1 /* 2 * The Virtio 9p transport driver 3 * 4 * This is a block based transport driver based on the lguest block driver 5 * code. 6 * 7 * Copyright (C) 2007, 2008 Eric Van Hensbergen, IBM Corporation 8 * 9 * Based on virtio console driver 10 * Copyright (C) 2006, 2007 Rusty Russell, IBM Corporation 11 * 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License version 2 14 * as published by the Free Software Foundation. 15 * 16 * This program is distributed in the hope that it will be useful, 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19 * GNU General Public License for more details. 20 * 21 * You should have received a copy of the GNU General Public License 22 * along with this program; if not, write to: 23 * Free Software Foundation 24 * 51 Franklin Street, Fifth Floor 25 * Boston, MA 02111-1301 USA 26 * 27 */ 28 29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 30 31 #include <linux/in.h> 32 #include <linux/module.h> 33 #include <linux/net.h> 34 #include <linux/ipv6.h> 35 #include <linux/errno.h> 36 #include <linux/kernel.h> 37 #include <linux/un.h> 38 #include <linux/uaccess.h> 39 #include <linux/inet.h> 40 #include <linux/idr.h> 41 #include <linux/file.h> 42 #include <linux/highmem.h> 43 #include <linux/slab.h> 44 #include <net/9p/9p.h> 45 #include <linux/parser.h> 46 #include <net/9p/client.h> 47 #include <net/9p/transport.h> 48 #include <linux/scatterlist.h> 49 #include <linux/swap.h> 50 #include <linux/virtio.h> 51 #include <linux/virtio_9p.h> 52 #include "trans_common.h" 53 54 #define VIRTQUEUE_NUM 128 55 56 /* a single mutex to manage channel initialization and attachment */ 57 static DEFINE_MUTEX(virtio_9p_lock); 58 static DECLARE_WAIT_QUEUE_HEAD(vp_wq); 59 static atomic_t vp_pinned = ATOMIC_INIT(0); 60 61 /** 62 * struct virtio_chan - per-instance transport information 63 * @initialized: whether the channel is initialized 64 * @inuse: whether the channel is in use 65 * @lock: protects multiple elements within this structure 66 * @client: client instance 67 * @vdev: virtio dev associated with this channel 68 * @vq: virtio queue associated with this channel 69 * @sg: scatter gather list which is used to pack a request (protected?) 70 * 71 * We keep all per-channel information in a structure. 72 * This structure is allocated within the devices dev->mem space. 73 * A pointer to the structure will get put in the transport private. 74 * 75 */ 76 77 struct virtio_chan { 78 bool inuse; 79 80 spinlock_t lock; 81 82 struct p9_client *client; 83 struct virtio_device *vdev; 84 struct virtqueue *vq; 85 int ring_bufs_avail; 86 wait_queue_head_t *vc_wq; 87 /* This is global limit. Since we don't have a global structure, 88 * will be placing it in each channel. 89 */ 90 unsigned long p9_max_pages; 91 /* Scatterlist: can be too big for stack. */ 92 struct scatterlist sg[VIRTQUEUE_NUM]; 93 94 int tag_len; 95 /* 96 * tag name to identify a mount Non-null terminated 97 */ 98 char *tag; 99 100 struct list_head chan_list; 101 }; 102 103 static struct list_head virtio_chan_list; 104 105 /* How many bytes left in this page. */ 106 static unsigned int rest_of_page(void *data) 107 { 108 return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE); 109 } 110 111 /** 112 * p9_virtio_close - reclaim resources of a channel 113 * @client: client instance 114 * 115 * This reclaims a channel by freeing its resources and 116 * reseting its inuse flag. 117 * 118 */ 