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 \
62 /* All UBLK_PARAM_TYPE_* should be included here */
63 #define UBLK_PARAM_TYPE_ALL \
64 (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
65 UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED)
68 struct llist_node node
;
76 struct ublk_uring_cmd_pdu
{
77 struct ublk_queue
*ubq
;
81 * io command is active: sqe cmd is received, and its cqe isn't done
83 * If the flag is set, the io command is owned by ublk driver, and waited
84 * for incoming blk-mq request from the ublk block device.
86 * If the flag is cleared, the io command will be completed, and owned by
89 #define UBLK_IO_FLAG_ACTIVE 0x01
92 * IO command is completed via cqe, and it is being handled by ublksrv, and
95 * Basically exclusively with UBLK_IO_FLAG_ACTIVE, so can be served for
98 #define UBLK_IO_FLAG_OWNED_BY_SRV 0x02
101 * IO command is aborted, so this flag is set in case of
102 * !UBLK_IO_FLAG_ACTIVE.
104 * After this flag is observed, any pending or new incoming request
105 * associated with this io command will be failed immediately
107 #define UBLK_IO_FLAG_ABORTED 0x04
110 * UBLK_IO_FLAG_NEED_GET_DATA is set because IO command requires
111 * get data buffer address from ublksrv.
113 * Then, bio data could be copied into this data buffer for a WRITE request
114 * after the IO command is issued again and UBLK_IO_FLAG_NEED_GET_DATA is unset.
116 #define UBLK_IO_FLAG_NEED_GET_DATA 0x08
118 /* atomic RW with ubq->cancel_lock */
119 #define UBLK_IO_FLAG_CANCELED 0x80000000
122 /* userspace buffer address from io cmd */
127 struct io_uring_cmd
*cmd
;
135 struct task_struct
*ubq_daemon
;
138 struct llist_head io_cmds
;
140 unsigned long io_addr
; /* mapped vm address */
141 unsigned int max_io_sz
;
144 unsigned short nr_io_ready
; /* how many ios setup */
145 spinlock_t cancel_lock
;
146 struct ublk_device
*dev
;
147 struct ublk_io ios
[];
150 #define UBLK_DAEMON_MONITOR_PERIOD (5 * HZ)
153 struct gendisk
*ub_disk
;
157 unsigned int queue_size
;
158 struct ublksrv_ctrl_dev_info dev_info
;
160 struct blk_mq_tag_set tag_set
;
163 struct device cdev_dev
;
165 #define UB_STATE_OPEN 0
166 #define UB_STATE_USED 1
167 #define UB_STATE_DELETED 2
174 struct mm_struct
*mm
;
176 struct ublk_params params
;
178 struct completion completion
;
179 unsigned int nr_queues_ready
;
180 unsigned int nr_privileged_daemon
;
183 * Our ubq->daemon may be killed without any notification, so
184 * monitor each queue's daemon periodically
186 struct delayed_work monitor_work
;
187 struct work_struct quiesce_work
;
188 struct work_struct stop_work
;
191 /* header of ublk_params */
192 struct ublk_params_header
{
197 static inline unsigned int ublk_req_build_flags(struct request
*req
);
198 static inline struct ublksrv_io_desc
*ublk_get_iod(struct ublk_queue
*ubq
,
201 static inline bool ublk_dev_is_user_copy(const struct ublk_device
*ub
)
203 return ub
->dev_info
.flags
& UBLK_F_USER_COPY
;
206 static inline bool ublk_dev_is_zoned(const struct ublk_device
*ub
)
208 return ub
->dev_info
.flags
& UBLK_F_ZONED
;
211 static inline bool ublk_queue_is_zoned(struct ublk_queue
*ubq
)
213 return ubq
->flags
& UBLK_F_ZONED
;
216 #ifdef CONFIG_BLK_DEV_ZONED
218 static int ublk_get_nr_zones(const struct ublk_device
*ub
)
220 const struct ublk_param_basic
*p
= &ub
->params
.basic
;
222 /* Zone size is a power of 2 */
223 return p
->dev_sectors
>> ilog2(p
->chunk_sectors
);
226 static int ublk_revalidate_disk_zones(struct ublk_device
*ub
)
228 return blk_revalidate_disk_zones(ub
->ub_disk
, NULL
);
231 static int ublk_dev_param_zoned_validate(const struct ublk_device
*ub
)
233 const struct ublk_param_zoned
*p
= &ub
->params
.zoned
;
236 if (!ublk_dev_is_zoned(ub
))
239 if (!p
->max_zone_append_sectors
)
242 nr_zones
= ublk_get_nr_zones(ub
);
244 if (p
->max_active_zones
> nr_zones
)
247 if (p
->max_open_zones
> nr_zones
)
253 static int ublk_dev_param_zoned_apply(struct ublk_device
*ub
)
255 const struct ublk_param_zoned
*p
= &ub
->params
.zoned
;
257 disk_set_zoned(ub
->ub_disk
, BLK_ZONED_HM
);
258 blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL
, ub
->ub_disk
->queue
);
259 blk_queue_required_elevator_features(ub
->ub_disk
->queue
,
260 ELEVATOR_F_ZBD_SEQ_WRITE
);
261 disk_set_max_active_zones(ub
->ub_disk
, p
->max_active_zones
);
262 disk_set_max_open_zones(ub
->ub_disk
, p
->max_open_zones
);
263 blk_queue_max_zone_append_sectors(ub
->ub_disk
->queue
, p
->max_zone_append_sectors
);
265 ub
->ub_disk
->nr_zones
= ublk_get_nr_zones(ub
);
270 /* Based on virtblk_alloc_report_buffer */
271 static void *ublk_alloc_report_buffer(struct ublk_device
*ublk
,
272 unsigned int nr_zones
, size_t *buflen
)
274 struct request_queue
*q
= ublk
->ub_disk
->queue
;
278 nr_zones
= min_t(unsigned int, nr_zones
,
279 ublk
->ub_disk
->nr_zones
);
281 bufsize
= nr_zones
* sizeof(struct blk_zone
);
283 min_t(size_t, bufsize
, queue_max_hw_sectors(q
) << SECTOR_SHIFT
);
285 while (bufsize
>= sizeof(struct blk_zone
)) {
286 buf
= kvmalloc(bufsize
, GFP_KERNEL
| __GFP_NORETRY
);
298 static int ublk_report_zones(struct gendisk
*disk
, sector_t sector
,
299 unsigned int nr_zones
, report_zones_cb cb
, void *data
)
301 struct ublk_device
*ub
= disk
->private_data
;
302 unsigned int zone_size_sectors
= disk
->queue
->limits
.chunk_sectors
;
303 unsigned int first_zone
= sector
>> ilog2(zone_size_sectors
);
304 unsigned int done_zones
= 0;
305 unsigned int max_zones_per_request
;
307 struct blk_zone
*buffer
;
308 size_t buffer_length
;
310 nr_zones
= min_t(unsigned int, ub
->ub_disk
->nr_zones
- first_zone
,
313 buffer
= ublk_alloc_report_buffer(ub
, nr_zones
, &buffer_length
);
317 max_zones_per_request
= buffer_length
/ sizeof(struct blk_zone
);
319 while (done_zones
< nr_zones
) {
320 unsigned int remaining_zones
= nr_zones
- done_zones
;
321 unsigned int zones_in_request
=
322 min_t(unsigned int, remaining_zones
, max_zones_per_request
);
324 struct ublk_rq_data
*pdu
;
327 memset(buffer
, 0, buffer_length
);
329 req
= blk_mq_alloc_request(disk
->queue
, REQ_OP_DRV_IN
, 0);
335 pdu
= blk_mq_rq_to_pdu(req
);
336 pdu
->operation
= UBLK_IO_OP_REPORT_ZONES
;
337 pdu
->sector
= sector
;
338 pdu
->nr_zones
= zones_in_request
;
340 ret
= blk_rq_map_kern(disk
->queue
, req
, buffer
, buffer_length
,
343 blk_mq_free_request(req
);
347 status
= blk_execute_rq(req
, 0);
348 ret
= blk_status_to_errno(status
);
349 blk_mq_free_request(req
);
353 for (unsigned int i
= 0; i
< zones_in_request
; i
++) {
354 struct blk_zone
*zone
= buffer
+ i
;
356 /* A zero length zone means no more zones in this response */
360 ret
= cb(zone
, i
, data
);
365 sector
+= zone_size_sectors
;
377 static blk_status_t
ublk_setup_iod_zoned(struct ublk_queue
*ubq
,
380 struct ublksrv_io_desc
*iod
= ublk_get_iod(ubq
, req
->tag
);
381 struct ublk_io
*io
= &ubq
->ios
[req
->tag
];
382 struct ublk_rq_data
*pdu
= blk_mq_rq_to_pdu(req
);
385 switch (req_op(req
)) {
386 case REQ_OP_ZONE_OPEN
:
387 ublk_op
= UBLK_IO_OP_ZONE_OPEN
;
389 case REQ_OP_ZONE_CLOSE
:
390 ublk_op
= UBLK_IO_OP_ZONE_CLOSE
;
392 case REQ_OP_ZONE_FINISH
:
393 ublk_op
= UBLK_IO_OP_ZONE_FINISH
;
395 case REQ_OP_ZONE_RESET
:
396 ublk_op
= UBLK_IO_OP_ZONE_RESET
;
398 case REQ_OP_ZONE_APPEND
:
399 ublk_op
= UBLK_IO_OP_ZONE_APPEND
;
401 case REQ_OP_ZONE_RESET_ALL
:
402 ublk_op
= UBLK_IO_OP_ZONE_RESET_ALL
;
405 ublk_op
= pdu
->operation
;
407 case UBLK_IO_OP_REPORT_ZONES
:
408 iod
->op_flags
= ublk_op
| ublk_req_build_flags(req
);
409 iod
->nr_zones
= pdu
->nr_zones
;
410 iod
->start_sector
= pdu
->sector
;
413 return BLK_STS_IOERR
;
416 /* We do not support drv_out */
417 return BLK_STS_NOTSUPP
;
419 return BLK_STS_IOERR
;
422 iod
->op_flags
= ublk_op
| ublk_req_build_flags(req
);
423 iod
->nr_sectors
= blk_rq_sectors(req
);
424 iod
->start_sector
= blk_rq_pos(req
);
425 iod
->addr
= io
->addr
;
432 #define ublk_report_zones (NULL)
434 static int ublk_dev_param_zoned_validate(const struct ublk_device
*ub
)
439 static int ublk_dev_param_zoned_apply(struct ublk_device
*ub
)
444 static int ublk_revalidate_disk_zones(struct ublk_device
*ub
)
449 static blk_status_t
ublk_setup_iod_zoned(struct ublk_queue
*ubq
,
452 return BLK_STS_NOTSUPP
;
457 static inline void __ublk_complete_rq(struct request
*req
);
458 static void ublk_complete_rq(struct kref
*ref
);
460 static dev_t ublk_chr_devt
;
461 static const struct class ublk_chr_class
= {
465 static DEFINE_IDR(ublk_index_idr
);
466 static DEFINE_SPINLOCK(ublk_idr_lock
);
467 static wait_queue_head_t ublk_idr_wq
; /* wait until one idr is freed */
469 static DEFINE_MUTEX(ublk_ctl_mutex
);
472 * Max ublk devices allowed to add
474 * It can be extended to one per-user limit in future or even controlled
