1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Userspace block device - block device which IO is handled from userspace
5 * Take full use of io_uring passthrough command for communicating with
6 * ublk userspace daemon(ublksrvd) for handling basic IO request.
8 * Copyright 2022 Ming Lei <ming.lei@redhat.com>
10 * (part of code stolen from loop.c)
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/sched.h>
16 #include <linux/pagemap.h>
17 #include <linux/file.h>
18 #include <linux/stat.h>
19 #include <linux/errno.h>
20 #include <linux/major.h>
21 #include <linux/wait.h>
22 #include <linux/blkdev.h>
23 #include <linux/init.h>
24 #include <linux/swap.h>
25 #include <linux/slab.h>
26 #include <linux/compat.h>
27 #include <linux/mutex.h>
28 #include <linux/writeback.h>
29 #include <linux/completion.h>
30 #include <linux/highmem.h>
31 #include <linux/sysfs.h>
32 #include <linux/miscdevice.h>
33 #include <linux/falloc.h>
34 #include <linux/uio.h>
35 #include <linux/ioprio.h>
36 #include <linux/sched/mm.h>
37 #include <linux/uaccess.h>
38 #include <linux/cdev.h>
39 #include <linux/io_uring.h>
40 #include <linux/blk-mq.h>
41 #include <linux/delay.h>
44 #include <linux/task_work.h>
45 #include <linux/namei.h>
46 #include <linux/kref.h>
47 #include <uapi/linux/ublk_cmd.h>
49 #define UBLK_MINORS (1U << MINORBITS)
51 /* All UBLK_F_* have to be included into UBLK_F_ALL */
52 #define UBLK_F_ALL (UBLK_F_SUPPORT_ZERO_COPY \
53 | UBLK_F_URING_CMD_COMP_IN_TASK \
54 | UBLK_F_NEED_GET_DATA \
55 | UBLK_F_USER_RECOVERY \
56 | UBLK_F_USER_RECOVERY_REISSUE \
57 | UBLK_F_UNPRIVILEGED_DEV \
58 | UBLK_F_CMD_IOCTL_ENCODE \
61 /* All UBLK_PARAM_TYPE_* should be included here */
62 #define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | \
63 UBLK_PARAM_TYPE_DISCARD | UBLK_PARAM_TYPE_DEVT)
66 struct llist_node node
;
71 struct ublk_uring_cmd_pdu
{
72 struct ublk_queue
*ubq
;
76 * io command is active: sqe cmd is received, and its cqe isn't done
78 * If the flag is set, the io command is owned by ublk driver, and waited
79 * for incoming blk-mq request from the ublk block device.
81 * If the flag is cleared, the io command will be completed, and owned by
84 #define UBLK_IO_FLAG_ACTIVE 0x01
87 * IO command is completed via cqe, and it is being handled by ublksrv, and
90 * Basically exclusively with UBLK_IO_FLAG_ACTIVE, so can be served for
93 #define UBLK_IO_FLAG_OWNED_BY_SRV 0x02
96 * IO command is aborted, so this flag is set in case of
97 * !UBLK_IO_FLAG_ACTIVE.
99 * After this flag is observed, any pending or new incoming request
100 * associated with this io command will be failed immediately
102 #define UBLK_IO_FLAG_ABORTED 0x04
105 * UBLK_IO_FLAG_NEED_GET_DATA is set because IO command requires
106 * get data buffer address from ublksrv.
108 * Then, bio data could be copied into this data buffer for a WRITE request
109 * after the IO command is issued again and UBLK_IO_FLAG_NEED_GET_DATA is unset.
111 #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
114 /* userspace buffer address from io cmd */
119 struct io_uring_cmd
*cmd
;
127 struct task_struct
*ubq_daemon
;
130 struct llist_head io_cmds
;
132 unsigned long io_addr
; /* mapped vm address */
133 unsigned int max_io_sz
;
136 unsigned short nr_io_ready
; /* how many ios setup */
137 struct ublk_device
*dev
;
138 struct ublk_io ios
[];
141 #define UBLK_DAEMON_MONITOR_PERIOD (5 * HZ)
144 struct gendisk
*ub_disk
;
148 unsigned int queue_size
;
149 struct ublksrv_ctrl_dev_info dev_info
;
151 struct blk_mq_tag_set tag_set
;
154 struct device cdev_dev
;
156 #define UB_STATE_OPEN 0
157 #define UB_STATE_USED 1
158 #define UB_STATE_DELETED 2
165 struct mm_struct
*mm
;
167 struct ublk_params params
;
169 struct completion completion
;
170 unsigned int nr_queues_ready
;
171 unsigned int nr_privileged_daemon
;
174 * Our ubq->daemon may be killed without any notification, so
175 * monitor each queue's daemon periodically
177 struct delayed_work monitor_work
;
178 struct work_struct quiesce_work
;
179 struct work_struct stop_work
;
182 /* header of ublk_params */
183 struct ublk_params_header
{
188 static inline void __ublk_complete_rq(struct request
*req
);
189 static void ublk_complete_rq(struct kref
*ref
);
191 static dev_t ublk_chr_devt
;
192 static struct class *ublk_chr_class
;
194 static DEFINE_IDR(ublk_index_idr
);
195 static DEFINE_SPINLOCK(ublk_idr_lock
);
196 static wait_queue_head_t ublk_idr_wq
; /* wait until one idr is freed */
198 static DEFINE_MUTEX(ublk_ctl_mutex
);
201 * Max ublk devices allowed to add
203 * It can be extended to one per-user limit in future or even controlled
206 static unsigned int ublks_max
= 64;
207 static unsigned int ublks_added
; /* protected by ublk_ctl_mutex */
209 static struct miscdevice ublk_misc
;
211 static inline unsigned ublk_pos_to_hwq(loff_t pos
)
213 return ((pos
- UBLKSRV_IO_BUF_OFFSET
) >> UBLK_QID_OFF
) &
217 static inline unsigned ublk_pos_to_buf_off(loff_t pos
)
219 return (pos
- UBLKSRV_IO_BUF_OFFSET
) & UBLK_IO_BUF_BITS_MASK
;
222 static inline unsigned ublk_pos_to_tag(loff_t pos
)
224 return ((pos
- UBLKSRV_IO_BUF_OFFSET
) >> UBLK_TAG_OFF
) &
228 static void ublk_dev_param_basic_apply(struct ublk_device
*ub
)
230 struct request_queue
*q
= ub
->ub_disk
->queue
;
231 const struct ublk_param_basic
*p
= &ub
->params
.basic
;
233 blk_queue_logical_block_size(q
, 1 << p
->logical_bs_shift
);
234 blk_queue_physical_block_size(q
, 1 << p
->physical_bs_shift
);
235 blk_queue_io_min(q
, 1 << p
->io_min_shift
);
236 blk_queue_io_opt(q
, 1 << p
->io_opt_shift
);
238 blk_queue_write_cache(q
, p
->attrs
& UBLK_ATTR_VOLATILE_CACHE
,
239 p
->attrs
& UBLK_ATTR_FUA
);
240 if (p
->attrs
& UBLK_ATTR_ROTATIONAL
)
241 blk_queue_flag_clear(QUEUE_FLAG_NONROT
, q
);
243 blk_queue_flag_set(QUEUE_FLAG_NONROT
, q
);
245 blk_queue_max_hw_sectors(q
, p
->max_sectors
);
246 blk_queue_chunk_sectors(q
, p
->chunk_sectors
);
247 blk_queue_virt_boundary(q
, p
->virt_boundary_mask
);
249 if (p
->attrs
& UBLK_ATTR_READ_ONLY
)
250 set_disk_ro(ub
->ub_disk
, true);
252 set_capacity(ub
->ub_disk
, p
->dev_sectors
);
255 static void ublk_dev_param_discard_apply(struct ublk_device
*ub
)
257 struct request_queue
*q
= ub
->ub_disk
->queue
;
258 const struct ublk_param_discard
*p
= &ub
->params
.discard
;
260 q
->limits
.discard_alignment
= p
->discard_alignment
;
261 q
->limits
.discard_granularity
= p
->discard_granularity
;
262 blk_queue_max_discard_sectors(q
, p
->max_discard_sectors
);
263 blk_queue_max_write_zeroes_sectors(q
,
264 p
->max_write_zeroes_sectors
);
265 blk_queue_max_discard_segments(q
, p
->max_discard_segments
);
268 static int ublk_validate_params(const struct ublk_device
*ub
)
270 /* basic param is the only one which must be set */
271 if (ub
->params
.types
& UBLK_PARAM_TYPE_BASIC
) {
272 const struct ublk_param_basic
*p
= &ub
->params
.basic
;
274 if (p
->logical_bs_shift
> PAGE_SHIFT
|| p
->logical_bs_shift
< 9)
277 if (p
->logical_bs_shift
> p
->physical_bs_shift
)
280 if (p
->max_sectors
> (ub
->dev_info
.max_io_buf_bytes
>> 9))
285 if (ub
->params
.types
& UBLK_PARAM_TYPE_DISCARD
) {
286 const struct ublk_param_discard
*p
= &ub
->params
.discard
;
288 /* So far, only support single segment discard */
289 if (p
->max_discard_sectors
&& p
->max_discard_segments
!= 1)
292 if (!p
->discard_granularity
)
296 /* dev_t is read-only */
297 if (ub
->params
.types
& UBLK_PARAM_TYPE_DEVT
)
303 static int ublk_apply_params(struct ublk_device
*ub
)
305 if (!(ub
->params
.types
& UBLK_PARAM_TYPE_BASIC
))
308 ublk_dev_param_basic_apply(ub
);
310 if (ub
->params
.types
& UBLK_PARAM_TYPE_DISCARD
)
311 ublk_dev_param_discard_apply(ub
);
316 static inline bool ublk_support_user_copy(const struct ublk_queue
*ubq
)
318 return ubq
->flags
& UBLK_F_USER_COPY
;
321 static inline bool ublk_need_req_ref(const struct ublk_queue
*ubq
)
324 * read()/write() is involved in user copy, so request reference
327 return ublk_support_user_copy(ubq
);
330 static inline void ublk_init_req_ref(const struct ublk_queue
*ubq
,
333 if (ublk_need_req_ref(ubq
)) {
334 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(req
);
336 kref_init(&data
->ref
);
340 static inline bool ublk_get_req_ref(const struct ublk_queue
*ubq
,
343 if (ublk_need_req_ref(ubq
)) {
344 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(req
);
346 return kref_get_unless_zero(&data
->ref
);
352 static inline void ublk_put_req_ref(const struct ublk_queue
*ubq
,
355 if (ublk_need_req_ref(ubq
)) {
356 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(req
);
358 kref_put(&data
->ref
, ublk_complete_rq
);
360 __ublk_complete_rq(req
);
364 static inline bool ublk_need_get_data(const struct ublk_queue
*ubq
)
366 return ubq
->flags
& UBLK_F_NEED_GET_DATA
;
369 static struct ublk_device
*ublk_get_device(struct ublk_device
*ub
)
371 if (kobject_get_unless_zero(&ub
->cdev_dev
.kobj
))
376 static void ublk_put_device(struct ublk_device
*ub
)
378 put_device(&ub
->cdev_dev
);
381 static inline struct ublk_queue
*ublk_get_queue(struct ublk_device
*dev
,
384 return (struct ublk_queue
*)&(dev
->__queues
[qid
* dev
->queue_size
]);
387 static inline bool ublk_rq_has_data(const struct request
*rq
)
389 return bio_has_data(rq
->bio
);
392 static inline struct ublksrv_io_desc
*ublk_get_iod(struct ublk_queue
*ubq
,
395 return (struct ublksrv_io_desc
*)
396 &(ubq
->io_cmd_buf
[tag
* sizeof(struct ublksrv_io_desc
)]);
399 static inline char *ublk_queue_cmd_buf(struct ublk_device
*ub
, int q_id
)
401 return ublk_get_queue(ub
, q_id
)->io_cmd_buf
;
404 static inline int ublk_queue_cmd_buf_size(struct ublk_device
*ub
, int q_id
)
406 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
408 return round_up(ubq
->q_depth
* sizeof(struct ublksrv_io_desc
),
412 static inline bool ublk_queue_can_use_recovery_reissue(
413 struct ublk_queue
*ubq
)
415 return (ubq
->flags
& UBLK_F_USER_RECOVERY
) &&
416 (ubq
->flags
& UBLK_F_USER_RECOVERY_REISSUE
);
419 static inline bool ublk_queue_can_use_recovery(
420 struct ublk_queue
*ubq
)
422 return ubq
->flags
& UBLK_F_USER_RECOVERY
;
425 static inline bool ublk_can_use_recovery(struct ublk_device
*ub
)
427 return ub
->dev_info
.flags
& UBLK_F_USER_RECOVERY
;
430 static void ublk_free_disk(struct gendisk
*disk
)
432 struct ublk_device
*ub
= disk
->private_data
;
434 clear_bit(UB_STATE_USED
, &ub
->state
);
435 put_device(&ub
->cdev_dev
);
438 static void ublk_store_owner_uid_gid(unsigned int *owner_uid
,
439 unsigned int *owner_gid
)
444 current_uid_gid(&uid
, &gid
);
446 *owner_uid
= from_kuid(&init_user_ns
, uid
);
447 *owner_gid
= from_kgid(&init_user_ns
, gid
);
450 static int ublk_open(struct block_device
*bdev
, fmode_t mode
)
452 struct ublk_device
*ub
= bdev
->bd_disk
->private_data
;
454 if (capable(CAP_SYS_ADMIN
))
458 * If it is one unprivileged device, only owner can open
459 * the disk. Otherwise it could be one trap made by one
460 * evil user who grants this disk's privileges to other
461 * users deliberately.
