blob: 924ddd8bccd2b8fdd32e06a7db1c3e05918ebc12 [file] [log] [blame]
Rusty Russelle467cde2007-10-22 11:03:38 +10001//#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>
Jens Axboe3d1266c2007-10-24 13:21:21 +02007#include <linux/scatterlist.h>
8
9#define VIRTIO_MAX_SG (3+MAX_PHYS_SEGMENTS)
Rusty Russelle467cde2007-10-22 11:03:38 +100010
11static unsigned char virtblk_index = 'a';
12struct virtio_blk
13{
14 spinlock_t lock;
15
16 struct virtio_device *vdev;
17 struct virtqueue *vq;
18
19 /* The disk structure for the kernel. */
20 struct gendisk *disk;
21
22 /* Request tracking. */
23 struct list_head reqs;
24
25 mempool_t *pool;
26
27 /* Scatterlist: can be too big for stack. */
Jens Axboe3d1266c2007-10-24 13:21:21 +020028 struct scatterlist sg[VIRTIO_MAX_SG];
Rusty Russelle467cde2007-10-22 11:03:38 +100029};
30
31struct virtblk_req
32{
33 struct list_head list;
34 struct request *req;
35 struct virtio_blk_outhdr out_hdr;
36 struct virtio_blk_inhdr in_hdr;
37};
38
39static bool blk_done(struct virtqueue *vq)
40{
41 struct virtio_blk *vblk = vq->vdev->priv;
42 struct virtblk_req *vbr;
43 unsigned int len;
44 unsigned long flags;
45
46 spin_lock_irqsave(&vblk->lock, flags);
47 while ((vbr = vblk->vq->vq_ops->get_buf(vblk->vq, &len)) != NULL) {
48 int uptodate;
49 switch (vbr->in_hdr.status) {
50 case VIRTIO_BLK_S_OK:
51 uptodate = 1;
52 break;
53 case VIRTIO_BLK_S_UNSUPP:
54 uptodate = -ENOTTY;
55 break;
56 default:
57 uptodate = 0;
58 break;
59 }
60
61 end_dequeued_request(vbr->req, uptodate);
62 list_del(&vbr->list);
63 mempool_free(vbr, vblk->pool);
64 }
65 /* In case queue is stopped waiting for more buffers. */
66 blk_start_queue(vblk->disk->queue);
67 spin_unlock_irqrestore(&vblk->lock, flags);
68 return true;
69}
70
71static bool do_req(struct request_queue *q, struct virtio_blk *vblk,
72 struct request *req)
73{
74 unsigned long num, out, in;
75 struct virtblk_req *vbr;
76
77 vbr = mempool_alloc(vblk->pool, GFP_ATOMIC);
78 if (!vbr)
79 /* When another request finishes we'll try again. */
80 return false;
81
82 vbr->req = req;
83 if (blk_fs_request(vbr->req)) {
84 vbr->out_hdr.type = 0;
85 vbr->out_hdr.sector = vbr->req->sector;
86 vbr->out_hdr.ioprio = vbr->req->ioprio;
87 } else if (blk_pc_request(vbr->req)) {
88 vbr->out_hdr.type = VIRTIO_BLK_T_SCSI_CMD;
89 vbr->out_hdr.sector = 0;
90 vbr->out_hdr.ioprio = vbr->req->ioprio;
91 } else {
92 /* We don't put anything else in the queue. */
93 BUG();
94 }
95
96 if (blk_barrier_rq(vbr->req))
97 vbr->out_hdr.type |= VIRTIO_BLK_T_BARRIER;
98
Jens Axboe3d1266c2007-10-24 13:21:21 +020099 /* This init could be done at vblk creation time */
100 sg_init_table(vblk->sg, VIRTIO_MAX_SG);
Rusty Russelle467cde2007-10-22 11:03:38 +1000101 sg_set_buf(&vblk->sg[0], &vbr->out_hdr, sizeof(vbr->out_hdr));
102 num = blk_rq_map_sg(q, vbr->req, vblk->sg+1);
103 sg_set_buf(&vblk->sg[num+1], &vbr->in_hdr, sizeof(vbr->in_hdr));
104
105 if (rq_data_dir(vbr->req) == WRITE) {
