| 1 | //#define DEBUG |
| 2 | #include <linux/spinlock.h> |
| 3 | #include <linux/slab.h> |
| 4 | #include <linux/blkdev.h> |
| 5 | #include <linux/hdreg.h> |
| 6 | #include <linux/module.h> |
| 7 | #include <linux/mutex.h> |
| 8 | #include <linux/virtio.h> |
| 9 | #include <linux/virtio_blk.h> |
| 10 | #include <linux/scatterlist.h> |
| 11 | #include <linux/string_helpers.h> |
| 12 | #include <scsi/scsi_cmnd.h> |
| 13 | #include <linux/idr.h> |
| 14 | #include <linux/blk-mq.h> |
| 15 | #include <linux/numa.h> |
| 16 | |
| 17 | #define PART_BITS 4 |
| 18 | #define VQ_NAME_LEN 16 |
| 19 | |
| 20 | static int major; |
| 21 | static DEFINE_IDA(vd_index_ida); |
| 22 | |
| 23 | static struct workqueue_struct *virtblk_wq; |
| 24 | |
| 25 | struct virtio_blk_vq { |
| 26 | struct virtqueue *vq; |
| 27 | spinlock_t lock; |
| 28 | char name[VQ_NAME_LEN]; |
| 29 | } ____cacheline_aligned_in_smp; |
| 30 | |
| 31 | struct virtio_blk { |
| 32 | struct virtio_device *vdev; |
| 33 | |
| 34 | /* The disk structure for the kernel. */ |
| 35 | struct gendisk *disk; |
| 36 | |
| 37 | /* Block layer tags. */ |
| 38 | struct blk_mq_tag_set tag_set; |
| 39 | |
| 40 | /* Process context for config space updates */ |
| 41 | struct work_struct config_work; |
| 42 | |
| 43 | /* What host tells us, plus 2 for header & tailer. */ |
| 44 | unsigned int sg_elems; |
| 45 | |
| 46 | /* Ida index - used to track minor number allocations. */ |
| 47 | int index; |
| 48 | |
| 49 | /* num of vqs */ |
| 50 | int num_vqs; |
| 51 | struct virtio_blk_vq *vqs; |
| 52 | }; |
| 53 | |
| 54 | struct virtblk_req { |
| 55 | struct request *req; |
| 56 | struct virtio_blk_outhdr out_hdr; |
| 57 | struct virtio_scsi_inhdr in_hdr; |
| 58 | u8 status; |
| 59 | struct scatterlist sg[]; |
| 60 | }; |
| 61 | |
| 62 | static inline int virtblk_result(struct virtblk_req *vbr) |
| 63 | { |
| 64 | switch (vbr->status) { |
| 65 | case VIRTIO_BLK_S_OK: |
| 66 | return 0; |
| 67 | case VIRTIO_BLK_S_UNSUPP: |
| 68 | return -ENOTTY; |
| 69 | default: |
| 70 | return -EIO; |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | static int __virtblk_add_req(struct virtqueue *vq, |
| 75 | struct virtblk_req *vbr, |
| 76 | struct scatterlist *data_sg, |
| 77 | bool have_data) |
| 78 | { |
| 79 | struct scatterlist hdr, status, cmd, sense, inhdr, *sgs[6]; |
| 80 | unsigned int num_out = 0, num_in = 0; |
| 81 | __virtio32 type = vbr->out_hdr.type & ~cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT); |
| 82 | |
| 83 | sg_init_one(&hdr, &vbr->out_hdr, sizeof(vbr->out_hdr)); |
| 84 | sgs[num_out++] = &hdr; |
| 85 | |
| 86 | /* |
| 87 | * If this is a packet command we need a couple of additional headers. |
| 88 | * Behind the normal outhdr we put a segment with the scsi command |
| 89 | * block, and before the normal inhdr we put the sense data and the |
| 90 | * inhdr with additional status information. |
| 91 | */ |
| 92 | if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) { |
| 93 | sg_init_one(&cmd, vbr->req->cmd, vbr->req->cmd_len); |
| 94 | sgs[num_out++] = &cmd; |
| 95 | } |
| 96 | |
| 97 | if (have_data) { |
| 98 | if (vbr->out_hdr.type & cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_OUT)) |
| 99 | sgs[num_out++] = data_sg; |
| 100 | else |
| 101 | sgs[num_out + num_in++] = data_sg; |
| 102 | } |
| 103 | |
| 104 | if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) { |
| 105 | sg_init_one(&sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE); |
| 106 | sgs[num_out + num_in++] = &sense; |
| 107 | sg_init_one(&inhdr, &vbr->in_hdr, sizeof(vbr->in_hdr)); |
| 108 | sgs[num_out + num_in++] = &inhdr; |
| 109 | } |
| 110 | |
| 111 | sg_init_one(&status, &vbr->status, sizeof(vbr->status)); |
| 112 | sgs[num_out + num_in++] = &status; |
| 113 | |
| 114 | return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC); |
| 115 | } |
| 116 | |
| 117 | static inline void virtblk_request_done(struct request *req) |