463 * This way is reasonable too given anyone can create
464 * unprivileged device, and no need other's grant.
466 if (ub
->dev_info
.flags
& UBLK_F_UNPRIVILEGED_DEV
) {
467 unsigned int curr_uid
, curr_gid
;
469 ublk_store_owner_uid_gid(&curr_uid
, &curr_gid
);
471 if (curr_uid
!= ub
->dev_info
.owner_uid
|| curr_gid
!=
472 ub
->dev_info
.owner_gid
)
479 static const struct block_device_operations ub_fops
= {
480 .owner
= THIS_MODULE
,
482 .free_disk
= ublk_free_disk
,
485 #define UBLK_MAX_PIN_PAGES 32
487 struct ublk_io_iter
{
488 struct page
*pages
[UBLK_MAX_PIN_PAGES
];
490 struct bvec_iter iter
;
493 /* return how many pages are copied */
494 static void ublk_copy_io_pages(struct ublk_io_iter
*data
,
495 size_t total
, size_t pg_off
, int dir
)
500 while (done
< total
) {
501 struct bio_vec bv
= bio_iter_iovec(data
->bio
, data
->iter
);
502 unsigned int bytes
= min3(bv
.bv_len
, (unsigned)total
- done
,
503 (unsigned)(PAGE_SIZE
- pg_off
));
504 void *bv_buf
= bvec_kmap_local(&bv
);
505 void *pg_buf
= kmap_local_page(data
->pages
[pg_idx
]);
507 if (dir
== ITER_DEST
)
508 memcpy(pg_buf
+ pg_off
, bv_buf
, bytes
);
510 memcpy(bv_buf
, pg_buf
+ pg_off
, bytes
);
512 kunmap_local(pg_buf
);
513 kunmap_local(bv_buf
);
515 /* advance page array */
517 if (pg_off
== PAGE_SIZE
) {
525 bio_advance_iter_single(data
->bio
, &data
->iter
, bytes
);
526 if (!data
->iter
.bi_size
) {
527 data
->bio
= data
->bio
->bi_next
;
528 if (data
->bio
== NULL
)
530 data
->iter
= data
->bio
->bi_iter
;
535 static bool ublk_advance_io_iter(const struct request
*req
,
536 struct ublk_io_iter
*iter
, unsigned int offset
)
538 struct bio
*bio
= req
->bio
;
541 if (bio
->bi_iter
.bi_size
> offset
) {
543 iter
->iter
= bio
->bi_iter
;
544 bio_advance_iter(iter
->bio
, &iter
->iter
, offset
);
547 offset
-= bio
->bi_iter
.bi_size
;
553 * Copy data between request pages and io_iter, and 'offset'
554 * is the start point of linear offset of request.
556 static size_t ublk_copy_user_pages(const struct request
*req
,
557 unsigned offset
, struct iov_iter
*uiter
, int dir
)
559 struct ublk_io_iter iter
;
562 if (!ublk_advance_io_iter(req
, &iter
, offset
))
565 while (iov_iter_count(uiter
) && iter
.bio
) {
570 len
= iov_iter_get_pages2(uiter
, iter
.pages
,
571 iov_iter_count(uiter
),
572 UBLK_MAX_PIN_PAGES
, &off
);
576 ublk_copy_io_pages(&iter
, len
, off
, dir
);
577 nr_pages
= DIV_ROUND_UP(len
+ off
, PAGE_SIZE
);
578 for (i
= 0; i
< nr_pages
; i
++) {
579 if (dir
== ITER_DEST
)
580 set_page_dirty(iter
.pages
[i
]);
581 put_page(iter
.pages
[i
]);
589 static inline bool ublk_need_map_req(const struct request
*req
)
591 return ublk_rq_has_data(req
) && req_op(req
) == REQ_OP_WRITE
;
594 static inline bool ublk_need_unmap_req(const struct request
*req
)
596 return ublk_rq_has_data(req
) && req_op(req
) == REQ_OP_READ
;
599 static int ublk_map_io(const struct ublk_queue
*ubq
, const struct request
*req
,
602 const unsigned int rq_bytes
= blk_rq_bytes(req
);
604 if (ublk_support_user_copy(ubq
))
608 * no zero copy, we delay copy WRITE request data into ublksrv
609 * context and the big benefit is that pinning pages in current
610 * context is pretty fast, see ublk_pin_user_pages
612 if (ublk_need_map_req(req
)) {
613 struct iov_iter iter
;
615 const int dir
= ITER_DEST
;
617 import_single_range(dir
, u64_to_user_ptr(io
->addr
), rq_bytes
,
620 return ublk_copy_user_pages(req
, 0, &iter
, dir
);
625 static int ublk_unmap_io(const struct ublk_queue
*ubq
,
626 const struct request
*req
,
629 const unsigned int rq_bytes
= blk_rq_bytes(req
);
631 if (ublk_support_user_copy(ubq
))
634 if (ublk_need_unmap_req(req
)) {
635 struct iov_iter iter
;
637 const int dir
= ITER_SOURCE
;
639 WARN_ON_ONCE(io
->res
> rq_bytes
);
641 import_single_range(dir
, u64_to_user_ptr(io
->addr
), io
->res
,
643 return ublk_copy_user_pages(req
, 0, &iter
, dir
);
648 static inline unsigned int ublk_req_build_flags(struct request
*req
)
652 if (req
->cmd_flags
& REQ_FAILFAST_DEV
)
653 flags
|= UBLK_IO_F_FAILFAST_DEV
;
655 if (req
->cmd_flags
& REQ_FAILFAST_TRANSPORT
)
656 flags
|= UBLK_IO_F_FAILFAST_TRANSPORT
;
658 if (req
->cmd_flags
& REQ_FAILFAST_DRIVER
)
659 flags
|= UBLK_IO_F_FAILFAST_DRIVER
;
661 if (req
->cmd_flags
& REQ_META
)
662 flags
|= UBLK_IO_F_META
;
664 if (req
->cmd_flags
& REQ_FUA
)
665 flags
|= UBLK_IO_F_FUA
;
667 if (req
->cmd_flags
& REQ_NOUNMAP
)
668 flags
|= UBLK_IO_F_NOUNMAP
;
670 if (req
->cmd_flags
& REQ_SWAP
)
671 flags
|= UBLK_IO_F_SWAP
;
676 static blk_status_t
ublk_setup_iod(struct ublk_queue
*ubq
, struct request
*req
)
678 struct ublksrv_io_desc
*iod
= ublk_get_iod(ubq
, req
->tag
);
679 struct ublk_io
*io
= &ubq
->ios
[req
->tag
];
682 switch (req_op(req
)) {
684 ublk_op
= UBLK_IO_OP_READ
;
687 ublk_op
= UBLK_IO_OP_WRITE
;
690 ublk_op
= UBLK_IO_OP_FLUSH
;
693 ublk_op
= UBLK_IO_OP_DISCARD
;
695 case REQ_OP_WRITE_ZEROES
:
696 ublk_op
= UBLK_IO_OP_WRITE_ZEROES
;
699 return BLK_STS_IOERR
;
702 /* need to translate since kernel may change */
703 iod
->op_flags
= ublk_op
| ublk_req_build_flags(req
);
704 iod
->nr_sectors
= blk_rq_sectors(req
);
705 iod
->start_sector
= blk_rq_pos(req
);
706 iod
->addr
= io
->addr
;
711 static inline struct ublk_uring_cmd_pdu
*ublk_get_uring_cmd_pdu(
712 struct io_uring_cmd
*ioucmd
)
714 return (struct ublk_uring_cmd_pdu
*)&ioucmd
->pdu
;
717 static inline bool ubq_daemon_is_dying(struct ublk_queue
*ubq
)
719 return ubq
->ubq_daemon
->flags
& PF_EXITING
;
722 /* todo: handle partial completion */
723 static inline void __ublk_complete_rq(struct request
*req
)
725 struct ublk_queue
*ubq
= req
->mq_hctx
->driver_data
;
726 struct ublk_io
*io
= &ubq
->ios
[req
->tag
];
727 unsigned int unmapped_bytes
;
728 blk_status_t res
= BLK_STS_OK
;
730 /* called from ublk_abort_queue() code path */
731 if (io
->flags
& UBLK_IO_FLAG_ABORTED
) {
736 /* failed read IO if nothing is read */
737 if (!io
->res
&& req_op(req
) == REQ_OP_READ
)
741 res
= errno_to_blk_status(io
->res
);
746 * FLUSH, DISCARD or WRITE_ZEROES usually won't return bytes returned, so end them
749 * Both the two needn't unmap.
