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 135                 /* If the failure is because the channel is rescinded;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