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e467cde2 RR |
1 | //#define DEBUG |
2 | #include <linux/spinlock.h> | |
3 | #include <linux/blkdev.h> | |
4 | #include <linux/hdreg.h> | |
5 | #include <linux/virtio.h> | |
6 | #include <linux/virtio_blk.h> | |
3d1266c7 JA |
7 | #include <linux/scatterlist.h> |
8 | ||
4f3bf19c | 9 | #define PART_BITS 4 |
e467cde2 | 10 | |
d50ed907 | 11 | static int major, index; |
4f3bf19c | 12 | |
e467cde2 RR |
13 | struct virtio_blk |
14 | { | |
15 | spinlock_t lock; | |
16 | ||
17 | struct virtio_device *vdev; | |
18 | struct virtqueue *vq; | |
19 | ||
20 | /* The disk structure for the kernel. */ | |
21 | struct gendisk *disk; | |
22 | ||
23 | /* Request tracking. */ | |
24 | struct list_head reqs; | |
25 | ||
26 | mempool_t *pool; | |
27 | ||
0864b79a RR |
28 | /* What host tells us, plus 2 for header & tailer. */ |
29 | unsigned int sg_elems; | |
30 | ||
e467cde2 | 31 | /* Scatterlist: can be too big for stack. */ |
0864b79a | 32 | struct scatterlist sg[/*sg_elems*/]; |
e467cde2 RR |
33 | }; |
34 | ||
35 | struct virtblk_req | |
36 | { | |
37 | struct list_head list; | |
38 | struct request *req; | |
39 | struct virtio_blk_outhdr out_hdr; | |
1cde26f9 | 40 | struct virtio_scsi_inhdr in_hdr; |
cb38fa23 | 41 | u8 status; |
e467cde2 RR |
42 | }; |
43 | ||
18445c4d | 44 | static void blk_done(struct virtqueue *vq) |
e467cde2 RR |
45 | { |
46 | struct virtio_blk *vblk = vq->vdev->priv; | |
47 | struct virtblk_req *vbr; | |
48 | unsigned int len; | |
49 | unsigned long flags; | |
50 | ||
51 | spin_lock_irqsave(&vblk->lock, flags); | |
52 | while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) { | |
8316982a | 53 | int error; |
1cde26f9 | 54 | |
cb38fa23 | 55 | switch (vbr->status) { |
e467cde2 | 56 | case VIRTIO_BLK_S_OK: |
8316982a | 57 | error = 0; |
e467cde2 RR |
58 | break; |
59 | case VIRTIO_BLK_S_UNSUPP: | |
8316982a | 60 | error = -ENOTTY; |
e467cde2 RR |
61 | break; |
62 | default: | |
8316982a | 63 | error = -EIO; |
e467cde2 RR |
64 | break; |
65 | } | |
66 | ||
1cde26f9 HR |
67 | if (blk_pc_request(vbr->req)) { |
68 | vbr->req->resid_len = vbr->in_hdr.residual; | |
69 | vbr->req->sense_len = vbr->in_hdr.sense_len; | |
70 | vbr->req->errors = vbr->in_hdr.errors; | |
71 | } | |
72 | ||
40cbbb78 | 73 | __blk_end_request_all(vbr->req, error); |
e467cde2 RR |
74 | list_del(&vbr->list); |
75 | mempool_free(vbr, vblk->pool); | |
76 | } | |
77 | /* In case queue is stopped waiting for more buffers. */ | |
78 | blk_start_queue(vblk->disk->queue); | |
79 | spin_unlock_irqrestore(&vblk->lock, flags); | |
e467cde2 RR |
80 | } |
81 | ||
82 | static bool do_req(struct request_queue *q, struct virtio_blk *vblk, | |
83 | struct request *req) | |
84 | { | |
1cde26f9 | 85 | unsigned long num, out = 0, in = 0; |
e467cde2 RR |
86 | struct virtblk_req *vbr; |
87 | ||
88 | vbr = mempool_alloc(vblk->pool, GFP_ATOMIC); | |
89 | if (!vbr) | |
90 | /* When another request finishes we'll try again. */ | |
91 | return false; | |
92 | ||
93 | vbr->req = req; | |
f1b0ef06 CH |
94 | switch (req->cmd_type) { |
95 | case REQ_TYPE_FS: | |
e467cde2 | 96 | vbr->out_hdr.type = 0; |
83096ebf | 97 | vbr->out_hdr.sector = blk_rq_pos(vbr->req); |
766ca442 | 98 | vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); |
f1b0ef06 CH |
99 | break; |
100 | case REQ_TYPE_BLOCK_PC: | |
e467cde2 RR |
