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 <asm/sync_bitops.h>
  33
  34 #include "hyperv_net.h"
  35
  36 /*
  37  * Switch the data path from the synthetic interface to the VF
  38  * interface.
  39  */
  40 void netvsc_switch_datapath(struct net_device *ndev, bool vf)
  41 {
  42         struct net_device_context *net_device_ctx = netdev_priv(ndev);
  43         struct hv_device *dev = net_device_ctx->device_ctx;
  44         struct netvsc_device *nv_dev = net_device_ctx->nvdev;
  45         struct nvsp_message *init_pkt = &nv_dev->channel_init_pkt;
  46
  47         memset(init_pkt, 0, sizeof(struct nvsp_message));
  48         init_pkt->hdr.msg_type = NVSP_MSG4_TYPE_SWITCH_DATA_PATH;
  49         if (vf)
  50                 init_pkt->msg.v4_msg.active_dp.active_datapath =
  51                         NVSP_DATAPATH_VF;
  52         else
  53                 init_pkt->msg.v4_msg.active_dp.active_datapath =
  54                         NVSP_DATAPATH_SYNTHETIC;
  55
  56         vmbus_sendpacket(dev->channel, init_pkt,
  57                                sizeof(struct nvsp_message),
  58                                (unsigned long)init_pkt,
  59                                VM_PKT_DATA_INBAND, 0);
  60 }
  61
  62
  63 static struct netvsc_device *alloc_net_device(void)
  64 {
  65         struct netvsc_device *net_device;
  66
  67         net_device = kzalloc(sizeof(struct netvsc_device), GFP_KERNEL);
  68         if (!net_device)
  69                 return NULL;
  70
  71         net_device->cb_buffer = kzalloc(NETVSC_PACKET_SIZE, GFP_KERNEL);
  72         if (!net_device->cb_buffer) {
  73                 kfree(net_device);
  74                 return NULL;
  75         }
  76
  77         init_waitqueue_head(&net_device->wait_drain);
  78         net_device->destroy = false;
  79         atomic_set(&net_device->open_cnt, 0);
  80         atomic_set(&net_device->vf_use_cnt, 0);
  81         net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
  82         net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;
  83
  84         net_device->vf_netdev = NULL;
  85         net_device->vf_inject = false;
  86
  87         return net_device;
  88 }
  89
  90 static void free_netvsc_device(struct netvsc_device *nvdev)
  91 {
  92         kfree(nvdev->cb_buffer);
  93         kfree(nvdev);
  94 }
  95
  96 static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
  97 {
  98         struct netvsc_device *net_device = hv_device_to_netvsc_device(device);
  99
 100         if (net_device && net_device->destroy)
 101                 net_device = NULL;
 102
 103         return net_device;
 104 }
 105
 106 static struct netvsc_device *get_inbound_net_device(struct hv_device *device)
 107 {
 108         struct netvsc_device *net_device = hv_device_to_netvsc_device(device);
 109
 110         if (!net_device)
 111                 goto get_in_err;
 112
 113         if (net_device->destroy &&
 114                 atomic_read(&net_device->num_outstanding_sends) == 0)
 115                 net_device = NULL;
 116
 117 get_in_err:
 118         return net_device;
 119 }
 120
 121
 122 static int netvsc_destroy_buf(struct hv_device *device)
 123 {
 124         struct nvsp_message *revoke_packet;
 125         int ret = 0;
 126         struct net_device *ndev = hv_get_drvdata(device);
 127         struct netvsc_device *net_device = net_device_to_netvsc_device(ndev);
 128
 129         /*
 130          * If we got a section count, it means we received a
 131          * SendReceiveBufferComplete msg (ie sent
 132          * NvspMessage1TypeSendReceiveBuffer msg) therefore, we need
 133          * to send a revoke msg here
 134          */
 135         if (net_device->recv_section_cnt) {
 136                 /* Send the revoke receive buffer */
 137                 revoke_packet = &net_device->revoke_packet;
 138                 memset(revoke_packet, 0, sizeof(struct nvsp_message));
 139
 140                 revoke_packet->hdr.msg_type =
 141                         NVSP_MSG1_TYPE_REVOKE_RECV_BUF;
 142                 revoke_packet->msg.v1_msg.
 143                 revoke_recv_buf.id = NETVSC_RECEIVE_BUFFER_ID;
 144
 145                 ret = vmbus_sendpacket(device->channel,
 146                                        revoke_packet,
 147                                        sizeof(struct nvsp_message),
 148                                        (unsigned long)revoke_packet,
 149                                        VM_PKT_DATA_INBAND, 0);
 150                 /*
 151                  * If we failed here, we might as well return and
 152                  * have a leak rather than continue and a bugchk
 153                  */
 154                 if (ret != 0) {
 155                         netdev_err(ndev, "unable to send "
 156                                 "revoke receive buffer to netvsp\n");
 157                         return ret;
 158                 }
 159         }
 160
 161         /* Teardown the gpadl on the vsp end */
 162         if (net_device->recv_buf_gpadl_handle) {
 163                 ret = vmbus_teardown_gpadl(device->channel,
 164                                            net_device->recv_buf_gpadl_handle);
 165
 166                 /* If we failed here, we might as well return and have a leak
 167                  * rather than continue and a bugchk
 168                  */
 169                 if (ret != 0) {
 170                         netdev_err(ndev,
 171                                    "unable to teardown receive buffer's gpadl\n");
 172                         return ret;
 173                 }
 174                 net_device->recv_buf_gpadl_handle = 0;
 175         }
 176
 177         if (net_device->recv_buf) {
 178                 /* Free up the receive buffer */
 179                 vfree(net_device->recv_buf);
 180                 net_device->recv_buf = NULL;
 181         }
 182
 183         if (net_device->recv_section) {
 184                 net_device->recv_section_cnt = 0;
 185                 kfree(net_device->recv_section);
 186                 net_device->recv_section = NULL;
 187         }
 188
 189         /* Deal with the send buffer we may have setup.