477 #define UBLK_MAX_UBLKS UBLK_MINORS
478 static unsigned int ublks_max
= 64;
479 static unsigned int ublks_added
; /* protected by ublk_ctl_mutex */
481 static struct miscdevice ublk_misc
;
483 static inline unsigned ublk_pos_to_hwq(loff_t pos
)
485 return ((pos
- UBLKSRV_IO_BUF_OFFSET
) >> UBLK_QID_OFF
) &
489 static inline unsigned ublk_pos_to_buf_off(loff_t pos
)
491 return (pos
- UBLKSRV_IO_BUF_OFFSET
) & UBLK_IO_BUF_BITS_MASK
;
494 static inline unsigned ublk_pos_to_tag(loff_t pos
)
496 return ((pos
- UBLKSRV_IO_BUF_OFFSET
) >> UBLK_TAG_OFF
) &
500 static void ublk_dev_param_basic_apply(struct ublk_device
*ub
)
502 struct request_queue
*q
= ub
->ub_disk
->queue
;
503 const struct ublk_param_basic
*p
= &ub
->params
.basic
;
505 blk_queue_logical_block_size(q
, 1 << p
->logical_bs_shift
);
506 blk_queue_physical_block_size(q
, 1 << p
->physical_bs_shift
);
507 blk_queue_io_min(q
, 1 << p
->io_min_shift
);
508 blk_queue_io_opt(q
, 1 << p
->io_opt_shift
);
510 blk_queue_write_cache(q
, p
->attrs
& UBLK_ATTR_VOLATILE_CACHE
,
511 p
->attrs
& UBLK_ATTR_FUA
);
512 if (p
->attrs
& UBLK_ATTR_ROTATIONAL
)
513 blk_queue_flag_clear(QUEUE_FLAG_NONROT
, q
);
515 blk_queue_flag_set(QUEUE_FLAG_NONROT
, q
);
517 blk_queue_max_hw_sectors(q
, p
->max_sectors
);
518 blk_queue_chunk_sectors(q
, p
->chunk_sectors
);
519 blk_queue_virt_boundary(q
, p
->virt_boundary_mask
);
521 if (p
->attrs
& UBLK_ATTR_READ_ONLY
)
522 set_disk_ro(ub
->ub_disk
, true);
524 set_capacity(ub
->ub_disk
, p
->dev_sectors
);
527 static void ublk_dev_param_discard_apply(struct ublk_device
*ub
)
529 struct request_queue
*q
= ub
->ub_disk
->queue
;
530 const struct ublk_param_discard
*p
= &ub
->params
.discard
;
532 q
->limits
.discard_alignment
= p
->discard_alignment
;
533 q
->limits
.discard_granularity
= p
->discard_granularity
;
534 blk_queue_max_discard_sectors(q
, p
->max_discard_sectors
);
535 blk_queue_max_write_zeroes_sectors(q
,
536 p
->max_write_zeroes_sectors
);
537 blk_queue_max_discard_segments(q
, p
->max_discard_segments
);
540 static int ublk_validate_params(const struct ublk_device
*ub
)
542 /* basic param is the only one which must be set */
543 if (ub
->params
.types
& UBLK_PARAM_TYPE_BASIC
) {
544 const struct ublk_param_basic
*p
= &ub
->params
.basic
;
546 if (p
->logical_bs_shift
> PAGE_SHIFT
|| p
->logical_bs_shift
< 9)
549 if (p
->logical_bs_shift
> p
->physical_bs_shift
)
552 if (p
->max_sectors
> (ub
->dev_info
.max_io_buf_bytes
>> 9))
555 if (ublk_dev_is_zoned(ub
) && !p
->chunk_sectors
)
560 if (ub
->params
.types
& UBLK_PARAM_TYPE_DISCARD
) {
561 const struct ublk_param_discard
*p
= &ub
->params
.discard
;
563 /* So far, only support single segment discard */
564 if (p
->max_discard_sectors
&& p
->max_discard_segments
!= 1)
567 if (!p
->discard_granularity
)
571 /* dev_t is read-only */
572 if (ub
->params
.types
& UBLK_PARAM_TYPE_DEVT
)
575 if (ub
->params
.types
& UBLK_PARAM_TYPE_ZONED
)
576 return ublk_dev_param_zoned_validate(ub
);
577 else if (ublk_dev_is_zoned(ub
))
583 static int ublk_apply_params(struct ublk_device
*ub
)
585 if (!(ub
->params
.types
& UBLK_PARAM_TYPE_BASIC
))
588 ublk_dev_param_basic_apply(ub
);
590 if (ub
->params
.types
& UBLK_PARAM_TYPE_DISCARD
)
591 ublk_dev_param_discard_apply(ub
);
593 if (ub
->params
.types
& UBLK_PARAM_TYPE_ZONED
)
594 return ublk_dev_param_zoned_apply(ub
);
599 static inline bool ublk_support_user_copy(const struct ublk_queue
*ubq
)
601 return ubq
->flags
& UBLK_F_USER_COPY
;
604 static inline bool ublk_need_req_ref(const struct ublk_queue
*ubq
)
607 * read()/write() is involved in user copy, so request reference
610 return ublk_support_user_copy(ubq
);
613 static inline void ublk_init_req_ref(const struct ublk_queue
*ubq
,
616 if (ublk_need_req_ref(ubq
)) {
617 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(req
);
619 kref_init(&data
->ref
);
623 static inline bool ublk_get_req_ref(const struct ublk_queue
*ubq
,
626 if (ublk_need_req_ref(ubq
)) {
627 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(req
);
629 return kref_get_unless_zero(&data
->ref
);
635 static inline void ublk_put_req_ref(const struct ublk_queue
*ubq
,
638 if (ublk_need_req_ref(ubq
)) {
639 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(req
);
641 kref_put(&data
->ref
, ublk_complete_rq
);
643 __ublk_complete_rq(req
);
647 static inline bool ublk_need_get_data(const struct ublk_queue
*ubq
)
649 return ubq
->flags
& UBLK_F_NEED_GET_DATA
;
652 static struct ublk_device
*ublk_get_device(struct ublk_device
*ub
)
654 if (kobject_get_unless_zero(&ub
->cdev_dev
.kobj
))
659 static void ublk_put_device(struct ublk_device
*ub
)
661 put_device(&ub
->cdev_dev
);
664 static inline struct ublk_queue
*ublk_get_queue(struct ublk_device
*dev
,
667 return (struct ublk_queue
*)&(dev
->__queues
[qid
* dev
->queue_size
]);
670 static inline bool ublk_rq_has_data(const struct request
*rq
)
672 return bio_has_data(rq
->bio
);
675 static inline struct ublksrv_io_desc
*ublk_get_iod(struct ublk_queue
*ubq
,
678 return (struct ublksrv_io_desc
*)
679 &(ubq
->io_cmd_buf
[tag
* sizeof(struct ublksrv_io_desc
)]);
682 static inline char *ublk_queue_cmd_buf(struct ublk_device
*ub
, int q_id
)
684 return ublk_get_queue(ub
, q_id
)->io_cmd_buf
;
687 static inline int ublk_queue_cmd_buf_size(struct ublk_device
*ub
, int q_id
)
689 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
691 return round_up(ubq
->q_depth
* sizeof(struct ublksrv_io_desc
),
695 static inline bool ublk_queue_can_use_recovery_reissue(
696 struct ublk_queue
*ubq
)
698 return (ubq
->flags
& UBLK_F_USER_RECOVERY
) &&
699 (ubq
->flags
& UBLK_F_USER_RECOVERY_REISSUE
);
702 static inline bool ublk_queue_can_use_recovery(
703 struct ublk_queue
*ubq
)
705 return ubq
->flags
& UBLK_F_USER_RECOVERY
;
708 static inline bool ublk_can_use_recovery(struct ublk_device
*ub
)
710 return ub
->dev_info
.flags
& UBLK_F_USER_RECOVERY
;
713 static void ublk_free_disk(struct gendisk
*disk
)
715 struct ublk_device
*ub
= disk
->private_data
;
717 clear_bit(UB_STATE_USED
, &ub
->state
);
718 put_device(&ub
->cdev_dev
);
721 static void ublk_store_owner_uid_gid(unsigned int *owner_uid
,
722 unsigned int *owner_gid
)
727 current_uid_gid(&uid
, &gid
);
729 *owner_uid
= from_kuid(&init_user_ns
, uid
);
730 *owner_gid
= from_kgid(&init_user_ns
, gid
);
733 static int ublk_open(struct gendisk
*disk
, blk_mode_t mode
)
735 struct ublk_device
*ub
= disk
->private_data
;
737 if (capable(CAP_SYS_ADMIN
))
741 * If it is one unprivileged device, only owner can open
742 * the disk. Otherwise it could be one trap made by one
743 * evil user who grants this disk's privileges to other
744 * users deliberately.
746 * This way is reasonable too given anyone can create
747 * unprivileged device, and no need other's grant.
749 if (ub
->dev_info
.flags
& UBLK_F_UNPRIVILEGED_DEV
) {
750 unsigned int curr_uid
, curr_gid
;
752 ublk_store_owner_uid_gid(&curr_uid
, &curr_gid
);
754 if (curr_uid
!= ub
->dev_info
.owner_uid
|| curr_gid
!=
755 ub
->dev_info
.owner_gid
)
762 static const struct block_device_operations ub_fops
= {
763 .owner
= THIS_MODULE
,
765 .free_disk
= ublk_free_disk
,
766 .report_zones
= ublk_report_zones
,
769 #define UBLK_MAX_PIN_PAGES 32
771 struct ublk_io_iter
{
772 struct page
*pages
[UBLK_MAX_PIN_PAGES
];
774 struct bvec_iter iter
;
777 /* return how many pages are copied */
778 static void ublk_copy_io_pages(struct ublk_io_iter
*data
,
779 size_t total
, size_t pg_off
, int dir
)
784 while (done
< total
) {
785 struct bio_vec bv
= bio_iter_iovec(data
->bio
, data
->iter
);
786 unsigned int bytes
= min3(bv
.bv_len
, (unsigned)total
- done
,
787 (unsigned)(PAGE_SIZE
- pg_off
));
788 void *bv_buf
= bvec_kmap_local(&bv
);
789 void *pg_buf
= kmap_local_page(data
->pages
[pg_idx
]);
791 if (dir
== ITER_DEST
)
792 memcpy(pg_buf
+ pg_off
, bv_buf
, bytes
);
794 memcpy(bv_buf
, pg_buf
+ pg_off
, bytes
);
796 kunmap_local(pg_buf
);
797 kunmap_local(bv_buf
);
799 /* advance page array */
801 if (pg_off
== PAGE_SIZE
) {
809 bio_advance_iter_single(data
->bio
, &data
->iter
, bytes
);
810 if (!data
->iter
.bi_size
) {
811 data
->bio
= data
->bio
->bi_next
;
812 if (data
->bio
== NULL
)
814 data
->iter
= data
->bio
->bi_iter
;
819 static bool ublk_advance_io_iter(const struct request
*req
,
820 struct ublk_io_iter
*iter
, unsigned int offset
)
822 struct bio
*bio
= req
->bio
;
825 if (bio
->bi_iter
.bi_size
> offset
) {
827 iter
->iter
= bio
->bi_iter
;
828 bio_advance_iter(iter
->bio
, &iter
->iter
, offset
);
831 offset
-= bio
->bi_iter
.bi_size
;
837 * Copy data between request pages and io_iter, and 'offset'
838 * is the start point of linear offset of request.