106 vbr->out_hdr.type |= VIRTIO_BLK_T_OUT;
107 out = 1 + num;
108 in = 1;
109 } else {
110 vbr->out_hdr.type |= VIRTIO_BLK_T_IN;
111 out = 1;
112 in = 1 + num;
113 }
114
115 if (vblk->vq->vq_ops->add_buf(vblk->vq, vblk->sg, out, in, vbr)) {
116 mempool_free(vbr, vblk->pool);
117 return false;
118 }
119
120 list_add_tail(&vbr->list, &vblk->reqs);
121 return true;
122}
123
124static void do_virtblk_request(struct request_queue *q)
125{
126 struct virtio_blk *vblk = NULL;
127 struct request *req;
128 unsigned int issued = 0;
129
130 while ((req = elv_next_request(q)) != NULL) {
131 vblk = req->rq_disk->private_data;
132 BUG_ON(req->nr_phys_segments > ARRAY_SIZE(vblk->sg));
133
134 /* If this request fails, stop queue and wait for something to
135 finish to restart it. */
136 if (!do_req(q, vblk, req)) {
137 blk_stop_queue(q);
138 break;
139 }
140 blkdev_dequeue_request(req);
141 issued++;
142 }
143
144 if (issued)
145 vblk->vq->vq_ops->kick(vblk->vq);
146}
147
148static int virtblk_ioctl(struct inode *inode, struct file *filp,
149 unsigned cmd, unsigned long data)
150{
151 return scsi_cmd_ioctl(filp, inode->i_bdev->bd_disk->queue,
152 inode->i_bdev->bd_disk, cmd,
153 (void __user *)data);
154}
155
156static struct block_device_operations virtblk_fops = {
157 .ioctl = virtblk_ioctl,
158 .owner = THIS_MODULE,
159};
160
161static int virtblk_probe(struct virtio_device *vdev)
162{
163 struct virtio_blk *vblk;
164 int err, major;
165 void *token;
166 unsigned int len;
167 u64 cap;
168 u32 v;
169
170 vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL);
171 if (!vblk) {
172 err = -ENOMEM;
173 goto out;
174 }
175
176 INIT_LIST_HEAD(&vblk->reqs);
177 spin_lock_init(&vblk->lock);
178 vblk->vdev = vdev;
179
180 /* We expect one virtqueue, for output. */
181 vblk->vq = vdev->config->find_vq(vdev, blk_done);
182 if (IS_ERR(vblk->vq)) {
183 err = PTR_ERR(vblk->vq);
184 goto out_free_vblk;
185 }
186
187 vblk->pool = mempool_create_kmalloc_pool(1,sizeof(struct virtblk_req));
188 if (!vblk->pool) {
189 err = -ENOMEM;
190 goto out_free_vq;
191 }
192
193 major = register_blkdev(0, "virtblk");
194 if (major < 0) {
195 err = major;
196 goto out_mempool;
197 }
198
199 /* FIXME: How many partitions? How long is a piece of string? */
200 vblk->disk = alloc_disk(1 << 4);
201 if (!vblk->disk) {
202 err = -ENOMEM;
203 goto out_unregister_blkdev;
204 }
205
206 vblk->disk->queue = blk_init_queue(do_virtblk_request, &vblk->lock);
207 if (!vblk->disk->queue) {
208 err = -ENOMEM;
209 goto out_put_disk;
210 }
211
212 sprintf(vblk->disk->disk_name, "vd%c", virtblk_index++);
213 vblk->disk->major = major;
214 vblk->disk->first_minor = 0;
215 vblk->disk->private_data = vblk;
216 vblk->disk->fops = &virtblk_fops;
217
218 /* If barriers are supported, tell block layer that queue is ordered */
219 token = vdev->config->find(vdev, VIRTIO_CONFIG_BLK_F, &len);
220 if (virtio_use_bit(vdev, token, len, VIRTIO_BLK_F_BARRIER))
221 blk_queue_ordered(vblk->disk->queue, QUEUE_ORDERED_TAG, NULL);
