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 netvsc_device *nv_dev, bool vf)
  41 {
  42         struct nvsp_message *init_pkt = &nv_dev->channel_init_pkt;
  43         struct hv_device *dev = nv_dev->dev;
  44
  45         memset(init_pkt, 0, sizeof(struct nvsp_message));
  46         init_pkt->hdr.msg_type = NVSP_MSG4_TYPE_SWITCH_DATA_PATH;
  47         if (vf)
  48                 init_pkt->msg.v4_msg.active_dp.active_datapath =
  49                         NVSP_DATAPATH_VF;
  50         else
  51                 init_pkt->msg.v4_msg.active_dp.active_datapath =
  52                         NVSP_DATAPATH_SYNTHETIC;
  53
  54         vmbus_sendpacket(dev->channel, init_pkt,
  55                                sizeof(struct nvsp_message),
  56                                (unsigned long)init_pkt,
  57                                VM_PKT_DATA_INBAND, 0);
  58 }
  59
  60
  61 static struct netvsc_device *alloc_net_device(struct hv_device *device)
  62 {
  63         struct netvsc_device *net_device;
  64         struct net_device *ndev = hv_get_drvdata(device);
  65
  66         net_device = kzalloc(sizeof(struct netvsc_device), GFP_KERNEL);
  67         if (!net_device)
  68                 return NULL;
  69
  70         net_device->cb_buffer = kzalloc(NETVSC_PACKET_SIZE, GFP_KERNEL);
  71         if (!net_device->cb_buffer) {
  72                 kfree(net_device);
  73                 return NULL;
  74         }
  75
  76         init_waitqueue_head(&net_device->wait_drain);
  77         net_device->start_remove = false;
  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->dev = device;
  82         net_device->ndev = ndev;
  83         net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
  84         net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;
  85
  86         net_device->vf_netdev = NULL;
  87         net_device->vf_inject = false;
  88
  89         hv_set_drvdata(device, net_device);
  90         return net_device;
  91 }
  92
  93 static void free_netvsc_device(struct netvsc_device *nvdev)
  94 {
  95         kfree(nvdev->cb_buffer);
  96         kfree(nvdev);
  97 }
  98
  99 static struct netvsc_device *get_outbound_net_device(struct hv_device *device)
 100 {
 101         struct netvsc_device *net_device;
 102
 103         net_device = hv_get_drvdata(device);
 104         if (net_device && net_device->destroy)
 105                 net_device = NULL;
 106
 107         return net_device;
 108 }
 109
 110 static struct netvsc_device *get_inbound_net_device(struct hv_device *device)
 111 {
 112         struct netvsc_device *net_device;
 113
 114         net_device = hv_get_drvdata(device);
 115
 116         if (!net_device)
 117                 goto get_in_err;
 118
 119         if (net_device->destroy &&
 120                 atomic_read(&net_device->num_outstanding_sends) == 0)
 121                 net_device = NULL;
 122
 123 get_in_err:
 124         return net_device;
 125 }
 126
 127
 128 static int netvsc_destroy_buf(struct netvsc_device *net_device)
 129 {
 130         struct nvsp_message *revoke_packet;
 131         int ret = 0;
 132         struct net_device *ndev = net_device->ndev;
 133
 134         /*
 135          * If we got a section count, it means we received a
 136          * SendReceiveBufferComplete msg (ie sent
 137          * NvspMessage1TypeSendReceiveBuffer msg) therefore, we need
 138          * to send a revoke msg here
 139          */
 140         if (net_device->recv_section_cnt) {
 141                 /* Send the revoke receive buffer */
 142                 revoke_packet = &net_device->revoke_packet;
 143                 memset(revoke_packet, 0, sizeof(struct nvsp_message));
 144
 145                 revoke_packet->hdr.msg_type =
 146                         NVSP_MSG1_TYPE_REVOKE_RECV_BUF;
 147                 revoke_packet->msg.v1_msg.
 148                 revoke_recv_buf.id = NETVSC_RECEIVE_BUFFER_ID;
 149
 150                 ret = vmbus_sendpacket(net_device->dev->channel,
 151                                        revoke_packet,
 152                                        sizeof(struct nvsp_message),
 153                                        (unsigned long)revoke_packet,
 154                                        VM_PKT_DATA_INBAND, 0);
 155                 /*
 156                  * If we failed here, we might as well return and
 157                  * have a leak rather than continue and a bugchk
 158                  */
 159                 if (ret != 0) {
 160                         netdev_err(ndev, "unable to send "
 161                                 "revoke receive buffer to netvsp\n");
 162                         return ret;
 163                 }
 164         }
 165
 166         /* Teardown the gpadl on the vsp end */
 167         if (net_device->recv_buf_gpadl_handle) {
 168                 ret = vmbus_teardown_gpadl(net_device->dev->channel,
 169                            net_device->recv_buf_gpadl_handle);
 170
 171                 /* If we failed here, we might as well return and have a leak
 172                  * rather than continue and a bugchk
 173                  */
 174                 if (ret != 0) {
 175                         netdev_err(ndev,
 176                                    "unable to teardown receive buffer's gpadl\n");
 177                         return ret;
 178                 }
 179                 net_device->recv_buf_gpadl_handle = 0;
 180         }
 181
 182         if (net_device->recv_buf) {
 183                 /* Free up the receive buffer */
 184                 vfree(net_device->recv_buf);
 185                 net_device->recv_buf = NULL;
 186         }
 187
 188         if (net_device->recv_section) {
 189                 net_device->recv_section_cnt = 0;
 190                 kfree(net_device->recv_section);
 191                 net_device->recv_section = NULL;
 192         }
 193
 194         /* Deal with the send buffer we may have setup.