 190          * If we got a  send section size, it means we received a
 191          * NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE msg (ie sent
 192          * NVSP_MSG1_TYPE_SEND_SEND_BUF msg) therefore, we need
 193          * to send a revoke msg here
 194          */
 195         if (net_device->send_section_size) {
 196                 /* Send the revoke receive buffer */
 197                 revoke_packet = &net_device->revoke_packet;
 198                 memset(revoke_packet, 0, sizeof(struct nvsp_message));
 199
 200                 revoke_packet->hdr.msg_type =
 201                         NVSP_MSG1_TYPE_REVOKE_SEND_BUF;
 202                 revoke_packet->msg.v1_msg.revoke_send_buf.id =
 203                         NETVSC_SEND_BUFFER_ID;
 204
 205                 ret = vmbus_sendpacket(device->channel,
 206                                        revoke_packet,
 207                                        sizeof(struct nvsp_message),
 208                                        (unsigned long)revoke_packet,
 209                                        VM_PKT_DATA_INBAND, 0);
 210                 /* If we failed here, we might as well return and
 211                  * have a leak rather than continue and a bugchk
 212                  */
 213                 if (ret != 0) {
 214                         netdev_err(ndev, "unable to send "
 215                                    "revoke send buffer to netvsp\n");
 216                         return ret;
 217                 }
 218         }
 219         /* Teardown the gpadl on the vsp end */
 220         if (net_device->send_buf_gpadl_handle) {
 221                 ret = vmbus_teardown_gpadl(device->channel,
 222                                            net_device->send_buf_gpadl_handle);
 223
 224                 /* If we failed here, we might as well return and have a leak
 225                  * rather than continue and a bugchk
 226                  */
 227                 if (ret != 0) {
 228                         netdev_err(ndev,
 229                                    "unable to teardown send buffer's gpadl\n");
 230                         return ret;
 231                 }
 232                 net_device->send_buf_gpadl_handle = 0;
 233         }
 234         if (net_device->send_buf) {
 235                 /* Free up the send buffer */
 236                 vfree(net_device->send_buf);
 237                 net_device->send_buf = NULL;
 238         }
 239         kfree(net_device->send_section_map);
 240
 241         return ret;
 242 }
 243
 244 static int netvsc_init_buf(struct hv_device *device)
 245 {
 246         int ret = 0;
 247         struct netvsc_device *net_device;
 248         struct nvsp_message *init_packet;
 249         struct net_device *ndev;
 250         int node;
 251
 252         net_device = get_outbound_net_device(device);
 253         if (!net_device)
 254                 return -ENODEV;
 255         ndev = hv_get_drvdata(device);
 256
 257         node = cpu_to_node(device->channel->target_cpu);
 258         net_device->recv_buf = vzalloc_node(net_device->recv_buf_size, node);
 259         if (!net_device->recv_buf)
 260                 net_device->recv_buf = vzalloc(net_device->recv_buf_size);
 261
 262         if (!net_device->recv_buf) {
 263                 netdev_err(ndev, "unable to allocate receive "
 264                         "buffer of size %d\n", net_device->recv_buf_size);
 265                 ret = -ENOMEM;
 266                 goto cleanup;
 267         }
 268
 269         /*
 270          * Establish the gpadl handle for this buffer on this
 271          * channel.  Note: This call uses the vmbus connection rather
 272          * than the channel to establish the gpadl handle.
 273          */
 274         ret = vmbus_establish_gpadl(device->channel, net_device->recv_buf,
 275                                     net_device->recv_buf_size,
 276                                     &net_device->recv_buf_gpadl_handle);
 277         if (ret != 0) {
 278                 netdev_err(ndev,
 279                         "unable to establish receive buffer's gpadl\n");
 280                 goto cleanup;
 281         }
 282
 283
 284         /* Notify the NetVsp of the gpadl handle */
 285         init_packet = &net_device->channel_init_pkt;
 286
 287         memset(init_packet, 0, sizeof(struct nvsp_message));
 288
 289         init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_RECV_BUF;
 290         init_packet->msg.v1_msg.send_recv_buf.
 291                 gpadl_handle = net_device->recv_buf_gpadl_handle;
 292         init_packet->msg.v1_msg.
 293                 send_recv_buf.id = NETVSC_RECEIVE_BUFFER_ID;
 294
 295         /* Send the gpadl notification request */
 296         ret = vmbus_sendpacket(device->channel, init_packet,
 297                                sizeof(struct nvsp_message),
 298                                (unsigned long)init_packet,
 299                                VM_PKT_DATA_INBAND,
 300                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 301         if (ret != 0) {
 302                 netdev_err(ndev,
 303                         "unable to send receive buffer's gpadl to netvsp\n");
 304                 goto cleanup;
 305         }
 306
 307         wait_for_completion(&net_device->channel_init_wait);
 308
 309         /* Check the response */
 310         if (init_packet->msg.v1_msg.
 311             send_recv_buf_complete.status != NVSP_STAT_SUCCESS) {
 312                 netdev_err(ndev, "Unable to complete receive buffer "
 313                            "initialization with NetVsp - status %d\n",
 314                            init_packet->msg.v1_msg.
 315                            send_recv_buf_complete.status);
 316                 ret = -EINVAL;
 317                 goto cleanup;
 318         }
 319
 320         /* Parse the response */
 321
 322         net_device->recv_section_cnt = init_packet->msg.
 323                 v1_msg.send_recv_buf_complete.num_sections;
 324
 325         net_device->recv_section = kmemdup(
 326                 init_packet->msg.v1_msg.send_recv_buf_complete.sections,
 327                 net_device->recv_section_cnt *
 328                 sizeof(struct nvsp_1_receive_buffer_section),
 329                 GFP_KERNEL);
 330         if (net_device->recv_section == NULL) {
 331                 ret = -EINVAL;
 332                 goto cleanup;
 333         }
 334
 335         /*
 336          * For 1st release, there should only be 1 section that represents the
 337          * entire receive buffer
 338          */
 339         if (net_device->recv_section_cnt != 1 ||
 340             net_device->recv_section->offset != 0) {
 341                 ret = -EINVAL;
 342                 goto cleanup;
 343         }
 344
 345         /* Now setup the send buffer.