| 118 | { |
| 119 | struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); |
| 120 | struct virtio_blk *vblk = req->q->queuedata; |
| 121 | int error = virtblk_result(vbr); |
| 122 | |
| 123 | if (req->cmd_type == REQ_TYPE_BLOCK_PC) { |
| 124 | req->resid_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.residual); |
| 125 | req->sense_len = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.sense_len); |
| 126 | req->errors = virtio32_to_cpu(vblk->vdev, vbr->in_hdr.errors); |
| 127 | } else if (req->cmd_type == REQ_TYPE_DRV_PRIV) { |
| 128 | req->errors = (error != 0); |
| 129 | } |
| 130 | |
| 131 | blk_mq_end_request(req, error); |
| 132 | } |
| 133 | |
| 134 | static void virtblk_done(struct virtqueue *vq) |
| 135 | { |
| 136 | struct virtio_blk *vblk = vq->vdev->priv; |
| 137 | bool req_done = false; |
| 138 | int qid = vq->index; |
| 139 | struct virtblk_req *vbr; |
| 140 | unsigned long flags; |
| 141 | unsigned int len; |
| 142 | |
| 143 | spin_lock_irqsave(&vblk->vqs[qid].lock, flags); |
| 144 | do { |
| 145 | virtqueue_disable_cb(vq); |
| 146 | while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) { |
| 147 | blk_mq_complete_request(vbr->req, vbr->req->errors); |
| 148 | req_done = true; |
| 149 | } |
| 150 | if (unlikely(virtqueue_is_broken(vq))) |
| 151 | break; |
| 152 | } while (!virtqueue_enable_cb(vq)); |
| 153 | |
| 154 | /* In case queue is stopped waiting for more buffers. */ |
| 155 | if (req_done) |
| 156 | blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); |
| 157 | spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); |
| 158 | } |
| 159 | |
| 160 | static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, |
| 161 | const struct blk_mq_queue_data *bd) |
| 162 | { |
| 163 | struct virtio_blk *vblk = hctx->queue->queuedata; |
| 164 | struct request *req = bd->rq; |
| 165 | struct virtblk_req *vbr = blk_mq_rq_to_pdu(req); |
| 166 | unsigned long flags; |
| 167 | unsigned int num; |
| 168 | int qid = hctx->queue_num; |
| 169 | int err; |
| 170 | bool notify = false; |
| 171 | |
| 172 | BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems); |
| 173 | |
| 174 | vbr->req = req; |
| 175 | if (req->cmd_flags & REQ_FLUSH) { |
| 176 | vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_FLUSH); |
| 177 | vbr->out_hdr.sector = 0; |
| 178 | vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req)); |
| 179 | } else { |
| 180 | switch (req->cmd_type) { |
| 181 | case REQ_TYPE_FS: |
| 182 | vbr->out_hdr.type = 0; |
| 183 | vbr->out_hdr.sector = cpu_to_virtio64(vblk->vdev, blk_rq_pos(vbr->req)); |
| 184 | vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req)); |
| 185 | break; |
| 186 | case REQ_TYPE_BLOCK_PC: |
| 187 | vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_SCSI_CMD); |
| 188 | vbr->out_hdr.sector = 0; |
| 189 | vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req)); |
| 190 | break; |
| 191 | case REQ_TYPE_DRV_PRIV: |
| 192 | vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_ID); |
| 193 | vbr->out_hdr.sector = 0; |
| 194 | vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req)); |
| 195 | break; |
| 196 | default: |
| 197 | /* We don't put anything else in the queue. */ |
| 198 | BUG(); |
| 199 | } |
| 200 | } |
| 201 | |
| 202 | blk_mq_start_request(req); |
| 203 | |
| 204 | num = blk_rq_map_sg(hctx->queue, vbr->req, vbr->sg); |
| 205 | if (num) { |
| 206 | if (rq_data_dir(vbr->req) == WRITE) |
| 207 | vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT); |
| 208 | else |
| 209 | vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_IN); |
| 210 | } |
| 211 | |
| 212 | spin_lock_irqsave(&vblk->vqs[qid].lock, flags); |
| 213 | err = __virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num); |
| 214 | if (err) { |
| 215 | virtqueue_kick(vblk->vqs[qid].vq); |
| 216 | blk_mq_stop_hw_queue(hctx); |
| 217 | spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); |