 195          * If we got a  send section size, it means we received a
 196          * NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE msg (ie sent
 197          * NVSP_MSG1_TYPE_SEND_SEND_BUF msg) therefore, we need
 198          * to send a revoke msg here
 199          */
 200         if (net_device->send_section_size) {
 201                 /* Send the revoke receive buffer */
 202                 revoke_packet = &net_device->revoke_packet;
 203                 memset(revoke_packet, 0, sizeof(struct nvsp_message));
 204
 205                 revoke_packet->hdr.msg_type =
 206                         NVSP_MSG1_TYPE_REVOKE_SEND_BUF;
 207                 revoke_packet->msg.v1_msg.revoke_send_buf.id =
 208                         NETVSC_SEND_BUFFER_ID;
 209
 210                 ret = vmbus_sendpacket(net_device->dev->channel,
 211                                        revoke_packet,
 212                                        sizeof(struct nvsp_message),
 213                                        (unsigned long)revoke_packet,
 214                                        VM_PKT_DATA_INBAND, 0);
 215                 /* If we failed here, we might as well return and
 216                  * have a leak rather than continue and a bugchk
 217                  */
 218                 if (ret != 0) {
 219                         netdev_err(ndev, "unable to send "
 220                                    "revoke send buffer to netvsp\n");
 221                         return ret;
 222                 }
 223         }
 224         /* Teardown the gpadl on the vsp end */
 225         if (net_device->send_buf_gpadl_handle) {
 226                 ret = vmbus_teardown_gpadl(net_device->dev->channel,
 227                                            net_device->send_buf_gpadl_handle);
 228
 229                 /* If we failed here, we might as well return and have a leak
 230                  * rather than continue and a bugchk
 231                  */
 232                 if (ret != 0) {
 233                         netdev_err(ndev,
 234                                    "unable to teardown send buffer's gpadl\n");
 235                         return ret;
 236                 }
 237                 net_device->send_buf_gpadl_handle = 0;
 238         }
 239         if (net_device->send_buf) {
 240                 /* Free up the send buffer */
 241                 vfree(net_device->send_buf);
 242                 net_device->send_buf = NULL;
 243         }
 244         kfree(net_device->send_section_map);
 245
 246         return ret;
 247 }
 248
 249 static int netvsc_init_buf(struct hv_device *device)
 250 {
 251         int ret = 0;
 252         unsigned long t;
 253         struct netvsc_device *net_device;
 254         struct nvsp_message *init_packet;
 255         struct net_device *ndev;
 256         int node;
 257
 258         net_device = get_outbound_net_device(device);
 259         if (!net_device)
 260                 return -ENODEV;
 261         ndev = net_device->ndev;
 262
 263         node = cpu_to_node(device->channel->target_cpu);
 264         net_device->recv_buf = vzalloc_node(net_device->recv_buf_size, node);
 265         if (!net_device->recv_buf)
 266                 net_device->recv_buf = vzalloc(net_device->recv_buf_size);
 267
 268         if (!net_device->recv_buf) {
 269                 netdev_err(ndev, "unable to allocate receive "
 270                         "buffer of size %d\n", net_device->recv_buf_size);
 271                 ret = -ENOMEM;
 272                 goto cleanup;
 273         }
 274
 275         /*
 276          * Establish the gpadl handle for this buffer on this
 277          * channel.  Note: This call uses the vmbus connection rather
 278          * than the channel to establish the gpadl handle.
 279          */
 280         ret = vmbus_establish_gpadl(device->channel, net_device->recv_buf,
 281                                     net_device->recv_buf_size,
 282                                     &net_device->recv_buf_gpadl_handle);
 283         if (ret != 0) {
 284                 netdev_err(ndev,
 285                         "unable to establish receive buffer's gpadl\n");
 286                 goto cleanup;
 287         }
 288
 289
 290         /* Notify the NetVsp of the gpadl handle */
 291         init_packet = &net_device->channel_init_pkt;
 292
 293         memset(init_packet, 0, sizeof(struct nvsp_message));
 294
 295         init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_RECV_BUF;
 296         init_packet->msg.v1_msg.send_recv_buf.
 297                 gpadl_handle = net_device->recv_buf_gpadl_handle;
 298         init_packet->msg.v1_msg.
 299                 send_recv_buf.id = NETVSC_RECEIVE_BUFFER_ID;
 300
 301         /* Send the gpadl notification request */
 302         ret = vmbus_sendpacket(device->channel, init_packet,
 303                                sizeof(struct nvsp_message),
 304                                (unsigned long)init_packet,
 305                                VM_PKT_DATA_INBAND,
 306                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 307         if (ret != 0) {
 308                 netdev_err(ndev,
 309                         "unable to send receive buffer's gpadl to netvsp\n");
 310                 goto cleanup;
 311         }
 312
 313         t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);
 314         BUG_ON(t == 0);
 315
 316
 317         /* Check the response */
 318         if (init_packet->msg.v1_msg.
 319             send_recv_buf_complete.status != NVSP_STAT_SUCCESS) {
 320                 netdev_err(ndev, "Unable to complete receive buffer "
 321                            "initialization with NetVsp - status %d\n",
 322                            init_packet->msg.v1_msg.
 323                            send_recv_buf_complete.status);
 324                 ret = -EINVAL;
 325                 goto cleanup;
 326         }
 327
 328         /* Parse the response */
 329
 330         net_device->recv_section_cnt = init_packet->msg.
 331                 v1_msg.send_recv_buf_complete.num_sections;
 332
 333         net_device->recv_section = kmemdup(
 334                 init_packet->msg.v1_msg.send_recv_buf_complete.sections,
 335                 net_device->recv_section_cnt *
 336                 sizeof(struct nvsp_1_receive_buffer_section),
 337                 GFP_KERNEL);
 338         if (net_device->recv_section == NULL) {
 339                 ret = -EINVAL;
 340                 goto cleanup;
 341         }
 342
 343         /*
 344          * For 1st release, there should only be 1 section that represents the
 345          * entire receive buffer
 346          */
 347         if (net_device->recv_section_cnt != 1 ||
 348             net_device->recv_section->offset != 0) {
 349                 ret = -EINVAL;
 350                 goto cleanup;
 351         }
 352
 353         /* Now setup the send buffer.
 354          */
 355         net_device->send_buf = vzalloc_node(net_device->send_buf_size, node);
 356         if (!net_device->send_buf)
 357                 net_device->send_buf = vzalloc(net_device->send_buf_size);
 358         if (!net_device->send_buf) {
 359                 netdev_err(ndev, "unable to allocate send "
 360                            "buffer of size %d\n", net_device->send_buf_size);
 361                 ret = -ENOMEM;
 362                 goto cleanup;
 363         }
 364
 365         /* Establish the gpadl handle for this buffer on this
 366          * channel.  Note: This call uses the vmbus connection rather
 367          * than the channel to establish the gpadl handle.