840 static size_t ublk_copy_user_pages(const struct request
*req
,
841 unsigned offset
, struct iov_iter
*uiter
, int dir
)
843 struct ublk_io_iter iter
;
846 if (!ublk_advance_io_iter(req
, &iter
, offset
))
849 while (iov_iter_count(uiter
) && iter
.bio
) {
855 len
= iov_iter_get_pages2(uiter
, iter
.pages
,
856 iov_iter_count(uiter
),
857 UBLK_MAX_PIN_PAGES
, &off
);
861 ublk_copy_io_pages(&iter
, len
, off
, dir
);
862 nr_pages
= DIV_ROUND_UP(len
+ off
, PAGE_SIZE
);
863 for (i
= 0; i
< nr_pages
; i
++) {
864 if (dir
== ITER_DEST
)
865 set_page_dirty(iter
.pages
[i
]);
866 put_page(iter
.pages
[i
]);
874 static inline bool ublk_need_map_req(const struct request
*req
)
876 return ublk_rq_has_data(req
) && req_op(req
) == REQ_OP_WRITE
;
879 static inline bool ublk_need_unmap_req(const struct request
*req
)
881 return ublk_rq_has_data(req
) &&
882 (req_op(req
) == REQ_OP_READ
|| req_op(req
) == REQ_OP_DRV_IN
);
885 static int ublk_map_io(const struct ublk_queue
*ubq
, const struct request
*req
,
888 const unsigned int rq_bytes
= blk_rq_bytes(req
);
890 if (ublk_support_user_copy(ubq
))
894 * no zero copy, we delay copy WRITE request data into ublksrv
895 * context and the big benefit is that pinning pages in current
896 * context is pretty fast, see ublk_pin_user_pages
898 if (ublk_need_map_req(req
)) {
899 struct iov_iter iter
;
901 const int dir
= ITER_DEST
;
903 import_single_range(dir
, u64_to_user_ptr(io
->addr
), rq_bytes
,
906 return ublk_copy_user_pages(req
, 0, &iter
, dir
);
911 static int ublk_unmap_io(const struct ublk_queue
*ubq
,
912 const struct request
*req
,
915 const unsigned int rq_bytes
= blk_rq_bytes(req
);
917 if (ublk_support_user_copy(ubq
))
920 if (ublk_need_unmap_req(req
)) {
921 struct iov_iter iter
;
923 const int dir
= ITER_SOURCE
;
925 WARN_ON_ONCE(io
->res
> rq_bytes
);
927 import_single_range(dir
, u64_to_user_ptr(io
->addr
), io
->res
,
929 return ublk_copy_user_pages(req
, 0, &iter
, dir
);
934 static inline unsigned int ublk_req_build_flags(struct request
*req
)
938 if (req
->cmd_flags
& REQ_FAILFAST_DEV
)
939 flags
|= UBLK_IO_F_FAILFAST_DEV
;
941 if (req
->cmd_flags
& REQ_FAILFAST_TRANSPORT
)
942 flags
|= UBLK_IO_F_FAILFAST_TRANSPORT
;
944 if (req
->cmd_flags
& REQ_FAILFAST_DRIVER
)
945 flags
|= UBLK_IO_F_FAILFAST_DRIVER
;
947 if (req
->cmd_flags
& REQ_META
)
948 flags
|= UBLK_IO_F_META
;
950 if (req
->cmd_flags
& REQ_FUA
)
951 flags
|= UBLK_IO_F_FUA
;
953 if (req
->cmd_flags
& REQ_NOUNMAP
)
954 flags
|= UBLK_IO_F_NOUNMAP
;
956 if (req
->cmd_flags
& REQ_SWAP
)
957 flags
|= UBLK_IO_F_SWAP
;
962 static blk_status_t
ublk_setup_iod(struct ublk_queue
*ubq
, struct request
*req
)
964 struct ublksrv_io_desc
*iod
= ublk_get_iod(ubq
, req
->tag
);
965 struct ublk_io
*io
= &ubq
->ios
[req
->tag
];
966 enum req_op op
= req_op(req
);
969 if (!ublk_queue_is_zoned(ubq
) &&
970 (op_is_zone_mgmt(op
) || op
== REQ_OP_ZONE_APPEND
))
971 return BLK_STS_IOERR
;
973 switch (req_op(req
)) {
975 ublk_op
= UBLK_IO_OP_READ
;
978 ublk_op
= UBLK_IO_OP_WRITE
;
981 ublk_op
= UBLK_IO_OP_FLUSH
;
984 ublk_op
= UBLK_IO_OP_DISCARD
;
986 case REQ_OP_WRITE_ZEROES
:
987 ublk_op
= UBLK_IO_OP_WRITE_ZEROES
;
990 if (ublk_queue_is_zoned(ubq
))
991 return ublk_setup_iod_zoned(ubq
, req
);
992 return BLK_STS_IOERR
;
995 /* need to translate since kernel may change */
996 iod
->op_flags
= ublk_op
| ublk_req_build_flags(req
);
997 iod
->nr_sectors
= blk_rq_sectors(req
);
998 iod
->start_sector
= blk_rq_pos(req
);
999 iod
->addr
= io
->addr
;
1004 static inline struct ublk_uring_cmd_pdu
*ublk_get_uring_cmd_pdu(
1005 struct io_uring_cmd
*ioucmd
)
1007 return (struct ublk_uring_cmd_pdu
*)&ioucmd
->pdu
;
1010 static inline bool ubq_daemon_is_dying(struct ublk_queue
*ubq
)
1012 return ubq
->ubq_daemon
->flags
& PF_EXITING
;
1015 /* todo: handle partial completion */
1016 static inline void __ublk_complete_rq(struct request
*req
)
1018 struct ublk_queue
*ubq
= req
->mq_hctx
->driver_data
;
1019 struct ublk_io
*io
= &ubq
->ios
[req
->tag
];
1020 unsigned int unmapped_bytes
;
1021 blk_status_t res
= BLK_STS_OK
;
1023 /* called from ublk_abort_queue() code path */
1024 if (io
->flags
& UBLK_IO_FLAG_ABORTED
) {
1025 res
= BLK_STS_IOERR
;
1029 /* failed read IO if nothing is read */
1030 if (!io
->res
&& req_op(req
) == REQ_OP_READ
)
1034 res
= errno_to_blk_status(io
->res
);
1039 * FLUSH, DISCARD or WRITE_ZEROES usually won't return bytes returned, so end them
1042 * Both the two needn't unmap.
1044 if (req_op(req
) != REQ_OP_READ
&& req_op(req
) != REQ_OP_WRITE
&&
1045 req_op(req
) != REQ_OP_DRV_IN
)
1048 /* for READ request, writing data in iod->addr to rq buffers */
1049 unmapped_bytes
= ublk_unmap_io(ubq
, req
, io
);
1052 * Extremely impossible since we got data filled in just before
1054 * Re-read simply for this unlikely case.
1056 if (unlikely(unmapped_bytes
< io
->res
))
1057 io
->res
= unmapped_bytes
;
1059 if (blk_update_request(req
, BLK_STS_OK
, io
->res
))
1060 blk_mq_requeue_request(req
, true);
1062 __blk_mq_end_request(req
, BLK_STS_OK
);
1066 blk_mq_end_request(req
, res
);
1069 static void ublk_complete_rq(struct kref
*ref
)
1071 struct ublk_rq_data
*data
= container_of(ref
, struct ublk_rq_data
,
1073 struct request
*req
= blk_mq_rq_from_pdu(data
);
1075 __ublk_complete_rq(req
);
1079 * Since __ublk_rq_task_work always fails requests immediately during
1080 * exiting, __ublk_fail_req() is only called from abort context during
1081 * exiting. So lock is unnecessary.
1083 * Also aborting may not be started yet, keep in mind that one failed
1084 * request may be issued by block layer again.
1086 static void __ublk_fail_req(struct ublk_queue
*ubq
, struct ublk_io
*io
,
1087 struct request
*req
)
1089 WARN_ON_ONCE(io
->flags
& UBLK_IO_FLAG_ACTIVE
);
1091 if (!(io
->flags
& UBLK_IO_FLAG_ABORTED
)) {
1092 io
->flags
|= UBLK_IO_FLAG_ABORTED
;
1093 if (ublk_queue_can_use_recovery_reissue(ubq
))
1094 blk_mq_requeue_request(req
, false);
1096 ublk_put_req_ref(ubq
, req
);
1100 static void ubq_complete_io_cmd(struct ublk_io
*io
, int res
,
1101 unsigned issue_flags
)
1103 /* mark this cmd owned by ublksrv */
1104 io
->flags
|= UBLK_IO_FLAG_OWNED_BY_SRV
;
1107 * clear ACTIVE since we are done with this sqe/cmd slot
1108 * We can only accept io cmd in case of being not active.
1110 io
->flags
&= ~UBLK_IO_FLAG_ACTIVE
;
1112 /* tell ublksrv one io request is coming */
1113 io_uring_cmd_done(io
->cmd
, res
, 0, issue_flags
);
1116 #define UBLK_REQUEUE_DELAY_MS 3
1118 static inline void __ublk_abort_rq(struct ublk_queue
*ubq
,
1121 /* We cannot process this rq so just requeue it. */
1122 if (ublk_queue_can_use_recovery(ubq
))
1123 blk_mq_requeue_request(rq
, false);
1125 blk_mq_end_request(rq
, BLK_STS_IOERR
);
1127 mod_delayed_work(system_wq
, &ubq
->dev
->monitor_work
, 0);
1130 static inline void __ublk_rq_task_work(struct request
*req
,
1131 unsigned issue_flags
)
1133 struct ublk_queue
*ubq
= req
->mq_hctx
->driver_data
;
1135 struct ublk_io
*io
= &ubq
->ios
[tag
];
1136 unsigned int mapped_bytes
;
1138 pr_devel("%s: complete: op %d, qid %d tag %d io_flags %x addr %llx\n",
1139 __func__
, io
->cmd
->cmd_op
, ubq
->q_id
, req
->tag
, io
->flags
,
1140 ublk_get_iod(ubq
, req
->tag
)->addr
);
1143 * Task is exiting if either:
1145 * (1) current != ubq_daemon.
1146 * io_uring_cmd_complete_in_task() tries to run task_work
1147 * in a workqueue if ubq_daemon(cmd's task) is PF_EXITING.
1149 * (2) current->flags & PF_EXITING.
1151 if (unlikely(current
!= ubq
->ubq_daemon
|| current
->flags
& PF_EXITING
)) {
1152 __ublk_abort_rq(ubq
, req
);
1156 if (ublk_need_get_data(ubq
) && ublk_need_map_req(req
)) {
1158 * We have not handled UBLK_IO_NEED_GET_DATA command yet,
1159 * so immepdately pass UBLK_IO_RES_NEED_GET_DATA to ublksrv
1162 if (!(io
->flags
& UBLK_IO_FLAG_NEED_GET_DATA
)) {
1163 io
->flags
|= UBLK_IO_FLAG_NEED_GET_DATA
;
1164 pr_devel("%s: need get data. op %d, qid %d tag %d io_flags %x\n",
1165 __func__
, io
->cmd
->cmd_op
, ubq
->q_id
,
1166 req
->tag
, io
->flags
);
1167 ubq_complete_io_cmd(io
, UBLK_IO_RES_NEED_GET_DATA
, issue_flags
);
1171 * We have handled UBLK_IO_NEED_GET_DATA command,
1172 * so clear UBLK_IO_FLAG_NEED_GET_DATA now and just
1175 io
->flags
&= ~UBLK_IO_FLAG_NEED_GET_DATA
;
1176 /* update iod->addr because ublksrv may have passed a new io buffer */
1177 ublk_get_iod(ubq
, req
->tag
)->addr
= io
->addr
;
1178 pr_devel("%s: update iod->addr: op %d, qid %d tag %d io_flags %x addr %llx\n",
1179 __func__
, io
->cmd
->cmd_op
, ubq
->q_id
, req
->tag
, io
->flags
,
1180 ublk_get_iod(ubq
, req
->tag
)->addr
);
1183 mapped_bytes
= ublk_map_io(ubq
, req
, io
);
1185 /* partially mapped, update io descriptor */
1186 if (unlikely(mapped_bytes
!= blk_rq_bytes(req
))) {
1188 * Nothing mapped, retry until we succeed.
1190 * We may never succeed in mapping any bytes here because
1191 * of OOM. TODO: reserve one buffer with single page pinned
1192 * for providing forward progress guarantee.