| 218 | /* Out of mem doesn't actually happen, since we fall back |
| 219 | * to direct descriptors */ |
| 220 | if (err == -ENOMEM || err == -ENOSPC) |
| 221 | return BLK_MQ_RQ_QUEUE_BUSY; |
| 222 | return BLK_MQ_RQ_QUEUE_ERROR; |
| 223 | } |
| 224 | |
| 225 | if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq)) |
| 226 | notify = true; |
| 227 | spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags); |
| 228 | |
| 229 | if (notify) |
| 230 | virtqueue_notify(vblk->vqs[qid].vq); |
| 231 | return BLK_MQ_RQ_QUEUE_OK; |
| 232 | } |
| 233 | |
| 234 | /* return id (s/n) string for *disk to *id_str |
| 235 | */ |
| 236 | static int virtblk_get_id(struct gendisk *disk, char *id_str) |
| 237 | { |
| 238 | struct virtio_blk *vblk = disk->private_data; |
| 239 | struct request *req; |
| 240 | struct bio *bio; |
| 241 | int err; |
| 242 | |
| 243 | bio = bio_map_kern(vblk->disk->queue, id_str, VIRTIO_BLK_ID_BYTES, |
| 244 | GFP_KERNEL); |
| 245 | if (IS_ERR(bio)) |
| 246 | return PTR_ERR(bio); |
| 247 | |
| 248 | req = blk_make_request(vblk->disk->queue, bio, GFP_KERNEL); |
| 249 | if (IS_ERR(req)) { |
| 250 | bio_put(bio); |
| 251 | return PTR_ERR(req); |
| 252 | } |
| 253 | |
| 254 | req->cmd_type = REQ_TYPE_DRV_PRIV; |
| 255 | err = blk_execute_rq(vblk->disk->queue, vblk->disk, req, false); |
| 256 | blk_put_request(req); |
| 257 | |
| 258 | return err; |
| 259 | } |
| 260 | |
| 261 | static int virtblk_ioctl(struct block_device *bdev, fmode_t mode, |
| 262 | unsigned int cmd, unsigned long data) |
| 263 | { |
| 264 | struct gendisk *disk = bdev->bd_disk; |
| 265 | struct virtio_blk *vblk = disk->private_data; |
| 266 | |
| 267 | /* |
| 268 | * Only allow the generic SCSI ioctls if the host can support it. |
| 269 | */ |
| 270 | if (!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_SCSI)) |
| 271 | return -ENOTTY; |
| 272 | |
| 273 | return scsi_cmd_blk_ioctl(bdev, mode, cmd, |
| 274 | (void __user *)data); |
| 275 | } |
| 276 | |
| 277 | /* We provide getgeo only to please some old bootloader/partitioning tools */ |
| 278 | static int virtblk_getgeo(struct block_device *bd, struct hd_geometry *geo) |
| 279 | { |
| 280 | struct virtio_blk *vblk = bd->bd_disk->private_data; |
| 281 | |
| 282 | /* see if the host passed in geometry config */ |
| 283 | if (virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_GEOMETRY)) { |
| 284 | virtio_cread(vblk->vdev, struct virtio_blk_config, |
| 285 | geometry.cylinders, &geo->cylinders); |
| 286 | virtio_cread(vblk->vdev, struct virtio_blk_config, |
| 287 | geometry.heads, &geo->heads); |
| 288 | virtio_cread(vblk->vdev, struct virtio_blk_config, |
| 289 | geometry.sectors, &geo->sectors); |
| 290 | } else { |
| 291 | /* some standard values, similar to sd */ |
| 292 | geo->heads = 1 << 6; |
| 293 | geo->sectors = 1 << 5; |
| 294 | geo->cylinders = get_capacity(bd->bd_disk) >> 11; |
| 295 | } |
| 296 | return 0; |
| 297 | } |
| 298 | |
| 299 | static const struct block_device_operations virtblk_fops = { |
| 300 | .ioctl = virtblk_ioctl, |
| 301 | .owner = THIS_MODULE, |
| 302 | .getgeo = virtblk_getgeo, |
| 303 | }; |
| 304 | |
| 305 | static int index_to_minor(int index) |
| 306 | { |
| 307 | return index << PART_BITS; |
| 308 | } |
| 309 | |
| 310 | static int minor_to_index(int minor) |
| 311 | { |
| 312 | return minor >> PART_BITS; |
| 313 | } |
| 314 | |
| 315 | static ssize_t virtblk_serial_show(struct device *dev, |
| 316 | struct device_attribute *attr, char *buf) |
| 317 | { |
| 318 | struct gendisk *disk = dev_to_disk(dev); |
| 319 | int err; |
| 320 | |
| 321 | /* sysfs gives us a PAGE_SIZE buffer */ |
| 322 | BUILD_BUG_ON(PAGE_SIZE < VIRTIO_BLK_ID_BYTES); |
| 323 | |
| 324 | buf[VIRTIO_BLK_ID_BYTES] = '\0'; |
| 325 | err = virtblk_get_id(disk, buf); |
| 326 | if (!err) |
| 327 | return strlen(buf); |
| 328 | |
| 329 | if (err == -EIO) /* Unsupported? Make it empty. */ |
| 330 | return 0; |
| 331 | |
