNDIS pkt that contains 1 ethernet frame */
1076         for (i = 0; i < count; i++) {
1077                 void *data = recv_buf
1078                         + vmxferpage_packet->ranges[i].byte_offset;
1079                 u32 buflen = vmxferpage_packet->ranges[i].byte_count;
1080
1081                 /* Pass it to the upper layer */
1082                 status = rndis_filter_receive(ndev, net_device, device,
1083                                               channel, data, buflen);
1084         }
1085
1086         enq_receive_complete(ndev, net_device, q_idx,
1087                              vmxferpage_packet->d.trans_id, status);
1088
1089         return count;
1090 }
1091
1092 static void netvsc_send_table(struct hv_device *hdev,
1093                               struct nvsp_message *nvmsg)
1094 {
1095         struct net_device *ndev = hv_get_drvdata(hdev);
1096         struct net_device_context *net_device_ctx = netdev_priv(ndev);
1097         int i;
1098         u32 count, *tab;
1099
1100         count = nvmsg->msg.v5_msg.send_table.count;
1101         if (count != VRSS_SEND_TAB_SIZE) {
1102                 netdev_err(ndev, "Received wrong send-table size:%u\n", count);
1103                 return;
1104         }
1105
1106         tab = (u32 *)((unsigned long)&nvmsg->msg.v5_msg.send_table +
1107                       nvmsg->msg.v5_msg.send_table.offset);
1108
1109         for (i = 0; i < count; i++)
1110                 net_device_ctx->tx_send_table[i] = tab[i];
1111 }
1112
1113 static void netvsc_send_vf(struct net_device_context *net_device_ctx,
1114                            struct nvsp_message *nvmsg)
1115 {
1116         net_device_ctx->vf_alloc = nvmsg->msg.v4_msg.vf_assoc.allocated;
1117         net_device_ctx->vf_serial = nvmsg->msg.v4_msg.vf_assoc.serial;
1118 }
1119
1120 static inline void netvsc_receive_inband(struct hv_device *hdev,
1121                                  struct net_device_context *net_device_ctx,
1122                                  struct nvsp_message *nvmsg)
1123 {
1124         switch (nvmsg->hdr.msg_type) {
1125         case NVSP_MSG5_TYPE_SEND_INDIRECTION_TABLE:
1126                 netvsc_send_table(hdev, nvmsg);
1127                 break;
1128
1129         case NVSP_MSG4_TYPE_SEND_VF_ASSOCIATION:
1130                 netvsc_send_vf(net_device_ctx, nvmsg);
1131                 break;
1132         }
1133 }
1134
1135 static int netvsc_process_raw_pkt(struct hv_device *device,
1136                                   struct vmbus_channel *channel,
1137                                   struct netvsc_device *net_device,
1138                                   struct net_device *ndev,
1139                                   const struct vmpacket_descriptor *desc,
1140                                   int budget)
1141 {
1142         struct net_device_context *net_device_ctx = netdev_priv(ndev);
1143         struct nvsp_message *nvmsg = hv_pkt_data(desc);
1144
1145         switch (desc->type) {
1146         case VM_PKT_COMP:
1147                 netvsc_send_completion(net_device, channel, device,
1148                                        desc, budget);
1149                 break;
1150
1151         case VM_PKT_DATA_USING_XFER_PAGES:
1152                 return netvsc_receive(ndev, net_device, net_device_ctx,
1153                                       device, channel, desc, nvmsg);
1154                 break;
1155
1156         case VM_PKT_DATA_INBAND:
1157                 netvsc_receive_inband(device, net_device_ctx, nvmsg);
1158                 break;
1159
1160         default:
1161                 netdev_err(ndev, "unhandled packet type %d, tid %llx\n",
1162                            desc->type, desc->trans_id);
1163                 break;
1164         }
1165
1166         return 0;
1167 }
1168
1169 static struct hv_device *netvsc_channel_to_device(struct vmbus_channel *channel)
1170 {
1171         struct vmbus_channel *primary = channel->primary_channel;
1172
1173         return primary ? primary->device_obj : channel->device_obj;
1174 }
1175
1176 /* Network processing softirq
1177  * Process data in incoming ring buffer from host
1178  * Stops when ring is empty or budget is met or exceeded.
1179  */
1180 int netvsc_poll(struct napi_struct *napi, int budget)
1181 {
1182         struct netvsc_channel *nvchan
1183                 = container_of(napi, struct netvsc_channel, napi);
1184         struct netvsc_device *net_device = nvchan->net_device;
1185         struct vmbus_channel *channel = nvchan->channel;
1186         struct hv_device *device = netvsc_channel_to_device(channel);
1187         struct net_device *ndev = hv_get_drvdata(device);
1188         int work_done = 0;
1189
1190         /* If starting a new interval */
1191         if (!nvchan->desc)
1192                 nvchan->desc = hv_pkt_iter_first(channel);
1193
1194         while (nvchan->desc && work_done < budget) {
1195                 work_done += netvsc_process_raw_pkt(device, channel, net_device,
1196                                                     ndev, nvchan->desc, budget);
1197                 nvchan->desc = hv_pkt_iter_next(channel, nvchan->desc);
1198         }
1199
1200         /* If send of pending receive completions suceeded
1201          *   and did not exhaust NAPI budget this time
1202          *   and not doing busy poll
1203          * then re-enable host interrupts
1204          *     and reschedule if ring is not empty.