101 | vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD; |
102 | vbr->out_hdr.sector = 0; | |
766ca442 | 103 | vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); |
f1b0ef06 CH |
104 | break; |
105 | case REQ_TYPE_LINUX_BLOCK: | |
106 | if (req->cmd[0] == REQ_LB_OP_FLUSH) { | |
107 | vbr->out_hdr.type = VIRTIO_BLK_T_FLUSH; | |
108 | vbr->out_hdr.sector = 0; | |
109 | vbr->out_hdr.ioprio = req_get_ioprio(vbr->req); | |
110 | break; | |
111 | } | |
112 | /*FALLTHRU*/ | |
113 | default: | |
e467cde2 RR |
114 | /* We don't put anything else in the queue. */ |
115 | BUG(); | |
116 | } | |
117 | ||
118 | if (blk_barrier_rq(vbr->req)) | |
119 | vbr->out_hdr.type |= VIRTIO_BLK_T_BARRIER; | |
120 | ||
1cde26f9 | 121 | sg_set_buf(&vblk->sg[out++], &vbr->out_hdr, sizeof(vbr->out_hdr)); |
e467cde2 | 122 | |
1cde26f9 HR |
123 | /* |
124 | * If this is a packet command we need a couple of additional headers. | |
125 | * Behind the normal outhdr we put a segment with the scsi command | |
126 | * block, and before the normal inhdr we put the sense data and the | |
127 | * inhdr with additional status information before the normal inhdr. | |
128 | */ | |
129 | if (blk_pc_request(vbr->req)) | |
130 | sg_set_buf(&vblk->sg[out++], vbr->req->cmd, vbr->req->cmd_len); | |
131 | ||
132 | num = blk_rq_map_sg(q, vbr->req, vblk->sg + out); | |
133 | ||
134 | if (blk_pc_request(vbr->req)) { | |
135 | sg_set_buf(&vblk->sg[num + out + in++], vbr->req->sense, 96); | |
136 | sg_set_buf(&vblk->sg[num + out + in++], &vbr->in_hdr, | |
137 | sizeof(vbr->in_hdr)); | |
138 | } | |
139 | ||
140 | sg_set_buf(&vblk->sg[num + out + in++], &vbr->status, | |
141 | sizeof(vbr->status)); | |
142 | ||
143 | if (num) { | |
144 | if (rq_data_dir(vbr->req) == WRITE) { | |
145 | vbr->out_hdr.type |= VIRTIO_BLK_T_OUT; | |
146 | out += num; | |
147 | } else { | |
148 | vbr->out_hdr.type |= VIRTIO_BLK_T_IN; | |
149 | in += num; | |
150 | } | |
e467cde2 RR |
151 | } |
152 | ||
3c1b27d5 | 153 | if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr) < 0) { |
e467cde2 RR |
154 | mempool_free(vbr, vblk->pool); |
155 | return false; | |
156 | } | |
157 | ||
158 | list_add_tail(&vbr->list, &vblk->reqs); | |
159 | return true; | |
160 | } | |
161 | ||
162 | static void do_virtblk_request(struct request_queue *q) | |
163 | { | |
6c3b46f7 | 164 | struct virtio_blk *vblk = q->queuedata; |
e467cde2 RR |
165 | struct request *req; |
166 | unsigned int issued = 0; | |
167 | ||
9934c8c0 | 168 | while ((req = blk_peek_request(q)) != NULL) { |
0864b79a | 169 | BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); |
e467cde2 RR |
170 | |
171 | /* If this request fails, stop queue and wait for something to | |
172 | finish to restart it. */ | |
173 | if (!do_req(q, vblk, req)) { | |
174 | blk_stop_queue(q); | |
175 | break; | |
176 | } | |
9934c8c0 | 177 | blk_start_request(req); |
e467cde2 RR |
178 | issued++; |
179 | } | |
180 | ||
181 | if (issued) | |
182 | vblk->vq->vq_ops->kick(vblk->vq); | |
183 | } | |
184 | ||
f1b0ef06 CH |
185 | static void virtblk_prepare_flush(struct request_queue *q, struct request *req) |
186 | { | |
187 | req->cmd_type = REQ_TYPE_LINUX_BLOCK; | |
188 | req->cmd[0] = REQ_LB_OP_FLUSH; | |
189 | } | |
190 | ||
4e109852 | 191 | static int virtblk_ioctl(struct block_device *bdev, fmode_t mode, |
e467cde2 RR |
192 | unsigned cmd, unsigned long data) |
