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 * @inuse: whether the channel is in use 64 * @lock: protects multiple elements within this structure 65 * @client: client instance 66 * @vdev: virtio dev associated with this channel 67 * @vq: virtio queue associated with this channel 68 * @sg: scatter gather list which is used to pack a request (protected?) 69 * 70 * We keep all per-channel information in a structure. 71 * This structure is allocated within the devices dev->mem space. 72 * A pointer to the structure will get put in the transport private. 73 * 74 */ 75 76 struct virtio_chan { 77 bool inuse; 78 79 spinlock_t lock; 80 81 struct p9_client *client; 82 struct virtio_device *vdev; 83 struct virtqueue *vq; 84 int ring_bufs_avail; 85 wait_queue_head_t *vc_wq; 86 /* This is global limit. Since we don't have a global structure, 87 * will be placing it in each channel. 88 */ 89 unsigned long p9_max_pages; 90 /* Scatterlist: can be too big for stack. */ 91 struct scatterlist sg[VIRTQUEUE_NUM]; 92 93 int tag_len; 94 /* 95 * tag name to identify a mount Non-null terminated 96 */ 97 char *tag; 98 99 struct list_head chan_list; 100 }; 101 102 static struct list_head virtio_chan_list; 103 104 /* How many bytes left in this page. */ 105 static unsigned int rest_of_page(void *data) 106 { 107 return PAGE_SIZE - offset_in_page(data); 108 } 109 110 /** 111 * p9_virtio_close - reclaim resources of a channel 112 * @client: client instance 113 * 114 * This reclaims a channel by freeing its resources and 115 * reseting its inuse flag. 116 * 117 */ 118 119 static void p9_virtio_close(struct p9_client *client) 120 { 121 struct virtio_chan *chan = client->trans; 122 123 mutex_lock(&virtio_9p_lock); 124 if (chan) 125 chan->inuse = false; 126 mutex_unlock(&virtio_9p_lock); 127 } 128 129 /** 130 * req_done - callback which signals activity from the server 131 * @vq: virtio queue activity was received on 132 * 133 * This notifies us that the server has triggered some activity 134 * on the virtio channel - most likely a response to request we 135 * sent. Figure out which requests now have responses and wake up 136 * those threads. 137 * 138 * Bugs: could do with some additional sanity checking, but appears to work. 139 * 140 */ 141 142 static void req_done(struct virtqueue *vq) 143 { 144 struct virtio_chan *chan = vq->vdev->priv; 145 unsigned int len; 146 struct p9_req_t *req; 147 unsigned long flags; 148 149 p9_debug(P9_DEBUG_TRANS, ": request done\n"); 150 151 while (1) { 152 spin_lock_irqsave(&chan->lock, flags); 153 req = virtqueue_get_buf(chan->vq, &len); 154 if (req == NULL) { 155 spin_unlock_irqrestore(&chan->lock, flags); 156 break; 157 } 158 chan->ring_bufs_avail = 1; 159 spin_unlock_irqrestore(&chan->lock, flags); 160 /* Wakeup if anyone waiting for VirtIO ring space. */ 161 wake_up(chan->vc_wq); 162 if (len) 163 p9_client_cb(chan->client, req, REQ_STATUS_RCVD); 164 } 165 } 166 167 /** 168 * pack_sg_list - pack a scatter gather list from a linear buffer 169 * @sg: scatter/gather list to pack into 170 * @start: which segment of the sg_list to start at 171 * @limit: maximum segment to pack data to 172 * @data: data to pack into scatter/gather list 173 * @count: amount of data to pack into the scatter/gather list 174 * 175 * sg_lists have multiple segments of various sizes. This will pack 176 * arbitrary data into an existing scatter gather list, segmenting the 177 * data as necessary within constraints. 