 346          */
 347         net_device->send_buf = vzalloc_node(net_device->send_buf_size, node);
 348         if (!net_device->send_buf)
 349                 net_device->send_buf = vzalloc(net_device->send_buf_size);
 350         if (!net_device->send_buf) {
 351                 netdev_err(ndev, "unable to allocate send "
 352                            "buffer of size %d\n", net_device->send_buf_size);
 353                 ret = -ENOMEM;
 354                 goto cleanup;
 355         }
 356
 357         /* Establish the gpadl handle for this buffer on this
 358          * channel.  Note: This call uses the vmbus connection rather
 359          * than the channel to establish the gpadl handle.
 360          */
 361         ret = vmbus_establish_gpadl(device->channel, net_device->send_buf,
 362                                     net_device->send_buf_size,
 363                                     &net_device->send_buf_gpadl_handle);
 364         if (ret != 0) {
 365                 netdev_err(ndev,
 366                            "unable to establish send buffer's gpadl\n");
 367                 goto cleanup;
 368         }
 369
 370         /* Notify the NetVsp of the gpadl handle */
 371         init_packet = &net_device->channel_init_pkt;
 372         memset(init_packet, 0, sizeof(struct nvsp_message));
 373         init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_SEND_BUF;
 374         init_packet->msg.v1_msg.send_send_buf.gpadl_handle =
 375                 net_device->send_buf_gpadl_handle;
 376         init_packet->msg.v1_msg.send_send_buf.id = NETVSC_SEND_BUFFER_ID;
 377
 378         /* Send the gpadl notification request */
 379         ret = vmbus_sendpacket(device->channel, init_packet,
 380                                sizeof(struct nvsp_message),
 381                                (unsigned long)init_packet,
 382                                VM_PKT_DATA_INBAND,
 383                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 384         if (ret != 0) {
 385                 netdev_err(ndev,
 386                            "unable to send send buffer's gpadl to netvsp\n");
 387                 goto cleanup;
 388         }
 389
 390         wait_for_completion(&net_device->channel_init_wait);
 391
 392         /* Check the response */
 393         if (init_packet->msg.v1_msg.
 394             send_send_buf_complete.status != NVSP_STAT_SUCCESS) {
 395                 netdev_err(ndev, "Unable to complete send buffer "
 396                            "initialization with NetVsp - status %d\n",
 397                            init_packet->msg.v1_msg.
 398                            send_send_buf_complete.status);
 399                 ret = -EINVAL;
 400                 goto cleanup;
 401         }
 402
 403         /* Parse the response */
 404         net_device->send_section_size = init_packet->msg.
 405                                 v1_msg.send_send_buf_complete.section_size;
 406
 407         /* Section count is simply the size divided by the section size.
 408          */
 409         net_device->send_section_cnt =
 410                 net_device->send_buf_size/net_device->send_section_size;
 411
 412         dev_info(&device->device, "Send section size: %d, Section count:%d\n",
 413                  net_device->send_section_size, net_device->send_section_cnt);
 414
 415         /* Setup state for managing the send buffer. */
 416         net_device->map_words = DIV_ROUND_UP(net_device->send_section_cnt,
 417                                              BITS_PER_LONG);
 418
 419         net_device->send_section_map =
 420                 kzalloc(net_device->map_words * sizeof(ulong), GFP_KERNEL);
 421         if (net_device->send_section_map == NULL) {
 422                 ret = -ENOMEM;
 423                 goto cleanup;
 424         }
 425
 426         goto exit;
 427
 428 cleanup:
 429         netvsc_destroy_buf(device);
 430
 431 exit:
 432         return ret;
 433 }
 434
 435
 436 /* Negotiate NVSP protocol version */
 437 static int negotiate_nvsp_ver(struct hv_device *device,
 438                               struct netvsc_device *net_device,
 439                               struct nvsp_message *init_packet,
 440                               u32 nvsp_ver)
 441 {
 442         struct net_device *ndev = hv_get_drvdata(device);
 443         int ret;
 444
 445         memset(init_packet, 0, sizeof(struct nvsp_message));
 446         init_packet->hdr.msg_type = NVSP_MSG_TYPE_INIT;
 447         init_packet->msg.init_msg.init.min_protocol_ver = nvsp_ver;
 448         init_packet->msg.init_msg.init.max_protocol_ver = nvsp_ver;
 449
 450         /* Send the init request */
 451         ret = vmbus_sendpacket(device->channel, init_packet,
 452                                sizeof(struct nvsp_message),
 453                                (unsigned long)init_packet,
 454                                VM_PKT_DATA_INBAND,
 455                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 456
 457         if (ret != 0)
 458                 return ret;
 459
 460         wait_for_completion(&net_device->channel_init_wait);
 461
 462         if (init_packet->msg.init_msg.init_complete.status !=
 463             NVSP_STAT_SUCCESS)
 464                 return -EINVAL;
 465
 466         if (nvsp_ver == NVSP_PROTOCOL_VERSION_1)
 467                 return 0;
 468
 469         /* NVSPv2 or later: Send NDIS config */
 470         memset(init_packet, 0, sizeof(struct nvsp_message));
 471         init_packet->hdr.msg_type = NVSP_MSG2_TYPE_SEND_NDIS_CONFIG;
 472         init_packet->msg.v2_msg.send_ndis_config.mtu = ndev->mtu + ETH_HLEN;
 473         init_packet->msg.v2_msg.send_ndis_config.capability.ieee8021q = 1;
 474
 475         if (nvsp_ver >= NVSP_PROTOCOL_VERSION_5) {
 476                 init_packet->msg.v2_msg.send_ndis_config.capability.sriov = 1;
 477
 478                 /* Teaming bit is needed to receive link speed updates */
 479                 init_packet->msg.v2_msg.send_ndis_config.capability.teaming = 1;
 480         }
 481
 482         ret = vmbus_sendpacket(device->channel, init_packet,
 483                                 sizeof(struct nvsp_message),
 484                                 (unsigned long)init_packet,
 485                                 VM_PKT_DATA_INBAND, 0);
 486
 487         return ret;
 488 }
 489
 490 static int netvsc_connect_vsp(struct hv_device *device)
 491 {
 492         int ret;
 493         struct netvsc_device *net_device;
 494         struct nvsp_message *init_packet;
 495         int ndis_version;
 496         u32 ver_list[] = { NVSP_PROTOCOL_VERSION_1, NVSP_PROTOCOL_VERSION_2,
 497                 NVSP_PROTOCOL_VERSION_4, NVSP_PROTOCOL_VERSION_5 };
 498         int i, num_ver = 4; /* number of different NVSP versions */
 499
 500         net_device = get_outbound_net_device(device);
 501         if (!net_device)
 502                 return -ENODEV;
 503
 504         init_packet = &net_device->channel_init_pkt;
 505
 506         /* Negotiate the latest NVSP protocol supported */
 507         for (i = num_ver - 1; i >= 0; i--)
 508                 if (negotiate_nvsp_ver(device, net_device, init_packet,
 509                                        ver_list[i])  == 0) {
 510                         net_device->nvsp_version = ver_list[i];
 511                         break;
 512                 }
 513
 514         if (i < 0) {
 515                 ret = -EPROTO;
 516                 goto cleanup;
 517         }
 518
 519         pr_debug("Negotiated NVSP version:%x\n", net_device->nvsp_version);
 520
 521         /* Send the ndis version */
 522         memset(init_packet, 0, sizeof(struct nvsp_message));
 523
 524         if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_4)
 525                 ndis_version = 0x00060001;
 526         else
 527                 ndis_version = 0x0006001e;
 528
 529         init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_NDIS_VER;
 530         init_packet->msg.v1_msg.