| 332 | return err; |
| 333 | } |
| 334 | |
| 335 | static DEVICE_ATTR(serial, S_IRUGO, virtblk_serial_show, NULL); |
| 336 | |
| 337 | static void virtblk_config_changed_work(struct work_struct *work) |
| 338 | { |
| 339 | struct virtio_blk *vblk = |
| 340 | container_of(work, struct virtio_blk, config_work); |
| 341 | struct virtio_device *vdev = vblk->vdev; |
| 342 | struct request_queue *q = vblk->disk->queue; |
| 343 | char cap_str_2[10], cap_str_10[10]; |
| 344 | char *envp[] = { "RESIZE=1", NULL }; |
| 345 | u64 capacity; |
| 346 | |
| 347 | /* Host must always specify the capacity. */ |
| 348 | virtio_cread(vdev, struct virtio_blk_config, capacity, &capacity); |
| 349 | |
| 350 | /* If capacity is too big, truncate with warning. */ |
| 351 | if ((sector_t)capacity != capacity) { |
| 352 | dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", |
| 353 | (unsigned long long)capacity); |
| 354 | capacity = (sector_t)-1; |
| 355 | } |
| 356 | |
| 357 | string_get_size(capacity, queue_logical_block_size(q), |
| 358 | STRING_UNITS_2, cap_str_2, sizeof(cap_str_2)); |
| 359 | string_get_size(capacity, queue_logical_block_size(q), |
| 360 | STRING_UNITS_10, cap_str_10, sizeof(cap_str_10)); |
| 361 | |
| 362 | dev_notice(&vdev->dev, |
| 363 | "new size: %llu %d-byte logical blocks (%s/%s)\n", |
| 364 | (unsigned long long)capacity, |
| 365 | queue_logical_block_size(q), |
| 366 | cap_str_10, cap_str_2); |
| 367 | |
| 368 | set_capacity(vblk->disk, capacity); |
| 369 | revalidate_disk(vblk->disk); |
| 370 | kobject_uevent_env(&disk_to_dev(vblk->disk)->kobj, KOBJ_CHANGE, envp); |
| 371 | } |
| 372 | |
| 373 | static void virtblk_config_changed(struct virtio_device *vdev) |
| 374 | { |
| 375 | struct virtio_blk *vblk = vdev->priv; |
| 376 | |
| 377 | queue_work(virtblk_wq, &vblk->config_work); |
| 378 | } |
| 379 | |
| 380 | static int init_vq(struct virtio_blk *vblk) |
| 381 | { |
| 382 | int err = 0; |
| 383 | int i; |
| 384 | vq_callback_t **callbacks; |
| 385 | const char **names; |
| 386 | struct virtqueue **vqs; |
| 387 | unsigned short num_vqs; |
| 388 | struct virtio_device *vdev = vblk->vdev; |
| 389 | |
| 390 | err = virtio_cread_feature(vdev, VIRTIO_BLK_F_MQ, |
| 391 | struct virtio_blk_config, num_queues, |
| 392 | &num_vqs); |
| 393 | if (err) |
| 394 | num_vqs = 1; |
| 395 | |
| 396 | vblk->vqs = kmalloc(sizeof(*vblk->vqs) * num_vqs, GFP_KERNEL); |
| 397 | if (!vblk->vqs) { |
| 398 | err = -ENOMEM; |
| 399 | goto out; |
| 400 | } |
| 401 | |
| 402 | names = kmalloc(sizeof(*names) * num_vqs, GFP_KERNEL); |
| 403 | if (!names) |
| 404 | goto err_names; |
| 405 | |
| 406 | callbacks = kmalloc(sizeof(*callbacks) * num_vqs, GFP_KERNEL); |
| 407 | if (!callbacks) |
| 408 | goto err_callbacks; |
| 409 | |
| 410 | vqs = kmalloc(sizeof(*vqs) * num_vqs, GFP_KERNEL); |
| 411 | if (!vqs) |
| 412 | goto err_vqs; |
| 413 | |
| 414 | for (i = 0; i < num_vqs; i++) { |
| 415 | callbacks[i] = virtblk_done; |
| 416 | snprintf(vblk->vqs[i].name, VQ_NAME_LEN, "req.%d", i); |
| 417 | names[i] = vblk->vqs[i].name; |
| 418 | } |
| 419 | |
| 420 | /* Discover virtqueues and write information to configuration. */ |
| 421 | err = vdev->config->find_vqs(vdev, num_vqs, vqs, callbacks, names); |
| 422 | if (err) |
| 423 | goto err_find_vqs; |
| 424 | |
| 425 | for (i = 0; i < num_vqs; i++) { |
| 426 | spin_lock_init(&vblk->vqs[i].lock); |
| 427 | vblk->vqs[i].vq = vqs[i]; |
| 428 | } |
| 429 | vblk->num_vqs = num_vqs; |
| 430 | |
| 431 | err_find_vqs: |
| 432 | kfree(vqs); |
| 433 | err_vqs: |
| 434 | kfree(callbacks); |
| 435 | err_callbacks: |
| 436 | kfree(names); |
| 437 | err_names: |
| 438 | if (err) |
| 439 | kfree(vblk->vqs); |
| 440 | out: |
| 441 | return err; |
| 442 | } |
| 443 | |
| 444 | /* |
| 445 | * Legacy naming scheme used for virtio devices. We are stuck with it for |
| 446 | * virtio blk but don't ever use it for any new driver. |
| 447 | */ |