1194 if (unlikely(!mapped_bytes
)) {
1195 blk_mq_requeue_request(req
, false);
1196 blk_mq_delay_kick_requeue_list(req
->q
,
1197 UBLK_REQUEUE_DELAY_MS
);
1201 ublk_get_iod(ubq
, req
->tag
)->nr_sectors
=
1205 ublk_init_req_ref(ubq
, req
);
1206 ubq_complete_io_cmd(io
, UBLK_IO_RES_OK
, issue_flags
);
1209 static inline void ublk_forward_io_cmds(struct ublk_queue
*ubq
,
1210 unsigned issue_flags
)
1212 struct llist_node
*io_cmds
= llist_del_all(&ubq
->io_cmds
);
1213 struct ublk_rq_data
*data
, *tmp
;
1215 io_cmds
= llist_reverse_order(io_cmds
);
1216 llist_for_each_entry_safe(data
, tmp
, io_cmds
, node
)
1217 __ublk_rq_task_work(blk_mq_rq_from_pdu(data
), issue_flags
);
1220 static inline void ublk_abort_io_cmds(struct ublk_queue
*ubq
)
1222 struct llist_node
*io_cmds
= llist_del_all(&ubq
->io_cmds
);
1223 struct ublk_rq_data
*data
, *tmp
;
1225 llist_for_each_entry_safe(data
, tmp
, io_cmds
, node
)
1226 __ublk_abort_rq(ubq
, blk_mq_rq_from_pdu(data
));
1229 static void ublk_rq_task_work_cb(struct io_uring_cmd
*cmd
, unsigned issue_flags
)
1231 struct ublk_uring_cmd_pdu
*pdu
= ublk_get_uring_cmd_pdu(cmd
);
1232 struct ublk_queue
*ubq
= pdu
->ubq
;
1234 ublk_forward_io_cmds(ubq
, issue_flags
);
1237 static void ublk_queue_cmd(struct ublk_queue
*ubq
, struct request
*rq
)
1239 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(rq
);
1242 if (!llist_add(&data
->node
, &ubq
->io_cmds
))
1245 io
= &ubq
->ios
[rq
->tag
];
1247 * If the check pass, we know that this is a re-issued request aborted
1248 * previously in monitor_work because the ubq_daemon(cmd's task) is
1249 * PF_EXITING. We cannot call io_uring_cmd_complete_in_task() anymore
1250 * because this ioucmd's io_uring context may be freed now if no inflight
1251 * ioucmd exists. Otherwise we may cause null-deref in ctx->fallback_work.
1253 * Note: monitor_work sets UBLK_IO_FLAG_ABORTED and ends this request(releasing
1254 * the tag). Then the request is re-started(allocating the tag) and we are here.
1255 * Since releasing/allocating a tag implies smp_mb(), finding UBLK_IO_FLAG_ABORTED
1256 * guarantees that here is a re-issued request aborted previously.
1258 if (unlikely(io
->flags
& UBLK_IO_FLAG_ABORTED
)) {
1259 ublk_abort_io_cmds(ubq
);
1261 struct io_uring_cmd
*cmd
= io
->cmd
;
1262 struct ublk_uring_cmd_pdu
*pdu
= ublk_get_uring_cmd_pdu(cmd
);
1265 io_uring_cmd_complete_in_task(cmd
, ublk_rq_task_work_cb
);
1269 static enum blk_eh_timer_return
ublk_timeout(struct request
*rq
)
1271 struct ublk_queue
*ubq
= rq
->mq_hctx
->driver_data
;
1273 if (ubq
->flags
& UBLK_F_UNPRIVILEGED_DEV
) {
1274 if (!ubq
->timeout
) {
1275 send_sig(SIGKILL
, ubq
->ubq_daemon
, 0);
1276 ubq
->timeout
= true;
1282 return BLK_EH_RESET_TIMER
;
1285 static blk_status_t
ublk_queue_rq(struct blk_mq_hw_ctx
*hctx
,
1286 const struct blk_mq_queue_data
*bd
)
1288 struct ublk_queue
*ubq
= hctx
->driver_data
;
1289 struct request
*rq
= bd
->rq
;
1292 /* fill iod to slot in io cmd buffer */
1293 res
= ublk_setup_iod(ubq
, rq
);
1294 if (unlikely(res
!= BLK_STS_OK
))
1295 return BLK_STS_IOERR
;
1297 /* With recovery feature enabled, force_abort is set in
1298 * ublk_stop_dev() before calling del_gendisk(). We have to
1299 * abort all requeued and new rqs here to let del_gendisk()
1300 * move on. Besides, we cannot not call io_uring_cmd_complete_in_task()
1301 * to avoid UAF on io_uring ctx.
1303 * Note: force_abort is guaranteed to be seen because it is set
1304 * before request queue is unqiuesced.
1306 if (ublk_queue_can_use_recovery(ubq
) && unlikely(ubq
->force_abort
))
1307 return BLK_STS_IOERR
;
1309 blk_mq_start_request(bd
->rq
);
1311 if (unlikely(ubq_daemon_is_dying(ubq
))) {
1312 __ublk_abort_rq(ubq
, rq
);
1316 ublk_queue_cmd(ubq
, rq
);
1321 static int ublk_init_hctx(struct blk_mq_hw_ctx
*hctx
, void *driver_data
,
1322 unsigned int hctx_idx
)
1324 struct ublk_device
*ub
= driver_data
;
1325 struct ublk_queue
*ubq
= ublk_get_queue(ub
, hctx
->queue_num
);
1327 hctx
->driver_data
= ubq
;
1331 static const struct blk_mq_ops ublk_mq_ops
= {
1332 .queue_rq
= ublk_queue_rq
,
1333 .init_hctx
= ublk_init_hctx
,
1334 .timeout
= ublk_timeout
,
1337 static int ublk_ch_open(struct inode
*inode
, struct file
*filp
)
1339 struct ublk_device
*ub
= container_of(inode
->i_cdev
,
1340 struct ublk_device
, cdev
);
1342 if (test_and_set_bit(UB_STATE_OPEN
, &ub
->state
))
1344 filp
->private_data
= ub
;
1348 static int ublk_ch_release(struct inode
*inode
, struct file
*filp
)
1350 struct ublk_device
*ub
= filp
->private_data
;
1352 clear_bit(UB_STATE_OPEN
, &ub
->state
);
1356 /* map pre-allocated per-queue cmd buffer to ublksrv daemon */
1357 static int ublk_ch_mmap(struct file
*filp
, struct vm_area_struct
*vma
)
1359 struct ublk_device
*ub
= filp
->private_data
;
1360 size_t sz
= vma
->vm_end
- vma
->vm_start
;
1361 unsigned max_sz
= UBLK_MAX_QUEUE_DEPTH
* sizeof(struct ublksrv_io_desc
);
1362 unsigned long pfn
, end
, phys_off
= vma
->vm_pgoff
<< PAGE_SHIFT
;
1365 spin_lock(&ub
->mm_lock
);
1367 ub
->mm
= current
->mm
;
1368 if (current
->mm
!= ub
->mm
)
1370 spin_unlock(&ub
->mm_lock
);
1375 if (vma
->vm_flags
& VM_WRITE
)
1378 end
= UBLKSRV_CMD_BUF_OFFSET
+ ub
->dev_info
.nr_hw_queues
* max_sz
;
1379 if (phys_off
< UBLKSRV_CMD_BUF_OFFSET
|| phys_off
>= end
)
1382 q_id
= (phys_off
- UBLKSRV_CMD_BUF_OFFSET
) / max_sz
;
1383 pr_devel("%s: qid %d, pid %d, addr %lx pg_off %lx sz %lu\n",
1384 __func__
, q_id
, current
->pid
, vma
->vm_start
,
1385 phys_off
, (unsigned long)sz
);
1387 if (sz
!= ublk_queue_cmd_buf_size(ub
, q_id
))
1390 pfn
= virt_to_phys(ublk_queue_cmd_buf(ub
, q_id
)) >> PAGE_SHIFT
;
1391 return remap_pfn_range(vma
, vma
->vm_start
, pfn
, sz
, vma
->vm_page_prot
);
1394 static void ublk_commit_completion(struct ublk_device
*ub
,
1395 const struct ublksrv_io_cmd
*ub_cmd
)
1397 u32 qid
= ub_cmd
->q_id
, tag
= ub_cmd
->tag
;
1398 struct ublk_queue
*ubq
= ublk_get_queue(ub
, qid
);
1399 struct ublk_io
*io
= &ubq
->ios
[tag
];
1400 struct request
*req
;
1402 /* now this cmd slot is owned by nbd driver */
1403 io
->flags
&= ~UBLK_IO_FLAG_OWNED_BY_SRV
;
1404 io
->res
= ub_cmd
->result
;
1406 /* find the io request and complete */
1407 req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[qid
], tag
);
1408 if (WARN_ON_ONCE(unlikely(!req
)))
1411 if (req_op(req
) == REQ_OP_ZONE_APPEND
)
1412 req
->__sector
= ub_cmd
->zone_append_lba
;
1414 if (likely(!blk_should_fake_timeout(req
->q
)))
1415 ublk_put_req_ref(ubq
, req
);
1419 * When ->ubq_daemon is exiting, either new request is ended immediately,
1420 * or any queued io command is drained, so it is safe to abort queue
1423 static void ublk_abort_queue(struct ublk_device
*ub
, struct ublk_queue
*ubq
)
1427 for (i
= 0; i
< ubq
->q_depth
; i
++) {
1428 struct ublk_io
*io
= &ubq
->ios
[i
];
1430 if (!(io
->flags
& UBLK_IO_FLAG_ACTIVE
)) {
1434 * Either we fail the request or ublk_rq_task_work_fn
1437 rq
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[ubq
->q_id
], i
);
1439 __ublk_fail_req(ubq
, io
, rq
);
1444 static void ublk_daemon_monitor_work(struct work_struct
*work
)
1446 struct ublk_device
*ub
=
1447 container_of(work
, struct ublk_device
, monitor_work
.work
);
1450 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++) {
1451 struct ublk_queue
*ubq
= ublk_get_queue(ub
, i
);
1453 if (ubq_daemon_is_dying(ubq
)) {
1454 if (ublk_queue_can_use_recovery(ubq
))
1455 schedule_work(&ub
->quiesce_work
);
1457 schedule_work(&ub
->stop_work
);
1459 /* abort queue is for making forward progress */
1460 ublk_abort_queue(ub
, ubq
);
1465 * We can't schedule monitor work after ub's state is not UBLK_S_DEV_LIVE.
1466 * after ublk_remove() or __ublk_quiesce_dev() is started.
1468 * No need ub->mutex, monitor work are canceled after state is marked
1469 * as not LIVE, so new state is observed reliably.
1471 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
)
1472 schedule_delayed_work(&ub
->monitor_work
,
1473 UBLK_DAEMON_MONITOR_PERIOD
);
1476 static inline bool ublk_queue_ready(struct ublk_queue
*ubq
)
1478 return ubq
->nr_io_ready
== ubq
->q_depth
;
1481 static void ublk_cancel_queue(struct ublk_queue
*ubq
)
1485 for (i
= 0; i
< ubq
->q_depth
; i
++) {
1486 struct ublk_io
*io
= &ubq
->ios
[i
];
1488 if (io
->flags
& UBLK_IO_FLAG_ACTIVE
) {
1491 spin_lock(&ubq
->cancel_lock
);
1492 done
= !!(io
->flags
& UBLK_IO_FLAG_CANCELED
);
1494 io
->flags
|= UBLK_IO_FLAG_CANCELED
;
1495 spin_unlock(&ubq
->cancel_lock
);
1498 io_uring_cmd_done(io
->cmd
,
1499 UBLK_IO_RES_ABORT
, 0,
1500 IO_URING_F_UNLOCKED
);
1505 /* Cancel all pending commands, must be called after del_gendisk() returns */
1506 static void ublk_cancel_dev(struct ublk_device
*ub
)
1510 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++)
1511 ublk_cancel_queue(ublk_get_queue(ub
, i
));
1514 static bool ublk_check_inflight_rq(struct request
*rq
, void *data
)
1518 if (blk_mq_request_started(rq
)) {
1525 static void ublk_wait_tagset_rqs_idle(struct ublk_device
*ub
)
1529 WARN_ON_ONCE(!blk_queue_quiesced(ub
->ub_disk
->queue
));
1532 blk_mq_tagset_busy_iter(&ub
->tag_set
,
1533 ublk_check_inflight_rq
, &idle
);
1536 msleep(UBLK_REQUEUE_DELAY_MS
);
1540 static void __ublk_quiesce_dev(struct ublk_device
*ub
)
1542 pr_devel("%s: quiesce ub: dev_id %d state %s\n",
1543 __func__
, ub
->dev_info
.dev_id
,
1544 ub
->dev_info
.state
== UBLK_S_DEV_LIVE
?