 368          */
 369         ret = vmbus_establish_gpadl(device->channel, net_device->send_buf,
 370                                     net_device->send_buf_size,
 371                                     &net_device->send_buf_gpadl_handle);
 372         if (ret != 0) {
 373                 netdev_err(ndev,
 374                            "unable to establish send buffer's gpadl\n");
 375                 goto cleanup;
 376         }
 377
 378         /* Notify the NetVsp of the gpadl handle */
 379         init_packet = &net_device->channel_init_pkt;
 380         memset(init_packet, 0, sizeof(struct nvsp_message));
 381         init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_SEND_BUF;
 382         init_packet->msg.v1_msg.send_send_buf.gpadl_handle =
 383                 net_device->send_buf_gpadl_handle;
 384         init_packet->msg.v1_msg.send_send_buf.id = NETVSC_SEND_BUFFER_ID;
 385
 386         /* Send the gpadl notification request */
 387         ret = vmbus_sendpacket(device->channel, init_packet,
 388                                sizeof(struct nvsp_message),
 389                                (unsigned long)init_packet,
 390                                VM_PKT_DATA_INBAND,
 391                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 392         if (ret != 0) {
 393                 netdev_err(ndev,
 394                            "unable to send send buffer's gpadl to netvsp\n");
 395                 goto cleanup;
 396         }
 397
 398         t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);
 399         BUG_ON(t == 0);
 400
 401         /* Check the response */
 402         if (init_packet->msg.v1_msg.
 403             send_send_buf_complete.status != NVSP_STAT_SUCCESS) {
 404                 netdev_err(ndev, "Unable to complete send buffer "
 405                            "initialization with NetVsp - status %d\n",
 406                            init_packet->msg.v1_msg.
 407                            send_send_buf_complete.status);
 408                 ret = -EINVAL;
 409                 goto cleanup;
 410         }
 411
 412         /* Parse the response */
 413         net_device->send_section_size = init_packet->msg.
 414                                 v1_msg.send_send_buf_complete.section_size;
 415
 416         /* Section count is simply the size divided by the section size.
 417          */
 418         net_device->send_section_cnt =
 419                 net_device->send_buf_size/net_device->send_section_size;
 420
 421         dev_info(&device->device, "Send section size: %d, Section count:%d\n",
 422                  net_device->send_section_size, net_device->send_section_cnt);
 423
 424         /* Setup state for managing the send buffer. */
 425         net_device->map_words = DIV_ROUND_UP(net_device->send_section_cnt,
 426                                              BITS_PER_LONG);
 427
 428         net_device->send_section_map =
 429                 kzalloc(net_device->map_words * sizeof(ulong), GFP_KERNEL);
 430         if (net_device->send_section_map == NULL) {
 431                 ret = -ENOMEM;
 432                 goto cleanup;
 433         }
 434
 435         goto exit;
 436
 437 cleanup:
 438         netvsc_destroy_buf(net_device);
 439
 440 exit:
 441         return ret;
 442 }
 443
 444
 445 /* Negotiate NVSP protocol version */
 446 static int negotiate_nvsp_ver(struct hv_device *device,
 447                               struct netvsc_device *net_device,
 448                               struct nvsp_message *init_packet,
 449                               u32 nvsp_ver)
 450 {
 451         int ret;
 452         unsigned long t;
 453
 454         memset(init_packet, 0, sizeof(struct nvsp_message));
 455         init_packet->hdr.msg_type = NVSP_MSG_TYPE_INIT;
 456         init_packet->msg.init_msg.init.min_protocol_ver = nvsp_ver;
 457         init_packet->msg.init_msg.init.max_protocol_ver = nvsp_ver;
 458
 459         /* Send the init request */
 460         ret = vmbus_sendpacket(device->channel, init_packet,
 461                                sizeof(struct nvsp_message),
 462                                (unsigned long)init_packet,
 463                                VM_PKT_DATA_INBAND,
 464                                VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
 465
 466         if (ret != 0)
 467                 return ret;
 468
 469         t = wait_for_completion_timeout(&net_device->channel_init_wait, 5*HZ);
 470
 471         if (t == 0)
 472                 return -ETIMEDOUT;
 473
 474         if (init_packet->msg.init_msg.init_complete.status !=
 475             NVSP_STAT_SUCCESS)
 476                 return -EINVAL;
 477
 478         if (nvsp_ver == NVSP_PROTOCOL_VERSION_1)
 479                 return 0;
 480
 481         /* NVSPv2 or later: Send NDIS config */
 482         memset(init_packet, 0, sizeof(struct nvsp_message));
 483         init_packet->hdr.msg_type = NVSP_MSG2_TYPE_SEND_NDIS_CONFIG;
 484         init_packet->msg.v2_msg.send_ndis_config.mtu = net_device->ndev->mtu +
 485                                                        ETH_HLEN;
 486         init_packet->msg.v2_msg.send_ndis_config.capability.ieee8021q = 1;
 487
 488         if (nvsp_ver >= NVSP_PROTOCOL_VERSION_5)
 489                 init_packet->msg.v2_msg.send_ndis_config.capability.sriov = 1;
 490
 491         ret = vmbus_sendpacket(device->channel, init_packet,
 492                                 sizeof(struct nvsp_message),
 493                                 (unsigned long)init_packet,
 494                                 VM_PKT_DATA_INBAND, 0);
 495
 496         return ret;
 497 }
 498
 499 static int netvsc_connect_vsp(struct hv_device *device)
 500 {
 501         int ret;
 502         struct netvsc_device *net_device;
 503         struct nvsp_message *init_packet;
 504         int ndis_version;
 505         struct net_device *ndev;
 506         u32 ver_list[] = { NVSP_PROTOCOL_VERSION_1, NVSP_PROTOCOL_VERSION_2,
 507                 NVSP_PROTOCOL_VERSION_4, NVSP_PROTOCOL_VERSION_5 };
 508         int i, num_ver = 4; /* number of different NVSP versions */
 509
 510         net_device = get_outbound_net_device(device);
 511         if (!net_device)
 512                 return -ENODEV;
 513         ndev = net_device->ndev;
 514
 515         init_packet = &net_device->channel_init_pkt;
 516
 517         /* Negotiate the latest NVSP protocol supported */
 518         for (i = num_ver - 1; i >= 0; i--)
 519                 if (negotiate_nvsp_ver(device, net_device, init_packet,
 520                                        ver_list[i])  == 0) {
 521                         net_device->nvsp_version = ver_list[i];
 522                         break;
 523                 }
 524
 525         if (i < 0) {
 526                 ret = -EPROTO;
 527                 goto cleanup;
 528         }
 529
 530         pr_debug("Negotiated NVSP version:%x\n", net_device->nvsp_version);
 531
 532         /* Send the ndis version */
 533         memset(init_packet, 0, sizeof(struct nvsp_message));
 534
 535         if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_4)
 536                 ndis_version = 0x00060001;
 537         else
 538                 ndis_version = 0x0006001e;
 539
 540         init_packet->hdr.msg_type = NVSP_MSG1_TYPE_SEND_NDIS_VER;
 541         init_packet->msg.v1_msg.