751 if (req_op(req
) != REQ_OP_READ
&& req_op(req
) != REQ_OP_WRITE
)
754 /* for READ request, writing data in iod->addr to rq buffers */
755 unmapped_bytes
= ublk_unmap_io(ubq
, req
, io
);
758 * Extremely impossible since we got data filled in just before
760 * Re-read simply for this unlikely case.
762 if (unlikely(unmapped_bytes
< io
->res
))
763 io
->res
= unmapped_bytes
;
765 if (blk_update_request(req
, BLK_STS_OK
, io
->res
))
766 blk_mq_requeue_request(req
, true);
768 __blk_mq_end_request(req
, BLK_STS_OK
);
772 blk_mq_end_request(req
, res
);
775 static void ublk_complete_rq(struct kref
*ref
)
777 struct ublk_rq_data
*data
= container_of(ref
, struct ublk_rq_data
,
779 struct request
*req
= blk_mq_rq_from_pdu(data
);
781 __ublk_complete_rq(req
);
785 * Since __ublk_rq_task_work always fails requests immediately during
786 * exiting, __ublk_fail_req() is only called from abort context during
787 * exiting. So lock is unnecessary.
789 * Also aborting may not be started yet, keep in mind that one failed
790 * request may be issued by block layer again.
792 static void __ublk_fail_req(struct ublk_queue
*ubq
, struct ublk_io
*io
,
795 WARN_ON_ONCE(io
->flags
& UBLK_IO_FLAG_ACTIVE
);
797 if (!(io
->flags
& UBLK_IO_FLAG_ABORTED
)) {
798 io
->flags
|= UBLK_IO_FLAG_ABORTED
;
799 if (ublk_queue_can_use_recovery_reissue(ubq
))
800 blk_mq_requeue_request(req
, false);
802 ublk_put_req_ref(ubq
, req
);
806 static void ubq_complete_io_cmd(struct ublk_io
*io
, int res
,
807 unsigned issue_flags
)
809 /* mark this cmd owned by ublksrv */
810 io
->flags
|= UBLK_IO_FLAG_OWNED_BY_SRV
;
813 * clear ACTIVE since we are done with this sqe/cmd slot
814 * We can only accept io cmd in case of being not active.
816 io
->flags
&= ~UBLK_IO_FLAG_ACTIVE
;
818 /* tell ublksrv one io request is coming */
819 io_uring_cmd_done(io
->cmd
, res
, 0, issue_flags
);
822 #define UBLK_REQUEUE_DELAY_MS 3
824 static inline void __ublk_abort_rq(struct ublk_queue
*ubq
,
827 /* We cannot process this rq so just requeue it. */
828 if (ublk_queue_can_use_recovery(ubq
))
829 blk_mq_requeue_request(rq
, false);
831 blk_mq_end_request(rq
, BLK_STS_IOERR
);
833 mod_delayed_work(system_wq
, &ubq
->dev
->monitor_work
, 0);
836 static inline void __ublk_rq_task_work(struct request
*req
,
837 unsigned issue_flags
)
839 struct ublk_queue
*ubq
= req
->mq_hctx
->driver_data
;
841 struct ublk_io
*io
= &ubq
->ios
[tag
];
842 unsigned int mapped_bytes
;
844 pr_devel("%s: complete: op %d, qid %d tag %d io_flags %x addr %llx\n",
845 __func__
, io
->cmd
->cmd_op
, ubq
->q_id
, req
->tag
, io
->flags
,
846 ublk_get_iod(ubq
, req
->tag
)->addr
);
849 * Task is exiting if either:
851 * (1) current != ubq_daemon.
852 * io_uring_cmd_complete_in_task() tries to run task_work
853 * in a workqueue if ubq_daemon(cmd's task) is PF_EXITING.
855 * (2) current->flags & PF_EXITING.
857 if (unlikely(current
!= ubq
->ubq_daemon
|| current
->flags
& PF_EXITING
)) {
858 __ublk_abort_rq(ubq
, req
);
862 if (ublk_need_get_data(ubq
) && ublk_need_map_req(req
)) {
864 * We have not handled UBLK_IO_NEED_GET_DATA command yet,
865 * so immepdately pass UBLK_IO_RES_NEED_GET_DATA to ublksrv
868 if (!(io
->flags
& UBLK_IO_FLAG_NEED_GET_DATA
)) {
869 io
->flags
|= UBLK_IO_FLAG_NEED_GET_DATA
;
870 pr_devel("%s: need get data. op %d, qid %d tag %d io_flags %x\n",
871 __func__
, io
->cmd
->cmd_op
, ubq
->q_id
,
872 req
->tag
, io
->flags
);
873 ubq_complete_io_cmd(io
, UBLK_IO_RES_NEED_GET_DATA
, issue_flags
);
877 * We have handled UBLK_IO_NEED_GET_DATA command,
878 * so clear UBLK_IO_FLAG_NEED_GET_DATA now and just
881 io
->flags
&= ~UBLK_IO_FLAG_NEED_GET_DATA
;
882 /* update iod->addr because ublksrv may have passed a new io buffer */
883 ublk_get_iod(ubq
, req
->tag
)->addr
= io
->addr
;
884 pr_devel("%s: update iod->addr: op %d, qid %d tag %d io_flags %x addr %llx\n",
885 __func__
, io
->cmd
->cmd_op
, ubq
->q_id
, req
->tag
, io
->flags
,
886 ublk_get_iod(ubq
, req
->tag
)->addr
);
889 mapped_bytes
= ublk_map_io(ubq
, req
, io
);
891 /* partially mapped, update io descriptor */
892 if (unlikely(mapped_bytes
!= blk_rq_bytes(req
))) {
894 * Nothing mapped, retry until we succeed.
896 * We may never succeed in mapping any bytes here because
897 * of OOM. TODO: reserve one buffer with single page pinned
898 * for providing forward progress guarantee.
900 if (unlikely(!mapped_bytes
)) {
901 blk_mq_requeue_request(req
, false);
902 blk_mq_delay_kick_requeue_list(req
->q
,
903 UBLK_REQUEUE_DELAY_MS
);
907 ublk_get_iod(ubq
, req
->tag
)->nr_sectors
=
911 ublk_init_req_ref(ubq
, req
);
912 ubq_complete_io_cmd(io
, UBLK_IO_RES_OK
, issue_flags
);
915 static inline void ublk_forward_io_cmds(struct ublk_queue
*ubq
,
916 unsigned issue_flags
)
918 struct llist_node
*io_cmds
= llist_del_all(&ubq
->io_cmds
);
919 struct ublk_rq_data
*data
, *tmp
;
921 io_cmds
= llist_reverse_order(io_cmds
);
922 llist_for_each_entry_safe(data
, tmp
, io_cmds
, node
)
923 __ublk_rq_task_work(blk_mq_rq_from_pdu(data
), issue_flags
);
926 static inline void ublk_abort_io_cmds(struct ublk_queue
*ubq
)
928 struct llist_node
*io_cmds
= llist_del_all(&ubq
->io_cmds
);
929 struct ublk_rq_data
*data
, *tmp
;
931 llist_for_each_entry_safe(data
, tmp
, io_cmds
, node
)
932 __ublk_abort_rq(ubq
, blk_mq_rq_from_pdu(data
));
935 static void ublk_rq_task_work_cb(struct io_uring_cmd
*cmd
, unsigned issue_flags
)
937 struct ublk_uring_cmd_pdu
*pdu
= ublk_get_uring_cmd_pdu(cmd
);
938 struct ublk_queue
*ubq
= pdu
->ubq
;
940 ublk_forward_io_cmds(ubq
, issue_flags
);
943 static void ublk_queue_cmd(struct ublk_queue
*ubq
, struct request
*rq
)
945 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(rq
);
948 if (!llist_add(&data
->node
, &ubq
->io_cmds
))
951 io
= &ubq
->ios
[rq
->tag
];
953 * If the check pass, we know that this is a re-issued request aborted
954 * previously in monitor_work because the ubq_daemon(cmd's task) is
955 * PF_EXITING. We cannot call io_uring_cmd_complete_in_task() anymore
956 * because this ioucmd's io_uring context may be freed now if no inflight
957 * ioucmd exists. Otherwise we may cause null-deref in ctx->fallback_work.
959 * Note: monitor_work sets UBLK_IO_FLAG_ABORTED and ends this request(releasing
960 * the tag). Then the request is re-started(allocating the tag) and we are here.
961 * Since releasing/allocating a tag implies smp_mb(), finding UBLK_IO_FLAG_ABORTED
962 * guarantees that here is a re-issued request aborted previously.
964 if (unlikely(io
->flags
& UBLK_IO_FLAG_ABORTED
)) {
965 ublk_abort_io_cmds(ubq
);
967 struct io_uring_cmd
*cmd
= io
->cmd
;
968 struct ublk_uring_cmd_pdu
*pdu
= ublk_get_uring_cmd_pdu(cmd
);
971 io_uring_cmd_complete_in_task(cmd
, ublk_rq_task_work_cb
);
975 static enum blk_eh_timer_return
ublk_timeout(struct request
*rq
)
977 struct ublk_queue
*ubq
= rq
->mq_hctx
->driver_data
;
979 if (ubq
->flags
& UBLK_F_UNPRIVILEGED_DEV
) {
981 send_sig(SIGKILL
, ubq
->ubq_daemon
, 0);
988 return BLK_EH_RESET_TIMER
;
991 static blk_status_t
ublk_queue_rq(struct blk_mq_hw_ctx
*hctx
,
992 const struct blk_mq_queue_data
*bd
)
994 struct ublk_queue
*ubq
= hctx
->driver_data
;
995 struct request
*rq
= bd
->rq
;
998 /* fill iod to slot in io cmd buffer */
999 res
= ublk_setup_iod(ubq
, rq
);
1000 if (unlikely(res
!= BLK_STS_OK
))
1001 return BLK_STS_IOERR
;
1003 /* With recovery feature enabled, force_abort is set in
1004 * ublk_stop_dev() before calling del_gendisk(). We have to
1005 * abort all requeued and new rqs here to let del_gendisk()
1006 * move on. Besides, we cannot not call io_uring_cmd_complete_in_task()
1007 * to avoid UAF on io_uring ctx.