119 120 static void p9_virtio_close(struct p9_client *client) 121 { 122 struct virtio_chan *chan = client->trans; 123 124 mutex_lock(&virtio_9p_lock); 125 if (chan) 126 chan->inuse = false; 127 mutex_unlock(&virtio_9p_lock); 128 } 129 130 /** 131 * req_done - callback which signals activity from the server 132 * @vq: virtio queue activity was received on 133 * 134 * This notifies us that the server has triggered some activity 135 * on the virtio channel - most likely a response to request we 136 * sent. Figure out which requests now have responses and wake up 137 * those threads. 138 * 139 * Bugs: could do with some additional sanity checking, but appears to work. 140 * 141 */ 142 143 static void req_done(struct virtqueue *vq) 144 { 145 struct virtio_chan *chan = vq->vdev->priv; 146 struct p9_fcall *rc; 147 unsigned int len; 148 struct p9_req_t *req; 149 unsigned long flags; 150 151 p9_debug(P9_DEBUG_TRANS, ": request done\n"); 152 153 while (1) { 154 spin_lock_irqsave(&chan->lock, flags); 155 rc = virtqueue_get_buf(chan->vq, &len); 156 if (rc == NULL) { 157 spin_unlock_irqrestore(&chan->lock, flags); 158 break; 159 } 160 chan->ring_bufs_avail = 1; 161 spin_unlock_irqrestore(&chan->lock, flags); 162 /* Wakeup if anyone waiting for VirtIO ring space. */ 163 wake_up(chan->vc_wq); 164 p9_debug(P9_DEBUG_TRANS, ": rc %p\n", rc); 165 p9_debug(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag); 166 req = p9_tag_lookup(chan->client, rc->tag); 167 req->status = REQ_STATUS_RCVD; 168 p9_client_cb(chan->client, req); 169 } 170 } 171 172 /** 173 * pack_sg_list - pack a scatter gather list from a linear buffer 174 * @sg: scatter/gather list to pack into 175 * @start: which segment of the sg_list to start at 176 * @limit: maximum segment to pack data to 177 * @data: data to pack into scatter/gather list 178 * @count: amount of data to pack into the scatter/gather list 179 * 180 * sg_lists have multiple segments of various sizes. This will pack 181 * arbitrary data into an existing scatter gather list, segmenting the 182 * data as necessary within constraints. 183 * 184 */ 185 186 static int pack_sg_list(struct scatterlist *sg, int start, 187 int limit, char *data, int count) 188 { 189 int s; 190 int index = start; 191 192 while (count) { 193 s = rest_of_page(data); 194 if (s > count) 195 s = count; 196 BUG_ON(index > limit); 197 /* Make sure we don't terminate early. */ 198 sg_unmark_end(&sg[index]); 199 sg_set_buf(&sg[index++], data, s); 200 count -= s; 201 data += s; 202 } 203 if (index-start) 204 sg_mark_end(&sg[index - 1]); 205 return index-start; 206 } 207 208 /* We don't currently allow canceling of virtio requests */ 209 static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) 210 { 211 return 1; 212 } 213 214 /** 215 * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer, 216 * this takes a list of pages. 217 * @sg: scatter/gather list to pack into 218 * @start: which segment of the sg_list to start at 219 * @pdata: a list of pages to add into sg. 220 * @nr_pages: number of pages to pack into the scatter/gather list 221 * @data: data to pack into scatter/gather list 222 * @count: amount of data to pack into the scatter/gather list 223 */ 224 static int 225 pack_sg_list_p(struct scatterlist *sg, int start, int limit, 226 struct page **pdata, int nr_pages, char *data, int count) 227 { 228 int i = 0, s; 229 int data_off; 230 int index = start; 231 232 BUG_ON(nr_pages > (limit - start)); 233 /* 234 * if the first page doesn't start at 235 * page boundary find the offset 236 */ 237 data_off = offset_in_page(data); 238 while (nr_pages) { 239 s = rest_of_page(data); 240 if (s > count) 241 s = count; 242 /* Make sure we don't terminate early. */ 243 sg_unmark_end(&sg[index]); 244 sg_set_page(&sg[index++], pdata[i++], s, data_off); 245 data_off = 0; 246 data += s; 247 count -= s; 248 nr_pages--; 249 } 250 251 if (index-start) 252 sg_mark_end(&sg[index - 1]); 253 return index - start; 254 } 255 256 /** 257 * p9_virtio_request - issue a request 258 * @client: client instance issuing the request 259 * @req: request to be issued 260 * 261 */ 262 263 static int 264 p9_virtio_request(struct p9_client *client, struct p9_req_t *req) 265 { 266 int err; 267 int in, out, out_sgs, in_sgs; 268 unsigned long flags; 269 struct virtio_chan *chan = client->trans; 270 struct scatterlist *sgs[2]; 271 272 p9_debug(P9_DEBUG_TRANS, "9p debug: virtio request\n"); 273 274 req->status = REQ_STATUS_SENT; 275 req_retry: 276 spin_lock_irqsave(&chan->lock, flags); 277 278 out_sgs = in_sgs = 0; 279 /* Handle out VirtIO ring buffers */ 280 out = pack_sg_list(chan->sg, 0, 281 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size); 282 if (out) 283 sgs[out_sgs++] = chan->sg; 284 285 in = pack_sg_list(chan->sg, out, 286 VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity); 287 if (in) 288 sgs[out_sgs + in_sgs++] = chan->sg + out; 289 290 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc, 291 GFP_ATOMIC); 292 if (err < 0) { 293 if (err == -ENOSPC) { 294 chan->ring_bufs_avail = 0; 295 spin_unlock_irqrestore(&chan->lock, flags); 296 err = wait_event_interruptible(*chan->vc_wq, 297 chan->ring_bufs_avail); 298 if (err == -ERESTARTSYS) 299 return err; 300 301 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n"); 302 goto req_retry; 303 } else { 304 spin_unlock_irqrestore(&chan->lock, flags); 305 p9_debug(P9_DEBUG_TRANS, 306 "virtio rpc add_sgs returned failure\n"); 307 return -EIO; 308 } 309 } 310 virtqueue_kick(chan->vq); 311 spin_unlock_irqrestore(&chan->lock, flags); 312 313 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n"); 314 return 0; 315 } 316 317 static int p9_get_mapped_pages(struct virtio_chan *chan, 318 struct page **pages, char *data, 319 int nr_pages, int write, int kern_buf) 320 { 321 int err; 322 if (!kern_buf) { 323 /* 324 * We allow only p9_max_pages pinned. We wait for the 325 * Other zc request to finish here 326 */ 327 if (atomic_read(&vp_pinned) >= chan->p9_max_pages) { 328 err = wait_event_interruptible(vp_wq, 329 (atomic_read(&vp_pinned) < chan->p9_max_pages)); 330 if (err == -ERESTARTSYS) 331 return err; 332 } 333 err = p9_payload_gup(data, &nr_pages, pages, write); 334 if (err < 0) 335 return err; 336 atomic_add(nr_pages, &vp_pinned); 337 } else { 338 /* kernel buffer, no need to pin pages */ 339 int s, index = 0; 340 int count = nr_pages; 341 while (nr_pages) { 342 s = rest_of_page(data); 343 if (is_vmalloc_addr(data)) 344 pages[index++] = vmalloc_to_page(data); 345 else 346 pages[index++] = kmap_to_page(data); 347 data += s; 348 nr_pages--; 349 } 350 nr_pages = count; 351 } 352 return nr_pages; 353 } 354 355 /** 356 * p9_virtio_zc_request - issue a zero copy request 357 * @client: client instance issuing the request 358 * @req: request to be issued 359 * @uidata: user bffer that should be ued for zero copy read 