| 448 | static int virtblk_name_format(char *prefix, int index, char *buf, int buflen) |
| 449 | { |
| 450 | const int base = 'z' - 'a' + 1; |
| 451 | char *begin = buf + strlen(prefix); |
| 452 | char *end = buf + buflen; |
| 453 | char *p; |
| 454 | int unit; |
| 455 | |
| 456 | p = end - 1; |
| 457 | *p = '\0'; |
| 458 | unit = base; |
| 459 | do { |
| 460 | if (p == begin) |
| 461 | return -EINVAL; |
| 462 | *--p = 'a' + (index % unit); |
| 463 | index = (index / unit) - 1; |
| 464 | } while (index >= 0); |
| 465 | |
| 466 | memmove(begin, p, end - p); |
| 467 | memcpy(buf, prefix, strlen(prefix)); |
| 468 | |
| 469 | return 0; |
| 470 | } |
| 471 | |
| 472 | static int virtblk_get_cache_mode(struct virtio_device *vdev) |
| 473 | { |
| 474 | u8 writeback; |
| 475 | int err; |
| 476 | |
| 477 | err = virtio_cread_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE, |
| 478 | struct virtio_blk_config, wce, |
| 479 | &writeback); |
| 480 | if (err) |
| 481 | writeback = virtio_has_feature(vdev, VIRTIO_BLK_F_WCE); |
| 482 | |
| 483 | return writeback; |
| 484 | } |
| 485 | |
| 486 | static void virtblk_update_cache_mode(struct virtio_device *vdev) |
| 487 | { |
| 488 | u8 writeback = virtblk_get_cache_mode(vdev); |
| 489 | struct virtio_blk *vblk = vdev->priv; |
| 490 | |
| 491 | if (writeback) |
| 492 | blk_queue_flush(vblk->disk->queue, REQ_FLUSH); |
| 493 | else |
| 494 | blk_queue_flush(vblk->disk->queue, 0); |
| 495 | |
| 496 | revalidate_disk(vblk->disk); |
| 497 | } |
| 498 | |
| 499 | static const char *const virtblk_cache_types[] = { |
| 500 | "write through", "write back" |
| 501 | }; |
| 502 | |
| 503 | static ssize_t |
| 504 | virtblk_cache_type_store(struct device *dev, struct device_attribute *attr, |
| 505 | const char *buf, size_t count) |
| 506 | { |
| 507 | struct gendisk *disk = dev_to_disk(dev); |
| 508 | struct virtio_blk *vblk = disk->private_data; |
| 509 | struct virtio_device *vdev = vblk->vdev; |
| 510 | int i; |
| 511 | |
| 512 | BUG_ON(!virtio_has_feature(vblk->vdev, VIRTIO_BLK_F_CONFIG_WCE)); |
| 513 | for (i = ARRAY_SIZE(virtblk_cache_types); --i >= 0; ) |
| 514 | if (sysfs_streq(buf, virtblk_cache_types[i])) |
| 515 | break; |
| 516 | |
| 517 | if (i < 0) |
| 518 | return -EINVAL; |
| 519 | |
| 520 | virtio_cwrite8(vdev, offsetof(struct virtio_blk_config, wce), i); |
| 521 | virtblk_update_cache_mode(vdev); |
| 522 | return count; |
| 523 | } |
| 524 | |
| 525 | static ssize_t |
| 526 | virtblk_cache_type_show(struct device *dev, struct device_attribute *attr, |
| 527 | char *buf) |
| 528 | { |
| 529 | struct gendisk *disk = dev_to_disk(dev); |
| 530 | struct virtio_blk *vblk = disk->private_data; |
| 531 | u8 writeback = virtblk_get_cache_mode(vblk->vdev); |
| 532 | |
| 533 | BUG_ON(writeback >= ARRAY_SIZE(virtblk_cache_types)); |
| 534 | return snprintf(buf, 40, "%s\n", virtblk_cache_types[writeback]); |
| 535 | } |
| 536 | |
| 537 | static const struct device_attribute dev_attr_cache_type_ro = |
| 538 | __ATTR(cache_type, S_IRUGO, |
| 539 | virtblk_cache_type_show, NULL); |
| 540 | static const struct device_attribute dev_attr_cache_type_rw = |
| 541 | __ATTR(cache_type, S_IRUGO|S_IWUSR, |
| 542 | virtblk_cache_type_show, virtblk_cache_type_store); |
| 543 | |
| 544 | static int virtblk_init_request(void *data, struct request *rq, |
| 545 | unsigned int hctx_idx, unsigned int request_idx, |
| 546 | unsigned int numa_node) |
| 547 | { |
| 548 | struct virtio_blk *vblk = data; |
| 549 | struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq); |
| 550 | |
| 551 | sg_init_table(vbr->sg, vblk->sg_elems); |
| 552 | return 0; |
| 553 | } |
| 554 | |
| 555 | static struct blk_mq_ops virtio_mq_ops = { |
| 556 | .queue_rq = virtio_queue_rq, |
| 557 | .map_queue = blk_mq_map_queue, |
| 558 | .complete = virtblk_request_done, |
| 559 | .init_request = virtblk_init_request, |
| 560 | }; |
| 561 | |
| 562 | static unsigned int virtblk_queue_depth; |