1009 * Note: force_abort is guaranteed to be seen because it is set
1010 * before request queue is unqiuesced.
1012 if (ublk_queue_can_use_recovery(ubq
) && unlikely(ubq
->force_abort
))
1013 return BLK_STS_IOERR
;
1015 blk_mq_start_request(bd
->rq
);
1017 if (unlikely(ubq_daemon_is_dying(ubq
))) {
1018 __ublk_abort_rq(ubq
, rq
);
1022 ublk_queue_cmd(ubq
, rq
);
1027 static int ublk_init_hctx(struct blk_mq_hw_ctx
*hctx
, void *driver_data
,
1028 unsigned int hctx_idx
)
1030 struct ublk_device
*ub
= driver_data
;
1031 struct ublk_queue
*ubq
= ublk_get_queue(ub
, hctx
->queue_num
);
1033 hctx
->driver_data
= ubq
;
1037 static const struct blk_mq_ops ublk_mq_ops
= {
1038 .queue_rq
= ublk_queue_rq
,
1039 .init_hctx
= ublk_init_hctx
,
1040 .timeout
= ublk_timeout
,
1043 static int ublk_ch_open(struct inode
*inode
, struct file
*filp
)
1045 struct ublk_device
*ub
= container_of(inode
->i_cdev
,
1046 struct ublk_device
, cdev
);
1048 if (test_and_set_bit(UB_STATE_OPEN
, &ub
->state
))
1050 filp
->private_data
= ub
;
1054 static int ublk_ch_release(struct inode
*inode
, struct file
*filp
)
1056 struct ublk_device
*ub
= filp
->private_data
;
1058 clear_bit(UB_STATE_OPEN
, &ub
->state
);
1062 /* map pre-allocated per-queue cmd buffer to ublksrv daemon */
1063 static int ublk_ch_mmap(struct file
*filp
, struct vm_area_struct
*vma
)
1065 struct ublk_device
*ub
= filp
->private_data
;
1066 size_t sz
= vma
->vm_end
- vma
->vm_start
;
1067 unsigned max_sz
= UBLK_MAX_QUEUE_DEPTH
* sizeof(struct ublksrv_io_desc
);
1068 unsigned long pfn
, end
, phys_off
= vma
->vm_pgoff
<< PAGE_SHIFT
;
1071 spin_lock(&ub
->mm_lock
);
1073 ub
->mm
= current
->mm
;
1074 if (current
->mm
!= ub
->mm
)
1076 spin_unlock(&ub
->mm_lock
);
1081 if (vma
->vm_flags
& VM_WRITE
)
1084 end
= UBLKSRV_CMD_BUF_OFFSET
+ ub
->dev_info
.nr_hw_queues
* max_sz
;
1085 if (phys_off
< UBLKSRV_CMD_BUF_OFFSET
|| phys_off
>= end
)
1088 q_id
= (phys_off
- UBLKSRV_CMD_BUF_OFFSET
) / max_sz
;
1089 pr_devel("%s: qid %d, pid %d, addr %lx pg_off %lx sz %lu\n",
1090 __func__
, q_id
, current
->pid
, vma
->vm_start
,
1091 phys_off
, (unsigned long)sz
);
1093 if (sz
!= ublk_queue_cmd_buf_size(ub
, q_id
))
1096 pfn
= virt_to_phys(ublk_queue_cmd_buf(ub
, q_id
)) >> PAGE_SHIFT
;
1097 return remap_pfn_range(vma
, vma
->vm_start
, pfn
, sz
, vma
->vm_page_prot
);
1100 static void ublk_commit_completion(struct ublk_device
*ub
,
1101 const struct ublksrv_io_cmd
*ub_cmd
)
1103 u32 qid
= ub_cmd
->q_id
, tag
= ub_cmd
->tag
;
1104 struct ublk_queue
*ubq
= ublk_get_queue(ub
, qid
);
1105 struct ublk_io
*io
= &ubq
->ios
[tag
];
1106 struct request
*req
;
1108 /* now this cmd slot is owned by nbd driver */
1109 io
->flags
&= ~UBLK_IO_FLAG_OWNED_BY_SRV
;
1110 io
->res
= ub_cmd
->result
;
1112 /* find the io request and complete */
1113 req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[qid
], tag
);
1115 if (req
&& likely(!blk_should_fake_timeout(req
->q
)))
1116 ublk_put_req_ref(ubq
, req
);
1120 * When ->ubq_daemon is exiting, either new request is ended immediately,
1121 * or any queued io command is drained, so it is safe to abort queue
1124 static void ublk_abort_queue(struct ublk_device
*ub
, struct ublk_queue
*ubq
)
1128 if (!ublk_get_device(ub
))
1131 for (i
= 0; i
< ubq
->q_depth
; i
++) {
1132 struct ublk_io
*io
= &ubq
->ios
[i
];
1134 if (!(io
->flags
& UBLK_IO_FLAG_ACTIVE
)) {
1138 * Either we fail the request or ublk_rq_task_work_fn
1141 rq
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[ubq
->q_id
], i
);
1143 __ublk_fail_req(ubq
, io
, rq
);
1146 ublk_put_device(ub
);
1149 static void ublk_daemon_monitor_work(struct work_struct
*work
)
1151 struct ublk_device
*ub
=
1152 container_of(work
, struct ublk_device
, monitor_work
.work
);
1155 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++) {
1156 struct ublk_queue
*ubq
= ublk_get_queue(ub
, i
);
1158 if (ubq_daemon_is_dying(ubq
)) {
1159 if (ublk_queue_can_use_recovery(ubq
))
1160 schedule_work(&ub
->quiesce_work
);
1162 schedule_work(&ub
->stop_work
);
1164 /* abort queue is for making forward progress */
1165 ublk_abort_queue(ub
, ubq
);
1170 * We can't schedule monitor work after ub's state is not UBLK_S_DEV_LIVE.
1171 * after ublk_remove() or __ublk_quiesce_dev() is started.
1173 * No need ub->mutex, monitor work are canceled after state is marked
1174 * as not LIVE, so new state is observed reliably.
1176 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
)
1177 schedule_delayed_work(&ub
->monitor_work
,
1178 UBLK_DAEMON_MONITOR_PERIOD
);
1181 static inline bool ublk_queue_ready(struct ublk_queue
*ubq
)
1183 return ubq
->nr_io_ready
== ubq
->q_depth
;
1186 static void ublk_cancel_queue(struct ublk_queue
*ubq
)
1190 if (!ublk_queue_ready(ubq
))
1193 for (i
= 0; i
< ubq
->q_depth
; i
++) {
1194 struct ublk_io
*io
= &ubq
->ios
[i
];
1196 if (io
->flags
& UBLK_IO_FLAG_ACTIVE
)
1197 io_uring_cmd_done(io
->cmd
, UBLK_IO_RES_ABORT
, 0,
1198 IO_URING_F_UNLOCKED
);
1201 /* all io commands are canceled */
1202 ubq
->nr_io_ready
= 0;
1205 /* Cancel all pending commands, must be called after del_gendisk() returns */
1206 static void ublk_cancel_dev(struct ublk_device
*ub
)
1210 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++)
1211 ublk_cancel_queue(ublk_get_queue(ub
, i
));
1214 static bool ublk_check_inflight_rq(struct request
*rq
, void *data
)
1218 if (blk_mq_request_started(rq
)) {
1225 static void ublk_wait_tagset_rqs_idle(struct ublk_device
*ub
)
1229 WARN_ON_ONCE(!blk_queue_quiesced(ub
->ub_disk
->queue
));
1232 blk_mq_tagset_busy_iter(&ub
->tag_set
,
1233 ublk_check_inflight_rq
, &idle
);
1236 msleep(UBLK_REQUEUE_DELAY_MS
);
1240 static void __ublk_quiesce_dev(struct ublk_device
*ub
)
1242 pr_devel("%s: quiesce ub: dev_id %d state %s\n",
1243 __func__
, ub
->dev_info
.dev_id
,
1244 ub
->dev_info
.state
== UBLK_S_DEV_LIVE
?
1245 "LIVE" : "QUIESCED");
1246 blk_mq_quiesce_queue(ub
->ub_disk
->queue
);
1247 ublk_wait_tagset_rqs_idle(ub
);
1248 ub
->dev_info
.state
= UBLK_S_DEV_QUIESCED
;
1249 ublk_cancel_dev(ub
);
1250 /* we are going to release task_struct of ubq_daemon and resets
1251 * ->ubq_daemon to NULL. So in monitor_work, check on ubq_daemon causes UAF.
1252 * Besides, monitor_work is not necessary in QUIESCED state since we have
1253 * already scheduled quiesce_work and quiesced all ubqs.
1255 * Do not let monitor_work schedule itself if state it QUIESCED. And we cancel
1256 * it here and re-schedule it in END_USER_RECOVERY to avoid UAF.
1258 cancel_delayed_work_sync(&ub
->monitor_work
);
1261 static void ublk_quiesce_work_fn(struct work_struct
*work
)
1263 struct ublk_device
*ub
=
1264 container_of(work
, struct ublk_device
, quiesce_work
);
1266 mutex_lock(&ub
->mutex
);
1267 if (ub
->dev_info
.state
!= UBLK_S_DEV_LIVE
)
1269 __ublk_quiesce_dev(ub
);
1271 mutex_unlock(&ub
->mutex
);
1274 static void ublk_unquiesce_dev(struct ublk_device
*ub
)
1278 pr_devel("%s: unquiesce ub: dev_id %d state %s\n",
1279 __func__
, ub
->dev_info
.dev_id
,
1280 ub
->dev_info
.state
== UBLK_S_DEV_LIVE
?