 542                 send_ndis_ver.ndis_major_ver =
 543                                 (ndis_version & 0xFFFF0000) >> 16;
 544         init_packet->msg.v1_msg.
 545                 send_ndis_ver.ndis_minor_ver =
 546                                 ndis_version & 0xFFFF;
 547
 548         /* Send the init request */
 549         ret = vmbus_sendpacket(device->channel, init_packet,
 550                                 sizeof(struct nvsp_message),
 551                                 (unsigned long)init_packet,
 552                                 VM_PKT_DATA_INBAND, 0);
 553         if (ret != 0)
 554                 goto cleanup;
 555
 556         /* Post the big receive buffer to NetVSP */
 557         if (net_device->nvsp_version <= NVSP_PROTOCOL_VERSION_2)
 558                 net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE_LEGACY;
 559         else
 560                 net_device->recv_buf_size = NETVSC_RECEIVE_BUFFER_SIZE;
 561         net_device->send_buf_size = NETVSC_SEND_BUFFER_SIZE;
 562
 563         ret = netvsc_init_buf(device);
 564
 565 cleanup:
 566         return ret;
 567 }
 568
 569 static void netvsc_disconnect_vsp(struct netvsc_device *net_device)
 570 {
 571         netvsc_destroy_buf(net_device);
 572 }
 573
 574 /*
 575  * netvsc_device_remove - Callback when the root bus device is removed
 576  */
 577 int netvsc_device_remove(struct hv_device *device)
 578 {
 579         struct netvsc_device *net_device;
 580         unsigned long flags;
 581
 582         net_device = hv_get_drvdata(device);
 583
 584         netvsc_disconnect_vsp(net_device);
 585
 586         /*
 587          * Since we have already drained, we don't need to busy wait
 588          * as was done in final_release_stor_device()
 589          * Note that we cannot set the ext pointer to NULL until
 590          * we have drained - to drain the outgoing packets, we need to
 591          * allow incoming packets.
 592          */
 593
 594         spin_lock_irqsave(&device->channel->inbound_lock, flags);
 595         hv_set_drvdata(device, NULL);
 596         spin_unlock_irqrestore(&device->channel->inbound_lock, flags);
 597
 598         /*
 599          * At this point, no one should be accessing net_device
 600          * except in here
 601          */
 602         dev_notice(&device->device, "net device safe to remove\n");
 603
 604         /* Now, we can close the channel safely */
 605         vmbus_close(device->channel);
 606
 607         /* Release all resources */
 608         vfree(net_device->sub_cb_buf);
 609         free_netvsc_device(net_device);
 610         return 0;
 611 }
 612
 613
 614 #define RING_AVAIL_PERCENT_HIWATER 20
 615 #define RING_AVAIL_PERCENT_LOWATER 10
 616
 617 /*
 618  * Get the percentage of available bytes to write in the ring.
 619  * The return value is in range from 0 to 100.
 620  */
 621 static inline u32 hv_ringbuf_avail_percent(
 622                 struct hv_ring_buffer_info *ring_info)
 623 {
 624         u32 avail_read, avail_write;
 625
 626         hv_get_ringbuffer_availbytes(ring_info, &avail_read, &avail_write);
 627
 628         return avail_write * 100 / ring_info->ring_datasize;
 629 }
 630
 631 static inline void netvsc_free_send_slot(struct netvsc_device *net_device,
 632                                          u32 index)
 633 {
 634         sync_change_bit(index, net_device->send_section_map);
 635 }
 636
 637 static void netvsc_send_completion(struct netvsc_device *net_device,
 638                                    struct vmbus_channel *incoming_channel,
 639                                    struct hv_device *device,
 640                                    struct vmpacket_descriptor *packet)
 641 {
 642         struct nvsp_message *nvsp_packet;
 643         struct hv_netvsc_packet *nvsc_packet;
 644         struct net_device *ndev;
 645         u32 send_index;
 646         struct sk_buff *skb;
 647
 648         ndev = net_device->ndev;
 649
 650         nvsp_packet = (struct nvsp_message *)((unsigned long)packet +
 651                         (packet->offset8 << 3));
 652
 653         if ((nvsp_packet->hdr.msg_type == NVSP_MSG_TYPE_INIT_COMPLETE) ||
 654             (nvsp_packet->hdr.msg_type ==
 655              NVSP_MSG1_TYPE_SEND_RECV_BUF_COMPLETE) ||
 656             (nvsp_packet->hdr.msg_type ==
 657              NVSP_MSG1_TYPE_SEND_SEND_BUF_COMPLETE) ||
 658             (nvsp_packet->hdr.msg_type ==
 659              NVSP_MSG5_TYPE_SUBCHANNEL)) {
 660                 /* Copy the response back */
 661                 memcpy(&net_device->channel_init_pkt, nvsp_packet,
 662                        sizeof(struct nvsp_message));
 663                 complete(&net_device->channel_init_wait);
 664         } else if (nvsp_packet->hdr.msg_type ==
 665                    NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE) {
 666                 int num_outstanding_sends;
 667                 u16 q_idx = 0;
 668                 struct vmbus_channel *channel = device->channel;
 669                 int queue_sends;
 670
 671                 /* Get the send context */
 672                 skb = (struct sk_buff *)(unsigned long)packet->trans_id;
 673
 674                 /* Notify the layer above us */
 675                 if (skb) {
 676                         nvsc_packet = (struct hv_netvsc_packet *) skb->cb;
 677                         send_index = nvsc_packet->send_buf_index;
 678                         if (send_index != NETVSC_INVALID_INDEX)
 679                                 netvsc_free_send_slot(net_device, send_index);
 680                         q_idx = nvsc_packet->q_idx;
 681                         channel = incoming_channel;
 682                         dev_kfree_skb_any(skb);
 683                 }
 684
 685                 num_outstanding_sends =