222
223 err = virtio_config_val(vdev, VIRTIO_CONFIG_BLK_F_CAPACITY, &cap);
224 if (err) {
225 dev_err(&vdev->dev, "Bad/missing capacity in config\n");
Rusty Russell74b25532007-11-19 11:20:42 -0500226 goto out_cleanup_queue;
Rusty Russelle467cde2007-10-22 11:03:38 +1000227 }
228
229 /* If capacity is too big, truncate with warning. */
230 if ((sector_t)cap != cap) {
231 dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n",
232 (unsigned long long)cap);
233 cap = (sector_t)-1;
234 }
235 set_capacity(vblk->disk, cap);
236
237 err = virtio_config_val(vdev, VIRTIO_CONFIG_BLK_F_SIZE_MAX, &v);
238 if (!err)
239 blk_queue_max_segment_size(vblk->disk->queue, v);
240 else if (err != -ENOENT) {
241 dev_err(&vdev->dev, "Bad SIZE_MAX in config\n");
Rusty Russell74b25532007-11-19 11:20:42 -0500242 goto out_cleanup_queue;
Rusty Russelle467cde2007-10-22 11:03:38 +1000243 }
244
245 err = virtio_config_val(vdev, VIRTIO_CONFIG_BLK_F_SEG_MAX, &v);
246 if (!err)
247 blk_queue_max_hw_segments(vblk->disk->queue, v);
248 else if (err != -ENOENT) {
249 dev_err(&vdev->dev, "Bad SEG_MAX in config\n");
Rusty Russell74b25532007-11-19 11:20:42 -0500250 goto out_cleanup_queue;
Rusty Russelle467cde2007-10-22 11:03:38 +1000251 }
252
253 add_disk(vblk->disk);
254 return 0;
255
Rusty Russell74b25532007-11-19 11:20:42 -0500256out_cleanup_queue:
257 blk_cleanup_queue(vblk->disk->queue);
Rusty Russelle467cde2007-10-22 11:03:38 +1000258out_put_disk:
259 put_disk(vblk->disk);
260out_unregister_blkdev:
261 unregister_blkdev(major, "virtblk");
262out_mempool:
263 mempool_destroy(vblk->pool);
264out_free_vq:
265 vdev->config->del_vq(vblk->vq);
266out_free_vblk:
267 kfree(vblk);
268out:
269 return err;
270}
271
272static void virtblk_remove(struct virtio_device *vdev)
273{
274 struct virtio_blk *vblk = vdev->priv;
275 int major = vblk->disk->major;
276
277 BUG_ON(!list_empty(&vblk->reqs));
278 blk_cleanup_queue(vblk->disk->queue);
279 put_disk(vblk->disk);
280 unregister_blkdev(major, "virtblk");
281 mempool_destroy(vblk->pool);
Rusty Russell74b25532007-11-19 11:20:42 -0500282 /* There should be nothing in the queue now, so no need to shutdown */
283 vdev->config->del_vq(vblk->vq);
Rusty Russelle467cde2007-10-22 11:03:38 +1000284 kfree(vblk);
285}
286
287static struct virtio_device_id id_table[] = {
288 { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
289 { 0 },
290};
291
292static struct virtio_driver virtio_blk = {
293 .driver.name = KBUILD_MODNAME,
294 .driver.owner = THIS_MODULE,
295 .id_table = id_table,
296 .probe = virtblk_probe,
297 .remove = __devexit_p(virtblk_remove),
298};
299
300static int __init init(void)
301{
302 return register_virtio_driver(&virtio_blk);
303}
304
305static void __exit fini(void)
306{
307 unregister_virtio_driver(&virtio_blk);
308}
309module_init(init);
310module_exit(fini);
311
312MODULE_DEVICE_TABLE(virtio, id_table);
313MODULE_DESCRIPTION("Virtio block driver");
314MODULE_LICENSE("GPL");