1281 "LIVE" : "QUIESCED");
1282 /* quiesce_work has run. We let requeued rqs be aborted
1283 * before running fallback_wq. "force_abort" must be seen
1284 * after request queue is unqiuesced. Then del_gendisk()
1287 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++)
1288 ublk_get_queue(ub
, i
)->force_abort
= true;
1290 blk_mq_unquiesce_queue(ub
->ub_disk
->queue
);
1291 /* We may have requeued some rqs in ublk_quiesce_queue() */
1292 blk_mq_kick_requeue_list(ub
->ub_disk
->queue
);
1295 static void ublk_stop_dev(struct ublk_device
*ub
)
1297 mutex_lock(&ub
->mutex
);
1298 if (ub
->dev_info
.state
== UBLK_S_DEV_DEAD
)
1300 if (ublk_can_use_recovery(ub
)) {
1301 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
)
1302 __ublk_quiesce_dev(ub
);
1303 ublk_unquiesce_dev(ub
);
1305 del_gendisk(ub
->ub_disk
);
1306 ub
->dev_info
.state
= UBLK_S_DEV_DEAD
;
1307 ub
->dev_info
.ublksrv_pid
= -1;
1308 put_disk(ub
->ub_disk
);
1311 ublk_cancel_dev(ub
);
1312 mutex_unlock(&ub
->mutex
);
1313 cancel_delayed_work_sync(&ub
->monitor_work
);
1316 /* device can only be started after all IOs are ready */
1317 static void ublk_mark_io_ready(struct ublk_device
*ub
, struct ublk_queue
*ubq
)
1319 mutex_lock(&ub
->mutex
);
1321 if (ublk_queue_ready(ubq
)) {
1322 ubq
->ubq_daemon
= current
;
1323 get_task_struct(ubq
->ubq_daemon
);
1324 ub
->nr_queues_ready
++;
1326 if (capable(CAP_SYS_ADMIN
))
1327 ub
->nr_privileged_daemon
++;
1329 if (ub
->nr_queues_ready
== ub
->dev_info
.nr_hw_queues
)
1330 complete_all(&ub
->completion
);
1331 mutex_unlock(&ub
->mutex
);
1334 static void ublk_handle_need_get_data(struct ublk_device
*ub
, int q_id
,
1337 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
1338 struct request
*req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[q_id
], tag
);
1340 ublk_queue_cmd(ubq
, req
);
1343 static inline int ublk_check_cmd_op(u32 cmd_op
)
1345 u32 ioc_type
= _IOC_TYPE(cmd_op
);
1347 if (!IS_ENABLED(CONFIG_BLKDEV_UBLK_LEGACY_OPCODES
) && ioc_type
!= 'u')
1350 if (ioc_type
!= 'u' && ioc_type
!= 0)
1356 static inline void ublk_fill_io_cmd(struct ublk_io
*io
,
1357 struct io_uring_cmd
*cmd
, unsigned long buf_addr
)
1360 io
->flags
|= UBLK_IO_FLAG_ACTIVE
;
1361 io
->addr
= buf_addr
;
1364 static int __ublk_ch_uring_cmd(struct io_uring_cmd
*cmd
,
1365 unsigned int issue_flags
,
1366 const struct ublksrv_io_cmd
*ub_cmd
)
1368 struct ublk_device
*ub
= cmd
->file
->private_data
;
1369 struct ublk_queue
*ubq
;
1371 u32 cmd_op
= cmd
->cmd_op
;
1372 unsigned tag
= ub_cmd
->tag
;
1374 struct request
*req
;
1376 pr_devel("%s: received: cmd op %d queue %d tag %d result %d\n",
1377 __func__
, cmd
->cmd_op
, ub_cmd
->q_id
, tag
,
1380 if (ub_cmd
->q_id
>= ub
->dev_info
.nr_hw_queues
)
1383 ubq
= ublk_get_queue(ub
, ub_cmd
->q_id
);
1384 if (!ubq
|| ub_cmd
->q_id
!= ubq
->q_id
)
1387 if (ubq
->ubq_daemon
&& ubq
->ubq_daemon
!= current
)
1390 if (tag
>= ubq
->q_depth
)
1393 io
= &ubq
->ios
[tag
];
1395 /* there is pending io cmd, something must be wrong */
1396 if (io
->flags
& UBLK_IO_FLAG_ACTIVE
) {
1402 * ensure that the user issues UBLK_IO_NEED_GET_DATA
1403 * iff the driver have set the UBLK_IO_FLAG_NEED_GET_DATA.
1405 if ((!!(io
->flags
& UBLK_IO_FLAG_NEED_GET_DATA
))
1406 ^ (_IOC_NR(cmd_op
) == UBLK_IO_NEED_GET_DATA
))
1409 if (ublk_support_user_copy(ubq
) && ub_cmd
->addr
) {
1414 ret
= ublk_check_cmd_op(cmd_op
);
1419 switch (_IOC_NR(cmd_op
)) {
1420 case UBLK_IO_FETCH_REQ
:
1421 /* UBLK_IO_FETCH_REQ is only allowed before queue is setup */
1422 if (ublk_queue_ready(ubq
)) {
1427 * The io is being handled by server, so COMMIT_RQ is expected
1428 * instead of FETCH_REQ
1430 if (io
->flags
& UBLK_IO_FLAG_OWNED_BY_SRV
)
1433 if (!ublk_support_user_copy(ubq
)) {
1435 * FETCH_RQ has to provide IO buffer if NEED GET
1436 * DATA is not enabled
1438 if (!ub_cmd
->addr
&& !ublk_need_get_data(ubq
))
1442 ublk_fill_io_cmd(io
, cmd
, ub_cmd
->addr
);
1443 ublk_mark_io_ready(ub
, ubq
);
1445 case UBLK_IO_COMMIT_AND_FETCH_REQ
:
1446 req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[ub_cmd
->q_id
], tag
);
1448 if (!(io
->flags
& UBLK_IO_FLAG_OWNED_BY_SRV
))
1451 if (!ublk_support_user_copy(ubq
)) {
1453 * COMMIT_AND_FETCH_REQ has to provide IO buffer if
1454 * NEED GET DATA is not enabled or it is Read IO.
1456 if (!ub_cmd
->addr
&& (!ublk_need_get_data(ubq
) ||
1457 req_op(req
) == REQ_OP_READ
))
1460 ublk_fill_io_cmd(io
, cmd
, ub_cmd
->addr
);
1461 ublk_commit_completion(ub
, ub_cmd
);
1463 case UBLK_IO_NEED_GET_DATA
:
1464 if (!(io
->flags
& UBLK_IO_FLAG_OWNED_BY_SRV
))
1466 ublk_fill_io_cmd(io
, cmd
, ub_cmd
->addr
);
1467 ublk_handle_need_get_data(ub
, ub_cmd
->q_id
, ub_cmd
->tag
);
1472 return -EIOCBQUEUED
;
1475 io_uring_cmd_done(cmd
, ret
, 0, issue_flags
);
1476 pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n",
1477 __func__
, cmd_op
, tag
, ret
, io
->flags
);
1478 return -EIOCBQUEUED
;
1481 static inline struct request
*__ublk_check_and_get_req(struct ublk_device
*ub
,
1482 struct ublk_queue
*ubq
, int tag
, size_t offset
)
1484 struct request
*req
;
1486 if (!ublk_need_req_ref(ubq
))
1489 req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[ubq
->q_id
], tag
);
1493 if (!ublk_get_req_ref(ubq
, req
))
1496 if (unlikely(!blk_mq_request_started(req
) || req
->tag
!= tag
))
1499 if (!ublk_rq_has_data(req
))
1502 if (offset
> blk_rq_bytes(req
))
1507 ublk_put_req_ref(ubq
, req
);
1511 static int ublk_ch_uring_cmd(struct io_uring_cmd
*cmd
, unsigned int issue_flags
)
1514 * Not necessary for async retry, but let's keep it simple and always
1515 * copy the values to avoid any potential reuse.