178 * 179 */ 180 181 static int pack_sg_list(struct scatterlist *sg, int start, 182 int limit, char *data, int count) 183 { 184 int s; 185 int index = start; 186 187 while (count) { 188 s = rest_of_page(data); 189 if (s > count) 190 s = count; 191 BUG_ON(index > limit); 192 /* Make sure we don't terminate early. */ 193 sg_unmark_end(&sg[index]); 194 sg_set_buf(&sg[index++], data, s); 195 count -= s; 196 data += s; 197 } 198 if (index-start) 199 sg_mark_end(&sg[index - 1]); 200 return index-start; 201 } 202 203 /* We don't currently allow canceling of virtio requests */ 204 static int p9_virtio_cancel(struct p9_client *client, struct p9_req_t *req) 205 { 206 return 1; 207 } 208 209 /** 210 * pack_sg_list_p - Just like pack_sg_list. Instead of taking a buffer, 211 * this takes a list of pages. 212 * @sg: scatter/gather list to pack into 213 * @start: which segment of the sg_list to start at 214 * @pdata: a list of pages to add into sg. 215 * @nr_pages: number of pages to pack into the scatter/gather list 216 * @offs: amount of data in the beginning of first page _not_ to pack 217 * @count: amount of data to pack into the scatter/gather list 218 */ 219 static int 220 pack_sg_list_p(struct scatterlist *sg, int start, int limit, 221 struct page **pdata, int nr_pages, size_t offs, int count) 222 { 223 int i = 0, s; 224 int data_off = offs; 225 int index = start; 226 227 BUG_ON(nr_pages > (limit - start)); 228 /* 229 * if the first page doesn't start at 230 * page boundary find the offset 231 */ 232 while (nr_pages) { 233 s = PAGE_SIZE - data_off; 234 if (s > count) 235 s = count; 236 /* Make sure we don't terminate early. */ 237 sg_unmark_end(&sg[index]); 238 sg_set_page(&sg[index++], pdata[i++], s, data_off); 239 data_off = 0; 240 count -= s; 241 nr_pages--; 242 } 243 244 if (index-start) 245 sg_mark_end(&sg[index - 1]); 246 return index - start; 247 } 248 249 /** 250 * p9_virtio_request - issue a request 251 * @client: client instance issuing the request 252 * @req: request to be issued 253 * 254 */ 255 256 static int 257 p9_virtio_request(struct p9_client *client, struct p9_req_t *req) 258 { 259 int err; 260 int in, out, out_sgs, in_sgs; 261 unsigned long flags; 262 struct virtio_chan *chan = client->trans; 263 struct scatterlist *sgs[2]; 264 265 p9_debug(P9_DEBUG_TRANS, "9p debug: virtio request\n"); 266 267 req->status = REQ_STATUS_SENT; 268 req_retry: 269 spin_lock_irqsave(&chan->lock, flags); 270 271 out_sgs = in_sgs = 0; 272 /* Handle out VirtIO ring buffers */ 273 out = pack_sg_list(chan->sg, 0, 274 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size); 275 if (out) 276 sgs[out_sgs++] = chan->sg; 277 278 in = pack_sg_list(chan->sg, out, 279 VIRTQUEUE_NUM, req->rc->sdata, req->rc->capacity); 280 if (in) 281 sgs[out_sgs + in_sgs++] = chan->sg + out; 282 283 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req, 284 GFP_ATOMIC); 285 if (err < 0) { 286 if (err == -ENOSPC) { 287 chan->ring_bufs_avail = 0; 288 spin_unlock_irqrestore(&chan->lock, flags); 289 err = wait_event_killable(*chan->vc_wq, 290 chan->ring_bufs_avail); 291 if (err == -ERESTARTSYS) 292 return err; 293 294 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n"); 295 goto