 686                         atomic_dec_return(&net_device->num_outstanding_sends);
 687                 queue_sends = atomic_dec_return(&net_device->
 688                                                 queue_sends[q_idx]);
 689
 690                 if (net_device->destroy && num_outstanding_sends == 0)
 691                         wake_up(&net_device->wait_drain);
 692
 693                 if (netif_tx_queue_stopped(netdev_get_tx_queue(ndev, q_idx)) &&
 694                     !net_device->start_remove &&
 695                     (hv_ringbuf_avail_percent(&channel->outbound) >
 696                      RING_AVAIL_PERCENT_HIWATER || queue_sends < 1))
 697                                 netif_tx_wake_queue(netdev_get_tx_queue(
 698                                                     ndev, q_idx));
 699         } else {
 700                 netdev_err(ndev, "Unknown send completion packet type- "
 701                            "%d received!!\n", nvsp_packet->hdr.msg_type);
 702         }
 703
 704 }
 705
 706 static u32 netvsc_get_next_send_section(struct netvsc_device *net_device)
 707 {
 708         unsigned long index;
 709         u32 max_words = net_device->map_words;
 710         unsigned long *map_addr = (unsigned long *)net_device->send_section_map;
 711         u32 section_cnt = net_device->send_section_cnt;
 712         int ret_val = NETVSC_INVALID_INDEX;
 713         int i;
 714         int prev_val;
 715
 716         for (i = 0; i < max_words; i++) {
 717                 if (!~(map_addr[i]))
 718                         continue;
 719                 index = ffz(map_addr[i]);
 720                 prev_val = sync_test_and_set_bit(index, &map_addr[i]);
 721                 if (prev_val)
 722                         continue;
 723                 if ((index + (i * BITS_PER_LONG)) >= section_cnt)
 724                         break;
 725                 ret_val = (index + (i * BITS_PER_LONG));
 726                 break;
 727         }
 728         return ret_val;
 729 }
 730
 731 static u32 netvsc_copy_to_send_buf(struct netvsc_device *net_device,
 732                                    unsigned int section_index,
 733                                    u32 pend_size,
 734                                    struct hv_netvsc_packet *packet,
 735                                    struct rndis_message *rndis_msg,
 736                                    struct hv_page_buffer **pb,
 737                                    struct sk_buff *skb)
 738 {
 739         char *start = net_device->send_buf;
 740         char *dest = start + (section_index * net_device->send_section_size)
 741                      + pend_size;
 742         int i;
 743         bool is_data_pkt = (skb != NULL) ? true : false;
 744         bool xmit_more = (skb != NULL) ? skb->xmit_more : false;
 745         u32 msg_size = 0;
 746         u32 padding = 0;
 747         u32 remain = packet->total_data_buflen % net_device->pkt_align;
 748         u32 page_count = packet->cp_partial ? packet->rmsg_pgcnt :
 749                 packet->page_buf_cnt;
 750
 751         /* Add padding */
 752         if (is_data_pkt && xmit_more && remain &&
 753             !packet->cp_partial) {
 754                 padding = net_device->pkt_align - remain;
 755                 rndis_msg->msg_len += padding;
 756                 packet->total_data_buflen += padding;
 757         }
 758
 759         for (i = 0; i < page_count; i++) {
 760                 char *src = phys_to_virt((*pb)[i].pfn << PAGE_SHIFT);
 761                 u32 offset = (*pb)[i].offset;
 762                 u32 len = (*pb)[i].len;
 763
 764                 memcpy(dest, (src + offset), len);
 765                 msg_size += len;
 766                 dest += len;
 767         }
 768
 769         if (padding) {
 770                 memset(dest, 0, padding);
 771                 msg_size += padding;
 772         }
 773
 774         return msg_size;
 775 }
 776
 777 static inline int netvsc_send_pkt(
 778         struct hv_netvsc_packet *packet,
 779         struct netvsc_device *net_device,
 780         struct hv_page_buffer **pb,
 781         struct sk_buff *skb)
 782 {
 783         struct nvsp_message nvmsg;
 784         u16 q_idx = packet->q_idx;
 785         struct vmbus_channel *out_channel = net_device->chn_table[q_idx];
 786         struct net_device *ndev = net_device->ndev;
 787         u64 req_id;
 788         int ret;
 789         struct hv_page_buffer *pgbuf;
 790         u32 ring_avail = hv_ringbuf_avail_percent(&out_channel->outbound);
 791         bool xmit_more = (skb != NULL) ? skb->xmit_more : false;
 792
 793         nvmsg.hdr.msg_type = NVSP_MSG1_TYPE_SEND_RNDIS_PKT;
 794         if (skb != NULL) {
 795                 /* 0 is RMC_DATA; */
 796                 nvmsg.msg.v1_msg.send_rndis_pkt.channel_type = 0;
 797         } else {
 798                 /* 1 is RMC_CONTROL; */
 799                 nvmsg.msg.v1_msg.send_rndis_pkt.channel_type = 1;
 800         }
 801
 802         nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_index =
 803                 packet->send_buf_index;
 804         if (packet->send_buf_index == NETVSC_INVALID_INDEX)
 805                 nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_size = 0;
 806         else
 807                 nvmsg.msg.v1_msg.send_rndis_pkt.send_buf_section_size =
 808                         packet->total_data_buflen;
 809
 810         req_id = (ulong)skb;
 811
 812         if (out_channel->rescind)
 813                 return -ENODEV;
 814
 815         /*
 816          * It is possible that once we successfully place this packet
 817          * on the ringbuffer, we may stop the queue. In that case, we want
 818          * to notify the host independent of the xmit_more flag. We don't
 819          * need to be precise here; in the worst case we may signal the host
 820          * unnecessarily.