1517 const struct ublksrv_io_cmd
*ub_src
= io_uring_sqe_cmd(cmd
->sqe
);
1518 const struct ublksrv_io_cmd ub_cmd
= {
1519 .q_id
= READ_ONCE(ub_src
->q_id
),
1520 .tag
= READ_ONCE(ub_src
->tag
),
1521 .result
= READ_ONCE(ub_src
->result
),
1522 .addr
= READ_ONCE(ub_src
->addr
)
1525 return __ublk_ch_uring_cmd(cmd
, issue_flags
, &ub_cmd
);
1528 static inline bool ublk_check_ubuf_dir(const struct request
*req
,
1531 /* copy ubuf to request pages */
1532 if (req_op(req
) == REQ_OP_READ
&& ubuf_dir
== ITER_SOURCE
)
1535 /* copy request pages to ubuf */
1536 if (req_op(req
) == REQ_OP_WRITE
&& ubuf_dir
== ITER_DEST
)
1542 static struct request
*ublk_check_and_get_req(struct kiocb
*iocb
,
1543 struct iov_iter
*iter
, size_t *off
, int dir
)
1545 struct ublk_device
*ub
= iocb
->ki_filp
->private_data
;
1546 struct ublk_queue
*ubq
;
1547 struct request
*req
;
1552 return ERR_PTR(-EACCES
);
1554 if (!user_backed_iter(iter
))
1555 return ERR_PTR(-EACCES
);
1557 if (ub
->dev_info
.state
== UBLK_S_DEV_DEAD
)
1558 return ERR_PTR(-EACCES
);
1560 tag
= ublk_pos_to_tag(iocb
->ki_pos
);
1561 q_id
= ublk_pos_to_hwq(iocb
->ki_pos
);
1562 buf_off
= ublk_pos_to_buf_off(iocb
->ki_pos
);
1564 if (q_id
>= ub
->dev_info
.nr_hw_queues
)
1565 return ERR_PTR(-EINVAL
);
1567 ubq
= ublk_get_queue(ub
, q_id
);
1569 return ERR_PTR(-EINVAL
);
1571 if (tag
>= ubq
->q_depth
)
1572 return ERR_PTR(-EINVAL
);
1574 req
= __ublk_check_and_get_req(ub
, ubq
, tag
, buf_off
);
1576 return ERR_PTR(-EINVAL
);
1578 if (!req
->mq_hctx
|| !req
->mq_hctx
->driver_data
)
1581 if (!ublk_check_ubuf_dir(req
, dir
))
1587 ublk_put_req_ref(ubq
, req
);
1588 return ERR_PTR(-EACCES
);
1591 static ssize_t
ublk_ch_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
1593 struct ublk_queue
*ubq
;
1594 struct request
*req
;
1598 req
= ublk_check_and_get_req(iocb
, to
, &buf_off
, ITER_DEST
);
1600 return PTR_ERR(req
);
1602 ret
= ublk_copy_user_pages(req
, buf_off
, to
, ITER_DEST
);
1603 ubq
= req
->mq_hctx
->driver_data
;
1604 ublk_put_req_ref(ubq
, req
);
1609 static ssize_t
ublk_ch_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
1611 struct ublk_queue
*ubq
;
1612 struct request
*req
;
1616 req
= ublk_check_and_get_req(iocb
, from
, &buf_off
, ITER_SOURCE
);
1618 return PTR_ERR(req
);
1620 ret
= ublk_copy_user_pages(req
, buf_off
, from
, ITER_SOURCE
);
1621 ubq
= req
->mq_hctx
->driver_data
;
1622 ublk_put_req_ref(ubq
, req
);
1627 static const struct file_operations ublk_ch_fops
= {
1628 .owner
= THIS_MODULE
,
1629 .open
= ublk_ch_open
,
1630 .release
= ublk_ch_release
,
1631 .llseek
= no_llseek
,
1632 .read_iter
= ublk_ch_read_iter
,
1633 .write_iter
= ublk_ch_write_iter
,
1634 .uring_cmd
= ublk_ch_uring_cmd
,
1635 .mmap
= ublk_ch_mmap
,
1638 static void ublk_deinit_queue(struct ublk_device
*ub
, int q_id
)
1640 int size
= ublk_queue_cmd_buf_size(ub
, q_id
);
1641 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
1643 if (ubq
->ubq_daemon
)
1644 put_task_struct(ubq
->ubq_daemon
);
1645 if (ubq
->io_cmd_buf
)
1646 free_pages((unsigned long)ubq
->io_cmd_buf
, get_order(size
));
1649 static int ublk_init_queue(struct ublk_device
*ub
, int q_id
)
1651 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
1652 gfp_t gfp_flags
= GFP_KERNEL
| __GFP_ZERO
;
1656 ubq
->flags
= ub
->dev_info
.flags
;
1658 ubq
->q_depth
= ub
->dev_info
.queue_depth
;
1659 size
= ublk_queue_cmd_buf_size(ub
, q_id
);
1661 ptr
= (void *) __get_free_pages(gfp_flags
, get_order(size
));
1665 ubq
->io_cmd_buf
= ptr
;
1670 static void ublk_deinit_queues(struct ublk_device
*ub
)
1672 int nr_queues
= ub
->dev_info
.nr_hw_queues
;
1678 for (i
= 0; i
< nr_queues
; i
++)
1679 ublk_deinit_queue(ub
, i
);
1680 kfree(ub
->__queues
);
1683 static int ublk_init_queues(struct ublk_device
*ub
)
1685 int nr_queues
= ub
->dev_info
.nr_hw_queues
;
1686 int depth
= ub
->dev_info
.queue_depth
;
1687 int ubq_size
= sizeof(struct ublk_queue
) + depth
* sizeof(struct ublk_io
);
1688 int i
, ret
= -ENOMEM
;
1690 ub
->queue_size
= ubq_size
;
1691 ub
->__queues
= kcalloc(nr_queues
, ubq_size
, GFP_KERNEL
);
1695 for (i
= 0; i
< nr_queues
; i
++) {
1696 if (ublk_init_queue(ub
, i
))
1700 init_completion(&ub
->completion
);
1704 ublk_deinit_queues(ub
);
1708 static int ublk_alloc_dev_number(struct ublk_device
*ub
, int idx
)
1713 spin_lock(&ublk_idr_lock
);
1714 /* allocate id, if @id >= 0, we're requesting that specific id */
1716 err
= idr_alloc(&ublk_index_idr
, ub
, i
, i
+ 1, GFP_NOWAIT
);
1720 err
= idr_alloc(&ublk_index_idr
, ub
, 0, 0, GFP_NOWAIT
);
1722 spin_unlock(&ublk_idr_lock
);
1725 ub
->ub_number
= err
;
1730 static void ublk_free_dev_number(struct ublk_device
*ub
)
1732 spin_lock(&ublk_idr_lock
);
1733 idr_remove(&ublk_index_idr
, ub
->ub_number
);
1734 wake_up_all(&ublk_idr_wq
);
1735 spin_unlock(&ublk_idr_lock
);
1738 static void ublk_cdev_rel(struct device
*dev
)
1740 struct ublk_device
*ub
= container_of(dev
, struct ublk_device
, cdev_dev
);
1742 blk_mq_free_tag_set(&ub
->tag_set
);
1743 ublk_deinit_queues(ub
);
1744 ublk_free_dev_number(ub
);
1745 mutex_destroy(&ub
->mutex
);
1749 static int ublk_add_chdev(struct ublk_device
*ub
)
1751 struct device
*dev
= &ub
->cdev_dev
;
1752 int minor
= ub
->ub_number
;
1755 dev
->parent
= ublk_misc
.this_device
;
1756 dev
->devt
= MKDEV(MAJOR(ublk_chr_devt
), minor
);
1757 dev
->class = ublk_chr_class
;
1758 dev
->release
= ublk_cdev_rel
;
1759 device_initialize(dev
);
1761 ret
= dev_set_name(dev
, "ublkc%d", minor
);
1765 cdev_init(&ub
->cdev
, &ublk_ch_fops
);
1766 ret
= cdev_device_add(&ub
->cdev
, dev
);
1777 static void ublk_stop_work_fn(struct work_struct
*work
)
1779 struct ublk_device
*ub
=
1780 container_of(work
, struct ublk_device
, stop_work
);
1785 /* align max io buffer size with PAGE_SIZE */
1786 static void ublk_align_max_io_size(struct ublk_device
*ub
)
1788 unsigned int max_io_bytes
= ub
->dev_info
.max_io_buf_bytes
;
1790 ub
->dev_info
.max_io_buf_bytes
=
1791 round_down(max_io_bytes
, PAGE_SIZE
);
1794 static int ublk_add_tag_set(struct ublk_device
*ub
)
1796 ub
->tag_set
.ops
= &ublk_mq_ops
;
1797 ub
->tag_set
.nr_hw_queues
= ub
->dev_info
.nr_hw_queues
;
1798 ub
->tag_set
.queue_depth
= ub
->dev_info
.queue_depth
;
1799 ub
->tag_set
.numa_node
= NUMA_NO_NODE
;
1800 ub
->tag_set
.cmd_size
= sizeof(struct ublk_rq_data
);
1801 ub
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
;
1802 ub
->tag_set
.driver_data
= ub
;
1803 return blk_mq_alloc_tag_set(&ub
->tag_set
);
1806 static void ublk_remove(struct ublk_device
*ub
)
1809 cancel_work_sync(&ub
->stop_work
);
1810 cancel_work_sync(&ub
->quiesce_work
);
1811 cdev_device_del(&ub
->cdev
, &ub
->cdev_dev
);
1812 put_device(&ub
->cdev_dev
);
1816 static struct ublk_device
*ublk_get_device_from_id(int idx
)
1818 struct ublk_device
*ub
= NULL
;
1823 spin_lock(&ublk_idr_lock
);
1824 ub
= idr_find(&ublk_index_idr
, idx
);
1826 ub
= ublk_get_device(ub
);
1827 spin_unlock(&ublk_idr_lock
);
1832 static int ublk_ctrl_start_dev(struct ublk_device
*ub
, struct io_uring_cmd
*cmd
)
1834 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
1835 int ublksrv_pid
= (int)header
->data
[0];
1836 struct gendisk
*disk
;
1839 if (ublksrv_pid
<= 0)
1842 wait_for_completion_interruptible(&ub
->completion
);
1844 schedule_delayed_work(&ub
->monitor_work
, UBLK_DAEMON_MONITOR_PERIOD
);
1846 mutex_lock(&ub
->mutex
);
1847 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
||
1848 test_bit(UB_STATE_USED
, &ub
->state
)) {
1853 disk
= blk_mq_alloc_disk(&ub
->tag_set
, NULL
);
1855 ret
= PTR_ERR(disk
);
1858 sprintf(disk
->disk_name
, "ublkb%d", ub
->ub_number
);
1859 disk
->fops
= &ub_fops
;
1860 disk
->private_data
= ub
;
1862 ub
->dev_info
.ublksrv_pid
= ublksrv_pid
;
1865 ret
= ublk_apply_params(ub
);
1869 /* don't probe partitions if any one ubq daemon is un-trusted */
1870 if (ub
->nr_privileged_daemon
!= ub
->nr_queues_ready
)
1871 set_bit(GD_SUPPRESS_PART_SCAN
, &disk
->state
);
1873 get_device(&ub
->cdev_dev
);
1874 ub
->dev_info
.state
= UBLK_S_DEV_LIVE
;
1875 ret
= add_disk(disk
);
1878 * Has to drop the reference since ->free_disk won't be
1879 * called in case of add_disk failure.