360 * @uodata: user buffer that shoud be user for zero copy write 361 * @inlen: read buffer size 362 * @olen: write buffer size 363 * @hdrlen: reader header size, This is the size of response protocol data 364 * 365 */ 366 static int 367 p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req, 368 char *uidata, char *uodata, int inlen, 369 int outlen, int in_hdr_len, int kern_buf) 370 { 371 int in, out, err, out_sgs, in_sgs; 372 unsigned long flags; 373 int in_nr_pages = 0, out_nr_pages = 0; 374 struct page **in_pages = NULL, **out_pages = NULL; 375 struct virtio_chan *chan = client->trans; 376 struct scatterlist *sgs[4]; 377 378 p9_debug(P9_DEBUG_TRANS, "virtio request\n"); 379 380 if (uodata) { 381 out_nr_pages = p9_nr_pages(uodata, outlen); 382 out_pages = kmalloc(sizeof(struct page *) * out_nr_pages, 383 GFP_NOFS); 384 if (!out_pages) { 385 err = -ENOMEM; 386 goto err_out; 387 } 388 out_nr_pages = p9_get_mapped_pages(chan, out_pages, uodata, 389 out_nr_pages, 0, kern_buf); 390 if (out_nr_pages < 0) { 391 err = out_nr_pages; 392 kfree(out_pages); 393 out_pages = NULL; 394 goto err_out; 395 } 396 } 397 if (uidata) { 398 in_nr_pages = p9_nr_pages(uidata, inlen); 399 in_pages = kmalloc(sizeof(struct page *) * in_nr_pages, 400 GFP_NOFS); 401 if (!in_pages) { 402 err = -ENOMEM; 403 goto err_out; 404 } 405 in_nr_pages = p9_get_mapped_pages(chan, in_pages, uidata, 406 in_nr_pages, 1, kern_buf); 407 if (in_nr_pages < 0) { 408 err = in_nr_pages; 409 kfree(in_pages); 410 in_pages = NULL; 411 goto err_out; 412 } 413 } 414 req->status = REQ_STATUS_SENT; 415 req_retry_pinned: 416 spin_lock_irqsave(&chan->lock, flags); 417 418 out_sgs = in_sgs = 0; 419 420 /* out data */ 421 out = pack_sg_list(chan->sg, 0, 422 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size); 423 424 if (out) 425 sgs[out_sgs++] = chan->sg; 426 427 if (out_pages) { 428 sgs[out_sgs++] = chan->sg + out; 429 out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM, 430 out_pages, out_nr_pages, uodata, outlen); 431 } 432 433 /* 434 * Take care of in data 435 * For example TREAD have 11. 436 * 11 is the read/write header = PDU Header(7) + IO Size (4). 437 * Arrange in such a way that server places header in the 438 * alloced memory and payload onto the user buffer. 439 */ 440 in = pack_sg_list(chan->sg, out, 441 VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len); 442 if (in) 443 sgs[out_sgs + in_sgs++] = chan->sg + out; 444 445 if (in_pages) { 446 sgs[out_sgs + in_sgs++] = chan->sg + out + in; 447 in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM, 448 in_pages, in_nr_pages, uidata, inlen); 449 } 450 451 BUG_ON(out_sgs + in_sgs > ARRAY_SIZE(sgs)); 452 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req->tc, 453 GFP_ATOMIC); 454 if (err < 0) { 455 if (err == -ENOSPC) { 456 chan->ring_bufs_avail = 0; 457 spin_unlock_irqrestore(&chan->lock, flags); 458 err = wait_event_interruptible(*chan->vc_wq, 459 chan->ring_bufs_avail); 460 if (err == -ERESTARTSYS) 461 goto err_out; 462 463 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n"); 464 goto req_retry_pinned; 465 } else { 466 spin_unlock_irqrestore(&chan->lock, flags); 467 p9_debug(P9_DEBUG_TRANS, 468 "virtio rpc add_sgs returned failure\n"); 469 err = -EIO; 470 goto err_out; 471 } 472 } 473 virtqueue_kick(chan->vq); 474 spin_unlock_irqrestore(&chan->lock, flags); 475 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n"); 476 