193 | { | |
1cde26f9 HR |
194 | struct gendisk *disk = bdev->bd_disk; |
195 | struct virtio_blk *vblk = disk->private_data; | |
196 | ||
197 | /* | |
198 | * Only allow the generic SCSI ioctls if the host can support it. | |
199 | */ | |
200 | if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI)) | |
d9ecdea7 | 201 | return -ENOTTY; |
1cde26f9 | 202 | |
3225beab RR |
203 | return scsi_cmd_ioctl(disk->queue, disk, mode, cmd, |
204 | (void __user *)data); | |
e467cde2 RR |
205 | } |
206 | ||
135da0b0 CB |
207 | /* We provide getgeo only to please some old bootloader/partitioning tools */ |
208 | static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) | |
209 | { | |
48e4043d RH |
210 | struct virtio_blk *vblk = bd->bd_disk->private_data; |
211 | struct virtio_blk_geometry vgeo; | |
212 | int err; | |
213 | ||
214 | /* see if the host passed in geometry config */ | |
215 | err = virtio_config_val(vblk->vdev, VIRTIO_BLK_F_GEOMETRY, | |
216 | offsetof(struct virtio_blk_config, geometry), | |
217 | &vgeo); | |
218 | ||
219 | if (!err) { | |
220 | geo->heads = vgeo.heads; | |
221 | geo->sectors = vgeo.sectors; | |
222 | geo->cylinders = vgeo.cylinders; | |
223 | } else { | |
224 | /* some standard values, similar to sd */ | |
225 | geo->heads = 1 << 6; | |
226 | geo->sectors = 1 << 5; | |
227 | geo->cylinders = get_capacity(bd->bd_disk) >> 11; | |
228 | } | |
135da0b0 CB |
229 | return 0; |
230 | } | |
231 | ||
83d5cde4 | 232 | static const struct block_device_operations virtblk_fops = { |
4e109852 | 233 | .locked_ioctl = virtblk_ioctl, |
135da0b0 CB |
234 | .owner = THIS_MODULE, |
235 | .getgeo = virtblk_getgeo, | |
e467cde2 RR |
236 | }; |
237 | ||
d50ed907 CB |
238 | static int index_to_minor(int index) |
239 | { | |
240 | return index << PART_BITS; | |
241 | } | |
242 | ||
98e94444 | 243 | static int __devinit virtblk_probe(struct virtio_device *vdev) |
e467cde2 RR |
244 | { |
245 | struct virtio_blk *vblk; | |
4f3bf19c | 246 | int err; |
e467cde2 RR |
247 | u64 cap; |
248 | u32 v; | |
0864b79a | 249 | u32 blk_size, sg_elems; |
e467cde2 | 250 | |
d50ed907 | 251 | if (index_to_minor(index) >= 1 << MINORBITS) |
4f3bf19c CB |
252 | return -ENOSPC; |
253 | ||
0864b79a RR |
254 | /* We need to know how many segments before we allocate. */ |
255 | err = virtio_config_val(vdev, VIRTIO_BLK_F_SEG_MAX, | |
256 | offsetof(struct virtio_blk_config, seg_max), | |
257 | &sg_elems); | |
258 | if (err) | |
259 | sg_elems = 1; | |
260 | ||
261 | /* We need an extra sg elements at head and tail. */ | |
262 | sg_elems += 2; | |
263 | vdev->priv = vblk = kmalloc(sizeof(*vblk) + | |
264 | sizeof(vblk->sg[0]) * sg_elems, GFP_KERNEL); | |
e467cde2 RR |
265 | if (!vblk) { |
266 | err = -ENOMEM; | |
267 | goto out; | |
268 | } | |
269 | ||
270 | INIT_LIST_HEAD(&vblk->reqs); | |
271 | spin_lock_init(&vblk->lock); | |
272 | vblk->vdev = vdev; | |
0864b79a RR |
273 | vblk->sg_elems = sg_elems; |
274 | sg_init_table(vblk->sg, vblk->sg_elems); | |
e467cde2 RR |
275 | |
276 | /* We expect one virtqueue, for output. */ | |
d2a7ddda | 277 | vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests"); |
e467cde2 RR |
278 | if (IS_ERR(vblk->vq)) { |
279 | err = PTR_ERR(vblk->vq); | |
280 | goto out_free_vblk; | |
281 | } | |
282 | ||
283 | vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req)); | |
284 | if (!vblk->pool) { | |