req_retry; 296 } else { 297 spin_unlock_irqrestore(&chan->lock, flags); 298 p9_debug(P9_DEBUG_TRANS, 299 "virtio rpc add_sgs returned failure\n"); 300 return -EIO; 301 } 302 } 303 virtqueue_kick(chan->vq); 304 spin_unlock_irqrestore(&chan->lock, flags); 305 306 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n"); 307 return 0; 308 } 309 310 static int p9_get_mapped_pages(struct virtio_chan *chan, 311 struct page ***pages, 312 struct iov_iter *data, 313 int count, 314 size_t *offs, 315 int *need_drop) 316 { 317 int nr_pages; 318 int err; 319 320 if (!iov_iter_count(data)) 321 return 0; 322 323 if (!(data->type & ITER_KVEC)) { 324 int n; 325 /* 326 * We allow only p9_max_pages pinned. We wait for the 327 * Other zc request to finish here 328 */ 329 if (atomic_read(&vp_pinned) >= chan->p9_max_pages) { 330 err = wait_event_killable(vp_wq, 331 (atomic_read(&vp_pinned) < chan->p9_max_pages)); 332 if (err == -ERESTARTSYS) 333 return err; 334 } 335 n = iov_iter_get_pages_alloc(data, pages, count, offs); 336 if (n < 0) 337 return n; 338 *need_drop = 1; 339 nr_pages = DIV_ROUND_UP(n + *offs, PAGE_SIZE); 340 atomic_add(nr_pages, &vp_pinned); 341 return n; 342 } else { 343 /* kernel buffer, no need to pin pages */ 344 int index; 345 size_t len; 346 void *p; 347 348 /* we'd already checked that it's non-empty */ 349 while (1) { 350 len = iov_iter_single_seg_count(data); 351 if (likely(len)) { 352 p = data->kvec->iov_base + data->iov_offset; 353 break; 354 } 355 iov_iter_advance(data, 0); 356 } 357 if (len > count) 358 len = count; 359 360 nr_pages = DIV_ROUND_UP((unsigned long)p + len, PAGE_SIZE) - 361 (unsigned long)p / PAGE_SIZE; 362 363 *pages = kmalloc_array(nr_pages, sizeof(struct page *), 364 GFP_NOFS); 365 if (!*pages) 366 return -ENOMEM; 367 368 *need_drop = 0; 369 p -= (*offs = offset_in_page(p)); 370 for (index = 0; index < nr_pages; index++) { 371 if (is_vmalloc_addr(p)) 372 (*pages)[index] = vmalloc_to_page(p); 373 else 374 (*pages)[index] = kmap_to_page(p); 375 p += PAGE_SIZE; 376 } 377 return len; 378 } 379 } 380 381 /** 382 * p9_virtio_zc_request - issue a zero copy request 383 * @client: client instance issuing the request 384 * @req: request to be issued 385 * @uidata: user buffer that should be used for zero copy read 386 * @uodata: user buffer that should be used for zero copy write 387 * @inlen: read buffer size 388 * @outlen: write buffer size 389 * @in_hdr_len: reader header size, This is the size of response protocol data 390 * 391 */ 392 static int 393 p9_virtio_zc_request(struct p9_client *client, struct p9_req_t *req, 394 struct iov_iter *uidata, struct iov_iter *uodata, 395 int inlen, int outlen, int in_hdr_len) 396 { 397 int in, out, err, out_sgs, in_sgs; 398 unsigned long flags; 399 int in_nr_pages = 0, out_nr_pages = 0; 400 struct page **in_pages = NULL, **out_pages = NULL; 401 struct virtio_chan *chan = client->trans; 402 struct scatterlist *sgs[4]; 403 size_t offs; 404 int need_drop = 0; 405 406 p9_debug(P9_DEBUG_TRANS, "virtio request\n"); 407 408 if (uodata) { 409 __le32 sz; 410 int n = p9_get_mapped_pages(chan, &out_pages, uodata, 411 outlen, &offs, &need_drop); 412 if (n < 0) 413 return n; 414 out_nr_pages = DIV_ROUND_UP(n + offs, PAGE_SIZE); 415 if (n != outlen) { 416 __le32 v = cpu_to_le32(n); 417 memcpy(&req->tc->sdata[req->tc->size - 4], &v, 