err = wait_event_interruptible(*req->wq, 477 req->status >= REQ_STATUS_RCVD); 478 /* 479 * Non kernel buffers are pinned, unpin them 480 */ 481 err_out: 482 if (!kern_buf) { 483 if (in_pages) { 484 p9_release_pages(in_pages, in_nr_pages); 485 atomic_sub(in_nr_pages, &vp_pinned); 486 } 487 if (out_pages) { 488 p9_release_pages(out_pages, out_nr_pages); 489 atomic_sub(out_nr_pages, &vp_pinned); 490 } 491 /* wakeup anybody waiting for slots to pin pages */ 492 wake_up(&vp_wq); 493 } 494 kfree(in_pages); 495 kfree(out_pages); 496 return err; 497 } 498 499 static ssize_t p9_mount_tag_show(struct device *dev, 500 struct device_attribute *attr, char *buf) 501 { 502 struct virtio_chan *chan; 503 struct virtio_device *vdev; 504 505 vdev = dev_to_virtio(dev); 506 chan = vdev->priv; 507 508 return snprintf(buf, chan->tag_len + 1, "%s", chan->tag); 509 } 510 511 static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL); 512 513 /** 514 * p9_virtio_probe - probe for existence of 9P virtio channels 515 * @vdev: virtio device to probe 516 * 517 * This probes for existing virtio channels. 518 * 519 */ 520 521 static int p9_virtio_probe(struct virtio_device *vdev) 522 { 523 __u16 tag_len; 524 char *tag; 525 int err; 526 struct virtio_chan *chan; 527 528 chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL); 529 if (!chan) { 530 pr_err("Failed to allocate virtio 9P channel\n"); 531 err = -ENOMEM; 532 goto fail; 533 } 534 535 chan->vdev = vdev; 536 537 /* We expect one virtqueue, for requests. */ 538 chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); 539 if (IS_ERR(chan->vq)) { 540 err = PTR_ERR(chan->vq); 541 goto out_free_vq; 542 } 543 chan->vq->vdev->priv = chan; 544 spin_lock_init(&chan->lock); 545 546 sg_init_table(chan->sg, VIRTQUEUE_NUM); 547 548 chan->inuse = false; 549 if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) { 550 virtio_cread(vdev, struct virtio_9p_config, tag_len, &tag_len); 551 } else { 552 err = -EINVAL; 553 goto out_free_vq; 554 } 555 tag = kmalloc(tag_len, GFP_KERNEL); 556 if (!tag) { 557 err = -ENOMEM; 558 goto out_free_vq; 559 } 560 561 virtio_cread_bytes(vdev, offsetof(struct virtio_9p_config, tag), 562 tag, tag_len); 563 chan->tag = tag; 564 chan->tag_len = tag_len; 565 err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); 566 if (err) { 567 goto out_free_tag; 568 } 569 chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL); 570 if (!chan->vc_wq) { 571 err = -ENOMEM; 572 goto out_free_tag; 573 } 574 init_waitqueue_head(chan->vc_wq); 575 chan->ring_bufs_avail = 1; 576 /* Ceiling limit to avoid denial of service attacks */ 577 chan->p9_max_pages = nr_free_buffer_pages()/4; 578 579 mutex_lock(&virtio_9p_lock); 580 list_add_tail(&chan->chan_list, &virtio_chan_list); 581 mutex_unlock(&virtio_9p_lock); 582 583 /* Let udev rules use the new mount_tag attribute. */ 584 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE); 585 586 return 0; 587 588 out_free_tag: 589 kfree(tag); 590 out_free_vq: 591 vdev->config->del_vqs(vdev); 592 kfree(chan); 593 fail: 594 return err; 595 } 596 597 598 /** 599 * p9_virtio_create - allocate a new virtio channel 600 * @client: client instance invoking this transport 601 * @devname: string identifying the channel to connect to (unused) 602 * @args: args passed from sys_mount() for per-transport options (unused) 603 * 604 * This sets up a transport channel for 9p communication. Right now 605 * we only match the first available channel, but eventually we couldlook up 606 * alternate channels by matching devname versus a virtio_config entry. 