285 | err = -ENOMEM; | |
286 | goto out_free_vq; | |
287 | } | |
288 | ||
e467cde2 | 289 | /* FIXME: How many partitions? How long is a piece of string? */ |
4f3bf19c | 290 | vblk->disk = alloc_disk(1 << PART_BITS); |
e467cde2 RR |
291 | if (!vblk->disk) { |
292 | err = -ENOMEM; | |
4f3bf19c | 293 | goto out_mempool; |
e467cde2 RR |
294 | } |
295 | ||
296 | vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock); | |
297 | if (!vblk->disk->queue) { | |
298 | err = -ENOMEM; | |
299 | goto out_put_disk; | |
300 | } | |
301 | ||
6c3b46f7 | 302 | vblk->disk->queue->queuedata = vblk; |
7d116b62 | 303 | |
d50ed907 CB |
304 | if (index < 26) { |
305 | sprintf(vblk->disk->disk_name, "vd%c", 'a' + index % 26); | |
306 | } else if (index < (26 + 1) * 26) { | |
307 | sprintf(vblk->disk->disk_name, "vd%c%c", | |
308 | 'a' + index / 26 - 1, 'a' + index % 26); | |
309 | } else { | |
310 | const unsigned int m1 = (index / 26 - 1) / 26 - 1; | |
311 | const unsigned int m2 = (index / 26 - 1) % 26; | |
312 | const unsigned int m3 = index % 26; | |
313 | sprintf(vblk->disk->disk_name, "vd%c%c%c", | |
314 | 'a' + m1, 'a' + m2, 'a' + m3); | |
315 | } | |
316 | ||
e467cde2 | 317 | vblk->disk->major = major; |
d50ed907 | 318 | vblk->disk->first_minor = index_to_minor(index); |
e467cde2 RR |
319 | vblk->disk->private_data = vblk; |
320 | vblk->disk->fops = &virtblk_fops; | |
c4839346 | 321 | vblk->disk->driverfs_dev = &vdev->dev; |
d50ed907 | 322 | index++; |
4f3bf19c | 323 | |
e467cde2 | 324 | /* If barriers are supported, tell block layer that queue is ordered */ |
f1b0ef06 CH |
325 | if (virtio_has_feature(vdev, VIRTIO_BLK_F_FLUSH)) |
326 | blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_DRAIN_FLUSH, | |
327 | virtblk_prepare_flush); | |
328 | else if (virtio_has_feature(vdev, VIRTIO_BLK_F_BARRIER)) | |
e467cde2 RR |
329 | blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL); |
330 | ||
3ef53609 CB |
331 | /* If disk is read-only in the host, the guest should obey */ |
332 | if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) | |
333 | set_disk_ro(vblk->disk, 1); | |
334 | ||
a586d4f6 | 335 | /* Host must always specify the capacity. */ |
72e61eb4 RR |
336 | vdev->config->get(vdev, offsetof(struct virtio_blk_config, capacity), |
337 | &cap, sizeof(cap)); | |
e467cde2 RR |
338 | |
339 | /* If capacity is too big, truncate with warning. */ | |
340 | if ((sector_t)cap != cap) { | |
341 | dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", | |
342 | (unsigned long long)cap); | |
343 | cap = (sector_t)-1; | |
344 | } | |
345 | set_capacity(vblk->disk, cap); | |
346 | ||
0864b79a RR |
347 | /* We can handle whatever the host told us to handle. */ |
348 | blk_queue_max_phys_segments(vblk->disk->queue, vblk->sg_elems-2); | |
349 | blk_queue_max_hw_segments(vblk->disk->queue, vblk->sg_elems-2); | |
350 | ||
4eff3cae CH |
351 | /* No need to bounce any requests */ |
352 | blk_queue_bounce_limit(vblk->disk->queue, BLK_BOUNCE_ANY); | |
353 | ||
4b7f7e20 RR |
354 | /* No real sector limit. */ |
355 | blk_queue_max_sectors(vblk->disk->queue, -1U); | |
356 | ||
a586d4f6 RR |
357 | /* Host can optionally specify maximum segment size and number of |
358 | * segments. */ | |
359 | err = virtio_config_val(vdev, VIRTIO_BLK_F_SIZE_MAX, | |
360 | offsetof(struct virtio_blk_config, size_max), | |
361 | &v); | |