1545 "LIVE" : "QUIESCED");
1546 blk_mq_quiesce_queue(ub
->ub_disk
->queue
);
1547 ublk_wait_tagset_rqs_idle(ub
);
1548 ub
->dev_info
.state
= UBLK_S_DEV_QUIESCED
;
1549 /* we are going to release task_struct of ubq_daemon and resets
1550 * ->ubq_daemon to NULL. So in monitor_work, check on ubq_daemon causes UAF.
1551 * Besides, monitor_work is not necessary in QUIESCED state since we have
1552 * already scheduled quiesce_work and quiesced all ubqs.
1554 * Do not let monitor_work schedule itself if state it QUIESCED. And we cancel
1555 * it here and re-schedule it in END_USER_RECOVERY to avoid UAF.
1557 cancel_delayed_work_sync(&ub
->monitor_work
);
1560 static void ublk_quiesce_work_fn(struct work_struct
*work
)
1562 struct ublk_device
*ub
=
1563 container_of(work
, struct ublk_device
, quiesce_work
);
1565 mutex_lock(&ub
->mutex
);
1566 if (ub
->dev_info
.state
!= UBLK_S_DEV_LIVE
)
1568 __ublk_quiesce_dev(ub
);
1570 mutex_unlock(&ub
->mutex
);
1571 ublk_cancel_dev(ub
);
1574 static void ublk_unquiesce_dev(struct ublk_device
*ub
)
1578 pr_devel("%s: unquiesce ub: dev_id %d state %s\n",
1579 __func__
, ub
->dev_info
.dev_id
,
1580 ub
->dev_info
.state
== UBLK_S_DEV_LIVE
?
1581 "LIVE" : "QUIESCED");
1582 /* quiesce_work has run. We let requeued rqs be aborted
1583 * before running fallback_wq. "force_abort" must be seen
1584 * after request queue is unqiuesced. Then del_gendisk()
1587 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++)
1588 ublk_get_queue(ub
, i
)->force_abort
= true;
1590 blk_mq_unquiesce_queue(ub
->ub_disk
->queue
);
1591 /* We may have requeued some rqs in ublk_quiesce_queue() */
1592 blk_mq_kick_requeue_list(ub
->ub_disk
->queue
);
1595 static void ublk_stop_dev(struct ublk_device
*ub
)
1597 mutex_lock(&ub
->mutex
);
1598 if (ub
->dev_info
.state
== UBLK_S_DEV_DEAD
)
1600 if (ublk_can_use_recovery(ub
)) {
1601 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
)
1602 __ublk_quiesce_dev(ub
);
1603 ublk_unquiesce_dev(ub
);
1605 del_gendisk(ub
->ub_disk
);
1606 ub
->dev_info
.state
= UBLK_S_DEV_DEAD
;
1607 ub
->dev_info
.ublksrv_pid
= -1;
1608 put_disk(ub
->ub_disk
);
1611 mutex_unlock(&ub
->mutex
);
1612 ublk_cancel_dev(ub
);
1613 cancel_delayed_work_sync(&ub
->monitor_work
);
1616 /* device can only be started after all IOs are ready */
1617 static void ublk_mark_io_ready(struct ublk_device
*ub
, struct ublk_queue
*ubq
)
1619 mutex_lock(&ub
->mutex
);
1621 if (ublk_queue_ready(ubq
)) {
1622 ubq
->ubq_daemon
= current
;
1623 get_task_struct(ubq
->ubq_daemon
);
1624 ub
->nr_queues_ready
++;
1626 if (capable(CAP_SYS_ADMIN
))
1627 ub
->nr_privileged_daemon
++;
1629 if (ub
->nr_queues_ready
== ub
->dev_info
.nr_hw_queues
)
1630 complete_all(&ub
->completion
);
1631 mutex_unlock(&ub
->mutex
);
1634 static void ublk_handle_need_get_data(struct ublk_device
*ub
, int q_id
,
1637 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
1638 struct request
*req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[q_id
], tag
);
1640 ublk_queue_cmd(ubq
, req
);
1643 static inline int ublk_check_cmd_op(u32 cmd_op
)
1645 u32 ioc_type
= _IOC_TYPE(cmd_op
);
1647 if (!IS_ENABLED(CONFIG_BLKDEV_UBLK_LEGACY_OPCODES
) && ioc_type
!= 'u')
1650 if (ioc_type
!= 'u' && ioc_type
!= 0)
1656 static inline void ublk_fill_io_cmd(struct ublk_io
*io
,
1657 struct io_uring_cmd
*cmd
, unsigned long buf_addr
)
1660 io
->flags
|= UBLK_IO_FLAG_ACTIVE
;
1661 io
->addr
= buf_addr
;
1664 static int __ublk_ch_uring_cmd(struct io_uring_cmd
*cmd
,
1665 unsigned int issue_flags
,
1666 const struct ublksrv_io_cmd
*ub_cmd
)
1668 struct ublk_device
*ub
= cmd
->file
->private_data
;
1669 struct ublk_queue
*ubq
;
1671 u32 cmd_op
= cmd
->cmd_op
;
1672 unsigned tag
= ub_cmd
->tag
;
1674 struct request
*req
;
1676 pr_devel("%s: received: cmd op %d queue %d tag %d result %d\n",
1677 __func__
, cmd
->cmd_op
, ub_cmd
->q_id
, tag
,
1680 if (ub_cmd
->q_id
>= ub
->dev_info
.nr_hw_queues
)
1683 ubq
= ublk_get_queue(ub
, ub_cmd
->q_id
);
1684 if (!ubq
|| ub_cmd
->q_id
!= ubq
->q_id
)
1687 if (ubq
->ubq_daemon
&& ubq
->ubq_daemon
!= current
)
1690 if (tag
>= ubq
->q_depth
)
1693 io
= &ubq
->ios
[tag
];
1695 /* there is pending io cmd, something must be wrong */
1696 if (io
->flags
& UBLK_IO_FLAG_ACTIVE
) {
1702 * ensure that the user issues UBLK_IO_NEED_GET_DATA
1703 * iff the driver have set the UBLK_IO_FLAG_NEED_GET_DATA.
1705 if ((!!(io
->flags
& UBLK_IO_FLAG_NEED_GET_DATA
))
1706 ^ (_IOC_NR(cmd_op
) == UBLK_IO_NEED_GET_DATA
))
1709 ret
= ublk_check_cmd_op(cmd_op
);
1714 switch (_IOC_NR(cmd_op
)) {
1715 case UBLK_IO_FETCH_REQ
:
1716 /* UBLK_IO_FETCH_REQ is only allowed before queue is setup */
1717 if (ublk_queue_ready(ubq
)) {
1722 * The io is being handled by server, so COMMIT_RQ is expected
1723 * instead of FETCH_REQ
1725 if (io
->flags
& UBLK_IO_FLAG_OWNED_BY_SRV
)
1728 if (!ublk_support_user_copy(ubq
)) {
1730 * FETCH_RQ has to provide IO buffer if NEED GET
1731 * DATA is not enabled
1733 if (!ub_cmd
->addr
&& !ublk_need_get_data(ubq
))
1735 } else if (ub_cmd
->addr
) {
1736 /* User copy requires addr to be unset */
1741 ublk_fill_io_cmd(io
, cmd
, ub_cmd
->addr
);
1742 ublk_mark_io_ready(ub
, ubq
);
1744 case UBLK_IO_COMMIT_AND_FETCH_REQ
:
1745 req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[ub_cmd
->q_id
], tag
);
1747 if (!(io
->flags
& UBLK_IO_FLAG_OWNED_BY_SRV
))
1750 if (!ublk_support_user_copy(ubq
)) {
1752 * COMMIT_AND_FETCH_REQ has to provide IO buffer if
1753 * NEED GET DATA is not enabled or it is Read IO.
1755 if (!ub_cmd
->addr
&& (!ublk_need_get_data(ubq
) ||
1756 req_op(req
) == REQ_OP_READ
))
1758 } else if (req_op(req
) != REQ_OP_ZONE_APPEND
&& ub_cmd
->addr
) {
1760 * User copy requires addr to be unset when command is
1767 ublk_fill_io_cmd(io
, cmd
, ub_cmd
->addr
);
1768 ublk_commit_completion(ub
, ub_cmd
);
1770 case UBLK_IO_NEED_GET_DATA
:
1771 if (!(io
->flags
& UBLK_IO_FLAG_OWNED_BY_SRV
))
1773 ublk_fill_io_cmd(io
, cmd
, ub_cmd
->addr
);
1774 ublk_handle_need_get_data(ub
, ub_cmd
->q_id
, ub_cmd
->tag
);
1779 return -EIOCBQUEUED
;
1782 io_uring_cmd_done(cmd
, ret
, 0, issue_flags
);
1783 pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n",
1784 __func__
, cmd_op
, tag
, ret
, io
->flags
);
1785 return -EIOCBQUEUED
;
1788 static inline struct request
*__ublk_check_and_get_req(struct ublk_device
*ub
,
1789 struct ublk_queue
*ubq
, int tag
, size_t offset
)
1791 struct request
*req
;
1793 if (!ublk_need_req_ref(ubq
))
1796 req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[ubq
->q_id
], tag
);
1800 if (!ublk_get_req_ref(ubq
, req
))
1803 if (unlikely(!blk_mq_request_started(req
) || req
->tag
!= tag
))
1806 if (!ublk_rq_has_data(req
))
1809 if (offset
> blk_rq_bytes(req
))
1814 ublk_put_req_ref(ubq
, req
);
1818 static inline int ublk_ch_uring_cmd_local(struct io_uring_cmd
*cmd
,
1819 unsigned int issue_flags
)
1822 * Not necessary for async retry, but let's keep it simple and always
1823 * copy the values to avoid any potential reuse.