607 * We use a simple reference count mechanism to ensure that only a single 608 * mount has a channel open at a time. 609 * 610 */ 611 612 static int 613 p9_virtio_create(struct p9_client *client, const char *devname, char *args) 614 { 615 struct virtio_chan *chan; 616 int ret = -ENOENT; 617 int found = 0; 618 619 mutex_lock(&virtio_9p_lock); 620 list_for_each_entry(chan, &virtio_chan_list, chan_list) { 621 if (!strncmp(devname, chan->tag, chan->tag_len) && 622 strlen(devname) == chan->tag_len) { 623 if (!chan->inuse) { 624 chan->inuse = true; 625 found = 1; 626 break; 627 } 628 ret = -EBUSY; 629 } 630 } 631 mutex_unlock(&virtio_9p_lock); 632 633 if (!found) { 634 pr_err("no channels available\n"); 635 return ret; 636 } 637 638 client->trans = (void *)chan; 639 client->status = Connected; 640 chan->client = client; 641 642 return 0; 643 } 644 645 /** 646 * p9_virtio_remove - clean up resources associated with a virtio device 647 * @vdev: virtio device to remove 648 * 649 */ 650 651 static void p9_virtio_remove(struct virtio_device *vdev) 652 { 653 struct virtio_chan *chan = vdev->priv; 654 655 if (chan->inuse) 656 p9_virtio_close(chan->client); 657 vdev->config->del_vqs(vdev); 658 659 mutex_lock(&virtio_9p_lock); 660 list_del(&chan->chan_list); 661 mutex_unlock(&virtio_9p_lock); 662 sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); 663 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE); 664 kfree(chan->tag); 665 kfree(chan->vc_wq); 666 kfree(chan); 667 668 } 669 670 static struct virtio_device_id id_table[] = { 671 { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID }, 672 { 0 }, 673 }; 674 675 static unsigned int features[] = { 676 VIRTIO_9P_MOUNT_TAG, 677 }; 678 679 /* The standard "struct lguest_driver": */ 680 static struct virtio_driver p9_virtio_drv = { 681 .feature_table = features, 682 .feature_table_size = ARRAY_SIZE(features), 683 .driver.name = KBUILD_MODNAME, 684 .driver.owner = THIS_MODULE, 685 .id_table = id_table, 686 .probe = p9_virtio_probe, 687 .remove = p9_virtio_remove, 688 }; 689 690 static struct p9_trans_module p9_virtio_trans = { 691 .name = "virtio", 692 .create = p9_virtio_create, 693 .close = p9_virtio_close, 694 .request = p9_virtio_request, 695 .zc_request = p9_virtio_zc_request, 696 .cancel = p9_virtio_cancel, 697 /* 698 * We leave one entry for input and one entry for response 699 * headers. We also skip one more entry to accomodate, address 700 * that are not at page boundary, that can result in an extra 701 * page in zero copy. 702 */ 703 .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3), 704 .def = 1, 705 .owner = THIS_MODULE, 706 }; 707 708 /* The standard init function */ 709 static int __init p9_virtio_init(void) 710 { 711 INIT_LIST_HEAD(&virtio_chan_list); 712 713 v9fs_register_trans(&p9_virtio_trans); 714 return register_virtio_driver(&p9_virtio_drv); 715 } 716 717 static void __exit p9_virtio_cleanup(void) 718 { 719 unregister_virtio_driver(&p9_virtio_drv); 720 v9fs_unregister_trans(&p9_virtio_trans); 721 } 722 723 module_init(p9_virtio_init); 724 module_exit(p9_virtio_cleanup); 725 726 MODULE_DEVICE_TABLE(virtio, id_table); 727 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); 728 MODULE_DESCRIPTION("Virtio 9p Transport"); 729 MODULE_LICENSE("GPL"); 730