 531                 send_ndis_ver.ndis_major_ver =
 532                                 (ndis_version & 0xFFFF0000) >> 16;
 533         init_packet->msg.v1_msg.
 534                 send_ndis_ver.ndis_minor_ver =
 535                                 ndis_version & 0xFFFF;
 536
 537         /* Send the init request */
 538         ret = vmbus_sendpacket(device->channel, init_packet,
 539                                 sizeof(struct nvsp_message),
 540                                 (unsigned long)init_packet,
 541                                 VM_PKT_DATA_INBAND, 0);
 542         if (ret != 0)
 543                 goto cleanup;
 544
 545         /* Post the big receive buffer to NetVSP */
 546         if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_2)
 547                 net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE_LEGACY;
 548         else
 549                 net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE;
 550         net_device->send_buf_size = NETVSC_SEND_BUFFER_SIZE;
 551
 552         ret = netvsc_init_buf(device);
 553
 554 cleanup:
 555         return ret;
 556 }
 557
 558 static void netvsc_disconnect_vsp(struct hv_device *device)
 559 {
 560         netvsc_destroy_buf(device);
 561 }
 562
 563 /*
 564  * netvsc_device_remove - Callback when the root bus device is removed
 565  */
 566 int netvsc_device_remove(struct hv_device *device)
 567 {
 568         struct net_device *ndev = hv_get_drvdata(device);
 569         struct net_device_context *net_device_ctx = netdev_priv(ndev);
 570         struct netvsc_device *net_device = net_device_ctx->nvdev;
 571
 572         netvsc_disconnect_vsp(device);
 573
 574         net_device_ctx->nvdev = NULL;
 575
 576         /*
 577          * At this point, no one should be accessing net_device
 578          * except in here
 579          */
 580         dev_notice(&device->device, "net device safe to remove\n");
 581
 582         /* Now, we can close the channel safely */
 583         vmbus_close(device->channel);
 584
 585         /* Release all resources */
 586         vfree(net_device->sub_cb_buf);
 587         free_netvsc_device(net_device);
 588         return 0;
 589 }
 590
 591
 592 #define RING_AVAIL_PERCENT_HIWATER 20
 593 #define RING_AVAIL_PERCENT_LOWATER 10
 594
 595 /*
 596  * Get the percentage of available bytes to write in the ring.
 597  * The return value is in range from 0 to 100.
 598  */
 599 static inline u32 hv_ringbuf_avail_percent(
 600                 struct hv_ring_buffer_info *ring_info)
 601 {
 602         u32 avail_read, avail_write;
 603
 604         hv_get_ringbuffer_availbytes(ring_info, &avail_read, &avail_write);
 605
 606         return avail_write * 100 / ring_info->ring_datasize;
 607 }
 608
 609 static inline void netvsc_free_send_slot(struct netvsc_device *net_device,
 610                                          u32 index)
 611 {
 612         sync_change_bit(index, net_device->send_section_map);
 613 }
 614
 615 static void netvsc_send_completion(struct netvsc_device *net_device,
 616                                    struct vmbus_channel *incoming_channel,
 617                                    struct hv_device *device,
 618                                    struct vmpacket_descriptor *packet)
 619 {
 620         struct nvsp_message *nvsp_packet;
 621         struct hv_netvsc_packet *nvsc_packet;
 622         struct net_device *ndev = hv_get_drvdata(device);
 623         struct net_device_context *net_device_ctx = netdev_priv(ndev);
 624         u32 send_index;
 625         struct sk_buff *skb;
 626
 627         nvsp_packet = (struct nvsp_message *)((unsigned long)packet +
 628                         (packet->offset8 << 3));
 629
 630         if ((nvsp_packet->hdr.msg_type == NVSP_MSG_TYPE_INIT_COMPLETE) ||
 631             (nvsp_packet->hdr.msg_type ==
 632              NVSP_MSG1_TYPE_SEND_RECV_BUF_COMPLETE) ||
 633             (nvsp_packet->hdr.msg_type ==
 634              NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE) ||
 635             (nvsp_packet->hdr.msg_type ==
 636              NVSP_MSG5_TYPE_SUBCHANNEL)) {
 637                 /* Copy the response back */
 638                 memcpy(&net_device->channel_init_pkt, nvsp_packet,
 639                        sizeof(struct nvsp_message));
 640                 complete(&net_device->channel_init_wait);
 641         } else if (nvsp_packet->hdr.msg_type ==
 642                    NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE) {
 643                 int num_outstanding_sends;
 644                 u16 q_idx = 0;
 645                 struct vmbus_channel *channel = device->channel;
 646                 int queue_sends;
 647
 648                 /* Get the send context */
 649                 skb = (struct sk_buff *)(unsigned long)packet->trans_id;
 650
 651                 /* Notify the layer above us */
 652                 if (skb) {
 653                         nvsc_packet = (struct hv_netvsc_packet *) skb->cb;
 654                         send_index = nvsc_packet->send_buf_index;
 655                         if (send_index != NETVSC_INVALID_INDEX)
 656                                 netvsc_free_send_slot(net_device, send_index);
 657                         q_idx = nvsc_packet->q_idx;
 658                         channel = incoming_channel;
 659                         dev_kfree_skb_any(skb);
 660                 }
 661
 662                 num_outstanding_sends =
 663                         atomic_dec_return(&net_device->num_outstanding_sends);
 664                 queue_sends = atomic_dec_return(&net_device->
 665                                                 queue_sends[q_idx]);
 666