1825 const struct ublksrv_io_cmd
*ub_src
= io_uring_sqe_cmd(cmd
->sqe
);
1826 const struct ublksrv_io_cmd ub_cmd
= {
1827 .q_id
= READ_ONCE(ub_src
->q_id
),
1828 .tag
= READ_ONCE(ub_src
->tag
),
1829 .result
= READ_ONCE(ub_src
->result
),
1830 .addr
= READ_ONCE(ub_src
->addr
)
1833 WARN_ON_ONCE(issue_flags
& IO_URING_F_UNLOCKED
);
1835 return __ublk_ch_uring_cmd(cmd
, issue_flags
, &ub_cmd
);
1838 static void ublk_ch_uring_cmd_cb(struct io_uring_cmd
*cmd
,
1839 unsigned int issue_flags
)
1841 ublk_ch_uring_cmd_local(cmd
, issue_flags
);
1844 static int ublk_ch_uring_cmd(struct io_uring_cmd
*cmd
, unsigned int issue_flags
)
1846 /* well-implemented server won't run into unlocked */
1847 if (unlikely(issue_flags
& IO_URING_F_UNLOCKED
)) {
1848 io_uring_cmd_complete_in_task(cmd
, ublk_ch_uring_cmd_cb
);
1849 return -EIOCBQUEUED
;
1852 return ublk_ch_uring_cmd_local(cmd
, issue_flags
);
1855 static inline bool ublk_check_ubuf_dir(const struct request
*req
,
1858 /* copy ubuf to request pages */
1859 if ((req_op(req
) == REQ_OP_READ
|| req_op(req
) == REQ_OP_DRV_IN
) &&
1860 ubuf_dir
== ITER_SOURCE
)
1863 /* copy request pages to ubuf */
1864 if ((req_op(req
) == REQ_OP_WRITE
||
1865 req_op(req
) == REQ_OP_ZONE_APPEND
) &&
1866 ubuf_dir
== ITER_DEST
)
1872 static struct request
*ublk_check_and_get_req(struct kiocb
*iocb
,
1873 struct iov_iter
*iter
, size_t *off
, int dir
)
1875 struct ublk_device
*ub
= iocb
->ki_filp
->private_data
;
1876 struct ublk_queue
*ubq
;
1877 struct request
*req
;
1882 return ERR_PTR(-EACCES
);
1884 if (!user_backed_iter(iter
))
1885 return ERR_PTR(-EACCES
);
1887 if (ub
->dev_info
.state
== UBLK_S_DEV_DEAD
)
1888 return ERR_PTR(-EACCES
);
1890 tag
= ublk_pos_to_tag(iocb
->ki_pos
);
1891 q_id
= ublk_pos_to_hwq(iocb
->ki_pos
);
1892 buf_off
= ublk_pos_to_buf_off(iocb
->ki_pos
);
1894 if (q_id
>= ub
->dev_info
.nr_hw_queues
)
1895 return ERR_PTR(-EINVAL
);
1897 ubq
= ublk_get_queue(ub
, q_id
);
1899 return ERR_PTR(-EINVAL
);
1901 if (tag
>= ubq
->q_depth
)
1902 return ERR_PTR(-EINVAL
);
1904 req
= __ublk_check_and_get_req(ub
, ubq
, tag
, buf_off
);
1906 return ERR_PTR(-EINVAL
);
1908 if (!req
->mq_hctx
|| !req
->mq_hctx
->driver_data
)
1911 if (!ublk_check_ubuf_dir(req
, dir
))
1917 ublk_put_req_ref(ubq
, req
);
1918 return ERR_PTR(-EACCES
);
1921 static ssize_t
ublk_ch_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
1923 struct ublk_queue
*ubq
;
1924 struct request
*req
;
1928 req
= ublk_check_and_get_req(iocb
, to
, &buf_off
, ITER_DEST
);
1930 return PTR_ERR(req
);
1932 ret
= ublk_copy_user_pages(req
, buf_off
, to
, ITER_DEST
);
1933 ubq
= req
->mq_hctx
->driver_data
;
1934 ublk_put_req_ref(ubq
, req
);
1939 static ssize_t
ublk_ch_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
1941 struct ublk_queue
*ubq
;
1942 struct request
*req
;
1946 req
= ublk_check_and_get_req(iocb
, from
, &buf_off
, ITER_SOURCE
);
1948 return PTR_ERR(req
);
1950 ret
= ublk_copy_user_pages(req
, buf_off
, from
, ITER_SOURCE
);
1951 ubq
= req
->mq_hctx
->driver_data
;
1952 ublk_put_req_ref(ubq
, req
);
1957 static const struct file_operations ublk_ch_fops
= {
1958 .owner
= THIS_MODULE
,
1959 .open
= ublk_ch_open
,
1960 .release
= ublk_ch_release
,
1961 .llseek
= no_llseek
,
1962 .read_iter
= ublk_ch_read_iter
,
1963 .write_iter
= ublk_ch_write_iter
,
1964 .uring_cmd
= ublk_ch_uring_cmd
,
1965 .mmap
= ublk_ch_mmap
,
1968 static void ublk_deinit_queue(struct ublk_device
*ub
, int q_id
)
1970 int size
= ublk_queue_cmd_buf_size(ub
, q_id
);
1971 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
1973 if (ubq
->ubq_daemon
)
1974 put_task_struct(ubq
->ubq_daemon
);
1975 if (ubq
->io_cmd_buf
)
1976 free_pages((unsigned long)ubq
->io_cmd_buf
, get_order(size
));
1979 static int ublk_init_queue(struct ublk_device
*ub
, int q_id
)
1981 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
1982 gfp_t gfp_flags
= GFP_KERNEL
| __GFP_ZERO
;
1986 spin_lock_init(&ubq
->cancel_lock
);
1987 ubq
->flags
= ub
->dev_info
.flags
;
1989 ubq
->q_depth
= ub
->dev_info
.queue_depth
;
1990 size
= ublk_queue_cmd_buf_size(ub
, q_id
);
1992 ptr
= (void *) __get_free_pages(gfp_flags
, get_order(size
));
1996 ubq
->io_cmd_buf
= ptr
;
2001 static void ublk_deinit_queues(struct ublk_device
*ub
)
2003 int nr_queues
= ub
->dev_info
.nr_hw_queues
;
2009 for (i
= 0; i
< nr_queues
; i
++)
2010 ublk_deinit_queue(ub
, i
);
2011 kfree(ub
->__queues
);
2014 static int ublk_init_queues(struct ublk_device
*ub
)
2016 int nr_queues
= ub
->dev_info
.nr_hw_queues
;
2017 int depth
= ub
->dev_info
.queue_depth
;
2018 int ubq_size
= sizeof(struct ublk_queue
) + depth
* sizeof(struct ublk_io
);
2019 int i
, ret
= -ENOMEM
;
2021 ub
->queue_size
= ubq_size
;
2022 ub
->__queues
= kcalloc(nr_queues
, ubq_size
, GFP_KERNEL
);
2026 for (i
= 0; i
< nr_queues
; i
++) {
2027 if (ublk_init_queue(ub
, i
))
2031 init_completion(&ub
->completion
);
2035 ublk_deinit_queues(ub
);
2039 static int ublk_alloc_dev_number(struct ublk_device
*ub
, int idx
)
2044 spin_lock(&ublk_idr_lock
);
2045 /* allocate id, if @id >= 0, we're requesting that specific id */
2047 err
= idr_alloc(&ublk_index_idr
, ub
, i
, i
+ 1, GFP_NOWAIT
);
2051 err
= idr_alloc(&ublk_index_idr
, ub
, 0, UBLK_MAX_UBLKS
,
2054 spin_unlock(&ublk_idr_lock
);
2057 ub
->ub_number
= err
;
2062 static void ublk_free_dev_number(struct ublk_device
*ub
)
2064 spin_lock(&ublk_idr_lock
);
2065 idr_remove(&ublk_index_idr
, ub
->ub_number
);
2066 wake_up_all(&ublk_idr_wq
);
2067 spin_unlock(&ublk_idr_lock
);
2070 static void ublk_cdev_rel(struct device
*dev
)
2072 struct ublk_device
*ub
= container_of(dev
, struct ublk_device
, cdev_dev
);
2074 blk_mq_free_tag_set(&ub
->tag_set
);
2075 ublk_deinit_queues(ub
);
2076 ublk_free_dev_number(ub
);
2077 mutex_destroy(&ub
->mutex
);
2081 static int ublk_add_chdev(struct ublk_device
*ub
)
2083 struct device
*dev
= &ub
->cdev_dev
;
2084 int minor
= ub
->ub_number
;
2087 dev
->parent
= ublk_misc
.this_device
;
2088 dev
->devt
= MKDEV(MAJOR(ublk_chr_devt
), minor
);
2089 dev
->class = &ublk_chr_class
;
2090 dev
->release
= ublk_cdev_rel
;
2091 device_initialize(dev
);
2093 ret
= dev_set_name(dev
, "ublkc%d", minor
);
2097 cdev_init(&ub
->cdev
, &ublk_ch_fops
);
2098 ret
= cdev_device_add(&ub
->cdev
, dev
);
2109 static void ublk_stop_work_fn(struct work_struct
*work
)
2111 struct ublk_device
*ub
=
2112 container_of(work
, struct ublk_device
, stop_work
);
2117 /* align max io buffer size with PAGE_SIZE */
2118 static void ublk_align_max_io_size(struct ublk_device
*ub
)
2120 unsigned int max_io_bytes
= ub
->dev_info
.max_io_buf_bytes
;
2122 ub
->dev_info
.max_io_buf_bytes
=
2123 round_down(max_io_bytes
, PAGE_SIZE
);
2126 static int ublk_add_tag_set(struct ublk_device
*ub
)
2128 ub
->tag_set
.ops
= &ublk_mq_ops
;
2129 ub
->tag_set
.nr_hw_queues
= ub
->dev_info
.nr_hw_queues
;
2130 ub
->tag_set
.queue_depth
= ub
->dev_info
.queue_depth
;
2131 ub
->tag_set
.numa_node
= NUMA_NO_NODE
;
2132 ub
->tag_set
.cmd_size
= sizeof(struct ublk_rq_data
);
2133 ub
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
;
2134 ub
->tag_set
.driver_data
= ub
;
2135 return blk_mq_alloc_tag_set(&ub
->tag_set
);
2138 static void ublk_remove(struct ublk_device
*ub
)
2141 cancel_work_sync(&ub
->stop_work
);
2142 cancel_work_sync(&ub
->quiesce_work
);
2143 cdev_device_del(&ub
->cdev
, &ub
->cdev_dev
);
2144 put_device(&ub
->cdev_dev
);
2148 static struct ublk_device
*ublk_get_device_from_id(int idx
)
2150 struct ublk_device
*ub
= NULL
;
2155 spin_lock(&ublk_idr_lock
);
2156 ub
= idr_find(&ublk_index_idr
, idx
);
2158 ub
= ublk_get_device(ub
);
2159 spin_unlock(&ublk_idr_lock
);
2164 static int ublk_ctrl_start_dev(struct ublk_device
*ub
, struct io_uring_cmd
*cmd
)
2166 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2167 int ublksrv_pid
= (int)header
->data
[0];
2168 struct gendisk
*disk
;
2171 if (ublksrv_pid
<= 0)
2174 if (wait_for_completion_interruptible(&ub
->completion
) != 0)
2177 schedule_delayed_work(&ub
->monitor_work
, UBLK_DAEMON_MONITOR_PERIOD
);
2179 mutex_lock(&ub
->mutex
);
2180 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
||
2181 test_bit(UB_STATE_USED
, &ub
->state
)) {
2186 disk
= blk_mq_alloc_disk(&ub
->tag_set
, NULL
);
2188 ret
= PTR_ERR(disk
);
2191 sprintf(disk
->disk_name
, "ublkb%d", ub
->ub_number
);
2192 disk
->fops
= &ub_fops
;
2193 disk
->private_data
= ub
;
2195 ub
->dev_info
.ublksrv_pid
= ublksrv_pid
;
2198 ret
= ublk_apply_params(ub
);
2202 /* don't probe partitions if any one ubq daemon is un-trusted */
2203 if (ub
->nr_privileged_daemon
!= ub
->nr_queues_ready
)
2204 set_bit(GD_SUPPRESS_PART_SCAN
, &disk
->state
);
2206 get_device(&ub
->cdev_dev
);
2207 ub
->dev_info
.state
= UBLK_S_DEV_LIVE
;
2209 if (ublk_dev_is_zoned(ub
)) {
2210 ret
= ublk_revalidate_disk_zones(ub
);
2215 ret
= add_disk(disk
);
2219 set_bit(UB_STATE_USED
, &ub
->state
);
2223 ub
->dev_info
.state
= UBLK_S_DEV_DEAD
;
2224 ublk_put_device(ub
);
2230 mutex_unlock(&ub
->mutex
);
2234 static int ublk_ctrl_get_queue_affinity(struct ublk_device