 821          */
 822         if (ring_avail < (RING_AVAIL_PERCENT_LOWATER + 1))
 823                 xmit_more = false;
 824
 825         if (packet->page_buf_cnt) {
 826                 pgbuf = packet->cp_partial ? (*pb) +
 827                         packet->rmsg_pgcnt : (*pb);
 828                 ret = vmbus_sendpacket_pagebuffer_ctl(out_channel,
 829                                                       pgbuf,
 830                                                       packet->page_buf_cnt,
 831                                                       &nvmsg,
 832                                                       sizeof(struct nvsp_message),
 833                                                       req_id,
 834                                                       VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED,
 835                                                       !xmit_more);
 836         } else {
 837                 ret = vmbus_sendpacket_ctl(out_channel, &nvmsg,
 838                                            sizeof(struct nvsp_message),
 839                                            req_id,
 840                                            VM_PKT_DATA_INBAND,
 841                                            VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED,
 842                                            !xmit_more);
 843         }
 844
 845         if (ret == 0) {
 846                 atomic_inc(&net_device->num_outstanding_sends);
 847                 atomic_inc(&net_device->queue_sends[q_idx]);
 848
 849                 if (ring_avail < RING_AVAIL_PERCENT_LOWATER) {
 850                         netif_tx_stop_queue(netdev_get_tx_queue(ndev, q_idx));
 851
 852                         if (atomic_read(&net_device->
 853                                 queue_sends[q_idx]) < 1)
 854                                 netif_tx_wake_queue(netdev_get_tx_queue(
 855                                                     ndev, q_idx));
 856                 }
 857         } else if (ret == -EAGAIN) {
 858                 netif_tx_stop_queue(netdev_get_tx_queue(
 859                                     ndev, q_idx));
 860                 if (atomic_read(&net_device->queue_sends[q_idx]) < 1) {
 861                         netif_tx_wake_queue(netdev_get_tx_queue(
 862                                             ndev, q_idx));
 863                         ret = -ENOSPC;
 864                 }
 865         } else {
 866                 netdev_err(ndev, "Unable to send packet %p ret %d\n",
 867                            packet, ret);
 868         }
 869
 870         return ret;
 871 }
 872
 873 /* Move packet out of multi send data (msd), and clear msd */
 874 static inline void move_pkt_msd(struct hv_netvsc_packet **msd_send,
 875                                 struct sk_buff **msd_skb,
 876                                 struct multi_send_data *msdp)
 877 {
 878         *msd_skb = msdp->skb;
 879         *msd_send = msdp->pkt;
 880         msdp->skb = NULL;
 881         msdp->pkt = NULL;
 882         msdp->count = 0;
 883 }
 884
 885 int netvsc_send(struct hv_device *device,
 886                 struct hv_netvsc_packet *packet,
 887                 struct rndis_message *rndis_msg,
 888                 struct hv_page_buffer **pb,
 889                 struct sk_buff *skb)
 890 {
 891         struct netvsc_device *net_device;
 892         int ret = 0, m_ret = 0;
 893         struct vmbus_channel *out_channel;
 894         u16 q_idx = packet->q_idx;
 895         u32 pktlen = packet->total_data_buflen, msd_len = 0;
 896         unsigned int section_index = NETVSC_INVALID_INDEX;
 897         struct multi_send_data *msdp;
 898         struct hv_netvsc_packet *msd_send = NULL, *cur_send = NULL;
 899         struct sk_buff *msd_skb = NULL;
 900         bool try_batch;
 901         bool xmit_more = (skb != NULL) ? skb->xmit_more : false;
 902
 903         net_device = get_outbound_net_device(device);
 904         if (!net_device)
 905                 return -ENODEV;
 906
 907         out_channel = net_device->chn_table[q_idx];
 908
 909         packet->send_buf_index = NETVSC_INVALID_INDEX;
 910         packet->cp_partial = false;
 911
 912         /* Send control message directly without accessing msd (Multi-Send
 913          * Data) field which may be changed during data packet processing.
 914          */
 915         if (!skb) {
 916                 cur_send = packet;
 917                 goto send_now;
 918         }
 919
 920         msdp = &net_device->msd[q_idx];
 921
 922         /* batch packets in send buffer if possible */
 923         if (msdp->pkt)
 924                 msd_len = msdp->pkt->total_data_buflen;
 925
 926         try_batch = (skb != NULL) && msd_len > 0 && msdp->count <
 927                     net_device->max_pkt;
 928
 929         if (try_batch && msd_len + pktlen + net_device->pkt_align <
 930             net_device->send_section_size) {
 931                 section_index = msdp->pkt->send_buf_index;
 932
 933         } else if (try_batch && msd_len + packet->rmsg_size <
 934                    net_device->send_section_size) {
 935                 section_index = msdp->pkt->send_buf_index;
 936                 packet->cp_partial = true;
 937
 938         } else if ((skb != NULL) && pktlen + net_device->pkt_align <
 939                    net_device->send_section_size) {
 940                 section_index = netvsc_get_next_send_section(net_device);
 941                 if (section_index != NETVSC_INVALID_INDEX) {
 942                         move_pkt_msd(&msd_send, &msd_skb, msdp);
 943                         msd_len = 0;
 944                 }
 945         }
 946
 947         if (section_index != NETVSC_INVALID_INDEX) {
 948                 netvsc_copy_to_send_buf(net_device,
 949                                         section_index, msd_len,
 950                                         packet, rndis_msg, pb, skb);
 951
 952                 packet->send_buf_index = section_index;
 953
 954                 if (packet->cp_partial) {
 955                         packet->page_buf_cnt -= packet->rmsg_pgcnt;
 956                         packet->total_data_buflen = msd_len + packet->rmsg_size;
 957                 } else {
 958                         packet->page_buf_cnt = 0;
 959                         packet->total_data_buflen += msd_len;
 960                 }
 961
 962                 if (msdp->skb)
 963                         dev_kfree_skb_any(msdp->skb);
 964
 965                 if (xmit_more && !packet->cp_partial) {
 966                         msdp->skb = skb;
 967                         msdp->pkt = packet;
 968                         msdp->count++;
 969                 } else {
 970                         cur_send = packet;
 971                         msdp->skb = NULL;
 972                         msdp->pkt = NULL;
 973                         msdp->count = 0;
 974                 }
 975         } else {