1881 ub
->dev_info
.state
= UBLK_S_DEV_DEAD
;
1882 ublk_put_device(ub
);
1885 set_bit(UB_STATE_USED
, &ub
->state
);
1890 mutex_unlock(&ub
->mutex
);
1894 static int ublk_ctrl_get_queue_affinity(struct ublk_device
*ub
,
1895 struct io_uring_cmd
*cmd
)
1897 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
1898 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
1899 cpumask_var_t cpumask
;
1900 unsigned long queue
;
1901 unsigned int retlen
;
1905 if (header
->len
* BITS_PER_BYTE
< nr_cpu_ids
)
1907 if (header
->len
& (sizeof(unsigned long)-1))
1912 queue
= header
->data
[0];
1913 if (queue
>= ub
->dev_info
.nr_hw_queues
)
1916 if (!zalloc_cpumask_var(&cpumask
, GFP_KERNEL
))
1919 for_each_possible_cpu(i
) {
1920 if (ub
->tag_set
.map
[HCTX_TYPE_DEFAULT
].mq_map
[i
] == queue
)
1921 cpumask_set_cpu(i
, cpumask
);
1925 retlen
= min_t(unsigned short, header
->len
, cpumask_size());
1926 if (copy_to_user(argp
, cpumask
, retlen
))
1927 goto out_free_cpumask
;
1928 if (retlen
!= header
->len
&&
1929 clear_user(argp
+ retlen
, header
->len
- retlen
))
1930 goto out_free_cpumask
;
1934 free_cpumask_var(cpumask
);
1938 static inline void ublk_dump_dev_info(struct ublksrv_ctrl_dev_info
*info
)
1940 pr_devel("%s: dev id %d flags %llx\n", __func__
,
1941 info
->dev_id
, info
->flags
);
1942 pr_devel("\t nr_hw_queues %d queue_depth %d\n",
1943 info
->nr_hw_queues
, info
->queue_depth
);
1946 static int ublk_ctrl_add_dev(struct io_uring_cmd
*cmd
)
1948 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
1949 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
1950 struct ublksrv_ctrl_dev_info info
;
1951 struct ublk_device
*ub
;
1954 if (header
->len
< sizeof(info
) || !header
->addr
)
1956 if (header
->queue_id
!= (u16
)-1) {
1957 pr_warn("%s: queue_id is wrong %x\n",
1958 __func__
, header
->queue_id
);
1962 if (copy_from_user(&info
, argp
, sizeof(info
)))
1965 if (capable(CAP_SYS_ADMIN
))
1966 info
.flags
&= ~UBLK_F_UNPRIVILEGED_DEV
;
1967 else if (!(info
.flags
& UBLK_F_UNPRIVILEGED_DEV
))
1971 * unprivileged device can't be trusted, but RECOVERY and
1972 * RECOVERY_REISSUE still may hang error handling, so can't
1973 * support recovery features for unprivileged ublk now
1975 * TODO: provide forward progress for RECOVERY handler, so that
1976 * unprivileged device can benefit from it
1978 if (info
.flags
& UBLK_F_UNPRIVILEGED_DEV
)
1979 info
.flags
&= ~(UBLK_F_USER_RECOVERY_REISSUE
|
1980 UBLK_F_USER_RECOVERY
);
1982 /* the created device is always owned by current user */
1983 ublk_store_owner_uid_gid(&info
.owner_uid
, &info
.owner_gid
);
1985 if (header
->dev_id
!= info
.dev_id
) {
1986 pr_warn("%s: dev id not match %u %u\n",
1987 __func__
, header
->dev_id
, info
.dev_id
);
1991 ublk_dump_dev_info(&info
);
1993 ret
= mutex_lock_killable(&ublk_ctl_mutex
);
1998 if (ublks_added
>= ublks_max
)
2002 ub
= kzalloc(sizeof(*ub
), GFP_KERNEL
);
2005 mutex_init(&ub
->mutex
);
2006 spin_lock_init(&ub
->mm_lock
);
2007 INIT_WORK(&ub
->quiesce_work
, ublk_quiesce_work_fn
);
2008 INIT_WORK(&ub
->stop_work
, ublk_stop_work_fn
);
2009 INIT_DELAYED_WORK(&ub
->monitor_work
, ublk_daemon_monitor_work
);
2011 ret
= ublk_alloc_dev_number(ub
, header
->dev_id
);
2015 memcpy(&ub
->dev_info
, &info
, sizeof(info
));
2017 /* update device id */
2018 ub
->dev_info
.dev_id
= ub
->ub_number
;
2021 * 64bit flags will be copied back to userspace as feature
2022 * negotiation result, so have to clear flags which driver
2023 * doesn't support yet, then userspace can get correct flags
2024 * (features) to handle.
2026 ub
->dev_info
.flags
&= UBLK_F_ALL
;
2028 ub
->dev_info
.flags
|= UBLK_F_CMD_IOCTL_ENCODE
|
2029 UBLK_F_URING_CMD_COMP_IN_TASK
;
2031 /* GET_DATA isn't needed any more with USER_COPY */
2032 if (ub
->dev_info
.flags
& UBLK_F_USER_COPY
)
2033 ub
->dev_info
.flags
&= ~UBLK_F_NEED_GET_DATA
;
2035 /* We are not ready to support zero copy */
2036 ub
->dev_info
.flags
&= ~UBLK_F_SUPPORT_ZERO_COPY
;
2038 ub
->dev_info
.nr_hw_queues
= min_t(unsigned int,
2039 ub
->dev_info
.nr_hw_queues
, nr_cpu_ids
);
2040 ublk_align_max_io_size(ub
);
2042 ret
= ublk_init_queues(ub
);
2044 goto out_free_dev_number
;
2046 ret
= ublk_add_tag_set(ub
);
2048 goto out_deinit_queues
;
2051 if (copy_to_user(argp
, &ub
->dev_info
, sizeof(info
)))
2052 goto out_free_tag_set
;
2055 * Add the char dev so that ublksrv daemon can be setup.
2056 * ublk_add_chdev() will cleanup everything if it fails.
2058 ret
= ublk_add_chdev(ub
);
2062 blk_mq_free_tag_set(&ub
->tag_set
);
2064 ublk_deinit_queues(ub
);
2065 out_free_dev_number
:
2066 ublk_free_dev_number(ub
);
2068 mutex_destroy(&ub
->mutex
);
2071 mutex_unlock(&ublk_ctl_mutex
);
2075 static inline bool ublk_idr_freed(int id
)
2079 spin_lock(&ublk_idr_lock
);
2080 ptr
= idr_find(&ublk_index_idr
, id
);
2081 spin_unlock(&ublk_idr_lock
);
2086 static int ublk_ctrl_del_dev(struct ublk_device
**p_ub
)
2088 struct ublk_device
*ub
= *p_ub
;
2089 int idx
= ub
->ub_number
;
2092 ret
= mutex_lock_killable(&ublk_ctl_mutex
);
2096 if (!test_bit(UB_STATE_DELETED
, &ub
->state
)) {
2098 set_bit(UB_STATE_DELETED
, &ub
->state
);
2101 /* Mark the reference as consumed */
2103 ublk_put_device(ub
);
2104 mutex_unlock(&ublk_ctl_mutex
);
2107 * Wait until the idr is removed, then it can be reused after
2108 * DEL_DEV command is returned.
2110 * If we returns because of user interrupt, future delete command
2113 * - the device number isn't freed, this device won't or needn't
2114 * be deleted again, since UB_STATE_DELETED is set, and device
2115 * will be released after the last reference is dropped
2117 * - the device number is freed already, we will not find this
2118 * device via ublk_get_device_from_id()
2120 wait_event_interruptible(ublk_idr_wq
, ublk_idr_freed(idx
));
2125 static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd
*cmd
)
2127 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2129 pr_devel("%s: cmd_op %x, dev id %d qid %d data %llx buf %llx len %u\n",
2130 __func__
, cmd
->cmd_op
, header
->dev_id
, header
->queue_id
,
2131 header
->data
[0], header
->addr
, header
->len
);
2134 static int ublk_ctrl_stop_dev(struct ublk_device
*ub
)
2137 cancel_work_sync(&ub
->stop_work
);
2138 cancel_work_sync(&ub
->quiesce_work
);
2143 static int ublk_ctrl_get_dev_info(struct ublk_device
*ub
,
2144 struct io_uring_cmd
*cmd
)
2146 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2147 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2149 if (header
->len
< sizeof(struct ublksrv_ctrl_dev_info
) || !header
->addr
)
2152 if (copy_to_user(argp
, &ub
->dev_info
, sizeof(ub
->dev_info
)))
2158 /* TYPE_DEVT is readonly, so fill it up before returning to userspace */
2159 static void ublk_ctrl_fill_params_devt(struct ublk_device
*ub
)
2161 ub
->params
.devt
.char_major
= MAJOR(ub
->cdev_dev
.devt
);
2162 ub
->params
.devt
.char_minor
= MINOR(ub
->cdev_dev
.devt
);
2165 ub
->params
.devt
.disk_major
= MAJOR(disk_devt(ub
->ub_disk
));
2166 ub
->params
.devt
.disk_minor
= MINOR(disk_devt(ub
->ub_disk
));
2168 ub
->params
.devt
.disk_major
= 0;
2169 ub
->params
.devt
.disk_minor
= 0;
2171 ub
->params
.types
|= UBLK_PARAM_TYPE_DEVT
;
2174 static int ublk_ctrl_get_params(struct ublk_device
*ub
,
2175 struct io_uring_cmd
*cmd
)
2177 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2178 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2179 struct ublk_params_header ph
;
2182 if (header
->len
<= sizeof(ph
) || !header
->addr
)
2185 if (copy_from_user(&ph
, argp
, sizeof(ph
)))
2188 if (ph
.len
> header
->len
|| !ph
.len
)
2191 if (ph
.len
> sizeof(struct ublk_params
))
2192 ph
.len
= sizeof(struct ublk_params
);
2194 mutex_lock(&ub
->mutex
);
2195 ublk_ctrl_fill_params_devt(ub
);
2196 if (copy_to_user(argp
, &ub
->params
, ph
.len
))
2200 mutex_unlock(&ub
->mutex
);
2205 static int ublk_ctrl_set_params(struct ublk_device
*ub
,
2206 struct io_uring_cmd
*cmd
)
2208 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2209 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2210 struct ublk_params_header ph
;
2213 if (header
->len
<= sizeof(ph
) || !header
->addr
)
2216 if (copy_from_user(&ph
, argp
, sizeof(ph
)))
2219 if (ph
.len
> header
->len
|| !ph
.len
|| !ph
.types
)
2222 if (ph
.len
> sizeof(struct ublk_params
))
2223 ph
.len
= sizeof(struct ublk_params
);
2225 /* parameters can only be changed when device isn't live */
2226 mutex_lock(&ub
->mutex
);
2227 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
) {
2229 } else if (copy_from_user(&ub
->params
, argp
, ph
.len
)) {
2232 /* clear all we don't support yet */
2233 ub
->params
.types
&= UBLK_PARAM_TYPE_ALL
;
2234 ret
= ublk_validate_params(ub
);
2236 ub
->params