1205          */
1206         if (send_recv_completions(ndev, net_device, nvchan) == 0 &&
1207             work_done < budget &&
1208             napi_complete_done(napi, work_done) &&
1209             hv_end_read(&channel->inbound)) {
1210                 hv_begin_read(&channel->inbound);
1211                 napi_reschedule(napi);
1212         }
1213
1214         /* Driver may overshoot since multiple packets per descriptor */
1215         return min(work_done, budget);
1216 }
1217
1218 /* Call back when data is available in host ring buffer.
1219  * Processing is deferred until network softirq (NAPI)
1220  */
1221 void netvsc_channel_cb(void *context)
1222 {
1223         struct netvsc_channel *nvchan = context;
1224         struct vmbus_channel *channel = nvchan->channel;
1225         struct hv_ring_buffer_info *rbi = &channel->inbound;
1226
1227         /* preload first vmpacket descriptor */
1228         prefetch(hv_get_ring_buffer(rbi) + rbi->priv_read_index);
1229
1230         if (napi_schedule_prep(&nvchan->napi)) {
1231                 /* disable interupts from host */
1232                 hv_begin_read(rbi);
1233
1234                 __napi_schedule(&nvchan->napi);
1235         }
1236 }
1237
1238 /*
1239  * netvsc_device_add - Callback when the device belonging to this
1240  * driver is added
1241  */
1242 struct netvsc_device *netvsc_device_add(struct hv_device *device,
1243                                 const struct netvsc_device_info *device_info)
1244 {
1245         int i, ret = 0;
1246         int ring_size = device_info->ring_size;
1247         struct netvsc_device *net_device;
1248         struct net_device *ndev = hv_get_drvdata(device);
1249         struct net_device_context *net_device_ctx = netdev_priv(ndev);
1250
1251         net_device = alloc_net_device();
1252         if (!net_device)
1253                 return ERR_PTR(-ENOMEM);
1254
1255         net_device->ring_size = ring_size;
1256
1257         /* Because the device uses NAPI, all the interrupt batching and
1258          * control is done via Net softirq, not the channel handling
1259          */
1260         set_channel_read_mode(device->channel, HV_CALL_ISR);
1261
1262         /* If we're reopening the device we may have multiple queues, fill the
1263          * chn_table with the default channel to use it before subchannels are
1264          * opened.
1265          * Initialize the channel state before we open;
1266          * we can be interrupted as soon as we open the channel.
1267          */
1268
1269         for (i = 0; i < VRSS_CHANNEL_MAX; i++) {
1270                 struct netvsc_channel *nvchan = &net_device->chan_table[i];
1271
1272                 nvchan->channel = device->channel;
1273                 nvchan->net_device = net_device;
1274                 u64_stats_init(&nvchan->tx_stats.syncp);
1275                 u64_stats_init(&nvchan->rx_stats.syncp);
1276         }
1277
1278         /* Enable NAPI handler before init callbacks */
1279         netif_napi_add(ndev, &net_device->chan_table[0].napi,
1280                        netvsc_poll, NAPI_POLL_WEIGHT);
1281
1282         /* Open the channel */
1283         ret = vmbus_open(device->channel, ring_size * PAGE_SIZE,
1284                          ring_size * PAGE_SIZE, NULL, 0,
1285                          netvsc_channel_cb,
1286                          net_device->chan_table);
1287
1288         if (ret != 0) {
1289                 netif_napi_del(&net_device->chan_table[0].napi);
1290                 netdev_err(ndev, "unable to open channel: %d\n", ret);
1291                 goto cleanup;
1292         }
1293
1294         /* Channel is opened */
1295         netdev_dbg(ndev, "hv_netvsc channel opened successfully\n");
1296
1297         napi_enable(&net_device->chan_table[0].napi);
1298
1299         /* Writing nvdev pointer unlocks netvsc_send(), make sure chn_table is
1300          * populated.
1301          */
1302         rcu_assign_pointer(net_device_ctx->nvdev, net_device);
1303
1304         /* Connect with the NetVsp */
1305         ret = netvsc_connect_vsp(device, net_device, device_info);
1306         if (ret != 0) {
1307                 netdev_err(ndev,
1308                         "unable to connect to NetVSP - %d\n", ret);
1309                 goto close;
1310         }
1311
1312         return net_device;
1313
1314 close:
1315         RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
1316         napi_disable(&net_device->chan_table[0].napi);
1317
1318         /* Now, we can close the channel safely */
1319         vmbus_close(device->channel);
1320
1321 cleanup:
1322         free_netvsc_device(&net_device->rcu);
1323
1324         return ERR_PTR(ret);
1325 }