4); 418 outlen = n; 419 } 420 /* The size field of the message must include the length of the 421 * header and the length of the data. We didn't actually know 422 * the length of the data until this point so add it in now. 423 */ 424 sz = cpu_to_le32(req->tc->size + outlen); 425 memcpy(&req->tc->sdata[0], &sz, sizeof(sz)); 426 } else if (uidata) { 427 int n = p9_get_mapped_pages(chan, &in_pages, uidata, 428 inlen, &offs, &need_drop); 429 if (n < 0) 430 return n; 431 in_nr_pages = DIV_ROUND_UP(n + offs, PAGE_SIZE); 432 if (n != inlen) { 433 __le32 v = cpu_to_le32(n); 434 memcpy(&req->tc->sdata[req->tc->size - 4], &v, 4); 435 inlen = n; 436 } 437 } 438 req->status = REQ_STATUS_SENT; 439 req_retry_pinned: 440 spin_lock_irqsave(&chan->lock, flags); 441 442 out_sgs = in_sgs = 0; 443 444 /* out data */ 445 out = pack_sg_list(chan->sg, 0, 446 VIRTQUEUE_NUM, req->tc->sdata, req->tc->size); 447 448 if (out) 449 sgs[out_sgs++] = chan->sg; 450 451 if (out_pages) { 452 sgs[out_sgs++] = chan->sg + out; 453 out += pack_sg_list_p(chan->sg, out, VIRTQUEUE_NUM, 454 out_pages, out_nr_pages, offs, outlen); 455 } 456 457 /* 458 * Take care of in data 459 * For example TREAD have 11. 460 * 11 is the read/write header = PDU Header(7) + IO Size (4). 461 * Arrange in such a way that server places header in the 462 * alloced memory and payload onto the user buffer. 463 */ 464 in = pack_sg_list(chan->sg, out, 465 VIRTQUEUE_NUM, req->rc->sdata, in_hdr_len); 466 if (in) 467 sgs[out_sgs + in_sgs++] = chan->sg + out; 468 469 if (in_pages) { 470 sgs[out_sgs + in_sgs++] = chan->sg + out + in; 471 in += pack_sg_list_p(chan->sg, out + in, VIRTQUEUE_NUM, 472 in_pages, in_nr_pages, offs, inlen); 473 } 474 475 BUG_ON(out_sgs + in_sgs > ARRAY_SIZE(sgs)); 476 err = virtqueue_add_sgs(chan->vq, sgs, out_sgs, in_sgs, req, 477 GFP_ATOMIC); 478 if (err < 0) { 479 if (err == -ENOSPC) { 480 chan->ring_bufs_avail = 0; 481 spin_unlock_irqrestore(&chan->lock, flags); 482 err = wait_event_killable(*chan->vc_wq, 483 chan->ring_bufs_avail); 484 if (err == -ERESTARTSYS) 485 goto err_out; 486 487 p9_debug(P9_DEBUG_TRANS, "Retry virtio request\n"); 488 goto req_retry_pinned; 489 } else { 490 spin_unlock_irqrestore(&chan->lock, flags); 491 p9_debug(P9_DEBUG_TRANS, 492 "virtio rpc add_sgs returned failure\n"); 493 err = -EIO; 494 goto err_out; 495 } 496 } 497 virtqueue_kick(chan->vq); 498 spin_unlock_irqrestore(&chan->lock, flags); 499 p9_debug(P9_DEBUG_TRANS, "virtio request kicked\n"); 500 err = wait_event_killable(req->wq, req->status >= REQ_STATUS_RCVD); 501 /* 502 * Non kernel buffers are pinned, unpin them 503 */ 504 err_out: 505 if (need_drop) { 506 if (in_pages) { 507 p9_release_pages(in_pages, in_nr_pages); 508 atomic_sub(in_nr_pages, &vp_pinned); 509 } 510 if (out_pages) { 511 p9_release_pages(out_pages, out_nr_pages); 512 atomic_sub(out_nr_pages, &vp_pinned); 513 } 514 /* wakeup anybody waiting for slots to pin pages */ 515 wake_up(&vp_wq); 516 } 517 kvfree(in_pages); 518 kvfree(out_pages); 519 return err; 520 } 521 522 static ssize_t p9_mount_tag_show(struct device *dev, 523 struct device_attribute *attr, char *buf) 524 { 525 struct virtio_chan *chan; 526 struct virtio_device *vdev; 527 528 vdev = dev_to_virtio(dev); 529 chan = vdev->priv; 530 531 memcpy(buf, chan->tag, chan->tag_len); 532 buf[chan->tag_len] = 0; 533 534 return chan->tag_len + 1; 535 } 536 537 static DEVICE_ATTR(mount_tag, 0444, p9_mount_tag_show, NULL); 538 539 /** 540 * p9_virtio_probe - probe for existence of 9P virtio channels 541 * @vdev: virtio device to probe 542 * 543 * This probes for existing virtio channels. 