*ub
,
2235 struct io_uring_cmd
*cmd
)
2237 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2238 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2239 cpumask_var_t cpumask
;
2240 unsigned long queue
;
2241 unsigned int retlen
;
2245 if (header
->len
* BITS_PER_BYTE
< nr_cpu_ids
)
2247 if (header
->len
& (sizeof(unsigned long)-1))
2252 queue
= header
->data
[0];
2253 if (queue
>= ub
->dev_info
.nr_hw_queues
)
2256 if (!zalloc_cpumask_var(&cpumask
, GFP_KERNEL
))
2259 for_each_possible_cpu(i
) {
2260 if (ub
->tag_set
.map
[HCTX_TYPE_DEFAULT
].mq_map
[i
] == queue
)
2261 cpumask_set_cpu(i
, cpumask
);
2265 retlen
= min_t(unsigned short, header
->len
, cpumask_size());
2266 if (copy_to_user(argp
, cpumask
, retlen
))
2267 goto out_free_cpumask
;
2268 if (retlen
!= header
->len
&&
2269 clear_user(argp
+ retlen
, header
->len
- retlen
))
2270 goto out_free_cpumask
;
2274 free_cpumask_var(cpumask
);
2278 static inline void ublk_dump_dev_info(struct ublksrv_ctrl_dev_info
*info
)
2280 pr_devel("%s: dev id %d flags %llx\n", __func__
,
2281 info
->dev_id
, info
->flags
);
2282 pr_devel("\t nr_hw_queues %d queue_depth %d\n",
2283 info
->nr_hw_queues
, info
->queue_depth
);
2286 static int ublk_ctrl_add_dev(struct io_uring_cmd
*cmd
)
2288 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2289 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2290 struct ublksrv_ctrl_dev_info info
;
2291 struct ublk_device
*ub
;
2294 if (header
->len
< sizeof(info
) || !header
->addr
)
2296 if (header
->queue_id
!= (u16
)-1) {
2297 pr_warn("%s: queue_id is wrong %x\n",
2298 __func__
, header
->queue_id
);
2302 if (copy_from_user(&info
, argp
, sizeof(info
)))
2305 if (capable(CAP_SYS_ADMIN
))
2306 info
.flags
&= ~UBLK_F_UNPRIVILEGED_DEV
;
2307 else if (!(info
.flags
& UBLK_F_UNPRIVILEGED_DEV
))
2311 * unprivileged device can't be trusted, but RECOVERY and
2312 * RECOVERY_REISSUE still may hang error handling, so can't
2313 * support recovery features for unprivileged ublk now
2315 * TODO: provide forward progress for RECOVERY handler, so that
2316 * unprivileged device can benefit from it
2318 if (info
.flags
& UBLK_F_UNPRIVILEGED_DEV
)
2319 info
.flags
&= ~(UBLK_F_USER_RECOVERY_REISSUE
|
2320 UBLK_F_USER_RECOVERY
);
2322 /* the created device is always owned by current user */
2323 ublk_store_owner_uid_gid(&info
.owner_uid
, &info
.owner_gid
);
2325 if (header
->dev_id
!= info
.dev_id
) {
2326 pr_warn("%s: dev id not match %u %u\n",
2327 __func__
, header
->dev_id
, info
.dev_id
);
2331 if (header
->dev_id
!= U32_MAX
&& header
->dev_id
>= UBLK_MAX_UBLKS
) {
2332 pr_warn("%s: dev id is too large. Max supported is %d\n",
2333 __func__
, UBLK_MAX_UBLKS
- 1);
2337 ublk_dump_dev_info(&info
);
2339 ret
= mutex_lock_killable(&ublk_ctl_mutex
);
2344 if (ublks_added
>= ublks_max
)
2348 ub
= kzalloc(sizeof(*ub
), GFP_KERNEL
);
2351 mutex_init(&ub
->mutex
);
2352 spin_lock_init(&ub
->mm_lock
);
2353 INIT_WORK(&ub
->quiesce_work
, ublk_quiesce_work_fn
);
2354 INIT_WORK(&ub
->stop_work
, ublk_stop_work_fn
);
2355 INIT_DELAYED_WORK(&ub
->monitor_work
, ublk_daemon_monitor_work
);
2357 ret
= ublk_alloc_dev_number(ub
, header
->dev_id
);
2361 memcpy(&ub
->dev_info
, &info
, sizeof(info
));
2363 /* update device id */
2364 ub
->dev_info
.dev_id
= ub
->ub_number
;
2367 * 64bit flags will be copied back to userspace as feature
2368 * negotiation result, so have to clear flags which driver
2369 * doesn't support yet, then userspace can get correct flags
2370 * (features) to handle.
2372 ub
->dev_info
.flags
&= UBLK_F_ALL
;
2374 ub
->dev_info
.flags
|= UBLK_F_CMD_IOCTL_ENCODE
|
2375 UBLK_F_URING_CMD_COMP_IN_TASK
;
2377 /* GET_DATA isn't needed any more with USER_COPY */
2378 if (ublk_dev_is_user_copy(ub
))
2379 ub
->dev_info
.flags
&= ~UBLK_F_NEED_GET_DATA
;
2381 /* Zoned storage support requires user copy feature */
2382 if (ublk_dev_is_zoned(ub
) &&
2383 (!IS_ENABLED(CONFIG_BLK_DEV_ZONED
) || !ublk_dev_is_user_copy(ub
))) {
2385 goto out_free_dev_number
;
2388 /* We are not ready to support zero copy */
2389 ub
->dev_info
.flags
&= ~UBLK_F_SUPPORT_ZERO_COPY
;
2391 ub
->dev_info
.nr_hw_queues
= min_t(unsigned int,
2392 ub
->dev_info
.nr_hw_queues
, nr_cpu_ids
);
2393 ublk_align_max_io_size(ub
);
2395 ret
= ublk_init_queues(ub
);
2397 goto out_free_dev_number
;
2399 ret
= ublk_add_tag_set(ub
);
2401 goto out_deinit_queues
;
2404 if (copy_to_user(argp
, &ub
->dev_info
, sizeof(info
)))
2405 goto out_free_tag_set
;
2408 * Add the char dev so that ublksrv daemon can be setup.
2409 * ublk_add_chdev() will cleanup everything if it fails.
2411 ret
= ublk_add_chdev(ub
);
2415 blk_mq_free_tag_set(&ub
->tag_set
);
2417 ublk_deinit_queues(ub
);
2418 out_free_dev_number
:
2419 ublk_free_dev_number(ub
);
2421 mutex_destroy(&ub
->mutex
);
2424 mutex_unlock(&ublk_ctl_mutex
);
2428 static inline bool ublk_idr_freed(int id
)
2432 spin_lock(&ublk_idr_lock
);
2433 ptr
= idr_find(&ublk_index_idr
, id
);
2434 spin_unlock(&ublk_idr_lock
);
2439 static int ublk_ctrl_del_dev(struct ublk_device
**p_ub
)
2441 struct ublk_device
*ub
= *p_ub
;
2442 int idx
= ub
->ub_number
;
2445 ret
= mutex_lock_killable(&ublk_ctl_mutex
);
2449 if (!test_bit(UB_STATE_DELETED
, &ub
->state
)) {
2451 set_bit(UB_STATE_DELETED
, &ub
->state
);
2454 /* Mark the reference as consumed */
2456 ublk_put_device(ub
);
2457 mutex_unlock(&ublk_ctl_mutex
);
2460 * Wait until the idr is removed, then it can be reused after
2461 * DEL_DEV command is returned.
2463 * If we returns because of user interrupt, future delete command
2466 * - the device number isn't freed, this device won't or needn't
2467 * be deleted again, since UB_STATE_DELETED is set, and device
2468 * will be released after the last reference is dropped
2470 * - the device number is freed already, we will not find this
2471 * device via ublk_get_device_from_id()
2473 if (wait_event_interruptible(ublk_idr_wq
, ublk_idr_freed(idx
)))
2478 static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd
*cmd
)
2480 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2482 pr_devel("%s: cmd_op %x, dev id %d qid %d data %llx buf %llx len %u\n",
2483 __func__
, cmd
->cmd_op
, header
->dev_id
, header
->queue_id
,
2484 header
->data
[0], header
->addr
, header
->len
);
2487 static int ublk_ctrl_stop_dev(struct ublk_device
*ub
)
2490 cancel_work_sync(&ub
->stop_work
);
2491 cancel_work_sync(&ub
->quiesce_work
);
2496 static int ublk_ctrl_get_dev_info(struct ublk_device
*ub
,
2497 struct io_uring_cmd
*cmd
)
2499 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2500 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2502 if (header
->len
< sizeof(struct ublksrv_ctrl_dev_info
) || !header
->addr
)
2505 if (copy_to_user(argp
, &ub
->dev_info
, sizeof(ub
->dev_info
)))
2511 /* TYPE_DEVT is readonly, so fill it up before returning to userspace */
2512 static void ublk_ctrl_fill_params_devt(struct ublk_device
*ub
)
2514 ub
->params
.devt
.char_major
= MAJOR(ub
->cdev_dev
.devt
);
2515 ub
->params
.devt
.char_minor
= MINOR(ub
->cdev_dev
.devt
);
2518 ub
->params
.devt
.disk_major
= MAJOR(disk_devt(ub
->ub_disk
));
2519 ub
->params
.devt
.disk_minor
= MINOR(disk_devt(ub
->ub_disk
));
2521 ub
->params
.devt
.disk_major
= 0;
2522 ub
->params
.devt
.disk_minor
= 0;
2524 ub
->params
.types
|= UBLK_PARAM_TYPE_DEVT
;
2527 static int ublk_ctrl_get_params(struct ublk_device
*ub
,
2528 struct io_uring_cmd
*cmd
)
2530 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2531 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2532 struct ublk_params_header ph
;
2535 if (header
->len
<= sizeof(ph
) || !header
->addr
)
2538 if (copy_from_user(&ph
, argp
, sizeof(ph
)))
2541 if (ph
.len
> header
->len
|| !ph
.len
)
2544 if (ph
.len
> sizeof(struct ublk_params
))
2545 ph
.len
= sizeof(struct ublk_params
);
2547 mutex_lock(&ub
->mutex
);
2548 ublk_ctrl_fill_params_devt(ub
);
2549 if (copy_to_user(argp
, &ub
->params
, ph
.len
))
2553 mutex_unlock(&ub
->mutex
);
2558 static int ublk_ctrl_set_params(struct ublk_device
*ub
,
2559 struct io_uring_cmd
*cmd
)
2561 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2562 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2563 struct ublk_params_header ph
;
2566 if (header
->len
<= sizeof(ph
) || !header
->addr
)
2569 if (copy_from_user(&ph
, argp
, sizeof(ph
)))
2572 if (ph
.len
> header
->len
|| !ph
.len
|| !ph
.types
)
2575 if (ph
.len
> sizeof(struct ublk_params
))
2576 ph
.len
= sizeof(struct ublk_params
);
2578 /* parameters can only be changed when device isn't live */
2579 mutex_lock(&ub
->mutex
);
2580 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
) {
2582 } else if (copy_from_user(&ub
->params
, argp
, ph
.len
)) {
2585 /* clear all we don't support yet */
2586 ub
->params
.types
&= UBLK_PARAM_TYPE_ALL
;
2587 ret
= ublk_validate_params(ub
);
2589 ub
->params
.types
= 0;
2591 mutex_unlock(&ub
->mutex
);
2596 static void ublk_queue_reinit(struct ublk_device
*ub
, struct ublk_queue
*ubq
)
2600 WARN_ON_ONCE(!(ubq