| 563 | module_param_named(queue_depth, virtblk_queue_depth, uint, 0444); |
| 564 | |
| 565 | static int virtblk_probe(struct virtio_device *vdev) |
| 566 | { |
| 567 | struct virtio_blk *vblk; |
| 568 | struct request_queue *q; |
| 569 | int err, index; |
| 570 | |
| 571 | u64 cap; |
| 572 | u32 v, blk_size, sg_elems, opt_io_size; |
| 573 | u16 min_io_size; |
| 574 | u8 physical_block_exp, alignment_offset; |
| 575 | |
| 576 | if (!vdev->config->get) { |
| 577 | dev_err(&vdev->dev, "%s failure: config access disabled\n", |
| 578 | __func__); |
| 579 | return -EINVAL; |
| 580 | } |
| 581 | |
| 582 | err = ida_simple_get(&vd_index_ida, 0, minor_to_index(1 << MINORBITS), |
| 583 | GFP_KERNEL); |
| 584 | if (err < 0) |
| 585 | goto out; |
| 586 | index = err; |
| 587 | |
| 588 | /* We need to know how many segments before we allocate. */ |
| 589 | err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SEG_MAX, |
| 590 | struct virtio_blk_config, seg_max, |
| 591 | &sg_elems); |
| 592 | |
| 593 | /* We need at least one SG element, whatever they say. */ |
| 594 | if (err || !sg_elems) |
| 595 | sg_elems = 1; |
| 596 | |
| 597 | /* We need an extra sg elements at head and tail. */ |
| 598 | sg_elems += 2; |
| 599 | vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL); |
| 600 | if (!vblk) { |
| 601 | err = -ENOMEM; |
| 602 | goto out_free_index; |
| 603 | } |
| 604 | |
| 605 | vblk->vdev = vdev; |
| 606 | vblk->sg_elems = sg_elems; |
| 607 | |
| 608 | INIT_WORK(&vblk->config_work, virtblk_config_changed_work); |
| 609 | |
| 610 | err = init_vq(vblk); |
| 611 | if (err) |
| 612 | goto out_free_vblk; |
| 613 | |
| 614 | /* FIXME: How many partitions? How long is a piece of string? */ |
| 615 | vblk->disk = alloc_disk(1 << PART_BITS); |
| 616 | if (!vblk->disk) { |
| 617 | err = -ENOMEM; |
| 618 | goto out_free_vq; |
| 619 | } |
| 620 | |
| 621 | /* Default queue sizing is to fill the ring. */ |
| 622 | if (!virtblk_queue_depth) { |
| 623 | virtblk_queue_depth = vblk->vqs[0].vq->num_free; |
| 624 | /* ... but without indirect descs, we use 2 descs per req */ |
| 625 | if (!virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)) |
| 626 | virtblk_queue_depth /= 2; |
| 627 | } |
| 628 | |
| 629 | memset(&vblk->tag_set, 0, sizeof(vblk->tag_set)); |
| 630 | vblk->tag_set.ops = &virtio_mq_ops; |
| 631 | vblk->tag_set.queue_depth = virtblk_queue_depth; |
| 632 | vblk->tag_set.numa_node = NUMA_NO_NODE; |
| 633 | vblk->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; |
| 634 | vblk->tag_set.cmd_size = |
| 635 | sizeof(struct virtblk_req) + |
| 636 | sizeof(struct scatterlist) * sg_elems; |
| 637 | vblk->tag_set.driver_data = vblk; |
| 638 | vblk->tag_set.nr_hw_queues = vblk->num_vqs; |
| 639 | |
| 640 | err = blk_mq_alloc_tag_set(&vblk->tag_set); |
| 641 | if (err) |
| 642 | goto out_put_disk; |
| 643 | |
| 644 | q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set); |
| 645 | if (IS_ERR(q)) { |
| 646 | err = -ENOMEM; |
| 647 | goto out_free_tags; |
| 648 | } |
| 649 | |
| 650 | q->queuedata = vblk; |
| 651 | |
| 652 | virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN); |
| 653 | |
| 654 | vblk->disk->major = major; |
| 655 | vblk->disk->first_minor = index_to_minor(index); |
| 656 | vblk->disk->private_data = vblk; |
| 657 | vblk->disk->fops = &virtblk_fops; |
| 658 | vblk->disk->driverfs_dev = &vdev->dev; |
| 659 | vblk->disk->flags |= GENHD_FL_EXT_DEVT; |
| 660 | vblk->index = index; |
| 661 | |
| 662 | /* configure queue flush support */ |
| 663 | virtblk_update_cache_mode(vdev); |
| 664 | |
| 665 | /* If disk is read-only in the host, the guest should obey */ |
| 666 | if (virtio_has_feature(vdev, VIRTIO_BLK_F_RO)) |
| 667 | set_disk_ro(vblk->disk, 1); |
| 668 | |
| 669 | /* Host must always specify the capacity. */ |
| 670 | virtio_cread(vdev, struct virtio_blk_config, capacity, &cap); |
| 671 | |
| 672 | /* If capacity is too big, truncate with warning. */ |