544 * 545 */ 546 547 static int p9_virtio_probe(struct virtio_device *vdev) 548 { 549 __u16 tag_len; 550 char *tag; 551 int err; 552 struct virtio_chan *chan; 553 554 if (!vdev->config->get) { 555 dev_err(&vdev->dev, "%s failure: config access disabled\n", 556 __func__); 557 return -EINVAL; 558 } 559 560 chan = kmalloc(sizeof(struct virtio_chan), GFP_KERNEL); 561 if (!chan) { 562 pr_err("Failed to allocate virtio 9P channel\n"); 563 err = -ENOMEM; 564 goto fail; 565 } 566 567 chan->vdev = vdev; 568 569 /* We expect one virtqueue, for requests. */ 570 chan->vq = virtio_find_single_vq(vdev, req_done, "requests"); 571 if (IS_ERR(chan->vq)) { 572 err = PTR_ERR(chan->vq); 573 goto out_free_chan; 574 } 575 chan->vq->vdev->priv = chan; 576 spin_lock_init(&chan->lock); 577 578 sg_init_table(chan->sg, VIRTQUEUE_NUM); 579 580 chan->inuse = false; 581 if (virtio_has_feature(vdev, VIRTIO_9P_MOUNT_TAG)) { 582 virtio_cread(vdev, struct virtio_9p_config, tag_len, &tag_len); 583 } else { 584 err = -EINVAL; 585 goto out_free_vq; 586 } 587 tag = kmalloc(tag_len, GFP_KERNEL); 588 if (!tag) { 589 err = -ENOMEM; 590 goto out_free_vq; 591 } 592 593 virtio_cread_bytes(vdev, offsetof(struct virtio_9p_config, tag), 594 tag, tag_len); 595 chan->tag = tag; 596 chan->tag_len = tag_len; 597 err = sysfs_create_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); 598 if (err) { 599 goto out_free_tag; 600 } 601 chan->vc_wq = kmalloc(sizeof(wait_queue_head_t), GFP_KERNEL); 602 if (!chan->vc_wq) { 603 err = -ENOMEM; 604 goto out_free_tag; 605 } 606 init_waitqueue_head(chan->vc_wq); 607 chan->ring_bufs_avail = 1; 608 /* Ceiling limit to avoid denial of service attacks */ 609 chan->p9_max_pages = nr_free_buffer_pages()/4; 610 611 virtio_device_ready(vdev); 612 613 mutex_lock(&virtio_9p_lock); 614 list_add_tail(&chan->chan_list, &virtio_chan_list); 615 mutex_unlock(&virtio_9p_lock); 616 617 /* Let udev rules use the new mount_tag attribute. */ 618 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE); 619 620 return 0; 621 622 out_free_tag: 623 kfree(tag); 624 out_free_vq: 625 vdev->config->del_vqs(vdev); 626 out_free_chan: 627 kfree(chan); 628 fail: 629 return err; 630 } 631 632 633 /** 634 * p9_virtio_create - allocate a new virtio channel 635 * @client: client instance invoking this transport 636 * @devname: string identifying the channel to connect to (unused) 637 * @args: args passed from sys_mount() for per-transport options (unused) 638 * 639 * This sets up a transport channel for 9p communication. Right now 640 * we only match the first available channel, but eventually we couldlook up 641 * alternate channels by matching devname versus a virtio_config entry. 