.types
= 0;
2238 mutex_unlock(&ub
->mutex
);
2243 static void ublk_queue_reinit(struct ublk_device
*ub
, struct ublk_queue
*ubq
)
2247 WARN_ON_ONCE(!(ubq
->ubq_daemon
&& ubq_daemon_is_dying(ubq
)));
2248 /* All old ioucmds have to be completed */
2249 WARN_ON_ONCE(ubq
->nr_io_ready
);
2250 /* old daemon is PF_EXITING, put it now */
2251 put_task_struct(ubq
->ubq_daemon
);
2252 /* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */
2253 ubq
->ubq_daemon
= NULL
;
2254 ubq
->timeout
= false;
2256 for (i
= 0; i
< ubq
->q_depth
; i
++) {
2257 struct ublk_io
*io
= &ubq
->ios
[i
];
2259 /* forget everything now and be ready for new FETCH_REQ */
2266 static int ublk_ctrl_start_recovery(struct ublk_device
*ub
,
2267 struct io_uring_cmd
*cmd
)
2269 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2273 mutex_lock(&ub
->mutex
);
2274 if (!ublk_can_use_recovery(ub
))
2277 * START_RECOVERY is only allowd after:
2279 * (1) UB_STATE_OPEN is not set, which means the dying process is exited
2280 * and related io_uring ctx is freed so file struct of /dev/ublkcX is
2283 * (2) UBLK_S_DEV_QUIESCED is set, which means the quiesce_work:
2284 * (a)has quiesced request queue
2285 * (b)has requeued every inflight rqs whose io_flags is ACTIVE
2286 * (c)has requeued/aborted every inflight rqs whose io_flags is NOT ACTIVE
2287 * (d)has completed/camceled all ioucmds owned by ther dying process
2289 if (test_bit(UB_STATE_OPEN
, &ub
->state
) ||
2290 ub
->dev_info
.state
!= UBLK_S_DEV_QUIESCED
) {
2294 pr_devel("%s: start recovery for dev id %d.\n", __func__
, header
->dev_id
);
2295 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++)
2296 ublk_queue_reinit(ub
, ublk_get_queue(ub
, i
));
2297 /* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */
2299 ub
->nr_queues_ready
= 0;
2300 ub
->nr_privileged_daemon
= 0;
2301 init_completion(&ub
->completion
);
2304 mutex_unlock(&ub
->mutex
);
2308 static int ublk_ctrl_end_recovery(struct ublk_device
*ub
,
2309 struct io_uring_cmd
*cmd
)
2311 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2312 int ublksrv_pid
= (int)header
->data
[0];
2315 pr_devel("%s: Waiting for new ubq_daemons(nr: %d) are ready, dev id %d...\n",
2316 __func__
, ub
->dev_info
.nr_hw_queues
, header
->dev_id
);
2317 /* wait until new ubq_daemon sending all FETCH_REQ */
2318 wait_for_completion_interruptible(&ub
->completion
);
2319 pr_devel("%s: All new ubq_daemons(nr: %d) are ready, dev id %d\n",
2320 __func__
, ub
->dev_info
.nr_hw_queues
, header
->dev_id
);
2322 mutex_lock(&ub
->mutex
);
2323 if (!ublk_can_use_recovery(ub
))
2326 if (ub
->dev_info
.state
!= UBLK_S_DEV_QUIESCED
) {
2330 ub
->dev_info
.ublksrv_pid
= ublksrv_pid
;
2331 pr_devel("%s: new ublksrv_pid %d, dev id %d\n",
2332 __func__
, ublksrv_pid
, header
->dev_id
);
2333 blk_mq_unquiesce_queue(ub
->ub_disk
->queue
);
2334 pr_devel("%s: queue unquiesced, dev id %d.\n",
2335 __func__
, header
->dev_id
);
2336 blk_mq_kick_requeue_list(ub
->ub_disk
->queue
);
2337 ub
->dev_info
.state
= UBLK_S_DEV_LIVE
;
2338 schedule_delayed_work(&ub
->monitor_work
, UBLK_DAEMON_MONITOR_PERIOD
);
2341 mutex_unlock(&ub
->mutex
);
2346 * All control commands are sent via /dev/ublk-control, so we have to check
2347 * the destination device's permission
2349 static int ublk_char_dev_permission(struct ublk_device
*ub
,
2350 const char *dev_path
, int mask
)
2356 err
= kern_path(dev_path
, LOOKUP_FOLLOW
, &path
);
2360 err
= vfs_getattr(&path
, &stat
, STATX_TYPE
, AT_STATX_SYNC_AS_STAT
);
2365 if (stat
.rdev
!= ub
->cdev_dev
.devt
|| !S_ISCHR(stat
.mode
))
2368 err
= inode_permission(&nop_mnt_idmap
,
2369 d_backing_inode(path
.dentry
), mask
);
2375 static int ublk_ctrl_uring_cmd_permission(struct ublk_device
*ub
,
2376 struct io_uring_cmd
*cmd
)
2378 struct ublksrv_ctrl_cmd
*header
= (struct ublksrv_ctrl_cmd
*)io_uring_sqe_cmd(cmd
->sqe
);
2379 bool unprivileged
= ub
->dev_info
.flags
& UBLK_F_UNPRIVILEGED_DEV
;
2380 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2381 char *dev_path
= NULL
;
2385 if (!unprivileged
) {
2386 if (!capable(CAP_SYS_ADMIN
))
2389 * The new added command of UBLK_CMD_GET_DEV_INFO2 includes
2390 * char_dev_path in payload too, since userspace may not
2391 * know if the specified device is created as unprivileged
2394 if (_IOC_NR(cmd
->cmd_op
) != UBLK_CMD_GET_DEV_INFO2
)
2399 * User has to provide the char device path for unprivileged ublk
2401 * header->addr always points to the dev path buffer, and
2402 * header->dev_path_len records length of dev path buffer.
2404 if (!header
->dev_path_len
|| header
->dev_path_len
> PATH_MAX
)
2407 if (header
->len
< header
->dev_path_len
)
2410 dev_path
= kmalloc(header
->dev_path_len
+ 1, GFP_KERNEL
);
2415 if (copy_from_user(dev_path
, argp
, header
->dev_path_len
))
2417 dev_path
[header
->dev_path_len
] = 0;
2420 switch (_IOC_NR(cmd
->cmd_op
)) {
2421 case UBLK_CMD_GET_DEV_INFO
:
2422 case UBLK_CMD_GET_DEV_INFO2
:
2423 case UBLK_CMD_GET_QUEUE_AFFINITY
:
2424 case UBLK_CMD_GET_PARAMS
:
2427 case UBLK_CMD_START_DEV
:
2428 case UBLK_CMD_STOP_DEV
:
2429 case UBLK_CMD_ADD_DEV
:
2430 case UBLK_CMD_DEL_DEV
:
2431 case UBLK_CMD_SET_PARAMS
:
2432 case UBLK_CMD_START_USER_RECOVERY
:
2433 case UBLK_CMD_END_USER_RECOVERY
:
2434 mask
= MAY_READ
| MAY_WRITE
;
2440 ret
= ublk_char_dev_permission(ub
, dev_path
, mask
);
2442 header
->len
-= header
->dev_path_len
;
2443 header
->addr
+= header
->dev_path_len
;
2445 pr_devel("%s: dev id %d cmd_op %x uid %d gid %d path %s ret %d\n",
2446 __func__
, ub
->ub_number
, cmd
->cmd_op
,
2447 ub
->dev_info
.owner_uid
, ub
->dev_info
.owner_gid
,
2454 static int ublk_ctrl_uring_cmd(struct io_uring_cmd
*cmd
,
2455 unsigned int issue_flags
)
2457 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2458 struct ublk_device
*ub
= NULL
;
2459 u32 cmd_op
= cmd
->cmd_op
;
2462 if (issue_flags
& IO_URING_F_NONBLOCK
)
2465 ublk_ctrl_cmd_dump(cmd
);
2467 if (!(issue_flags
& IO_URING_F_SQE128
))
2470 ret
= ublk_check_cmd_op(cmd_op
);
2474 if (_IOC_NR(cmd_op
) != UBLK_CMD_ADD_DEV
) {
2476 ub
= ublk_get_device_from_id(header
->dev_id
);
2480 ret
= ublk_ctrl_uring_cmd_permission(ub
, cmd
);
2485 switch (_IOC_NR(cmd_op
)) {
2486 case UBLK_CMD_START_DEV
:
2487 ret
= ublk_ctrl_start_dev(ub
, cmd
);
2489 case UBLK_CMD_STOP_DEV
:
2490 ret
= ublk_ctrl_stop_dev(ub
);
2492 case UBLK_CMD_GET_DEV_INFO
:
2493 case UBLK_CMD_GET_DEV_INFO2
:
2494 ret
= ublk_ctrl_get_dev_info(ub
, cmd
);
2496 case UBLK_CMD_ADD_DEV
:
2497 ret
= ublk_ctrl_add_dev(cmd
);
2499 case UBLK_CMD_DEL_DEV
:
2500 ret
= ublk_ctrl_del_dev(&ub
);
2502 case UBLK_CMD_GET_QUEUE_AFFINITY
:
2503 ret
= ublk_ctrl_get_queue_affinity(ub
, cmd
);
2505 case UBLK_CMD_GET_PARAMS
:
2506 ret
= ublk_ctrl_get_params(ub
, cmd
);
2508 case UBLK_CMD_SET_PARAMS
:
2509 ret
= ublk_ctrl_set_params(ub
, cmd
);
2511 case UBLK_CMD_START_USER_RECOVERY
:
2512 ret
= ublk_ctrl_start_recovery(ub
, cmd
);
2514 case UBLK_CMD_END_USER_RECOVERY
:
2515 ret
= ublk_ctrl_end_recovery(ub
, cmd
);
2524 ublk_put_device(ub
);
2526 io_uring_cmd_done(cmd
, ret
, 0, issue_flags
);
2527 pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n",
2528 __func__
, ret
, cmd
->cmd_op
, header
->dev_id
, header
->queue_id
);
2529 return -EIOCBQUEUED
;
2532 static const struct file_operations ublk_ctl_fops
= {
2533 .open
= nonseekable_open
,
2534 .uring_cmd
= ublk_ctrl_uring_cmd
,
2535 .owner
= THIS_MODULE
,
2536 .llseek
= noop_llseek
,
2539 static struct miscdevice ublk_misc
= {
2540 .minor
= MISC_DYNAMIC_MINOR
,
2541 .name
= "ublk-control",
2542 .fops
= &ublk_ctl_fops
,
2545 static int __init
ublk_init(void)
2549 BUILD_BUG_ON((u64
)UBLKSRV_IO_BUF_OFFSET
+
2550 UBLKSRV_IO_BUF_TOTAL_SIZE
< UBLKSRV_IO_BUF_OFFSET
);
2552 init_waitqueue_head(&ublk_idr_wq
);
2554 ret
= misc_register(&ublk_misc
);
2558 ret
= alloc_chrdev_region(&ublk_chr_devt
, 0, UBLK_MINORS
, "ublk-char");
2560 goto unregister_mis
;
2562 ublk_chr_class
= class_create("ublk-char");
2563 if (IS_ERR(ublk_chr_class
)) {
2564 ret
= PTR_ERR(ublk_chr_class
);
2565 goto free_chrdev_region
;
2570 unregister_chrdev_region(ublk_chr_devt
, UBLK_MINORS
);
2572 misc_deregister(&ublk_misc
);
2576 static void __exit
ublk_exit(void)
2578 struct ublk_device
*ub
;
2581 idr_for_each_entry(&ublk_index_idr
, ub
, id
)
2584 class_destroy(ublk_chr_class
);
2585 misc_deregister(&ublk_misc
);
2587 idr_destroy(&ublk_index_idr
);
2588 unregister_chrdev_region(ublk_chr_devt
, UBLK_MINORS
);
2591 module_init(ublk_init
);
2592 module_exit(ublk_exit
);
2594 module_param(ublks_max
, int, 0444);
2595 MODULE_PARM_DESC(ublks_max
, "max number of ublk devices allowed to add(default: 64)");
2597 MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
2598 MODULE_LICENSE("GPL");