e467cde2 RR |
362 | if (!err) |
363 | blk_queue_max_segment_size(vblk->disk->queue, v); | |
4b7f7e20 | 364 | else |
b194aee9 | 365 | blk_queue_max_segment_size(vblk->disk->queue, -1U); |
e467cde2 | 366 | |
066f4d82 CB |
367 | /* Host can optionally specify the block size of the device */ |
368 | err = virtio_config_val(vdev, VIRTIO_BLK_F_BLK_SIZE, | |
369 | offsetof(struct virtio_blk_config, blk_size), | |
370 | &blk_size); | |
371 | if (!err) | |
e1defc4f | 372 | blk_queue_logical_block_size(vblk->disk->queue, blk_size); |
066f4d82 | 373 | |
e467cde2 RR |
374 | add_disk(vblk->disk); |
375 | return 0; | |
376 | ||
377 | out_put_disk: | |
378 | put_disk(vblk->disk); | |
e467cde2 RR |
379 | out_mempool: |
380 | mempool_destroy(vblk->pool); | |
381 | out_free_vq: | |
d2a7ddda | 382 | vdev->config->del_vqs(vdev); |
e467cde2 RR |
383 | out_free_vblk: |
384 | kfree(vblk); | |
385 | out: | |
386 | return err; | |
387 | } | |
388 | ||
98e94444 | 389 | static void __devexit virtblk_remove(struct virtio_device *vdev) |
e467cde2 RR |
390 | { |
391 | struct virtio_blk *vblk = vdev->priv; | |
e467cde2 | 392 | |
6e5aa7ef | 393 | /* Nothing should be pending. */ |
e467cde2 | 394 | BUG_ON(!list_empty(&vblk->reqs)); |
6e5aa7ef RR |
395 | |
396 | /* Stop all the virtqueues. */ | |
397 | vdev->config->reset(vdev); | |
398 | ||
ac9d463a | 399 | del_gendisk(vblk->disk); |
e467cde2 RR |
400 | blk_cleanup_queue(vblk->disk->queue); |
401 | put_disk(vblk->disk); | |
e467cde2 | 402 | mempool_destroy(vblk->pool); |
d2a7ddda | 403 | vdev->config->del_vqs(vdev); |
e467cde2 RR |
404 | kfree(vblk); |
405 | } | |
406 | ||
407 | static struct virtio_device_id id_table[] = { | |
408 | { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, | |
409 | { 0 }, | |
410 | }; | |
411 | ||
c45a6816 RR |
412 | static unsigned int features[] = { |
413 | VIRTIO_BLK_F_BARRIER, VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, | |
066f4d82 | 414 | VIRTIO_BLK_F_GEOMETRY, VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, |
3225beab | 415 | VIRTIO_BLK_F_SCSI, VIRTIO_BLK_F_FLUSH |
c45a6816 RR |
416 | }; |
417 | ||
4fbfff76 RM |
418 | /* |
419 | * virtio_blk causes spurious section mismatch warning by | |
420 | * simultaneously referring to a __devinit and a __devexit function. | |
421 | * Use __refdata to avoid this warning. | |
422 | */ | |
423 | static struct virtio_driver __refdata virtio_blk = { | |
c45a6816 RR |
424 | .feature_table = features, |
425 | .feature_table_size = ARRAY_SIZE(features), | |
e467cde2 RR |
426 | .driver.name = KBUILD_MODNAME, |
427 | .driver.owner = THIS_MODULE, | |
428 | .id_table = id_table, | |
429 | .probe = virtblk_probe, | |
430 | .remove = __devexit_p(virtblk_remove), | |
431 | }; | |
432 | ||
433 | static int __init init(void) | |
434 | { | |
4f3bf19c CB |
435 | major = register_blkdev(0, "virtblk"); |
436 | if (major < 0) | |
437 | return major; | |
e467cde2 RR |
438 | return register_virtio_driver(&virtio_blk); |
439 | } | |
440 | ||
441 | static void __exit fini(void) | |
442 | { | |
4f3bf19c | 443 | unregister_blkdev(major, "virtblk"); |
e467cde2 RR |
444 | unregister_virtio_driver(&virtio_blk); |
445 | } | |
446 | module_init(init); | |
447 | module_exit(fini); | |
448 | ||
449 | MODULE_DEVICE_TABLE(virtio, id_table); | |
450 | MODULE_DESCRIPTION("Virtio block driver"); | |
451 | MODULE_LICENSE("GPL"); |