 667                 if (net_device->destroy && num_outstanding_sends == 0)
 668                         wake_up(&net_device->wait_drain);
 669
 670                 if (netif_tx_queue_stopped(netdev_get_tx_queue(ndev, q_idx)) &&
 671                     !net_device_ctx->start_remove &&
 672                     (hv_ringbuf_avail_percent(&channel->outbound) >
 673                      RING_AVAIL_PERCENT_HIWATER || queue_sends < 1))
 674                                 netif_tx_wake_queue(netdev_get_tx_queue(
 675                                                     ndev, q_idx));
 676         } else {
 677                 netdev_err(ndev, "Unknown send completion packet type- "
 678                            "%d received!!\n", nvsp_packet->hdr.msg_type);
 679         }
 680
 681 }
 682
 683 static u32 netvsc_get_next_send_section(struct netvsc_device *net_device)
 684 {
 685         unsigned long index;
 686         u32 max_words = net_device->map_words;
 687         unsigned long *map_addr = (unsigned long *)net_device->send_section_map;
 688         u32 section_cnt = net_device->send_section_cnt;
 689         int ret_val = NETVSC_INVALID_INDEX;
 690         int i;
 691         int prev_val;
 692
 693         for (i = 0; i < max_words; i++) {
 694                 if (!~(map_addr[i]))
 695                         continue;
 696                 index = ffz(map_addr[i]);
 697                 prev_val = sync_test_and_set_bit(index, &map_addr[i]);
 698                 if (prev_val)
 699                         continue;
 700                 if ((index + (i * BITS_PER_LONG)) >= section_cnt)
 701                         break;
 702                 ret_val = (index + (i * BITS_PER_LONG));
 703                 break;
 704         }
 705         return ret_val;
 706 }
 707
 708 static u32 netvsc_copy_to_send_buf(struct netvsc_device *net_device,
 709                                    unsigned int section_index,
 710                                    u32 pend_size,
 711                                    struct hv_netvsc_packet *packet,
 712                                    struct rndis_message *rndis_msg,
 713                                    struct hv_page_buffer **pb,
 714                                    struct sk_buff *skb)
 715 {
 716         char *start = net_device->send_buf;
 717         char *dest = start + (section_index * net_device->send_section_size)
 718                      + pend_size;
 719         int i;
 720         bool is_data_pkt = (skb != NULL) ? true : false;
 721         bool xmit_more = (skb != NULL) ? skb->xmit_more : false;
 722         u32 msg_size = 0;
 723         u32 padding = 0;
 724         u32 remain = packet->total_data_buflen % net_device->pkt_align;
 725         u32 page_count = packet->cp_partial ? packet->rmsg_pgcnt :
 726                 packet->page_buf_cnt;
 727
 728         /* Add padding */
 729         if (is_data_pkt && xmit_more && remain &&
 730             !packet->cp_partial) {
 731                 padding = net_device->pkt_align - remain;
 732                 rndis_msg->msg_len += padding;
 733                 packet->total_data_buflen += padding;
 734         }
 735
 736         for (i = 0; i < page_count; i++) {
 737                 char *src = phys_to_virt((*pb)[i].pfn << PAGE_SHIFT);
 738                 u32 offset = (*pb)[i].offset;
 739                 u32 len = (*pb)[i].len;
 740
 741                 memcpy(dest, (src + offset), len);
 742                 msg_size += len;
 743                 dest += len;
 744         }
 745
 746         if (padding) {
 747                 memset(dest, 0, padding);
 748                 msg_size += padding;
 749         }
 750
 751         return msg_size;
 752 }
 753
 754 static inline int netvsc_send_pkt(
 755         struct hv_device *device,
 756         struct hv_netvsc_packet *packet,
 757         struct netvsc_device *net_device,
 758         struct hv_page_buffer **pb,
 759         struct sk_buff *skb)
 760 {
 761         struct nvsp_message nvmsg;
 762         u16 q_idx = packet->q_idx;
 763         struct vmbus_channel *out_channel = net_device->chn_table[q_idx];
 764         struct net_device *ndev = hv_get_drvdata(device);
 765         u64 req_id;
 766         int ret;
 767         struct hv_page_buffer *pgbuf;
 768         u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound);
 769         bool xmit_more = (skb != NULL) ? skb->xmit_more : false;
 770
 771         nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
 772         if (skb != NULL) {
 773                 /* 0 is RMC_DATA; */
 774                 nvmsg.msg.v1_msg.send_rndis_pkt.channel_type = 0;
 775         } else {
 776                 /* 1 is RMC_CONTROL; */
 777                 nvmsg.msg.v1_msg.send_rndis_pkt.channel_type = 1;
 778         }
 779
 780         nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_index =
 781                 packet->send_buf_index;
 782         if (packet->send_buf_index == NETVSC_INVALID_INDEX)
 783                 nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_size = 0;
 784         else
 785                 nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_size =
 786                         packet->total_data_buflen;
 787
 788         req_id = (ulong)skb;
 789
 790         if (out_channel->rescind)
 791                 return -ENODEV;
 792
 793         /*
 794          * It is possible that once we successfully place this packet
 795          * on the ringbuffer, we may stop the queue. In that case, we want
 796          * to notify the host independent of the xmit_more flag. We don't
 797          * need to be precise here; in the worst case we may signal the host
 798          * unnecessarily.