642 * We use a simple reference count mechanism to ensure that only a single 643 * mount has a channel open at a time. 644 * 645 */ 646 647 static int 648 p9_virtio_create(struct p9_client *client, const char *devname, char *args) 649 { 650 struct virtio_chan *chan; 651 int ret = -ENOENT; 652 int found = 0; 653 654 mutex_lock(&virtio_9p_lock); 655 list_for_each_entry(chan, &virtio_chan_list, chan_list) { 656 if (!strncmp(devname, chan->tag, chan->tag_len) && 657 strlen(devname) == chan->tag_len) { 658 if (!chan->inuse) { 659 chan->inuse = true; 660 found = 1; 661 break; 662 } 663 ret = -EBUSY; 664 } 665 } 666 mutex_unlock(&virtio_9p_lock); 667 668 if (!found) { 669 pr_err("no channels available for device %s\n", devname); 670 return ret; 671 } 672 673 client->trans = (void *)chan; 674 client->status = Connected; 675 chan->client = client; 676 677 return 0; 678 } 679 680 /** 681 * p9_virtio_remove - clean up resources associated with a virtio device 682 * @vdev: virtio device to remove 683 * 684 */ 685 686 static void p9_virtio_remove(struct virtio_device *vdev) 687 { 688 struct virtio_chan *chan = vdev->priv; 689 unsigned long warning_time; 690 691 mutex_lock(&virtio_9p_lock); 692 693 /* Remove self from list so we don't get new users. */ 694 list_del(&chan->chan_list); 695 warning_time = jiffies; 696 697 /* Wait for existing users to close. */ 698 while (chan->inuse) { 699 mutex_unlock(&virtio_9p_lock); 700 msleep(250); 701 if (time_after(jiffies, warning_time + 10 * HZ)) { 702 dev_emerg(&vdev->dev, 703 "p9_virtio_remove: waiting for device in use.\n"); 704 warning_time = jiffies; 705 } 706 mutex_lock(&virtio_9p_lock); 707 } 708 709 mutex_unlock(&virtio_9p_lock); 710 711 vdev->config->reset(vdev); 712 vdev->config->del_vqs(vdev); 713 714 sysfs_remove_file(&(vdev->dev.kobj), &dev_attr_mount_tag.attr); 715 kobject_uevent(&(vdev->dev.kobj), KOBJ_CHANGE); 716 kfree(chan->tag); 717 kfree(chan->vc_wq); 718 kfree(chan); 719 720 } 721 722 static struct virtio_device_id id_table[] = { 723 { VIRTIO_ID_9P, VIRTIO_DEV_ANY_ID }, 724 { 0 }, 725 }; 726 727 static unsigned int features[] = { 728 VIRTIO_9P_MOUNT_TAG, 729 }; 730 731 /* The standard "struct lguest_driver": */ 732 static struct virtio_driver p9_virtio_drv = { 733 .feature_table = features, 734 .feature_table_size = ARRAY_SIZE(features), 735 .driver.name = KBUILD_MODNAME, 736 .driver.owner = THIS_MODULE, 737 .id_table = id_table, 738 .probe = p9_virtio_probe, 739 .remove = p9_virtio_remove, 740 }; 741 742 static struct p9_trans_module p9_virtio_trans = { 743 .name = "virtio", 744 .create = p9_virtio_create, 745 .close = p9_virtio_close, 746 .request = p9_virtio_request, 747 .zc_request = p9_virtio_zc_request, 748 .cancel = p9_virtio_cancel, 749 /* 750 * We leave one entry for input and one entry for response 751 * headers. We also skip one more entry to accomodate, address 752 * that are not at page boundary, that can result in an extra 753 * page in zero copy. 754 */ 755 .maxsize = PAGE_SIZE * (VIRTQUEUE_NUM - 3), 756 .def = 1, 757 .owner = THIS_MODULE, 758 }; 759 760 /* The standard init function */ 761 static int __init p9_virtio_init(void) 762 { 763 INIT_LIST_HEAD(&virtio_chan_list); 764 765 v9fs_register_trans(&p9_virtio_trans); 766 return register_virtio_driver(&p9_virtio_drv); 767 } 768 769 static void __exit p9_virtio_cleanup(void) 770 { 771 unregister_virtio_driver(&p9_virtio_drv); 772 v9fs_unregister_trans(&p9_virtio_trans); 773 } 774 775 module_init(p9_virtio_init); 776 module_exit(p9_virtio_cleanup); 777 778 MODULE_DEVICE_TABLE(virtio, id_table); 779 MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>"); 780 MODULE_DESCRIPTION("Virtio 9p Transport"); 781 MODULE_LICENSE("GPL"); 782