Rusty Russell | e467cde | 2007-10-22 11:03:38 +1000 | [diff] [blame] | 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> |
Jens Axboe | 3d1266c | 2007-10-24 13:21:21 +0200 | [diff] [blame] | 7 | #include <linux/scatterlist.h> |
| 8 | |
| 9 | #define VIRTIO_MAX_SG (3+MAX_PHYS_SEGMENTS) |
Rusty Russell | e467cde | 2007-10-22 11:03:38 +1000 | [diff] [blame] | 10 | |
| 11 | static unsigned char virtblk_index = 'a'; |
| 12 | struct 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 Axboe | 3d1266c | 2007-10-24 13:21:21 +0200 | [diff] [blame] | 28 | struct scatterlist sg[VIRTIO_MAX_SG]; |
Rusty Russell | e467cde | 2007-10-22 11:03:38 +1000 | [diff] [blame] | 29 | }; |
| 30 | |
| 31 | struct 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 | |
| 39 | static 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 | |
| 71 | static 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 Axboe | 3d1266c | 2007-10-24 13:21:21 +0200 | [diff] [blame] | 99 | /* This init could be done at vblk creation time */ |
| 100 | sg_init_table(vblk->sg, VIRTIO_MAX_SG); |
Rusty Russell | e467cde | 2007-10-22 11:03:38 +1000 | [diff] [blame] | 101 | 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 | |
| 124 | static 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 | |
| 148 | static 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 | |
| 156 | static struct block_device_operations virtblk_fops = { |
| 157 | .ioctl = virtblk_ioctl, |
| 158 | .owner = THIS_MODULE, |
| 159 | }; |
| 160 | |
| 161 | static 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 Russell | 74b2553 | 2007-11-19 11:20:42 -0500 | [diff] [blame] | 226 | goto out_cleanup_queue; |
Rusty Russell | e467cde | 2007-10-22 11:03:38 +1000 | [diff] [blame] | 227 | } |
| 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 Russell | 74b2553 | 2007-11-19 11:20:42 -0500 | [diff] [blame] | 242 | goto out_cleanup_queue; |
Rusty Russell | e467cde | 2007-10-22 11:03:38 +1000 | [diff] [blame] | 243 | } |
| 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 Russell | 74b2553 | 2007-11-19 11:20:42 -0500 | [diff] [blame] | 250 | goto out_cleanup_queue; |
Rusty Russell | e467cde | 2007-10-22 11:03:38 +1000 | [diff] [blame] | 251 | } |
| 252 | |
| 253 | add_disk(vblk->disk); |
| 254 | return 0; |
| 255 | |
Rusty Russell | 74b2553 | 2007-11-19 11:20:42 -0500 | [diff] [blame] | 256 | out_cleanup_queue: |
| 257 | blk_cleanup_queue(vblk->disk->queue); |
Rusty Russell | e467cde | 2007-10-22 11:03:38 +1000 | [diff] [blame] | 258 | out_put_disk: |
| 259 | put_disk(vblk->disk); |
| 260 | out_unregister_blkdev: |
| 261 | unregister_blkdev(major, "virtblk"); |
| 262 | out_mempool: |
| 263 | mempool_destroy(vblk->pool); |
| 264 | out_free_vq: |
| 265 | vdev->config->del_vq(vblk->vq); |
| 266 | out_free_vblk: |
| 267 | kfree(vblk); |
| 268 | out: |
| 269 | return err; |
| 270 | } |
| 271 | |
| 272 | static 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 Russell | 74b2553 | 2007-11-19 11:20:42 -0500 | [diff] [blame] | 282 | /* There should be nothing in the queue now, so no need to shutdown */ |
| 283 | vdev->config->del_vq(vblk->vq); |
Rusty Russell | e467cde | 2007-10-22 11:03:38 +1000 | [diff] [blame] | 284 | kfree(vblk); |
| 285 | } |
| 286 | |
| 287 | static struct virtio_device_id id_table[] = { |
| 288 | { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, |
| 289 | { 0 }, |
| 290 | }; |
| 291 | |
| 292 | static 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 | |
| 300 | static int __init init(void) |
| 301 | { |
| 302 | return register_virtio_driver(&virtio_blk); |
| 303 | } |
| 304 | |
| 305 | static void __exit fini(void) |
| 306 | { |
| 307 | unregister_virtio_driver(&virtio_blk); |
| 308 | } |
| 309 | module_init(init); |
| 310 | module_exit(fini); |
| 311 | |
| 312 | MODULE_DEVICE_TABLE(virtio, id_table); |
| 313 | MODULE_DESCRIPTION("Virtio block driver"); |
| 314 | MODULE_LICENSE("GPL"); |