| 673 | if ((sector_t)cap != cap) { |
| 674 | dev_warn(&vdev->dev, "Capacity %llu too large: truncating\n", |
| 675 | (unsigned long long)cap); |
| 676 | cap = (sector_t)-1; |
| 677 | } |
| 678 | set_capacity(vblk->disk, cap); |
| 679 | |
| 680 | /* We can handle whatever the host told us to handle. */ |
| 681 | blk_queue_max_segments(q, vblk->sg_elems-2); |
| 682 | |
| 683 | /* No need to bounce any requests */ |
| 684 | blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); |
| 685 | |
| 686 | /* No real sector limit. */ |
| 687 | blk_queue_max_hw_sectors(q, -1U); |
| 688 | |
| 689 | /* Host can optionally specify maximum segment size and number of |
| 690 | * segments. */ |
| 691 | err = virtio_cread_feature(vdev, VIRTIO_BLK_F_SIZE_MAX, |
| 692 | struct virtio_blk_config, size_max, &v); |
| 693 | if (!err) |
| 694 | blk_queue_max_segment_size(q, v); |
| 695 | else |
| 696 | blk_queue_max_segment_size(q, -1U); |
| 697 | |
| 698 | /* Host can optionally specify the block size of the device */ |
| 699 | err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE, |
| 700 | struct virtio_blk_config, blk_size, |
| 701 | &blk_size); |
| 702 | if (!err) |
| 703 | blk_queue_logical_block_size(q, blk_size); |
| 704 | else |
| 705 | blk_size = queue_logical_block_size(q); |
| 706 | |
| 707 | /* Use topology information if available */ |
| 708 | err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, |
| 709 | struct virtio_blk_config, physical_block_exp, |
| 710 | &physical_block_exp); |
| 711 | if (!err && physical_block_exp) |
| 712 | blk_queue_physical_block_size(q, |
| 713 | blk_size * (1 << physical_block_exp)); |
| 714 | |
| 715 | err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, |
| 716 | struct virtio_blk_config, alignment_offset, |
| 717 | &alignment_offset); |
| 718 | if (!err && alignment_offset) |
| 719 | blk_queue_alignment_offset(q, blk_size * alignment_offset); |
| 720 | |
| 721 | err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, |
| 722 | struct virtio_blk_config, min_io_size, |
| 723 | &min_io_size); |
| 724 | if (!err && min_io_size) |
| 725 | blk_queue_io_min(q, blk_size * min_io_size); |
| 726 | |
| 727 | err = virtio_cread_feature(vdev, VIRTIO_BLK_F_TOPOLOGY, |
| 728 | struct virtio_blk_config, opt_io_size, |
| 729 | &opt_io_size); |
| 730 | if (!err && opt_io_size) |
| 731 | blk_queue_io_opt(q, blk_size * opt_io_size); |
| 732 | |
| 733 | virtio_device_ready(vdev); |
| 734 | |
| 735 | add_disk(vblk->disk); |
| 736 | err = device_create_file(disk_to_dev(vblk->disk), &dev_attr_serial); |
| 737 | if (err) |
| 738 | goto out_del_disk; |
| 739 | |
| 740 | if (virtio_has_feature(vdev, VIRTIO_BLK_F_CONFIG_WCE)) |
| 741 | err = device_create_file(disk_to_dev(vblk->disk), |
| 742 | &dev_attr_cache_type_rw); |
| 743 | else |
| 744 | err = device_create_file(disk_to_dev(vblk->disk), |
| 745 | &dev_attr_cache_type_ro); |
| 746 | if (err) |
| 747 | goto out_del_disk; |
| 748 | return 0; |
| 749 | |
| 750 | out_del_disk: |
| 751 | del_gendisk(vblk->disk); |
| 752 | blk_cleanup_queue(vblk->disk->queue); |
| 753 | out_free_tags: |
| 754 | blk_mq_free_tag_set(&vblk->tag_set); |
| 755 | out_put_disk: |
| 756 | put_disk(vblk->disk); |
| 757 | out_free_vq: |
| 758 | vdev->config->del_vqs(vdev); |
| 759 | out_free_vblk: |
| 760 | kfree(vblk); |
| 761 | out_free_index: |
| 762 | ida_simple_remove(&vd_index_ida, index); |
| 763 | out: |
| 764 | return err; |
| 765 | } |
| 766 | |
| 767 | static void virtblk_remove(struct virtio_device *vdev) |
| 768 | { |
| 769 | struct virtio_blk *vblk = vdev->priv; |
| 770 | int index = vblk->index; |
| 771 | int refc; |
| 772 | |
| 773 | /* Make sure no work handler is accessing the device. */ |
| 774 | flush_work(&vblk->config_work); |
| 775 | |
| 776 | del_gendisk(vblk->disk); |
| 777 | blk_cleanup_queue(vblk->disk->queue); |
| 778 | |
| 779 | blk_mq_free_tag_set(&vblk->tag_set); |
| 780 | |