 799          */
 800         if (ring_avail < (RING_AVAIL_PERCENT_LOWATER + 1))
 801                 xmit_more = false;
 802
 803         if (packet->page_buf_cnt) {
 804                 pgbuf = packet->cp_partial ? (*pb) +
 805                         packet->rmsg_pgcnt : (*pb);
 806                 ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,
 807                                                       pgbuf,
 808                                                       packet->page_buf_cnt,
 809                                                       &nvmsg,
 810                                                       sizeof(struct nvsp_message),
 811                                                       req_id,
 812                                                       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED,
 813                                                       !xmit_more);
 814         } else {
 815                 ret = vmbus_sendpacket_ctl(out_channel, &nvmsg,
 816                                            sizeof(struct nvsp_message),
 817                                            req_id,
 818                                            VM_PKT_DATA_INBAND,
 819                                            VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED,
 820                                            !xmit_more);
 821         }
 822
 823         if (ret == 0) {
 824                 atomic_inc(&net_device->num_outstanding_sends);
 825                 atomic_inc(&net_device->queue_sends[q_idx]);
 826
 827                 if (ring_avail < RING_AVAIL_PERCENT_LOWATER) {
 828                         netif_tx_stop_queue(netdev_get_tx_queue(ndev, q_idx));
 829
 830                         if (atomic_read(&net_device->
 831                                 queue_sends[q_idx]) < 1)
 832                                 netif_tx_wake_queue(netdev_get_tx_queue(
 833                                                     ndev, q_idx));
 834                 }
 835         } else if (ret == -EAGAIN) {
 836                 netif_tx_stop_queue(netdev_get_tx_queue(
 837                                     ndev, q_idx));
 838                 if (atomic_read(&net_device->queue_sends[q_idx]) < 1) {
 839                         netif_tx_wake_queue(netdev_get_tx_queue(
 840                                             ndev, q_idx));
 841                         ret = -ENOSPC;
 842                 }
 843         } else {
 844                 netdev_err(ndev, "Unable to send packet %p ret %d\n",
 845                            packet, ret);
 846         }
 847
 848         return ret;
 849 }
 850
 851 /* Move packet out of multi send data (msd), and clear msd */
 852 static inline void move_pkt_msd(struct hv_netvsc_packet **msd_send,
 853                                 struct sk_buff **msd_skb,
 854                                 struct multi_send_data *msdp)
 855 {
 856         *msd_skb = msdp->skb;
 857         *msd_send = msdp->pkt;
 858         msdp->skb = NULL;
 859         msdp->pkt = NULL;
 860         msdp->count = 0;
 861 }
 862
 863 int netvsc_send(struct hv_device *device,
 864                 struct hv_netvsc_packet *packet,
 865                 struct rndis_message *rndis_msg,
 866                 struct hv_page_buffer **pb,
 867                 struct sk_buff *skb)
 868 {
 869         struct netvsc_device *net_device;
 870         int ret = 0, m_ret = 0;
 871         struct vmbus_channel *out_channel;
 872         u16 q_idx = packet->q_idx;
 873         u32 pktlen = packet->total_data_buflen, msd_len = 0;
 874         unsigned int section_index = NETVSC_INVALID_INDEX;
 875         struct multi_send_data *msdp;
 876         struct hv_netvsc_packet *msd_send = NULL, *cur_send = NULL;
 877         struct sk_buff *msd_skb = NULL;
 878         bool try_batch;
 879         bool xmit_more = (skb != NULL) ? skb->xmit_more : false;
 880
 881         net_device = get_outbound_net_device(device);
 882         if (!net_device)
 883                 return -ENODEV;
 884
 885         out_channel = net_device->chn_table[q_idx];
 886
 887         packet->send_buf_index = NETVSC_INVALID_INDEX;
 888         packet->cp_partial = false;
 889
 890         /* Send control message directly without accessing msd (Multi-Send
 891          * Data) field which may be changed during data packet processing.
 892          */
 893         if (!skb) {
 894                 cur_send = packet;
 895                 goto send_now;
 896         }
 897
 898         msdp = &net_device->msd[q_idx];
 899
 900         /* batch packets in send buffer if possible */
 901         if (msdp->pkt)
 902                 msd_len = msdp->pkt->total_data_buflen;
 903
 904         try_batch = (skb != NULL) && msd_len > 0 && msdp->count <
 905                     net_device->max_pkt;
 906
 907         if (try_batch && msd_len + pktlen + net_device->pkt_align <
 908             net_device->send_section_size) {
 909                 section_index = msdp->pkt->send_buf_index;
 910
 911         } else if (try_batch && msd_len + packet->rmsg_size <
 912                    net_device->send_section_size) {
 913                 section_index = msdp->pkt->send_buf_index;
 914                 packet->cp_partial = true;
 915
 916         } else if ((skb != NULL) && pktlen + net_device->pkt_align <
 917                    net_device->send_section_size) {
 918                 section_index = netvsc_get_next_send_section(net_device);
 919                 if (section_index != NETVSC_INVALID_INDEX) {
 920                         move_pkt_msd(&msd_send, &msd_skb, msdp);
 921                         msd_len = 0;
 922                 }
 923         }
 924
 925         if (section_index != NETVSC_INVALID_INDEX) {
 926                 netvsc_copy_to_send_buf(net_device,
 927                                         section_index, msd_len,
 928                                         packet, rndis_msg, pb, skb);
 929
 930                 packet->send_buf_index = section_index;
 931
 932                 if (packet->cp_partial) {
 933                         packet->page_buf_cnt -= packet->rmsg_pgcnt;
 934                         packet->total_data_buflen = msd_len + packet->rmsg_size;
 935                 } else {
 936                         packet->page_buf_cnt = 0;
 937                         packet->total_data_buflen += msd_len;
 938                 }
 939
 940                 if (msdp->skb)
 941                         dev_kfree_skb_any(msdp->skb);
 942
 943                 if (xmit_more && !packet->cp_partial) {
 944                         msdp->skb = skb;
 945                         msdp->pkt = packet;
 946                         msdp->count++;
 947                 } else {
 948                         cur_send = packet;
 949                         msdp->skb = NULL;
 950                         msdp->pkt = NULL;
 951                         msdp->count = 0;
 952                 }
 953         } else {