 976                 move_pkt_msd(&msd_send, &msd_skb, msdp);
 977                 cur_send = packet;
 978         }
 979
 980         if (msd_send) {
 981                 m_ret = netvsc_send_pkt(msd_send, net_device, NULL, msd_skb);
 982
 983                 if (m_ret != 0) {
 984                         netvsc_free_send_slot(net_device,
 985                                               msd_send->send_buf_index);
 986                         dev_kfree_skb_any(msd_skb);
 987                 }
 988         }
 989
 990 send_now:
 991         if (cur_send)
 992                 ret = netvsc_send_pkt(cur_send, net_device, pb, skb);
 993
 994         if (ret != 0 && section_index != NETVSC_INVALID_INDEX)
 995                 netvsc_free_send_slot(net_device, section_index);
 996
 997         return ret;
 998 }
 999
1000 static void netvsc_send_recv_completion(struct hv_device *device,
1001                                         struct vmbus_channel *channel,
1002                                         struct netvsc_device *net_device,
1003                                         u64 transaction_id, u32 status)
1004 {
1005         struct nvsp_message recvcompMessage;
1006         int retries = 0;
1007         int ret;
1008         struct net_device *ndev;
1009
1010         ndev = net_device->ndev;
1011
1012         recvcompMessage.hdr.msg_type =
1013                                 NVSP_MSG1_TYPE_SEND_RNDIS_PKT_COMPLETE;
1014
1015         recvcompMessage.msg.v1_msg.send_rndis_pkt_complete.status = status;
1016
1017 retry_send_cmplt:
1018         /* Send the completion */
1019         ret = vmbus_sendpacket(channel, &recvcompMessage,
1020                                sizeof(struct nvsp_message), transaction_id,
1021                                VM_PKT_COMP, 0);
1022         if (ret == 0) {
1023                 /* success */
1024                 /* no-op */
1025         } else if (ret == -EAGAIN) {
1026                 /* no more room...wait a bit and attempt to retry 3 times */
1027                 retries++;
1028                 netdev_err(ndev, "unable to send receive completion pkt"
1029                         " (tid %llx)...retrying %d\n", transaction_id, retries);
1030
1031                 if (retries < 4) {
1032                         udelay(100);
1033                         goto retry_send_cmplt;
1034                 } else {
1035                         netdev_err(ndev, "unable to send receive "
1036                                 "completion pkt (tid %llx)...give up retrying\n",
1037                                 transaction_id);
1038                 }
1039         } else {
1040                 netdev_err(ndev, "unable to send receive "
1041                         "completion pkt - %llx\n", transaction_id);
1042         }
1043 }
1044
1045 static void netvsc_receive(struct netvsc_device *net_device,
1046                         struct vmbus_channel *channel,
1047                         struct hv_device *device,
1048                         struct vmpacket_descriptor *packet)
1049 {
1050         struct vmtransfer_page_packet_header *vmxferpage_packet;
1051         struct nvsp_message *nvsp_packet;
1052         struct hv_netvsc_packet nv_pkt;
1053         struct hv_netvsc_packet *netvsc_packet = &nv_pkt;
1054         u32 status = NVSP_STAT_SUCCESS;
1055         int i;
1056         int count = 0;
1057         struct net_device *ndev;
1058         void *data;
1059
1060         ndev = net_device->ndev;
1061
1062         /*
1063          * All inbound packets other than send completion should be xfer page
1064          * packet
1065          */
1066         if (packet->type != VM_PKT_DATA_USING_XFER_PAGES) {
1067                 netdev_err(ndev, "Unknown packet type received - %d\n",
1068                            packet->type);
1069                 return;
1070         }
1071
1072         nvsp_packet = (struct nvsp_message *)((unsigned long)packet +
1073                         (packet->offset8 << 3));
1074
1075         /* Make sure this is a valid nvsp packet */
1076         if (nvsp_packet->hdr.msg_type !=
1077             NVSP_MSG1_TYPE_SEND_RNDIS_PKT) {
1078                 netdev_err(ndev, "Unknown nvsp packet type received-"
1079                         " %d\n", nvsp_packet->hdr.msg_type);
1080                 return;
1081         }
1082
1083         vmxferpage_packet = (struct vmtransfer_page_packet_header *)packet;
1084
1085         if (vmxferpage_packet->xfer_pageset_id != NETVSC_RECEIVE_BUFFER_ID) {
1086                 netdev_err(ndev, "Invalid xfer page set id - "
1087                            "expecting %x got %x\n", NETVSC_RECEIVE_BUFFER_ID,
1088                            vmxferpage_packet->xfer_pageset_id);
1089                 return;
1090         }
1091
1092         count = vmxferpage_packet->range_cnt;
1093
1094         /* Each range represents 1 RNDIS pkt that contains 1 ethernet frame */
1095         for (i = 0; i < count; i++) {
1096                 /* Initialize the netvsc packet */
1097                 data = (void *)((unsigned long)net_device->
1098                         recv_buf + vmxferpage_packet->ranges[i].byte_offset);
1099                 netvsc_packet->total_data_buflen =
1100                                         vmxferpage_packet->ranges[i].byte_count;
1101
1102                 /* Pass it to the upper layer */
1103                 status = rndis_filter_receive(device, netvsc_packet, &data,
1104                                               channel);
1105
1106         }
1107
1108         netvsc_send_recv_completion(device, channel, net_device,
1109                                     vmxferpage_packet->d.trans_id, status);
1110 }
1111
1112
1113 static void netvsc_send_table(struct hv_device *hdev,
1114                               struct nvsp_message *nvmsg)
1115 {
1116         struct netvsc_device *nvscdev;
1117         struct net_device *ndev;
1118         int i;
1119         u32 count, *tab;
1120
1121         nvscdev = get_outbound_net_device(hdev);
1122         if (!nvscdev)
1123                 return;
1124         ndev = nvscdev->ndev;
1125
1126         count = nvmsg->msg.v5_msg.send_table.count;
1127         if (count != VRSS_SEND_TAB_SIZE) {
1128                 netdev_err(ndev, "Received wrong send-table size:%u\n", count);
1129                 return;
1130         }
1131
1132         tab = (u32 *)((unsigned long)&nvmsg->msg.v5_msg.send_table +
1133                       nvmsg->msg.v5_msg.send_table.offset);
1134
1135         for (i = 0; i < count; i++)
1136                 nvscdev->send_table[i] = tab[i];
1137 }
1138
1139 static void netvsc_send_vf(struct netvsc_device *nvdev,
1140                            struct nvsp_message *nvmsg)
1141 {
1142         nvdev->vf_alloc = nvmsg->msg.v4_msg.vf_assoc.allocated;
1143         nvdev->vf_serial = nvmsg->msg.v4_msg.vf_assoc.serial;
1144 }
1145
1146 static inline void netvsc_receive_inband(struct hv_device *hdev,
1147                                          struct netvsc_device *nvdev,