| 781 | /* Stop all the virtqueues. */ |
| 782 | vdev->config->reset(vdev); |
| 783 | |
| 784 | refc = atomic_read(&disk_to_dev(vblk->disk)->kobj.kref.refcount); |
| 785 | put_disk(vblk->disk); |
| 786 | vdev->config->del_vqs(vdev); |
| 787 | kfree(vblk->vqs); |
| 788 | kfree(vblk); |
| 789 | |
| 790 | /* Only free device id if we don't have any users */ |
| 791 | if (refc == 1) |
| 792 | ida_simple_remove(&vd_index_ida, index); |
| 793 | } |
| 794 | |
| 795 | #ifdef CONFIG_PM_SLEEP |
| 796 | static int virtblk_freeze(struct virtio_device *vdev) |
| 797 | { |
| 798 | struct virtio_blk *vblk = vdev->priv; |
| 799 | |
| 800 | /* Ensure we don't receive any more interrupts */ |
| 801 | vdev->config->reset(vdev); |
| 802 | |
| 803 | /* Make sure no work handler is accessing the device. */ |
| 804 | flush_work(&vblk->config_work); |
| 805 | |
| 806 | blk_mq_stop_hw_queues(vblk->disk->queue); |
| 807 | |
| 808 | vdev->config->del_vqs(vdev); |
| 809 | return 0; |
| 810 | } |
| 811 | |
| 812 | static int virtblk_restore(struct virtio_device *vdev) |
| 813 | { |
| 814 | struct virtio_blk *vblk = vdev->priv; |
| 815 | int ret; |
| 816 | |
| 817 | ret = init_vq(vdev->priv); |
| 818 | if (ret) |
| 819 | return ret; |
| 820 | |
| 821 | virtio_device_ready(vdev); |
| 822 | |
| 823 | blk_mq_start_stopped_hw_queues(vblk->disk->queue, true); |
| 824 | return 0; |
| 825 | } |
| 826 | #endif |
| 827 | |
| 828 | static const struct virtio_device_id id_table[] = { |
| 829 | { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID }, |
| 830 | { 0 }, |
| 831 | }; |
| 832 | |
| 833 | static unsigned int features_legacy[] = { |
| 834 | VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, |
| 835 | VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, VIRTIO_BLK_F_SCSI, |
| 836 | VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, |
| 837 | VIRTIO_BLK_F_MQ, |
| 838 | } |
| 839 | ; |
| 840 | static unsigned int features[] = { |
| 841 | VIRTIO_BLK_F_SEG_MAX, VIRTIO_BLK_F_SIZE_MAX, VIRTIO_BLK_F_GEOMETRY, |
| 842 | VIRTIO_BLK_F_RO, VIRTIO_BLK_F_BLK_SIZE, |
| 843 | VIRTIO_BLK_F_WCE, VIRTIO_BLK_F_TOPOLOGY, VIRTIO_BLK_F_CONFIG_WCE, |
| 844 | VIRTIO_BLK_F_MQ, |
| 845 | }; |
| 846 | |
| 847 | static struct virtio_driver virtio_blk = { |
| 848 | .feature_table = features, |
| 849 | .feature_table_size = ARRAY_SIZE(features), |
| 850 | .feature_table_legacy = features_legacy, |
| 851 | .feature_table_size_legacy = ARRAY_SIZE(features_legacy), |
| 852 | .driver.name = KBUILD_MODNAME, |
| 853 | .driver.owner = THIS_MODULE, |
| 854 | .id_table = id_table, |
| 855 | .probe = virtblk_probe, |
| 856 | .remove = virtblk_remove, |
| 857 | .config_changed = virtblk_config_changed, |
| 858 | #ifdef CONFIG_PM_SLEEP |
| 859 | .freeze = virtblk_freeze, |
| 860 | .restore = virtblk_restore, |
| 861 | #endif |
| 862 | }; |
| 863 | |
| 864 | static int __init init(void) |
| 865 | { |
| 866 | int error; |
| 867 | |
| 868 | virtblk_wq = alloc_workqueue("virtio-blk", 0, 0); |
| 869 | if (!virtblk_wq) |
| 870 | return -ENOMEM; |
| 871 | |
| 872 | major = register_blkdev(0, "virtblk"); |
| 873 | if (major < 0) { |
| 874 | error = major; |
| 875 | goto out_destroy_workqueue; |
| 876 | } |
| 877 | |
| 878 | error = register_virtio_driver(&virtio_blk); |
| 879 | if (error) |
| 880 | goto out_unregister_blkdev; |
| 881 | return 0; |
| 882 | |
| 883 | out_unregister_blkdev: |
| 884 | unregister_blkdev(major, "virtblk"); |
| 885 | out_destroy_workqueue: |
| 886 | destroy_workqueue(virtblk_wq); |
| 887 | return error; |
| 888 | } |
| 889 | |
| 890 | static void __exit fini(void) |
| 891 | { |
| 892 | unregister_virtio_driver(&virtio_blk); |
| 893 | unregister_blkdev(major, "virtblk"); |
| 894 | destroy_workqueue(virtblk_wq); |
| 895 | } |
| 896 | module_init(init); |
| 897 | module_exit(fini); |
| 898 | |
| 899 | MODULE_DEVICE_TABLE(virtio, id_table); |
| 900 | MODULE_DESCRIPTION("Virtio block driver"); |
| 901 | MODULE_LICENSE("GPL"); |