 954                 move_pkt_msd(&msd_send, &msd_skb, msdp);
 955                 cur_send = packet;
 956         }
 957
 958         if (msd_send) {
 959                 m_ret = netvsc_send_pkt(device, msd_send, net_device,
 960                                         NULL, msd_skb);
 961
 962                 if (m_ret != 0) {
 963                         netvsc_free_send_slot(net_device,
 964                                               msd_send->send_buf_index);
 965                         dev_kfree_skb_any(msd_skb);
 966                 }
 967         }
 968
 969 send_now:
 970         if (cur_send)
 971                 ret = netvsc_send_pkt(device, cur_send, net_device, pb, skb);
 972
 973         if (ret != 0 && section_index != NETVSC_INVALID_INDEX)
 974                 netvsc_free_send_slot(net_device, section_index);
 975
 976         return ret;
 977 }
 978
 979 static void netvsc_send_recv_completion(struct hv_device *device,
 980                                         struct vmbus_channel *channel,
 981                                         struct netvsc_device *net_device,
 982                                         u64 transaction_id, u32 status)
 983 {
 984         struct nvsp_message recvcompMessage;
 985         int retries = 0;
 986         int ret;
 987         struct net_device *ndev = hv_get_drvdata(device);
 988
 989         recvcompMessage.hdr.msg_type =
 990                                 NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE;
 991
 992         recvcompMessage.msg.v1_msg.send_rndis_pkt_complete.status = status;
 993
 994 retry_send_cmplt:
 995         /* Send the completion */
 996         ret = vmbus_sendpacket(channel, &recvcompMessage,
 997                                sizeof(struct nvsp_message), transaction_id,
 998                                VM_PKT_COMP, 0);
 999         if (ret == 0) {
1000                 /* success */
1001                 /* no-op */
1002         } else if (ret == -EAGAIN) {
1003                 /* no more room...wait a bit and attempt to retry 3 times */
1004                 retries++;
1005                 netdev_err(ndev, "unable to send receive completion pkt"
1006                         " (tid %llx)...retrying %d\n", transaction_id, retries);
1007
1008                 if (retries < 4) {
1009                         udelay(100);
1010                         goto retry_send_cmplt;
1011                 } else {
1012                         netdev_err(ndev, "unable to send receive "
1013                                 "completion pkt (tid %llx)...give up retrying\n",
1014                                 transaction_id);
1015                 }
1016         } else {
1017                 netdev_err(ndev, "unable to send receive "
1018                         "completion pkt - %llx\n", transaction_id);
1019         }
1020 }
1021
1022 static void netvsc_receive(struct netvsc_device *net_device,
1023                         struct vmbus_channel *channel,
1024                         struct hv_device *device,
1025                         struct vmpacket_descriptor *packet)
1026 {
1027         struct vmtransfer_page_packet_header *vmxferpage_packet;
1028         struct nvsp_message *nvsp_packet;
1029         struct hv_netvsc_packet nv_pkt;
1030         struct hv_netvsc_packet *netvsc_packet = &nv_pkt;
1031         u32 status = NVSP_STAT_SUCCESS;
1032         int i;
1033         int count = 0;
1034         struct net_device *ndev = hv_get_drvdata(device);
1035         void *data;
1036
1037         /*
1038          * All inbound packets other than send completion should be xfer page
1039          * packet
1040          */
1041         if (packet->type != VM_PKT_DATA_USING_XFER_PAGES) {
1042                 netdev_err(ndev, "Unknown packet type received - %d\n",
1043                            packet->type);
1044                 return;
1045         }
1046
1047         nvsp_packet = (struct nvsp_message *)((unsigned long)packet +
1048                         (packet->offset8 << 3));
1049
1050         /* Make sure this is a valid nvsp packet */
1051         if (nvsp_packet->hdr.msg_type !=
1052             NVSP_MSG1_TYPE_SEND_RNDIS_PKT) {
1053                 netdev_err(ndev, "Unknown nvsp packet type received-"
1054                         " %d\n", nvsp_packet->hdr.msg_type);
1055                 return;
1056         }
1057
1058         vmxferpage_packet = (struct vmtransfer_page_packet_header *)packet;
1059
1060         if (vmxferpage_packet->xfer_pageset_id != NETVSC_RECEIVE_BUFFER_ID) {
1061                 netdev_err(ndev, "Invalid xfer page set id - "
1062                            "expecting %x got %x\n", NETVSC_RECEIVE_BUFFER_ID,
1063                            vmxferpage_packet->xfer_pageset_id);
1064                 return;
1065         }
1066
1067         count = vmxferpage_packet->range_cnt;
1068
1069         /* Each range represents 1 RNDIS pkt that contains 1 ethernet frame */
1070         for (i = 0; i < count; i++) {
1071                 /* Initialize the netvsc packet */
1072                 data = (void *)((unsigned long)net_device->
1073                         recv_buf + vmxferpage_packet->ranges[i].byte_offset);
1074                 netvsc_packet->total_data_buflen =
1075                                         vmxferpage_packet->ranges[i].byte_count;
1076
1077                 /* Pass it to the upper layer */
1078                 status = rndis_filter_receive(device, netvsc_packet, &data,
1079                                               channel);
1080
1081         }
1082
1083         netvsc_send_recv_completion(device, channel, net_device,
1084                                     vmxferpage_packet->d.trans_id, status);
1085 }
1086
1087
1088 static void netvsc_send_table(struct hv_device *hdev,
1089                               struct nvsp_message *nvmsg)
1090 {
1091         struct netvsc_device *nvscdev;
1092         struct net_device *ndev = hv_get_drvdata(hdev);
1093         int i;
1094         u32 count, *tab;
1095
1096         nvscdev = get_outbound_net_device(hdev);
1097         if (!nvscdev)
1098                 return;
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                 nvscdev->send_table[i] = tab[i];
1111 }
1112
1113 static void netvsc_send_vf(struct netvsc_device *nvdev,
1114                            struct nvsp_message *nvmsg)
1115 {
1116         nvdev->vf_alloc = nvmsg->msg.v4_msg.vf_assoc.allocated;
1117         nvdev->vf_serial = nvmsg->msg.v4_msg.vf_assoc.serial;
1118 }
1119
1120 static inline void netvsc_receive_inband(struct hv_device *hdev,
1121                                          struct netvsc_device *nvdev,
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(nvdev, nvmsg);
1131                 break;
1132         }
1133 }
1134
1135 static void 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                                    u64 request_id,
1140                                    struct vmpacket_descriptor *desc)
1141 {
1142         struct nvsp_message *nvmsg;