1148                                          struct nvsp_message *nvmsg)
1149 {
1150         switch (nvmsg->hdr.msg_type) {
1151         case NVSP_MSG5_TYPE_SEND_INDIRECTION_TABLE:
1152                 netvsc_send_table(hdev, nvmsg);
1153                 break;
1154
1155         case NVSP_MSG4_TYPE_SEND_VF_ASSOCIATION:
1156                 netvsc_send_vf(nvdev, nvmsg);
1157                 break;
1158         }
1159 }
1160
1161 void netvsc_channel_cb(void *context)
1162 {
1163         int ret;
1164         struct vmbus_channel *channel = (struct vmbus_channel *)context;
1165         struct hv_device *device;
1166         struct netvsc_device *net_device;
1167         u32 bytes_recvd;
1168         u64 request_id;
1169         struct vmpacket_descriptor *desc;
1170         unsigned char *buffer;
1171         int bufferlen = NETVSC_PACKET_SIZE;
1172         struct net_device *ndev;
1173         struct nvsp_message *nvmsg;
1174
1175         if (channel->primary_channel != NULL)
1176                 device = channel->primary_channel->device_obj;
1177         else
1178                 device = channel->device_obj;
1179
1180         net_device = get_inbound_net_device(device);
1181         if (!net_device)
1182                 return;
1183         ndev = net_device->ndev;
1184         buffer = get_per_channel_state(channel);
1185
1186         do {
1187                 ret = vmbus_recvpacket_raw(channel, buffer, bufferlen,
1188                                            &bytes_recvd, &request_id);
1189                 if (ret == 0) {
1190                         if (bytes_recvd > 0) {
1191                                 desc = (struct vmpacket_descriptor *)buffer;
1192                                 nvmsg = (struct nvsp_message *)((unsigned long)
1193                                          desc + (desc->offset8 << 3));
1194                                 switch (desc->type) {
1195                                 case VM_PKT_COMP:
1196                                         netvsc_send_completion(net_device,
1197                                                                 channel,
1198                                                                 device, desc);
1199                                         break;
1200
1201                                 case VM_PKT_DATA_USING_XFER_PAGES:
1202                                         netvsc_receive(net_device, channel,
1203                                                        device, desc);
1204                                         break;
1205
1206                                 case VM_PKT_DATA_INBAND:
1207                                         netvsc_receive_inband(device,
1208                                                               net_device,
1209                                                               nvmsg);
1210                                         break;
1211
1212                                 default:
1213                                         netdev_err(ndev,
1214                                                    "unhandled packet type %d, "
1215                                                    "tid %llx len %d\n",
1216                                                    desc->type, request_id,
1217                                                    bytes_recvd);
1218                                         break;
1219                                 }
1220
1221                         } else {
1222                                 /*
1223                                  * We are done for this pass.
1224                                  */
1225                                 break;
1226                         }
1227
1228                 } else if (ret == -ENOBUFS) {
1229                         if (bufferlen > NETVSC_PACKET_SIZE)
1230                                 kfree(buffer);
1231                         /* Handle large packet */
1232                         buffer = kmalloc(bytes_recvd, GFP_ATOMIC);
1233                         if (buffer == NULL) {
1234                                 /* Try again next time around */
1235                                 netdev_err(ndev,
1236                                            "unable to allocate buffer of size "
1237                                            "(%d)!!\n", bytes_recvd);
1238                                 break;
1239                         }
1240
1241                         bufferlen = bytes_recvd;
1242                 }
1243         } while (1);
1244
1245         if (bufferlen > NETVSC_PACKET_SIZE)
1246                 kfree(buffer);
1247         return;
1248 }
1249
1250 /*
1251  * netvsc_device_add - Callback when the device belonging to this
1252  * driver is added
1253  */
1254 int netvsc_device_add(struct hv_device *device, void *additional_info)
1255 {
1256         int ret = 0;
1257         int ring_size =
1258         ((struct netvsc_device_info *)additional_info)->ring_size;
1259         struct netvsc_device *net_device;
1260         struct net_device *ndev;
1261
1262         net_device = alloc_net_device(device);
1263         if (!net_device)
1264                 return -ENOMEM;
1265
1266         net_device->ring_size = ring_size;
1267
1268         /*
1269          * Coming into this function, struct net_device * is
1270          * registered as the driver private data.
1271          * In alloc_net_device(), we register struct netvsc_device *
1272          * as the driver private data and stash away struct net_device *
1273          * in struct netvsc_device *.
1274          */
1275         ndev = net_device->ndev;
1276
1277         /* Add netvsc_device context to netvsc_device */
1278         net_device->nd_ctx = netdev_priv(ndev);
1279
1280         /* Initialize the NetVSC channel extension */
1281         init_completion(&net_device->channel_init_wait);
1282
1283         set_per_channel_state(device->channel, net_device->cb_buffer);
1284
1285         /* Open the channel */
1286         ret = vmbus_open(device->channel, ring_size * PAGE_SIZE,
1287                          ring_size * PAGE_SIZE, NULL, 0,
1288                          netvsc_channel_cb, device->channel);
1289
1290         if (ret != 0) {
1291                 netdev_err(ndev, "unable to open channel: %d\n", ret);
1292                 goto cleanup;
1293         }
1294
1295         /* Channel is opened */
1296         pr_info("hv_netvsc channel opened successfully\n");
1297
1298         net_device->chn_table[0] = device->channel;
1299
1300         /* Connect with the NetVsp */
1301         ret = netvsc_connect_vsp(device);
1302         if (ret != 0) {
1303                 netdev_err(ndev,
1304                         "unable to connect to NetVSP - %d\n", ret);
1305                 goto close;
1306         }
1307
1308         return ret;
1309
1310 close:
1311         /* Now, we can close the channel safely */
1312         vmbus_close(device->channel);
1313
1314 cleanup:
1315         free_netvsc_device(net_device);
1316
1317         return ret;
1318 }