1143
1144         nvmsg = (struct nvsp_message *)((unsigned long)
1145                 desc + (desc->offset8 << 3));
1146
1147         switch (desc->type) {
1148         case VM_PKT_COMP:
1149                 netvsc_send_completion(net_device, channel, device, desc);
1150                 break;
1151
1152         case VM_PKT_DATA_USING_XFER_PAGES:
1153                 netvsc_receive(net_device, channel, device, desc);
1154                 break;
1155
1156         case VM_PKT_DATA_INBAND:
1157                 netvsc_receive_inband(device, net_device, nvmsg);
1158                 break;
1159
1160         default:
1161                 netdev_err(ndev, "unhandled packet type %d, tid %llx\n",
1162                            desc->type, request_id);
1163                 break;
1164         }
1165 }
1166
1167
1168 void netvsc_channel_cb(void *context)
1169 {
1170         int ret;
1171         struct vmbus_channel *channel = (struct vmbus_channel *)context;
1172         struct hv_device *device;
1173         struct netvsc_device *net_device;
1174         u32 bytes_recvd;
1175         u64 request_id;
1176         struct vmpacket_descriptor *desc;
1177         unsigned char *buffer;
1178         int bufferlen = NETVSC_PACKET_SIZE;
1179         struct net_device *ndev;
1180         bool need_to_commit = false;
1181
1182         if (channel->primary_channel != NULL)
1183                 device = channel->primary_channel->device_obj;
1184         else
1185                 device = channel->device_obj;
1186
1187         net_device = get_inbound_net_device(device);
1188         if (!net_device)
1189                 return;
1190         ndev = hv_get_drvdata(device);
1191         buffer = get_per_channel_state(channel);
1192
1193         do {
1194                 desc = get_next_pkt_raw(channel);
1195                 if (desc != NULL) {
1196                         netvsc_process_raw_pkt(device,
1197                                                channel,
1198                                                net_device,
1199                                                ndev,
1200                                                desc->trans_id,
1201                                                desc);
1202
1203                         put_pkt_raw(channel, desc);
1204                         need_to_commit = true;
1205                         continue;
1206                 }
1207                 if (need_to_commit) {
1208                         need_to_commit = false;
1209                         commit_rd_index(channel);
1210                 }
1211
1212                 ret = vmbus_recvpacket_raw(channel, buffer, bufferlen,
1213                                            &bytes_recvd, &request_id);
1214                 if (ret == 0) {
1215                         if (bytes_recvd > 0) {
1216                                 desc = (struct vmpacket_descriptor *)buffer;
1217                                 netvsc_process_raw_pkt(device,
1218                                                        channel,
1219                                                        net_device,
1220                                                        ndev,
1221                                                        request_id,
1222                                                        desc);
1223
1224
1225                         } else {
1226                                 /*
1227                                  * We are done for this pass.
1228                                  */
1229                                 break;
1230                         }
1231
1232                 } else if (ret == -ENOBUFS) {
1233                         if (bufferlen > NETVSC_PACKET_SIZE)
1234                                 kfree(buffer);
1235                         /* Handle large packet */
1236                         buffer = kmalloc(bytes_recvd, GFP_ATOMIC);
1237                         if (buffer == NULL) {
1238                                 /* Try again next time around */
1239                                 netdev_err(ndev,
1240                                            "unable to allocate buffer of size "
1241                                            "(%d)!!\n", bytes_recvd);
1242                                 break;
1243                         }
1244
1245                         bufferlen = bytes_recvd;
1246                 }
1247         } while (1);
1248
1249         if (bufferlen > NETVSC_PACKET_SIZE)
1250                 kfree(buffer);
1251         return;
1252 }
1253
1254 /*
1255  * netvsc_device_add - Callback when the device belonging to this
1256  * driver is added
1257  */
1258 int netvsc_device_add(struct hv_device *device, void *additional_info)
1259 {
1260         int i, ret = 0;
1261         int ring_size =
1262         ((struct netvsc_device_info *)additional_info)->ring_size;
1263         struct netvsc_device *net_device;
1264         struct net_device *ndev = hv_get_drvdata(device);
1265         struct net_device_context *net_device_ctx = netdev_priv(ndev);
1266
1267         net_device = alloc_net_device();
1268         if (!net_device)
1269                 return -ENOMEM;
1270
1271         net_device->ring_size = ring_size;
1272
1273         /* Initialize the NetVSC channel extension */
1274         init_completion(&net_device->channel_init_wait);
1275
1276         set_per_channel_state(device->channel, net_device->cb_buffer);
1277
1278         /* Open the channel */
1279         ret = vmbus_open(device->channel, ring_size * PAGE_SIZE,
1280                          ring_size * PAGE_SIZE, NULL, 0,
1281                          netvsc_channel_cb, device->channel);
1282
1283         if (ret != 0) {
1284                 netdev_err(ndev, "unable to open channel: %d\n", ret);
1285                 goto cleanup;
1286         }
1287
1288         /* Channel is opened */
1289         pr_info("hv_netvsc channel opened successfully\n");
1290
1291         /* If we're reopening the device we may have multiple queues, fill the
1292          * chn_table with the default channel to use it before subchannels are
1293          * opened.
1294          */
1295         for (i = 0; i < VRSS_CHANNEL_MAX; i++)
1296                 net_device->chn_table[i] = device->channel;
1297
1298         /* Writing nvdev pointer unlocks netvsc_send(), make sure chn_table is
1299          * populated.
1300          */
1301         wmb();
1302
1303         net_device_ctx->nvdev = net_device;
1304
1305         /* Connect with the NetVsp */
1306         ret = netvsc_connect_vsp(device);
1307         if (ret != 0) {
1308                 netdev_err(ndev,
1309                         "unable to connect to NetVSP - %d\n", ret);
1310                 goto close;
1311         }
1312
1313         return ret;
1314
1315 close:
1316         /* Now, we can close the channel safely */
1317         vmbus_close(device->channel);
1318
1319 cleanup:
1320         free_netvsc_device(net_device);
1321
1322         return ret;
1323 }