->ubq_daemon
&& ubq_daemon_is_dying(ubq
)));
2602 /* All old ioucmds have to be completed */
2603 ubq
->nr_io_ready
= 0;
2604 /* old daemon is PF_EXITING, put it now */
2605 put_task_struct(ubq
->ubq_daemon
);
2606 /* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */
2607 ubq
->ubq_daemon
= NULL
;
2608 ubq
->timeout
= false;
2610 for (i
= 0; i
< ubq
->q_depth
; i
++) {
2611 struct ublk_io
*io
= &ubq
->ios
[i
];
2613 /* forget everything now and be ready for new FETCH_REQ */
2620 static int ublk_ctrl_start_recovery(struct ublk_device
*ub
,
2621 struct io_uring_cmd
*cmd
)
2623 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2627 mutex_lock(&ub
->mutex
);
2628 if (!ublk_can_use_recovery(ub
))
2631 * START_RECOVERY is only allowd after:
2633 * (1) UB_STATE_OPEN is not set, which means the dying process is exited
2634 * and related io_uring ctx is freed so file struct of /dev/ublkcX is
2637 * (2) UBLK_S_DEV_QUIESCED is set, which means the quiesce_work:
2638 * (a)has quiesced request queue
2639 * (b)has requeued every inflight rqs whose io_flags is ACTIVE
2640 * (c)has requeued/aborted every inflight rqs whose io_flags is NOT ACTIVE
2641 * (d)has completed/camceled all ioucmds owned by ther dying process
2643 if (test_bit(UB_STATE_OPEN
, &ub
->state
) ||
2644 ub
->dev_info
.state
!= UBLK_S_DEV_QUIESCED
) {
2648 pr_devel("%s: start recovery for dev id %d.\n", __func__
, header
->dev_id
);
2649 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++)
2650 ublk_queue_reinit(ub
, ublk_get_queue(ub
, i
));
2651 /* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */
2653 ub
->nr_queues_ready
= 0;
2654 ub
->nr_privileged_daemon
= 0;
2655 init_completion(&ub
->completion
);
2658 mutex_unlock(&ub
->mutex
);
2662 static int ublk_ctrl_end_recovery(struct ublk_device
*ub
,
2663 struct io_uring_cmd
*cmd
)
2665 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2666 int ublksrv_pid
= (int)header
->data
[0];
2669 pr_devel("%s: Waiting for new ubq_daemons(nr: %d) are ready, dev id %d...\n",
2670 __func__
, ub
->dev_info
.nr_hw_queues
, header
->dev_id
);
2671 /* wait until new ubq_daemon sending all FETCH_REQ */
2672 if (wait_for_completion_interruptible(&ub
->completion
))
2675 pr_devel("%s: All new ubq_daemons(nr: %d) are ready, dev id %d\n",
2676 __func__
, ub
->dev_info
.nr_hw_queues
, header
->dev_id
);
2678 mutex_lock(&ub
->mutex
);
2679 if (!ublk_can_use_recovery(ub
))
2682 if (ub
->dev_info
.state
!= UBLK_S_DEV_QUIESCED
) {
2686 ub
->dev_info
.ublksrv_pid
= ublksrv_pid
;
2687 pr_devel("%s: new ublksrv_pid %d, dev id %d\n",
2688 __func__
, ublksrv_pid
, header
->dev_id
);
2689 blk_mq_unquiesce_queue(ub
->ub_disk
->queue
);
2690 pr_devel("%s: queue unquiesced, dev id %d.\n",
2691 __func__
, header
->dev_id
);
2692 blk_mq_kick_requeue_list(ub
->ub_disk
->queue
);
2693 ub
->dev_info
.state
= UBLK_S_DEV_LIVE
;
2694 schedule_delayed_work(&ub
->monitor_work
, UBLK_DAEMON_MONITOR_PERIOD
);
2697 mutex_unlock(&ub
->mutex
);
2701 static int ublk_ctrl_get_features(struct io_uring_cmd
*cmd
)
2703 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2704 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2705 u64 features
= UBLK_F_ALL
& ~UBLK_F_SUPPORT_ZERO_COPY
;
2707 if (header
->len
!= UBLK_FEATURES_LEN
|| !header
->addr
)
2710 if (copy_to_user(argp
, &features
, UBLK_FEATURES_LEN
))
2717 * All control commands are sent via /dev/ublk-control, so we have to check
2718 * the destination device's permission
2720 static int ublk_char_dev_permission(struct ublk_device
*ub
,
2721 const char *dev_path
, int mask
)
2727 err
= kern_path(dev_path
, LOOKUP_FOLLOW
, &path
);
2731 err
= vfs_getattr(&path
, &stat
, STATX_TYPE
, AT_STATX_SYNC_AS_STAT
);
2736 if (stat
.rdev
!= ub
->cdev_dev
.devt
|| !S_ISCHR(stat
.mode
))
2739 err
= inode_permission(&nop_mnt_idmap
,
2740 d_backing_inode(path
.dentry
), mask
);
2746 static int ublk_ctrl_uring_cmd_permission(struct ublk_device
*ub
,
2747 struct io_uring_cmd
*cmd
)
2749 struct ublksrv_ctrl_cmd
*header
= (struct ublksrv_ctrl_cmd
*)io_uring_sqe_cmd(cmd
->sqe
);
2750 bool unprivileged
= ub
->dev_info
.flags
& UBLK_F_UNPRIVILEGED_DEV
;
2751 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2752 char *dev_path
= NULL
;
2756 if (!unprivileged
) {
2757 if (!capable(CAP_SYS_ADMIN
))
2760 * The new added command of UBLK_CMD_GET_DEV_INFO2 includes
2761 * char_dev_path in payload too, since userspace may not
2762 * know if the specified device is created as unprivileged
2765 if (_IOC_NR(cmd
->cmd_op
) != UBLK_CMD_GET_DEV_INFO2
)
2770 * User has to provide the char device path for unprivileged ublk
2772 * header->addr always points to the dev path buffer, and
2773 * header->dev_path_len records length of dev path buffer.
2775 if (!header
->dev_path_len
|| header
->dev_path_len
> PATH_MAX
)
2778 if (header
->len
< header
->dev_path_len
)
2781 dev_path
= memdup_user_nul(argp
, header
->dev_path_len
);
2782 if (IS_ERR(dev_path
))
2783 return PTR_ERR(dev_path
);
2786 switch (_IOC_NR(cmd
->cmd_op
)) {
2787 case UBLK_CMD_GET_DEV_INFO
:
2788 case UBLK_CMD_GET_DEV_INFO2
:
2789 case UBLK_CMD_GET_QUEUE_AFFINITY
:
2790 case UBLK_CMD_GET_PARAMS
:
2791 case (_IOC_NR(UBLK_U_CMD_GET_FEATURES
)):
2794 case UBLK_CMD_START_DEV
:
2795 case UBLK_CMD_STOP_DEV
:
2796 case UBLK_CMD_ADD_DEV
:
2797 case UBLK_CMD_DEL_DEV
:
2798 case UBLK_CMD_SET_PARAMS
:
2799 case UBLK_CMD_START_USER_RECOVERY
:
2800 case UBLK_CMD_END_USER_RECOVERY
:
2801 mask
= MAY_READ
| MAY_WRITE
;
2807 ret
= ublk_char_dev_permission(ub
, dev_path
, mask
);
2809 header
->len
-= header
->dev_path_len
;
2810 header
->addr
+= header
->dev_path_len
;
2812 pr_devel("%s: dev id %d cmd_op %x uid %d gid %d path %s ret %d\n",
2813 __func__
, ub
->ub_number
, cmd
->cmd_op
,
2814 ub
->dev_info
.owner_uid
, ub
->dev_info
.owner_gid
,
2821 static int ublk_ctrl_uring_cmd(struct io_uring_cmd
*cmd
,
2822 unsigned int issue_flags
)
2824 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2825 struct ublk_device
*ub
= NULL
;
2826 u32 cmd_op
= cmd
->cmd_op
;
2829 if (issue_flags
& IO_URING_F_NONBLOCK
)
2832 ublk_ctrl_cmd_dump(cmd
);
2834 if (!(issue_flags
& IO_URING_F_SQE128
))
2837 ret
= ublk_check_cmd_op(cmd_op
);
2841 if (cmd_op
== UBLK_U_CMD_GET_FEATURES
) {
2842 ret
= ublk_ctrl_get_features(cmd
);
2846 if (_IOC_NR(cmd_op
) != UBLK_CMD_ADD_DEV
) {
2848 ub
= ublk_get_device_from_id(header
->dev_id
);
2852 ret
= ublk_ctrl_uring_cmd_permission(ub
, cmd
);
2857 switch (_IOC_NR(cmd_op
)) {
2858 case UBLK_CMD_START_DEV
:
2859 ret
= ublk_ctrl_start_dev(ub
, cmd
);
2861 case UBLK_CMD_STOP_DEV
:
2862 ret
= ublk_ctrl_stop_dev(ub
);
2864 case UBLK_CMD_GET_DEV_INFO
:
2865 case UBLK_CMD_GET_DEV_INFO2
:
2866 ret
= ublk_ctrl_get_dev_info(ub
, cmd
);
2868 case UBLK_CMD_ADD_DEV
:
2869 ret
= ublk_ctrl_add_dev(cmd
);
2871 case UBLK_CMD_DEL_DEV
:
2872 ret
= ublk_ctrl_del_dev(&ub
);
2874 case UBLK_CMD_GET_QUEUE_AFFINITY
:
2875 ret
= ublk_ctrl_get_queue_affinity(ub
, cmd
);
2877 case UBLK_CMD_GET_PARAMS
:
2878 ret
= ublk_ctrl_get_params(ub
, cmd
);
2880 case UBLK_CMD_SET_PARAMS
:
2881 ret
= ublk_ctrl_set_params(ub
, cmd
);
2883 case UBLK_CMD_START_USER_RECOVERY
:
2884 ret
= ublk_ctrl_start_recovery(ub
, cmd
);
2886 case UBLK_CMD_END_USER_RECOVERY
:
2887 ret
= ublk_ctrl_end_recovery(ub
, cmd
);
2896 ublk_put_device(ub
);
2898 io_uring_cmd_done(cmd
, ret
, 0, issue_flags
);
2899 pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n",
2900 __func__
, ret
, cmd
->cmd_op
, header
->dev_id
, header
->queue_id
);
2901 return -EIOCBQUEUED
;
2904 static const struct file_operations ublk_ctl_fops
= {
2905 .open
= nonseekable_open
,
2906 .uring_cmd
= ublk_ctrl_uring_cmd
,
2907 .owner
= THIS_MODULE
,
2908 .llseek
= noop_llseek
,
2911 static struct miscdevice ublk_misc
= {
2912 .minor
= MISC_DYNAMIC_MINOR
,
2913 .name
= "ublk-control",
2914 .fops
= &ublk_ctl_fops
,
2917 static int __init
ublk_init(void)
2921 BUILD_BUG_ON((u64
)UBLKSRV_IO_BUF_OFFSET
+
2922 UBLKSRV_IO_BUF_TOTAL_SIZE
< UBLKSRV_IO_BUF_OFFSET
);
2924 init_waitqueue_head(&ublk_idr_wq
);
2926 ret
= misc_register(&ublk_misc
);
2930 ret
= alloc_chrdev_region(&ublk_chr_devt
, 0, UBLK_MINORS
, "ublk-char");
2932 goto unregister_mis
;
2934 ret
= class_register(&ublk_chr_class
);
2936 goto free_chrdev_region
;
2941 unregister_chrdev_region(ublk_chr_devt
, UBLK_MINORS
);
2943 misc_deregister(&ublk_misc
);
2947 static void __exit
ublk_exit(void)
2949 struct ublk_device
*ub
;
2952 idr_for_each_entry(&ublk_index_idr
, ub
, id
)
2955 class_unregister(&ublk_chr_class
);
2956 misc_deregister(&ublk_misc
);
2958 idr_destroy(&ublk_index_idr
);
2959 unregister_chrdev_region(ublk_chr_devt
, UBLK_MINORS
);
2962 module_init(ublk_init
);
2963 module_exit(ublk_exit
);
2965 static int ublk_set_max_ublks(const char *buf
, const struct kernel_param
*kp
)
2967 return param_set_uint_minmax(buf
, kp
, 0, UBLK_MAX_UBLKS
);
2970 static int ublk_get_max_ublks(char *buf
, const struct kernel_param
*kp
)
2972 return sysfs_emit(buf
, "%u\n", ublks_max
);
2975 static const struct kernel_param_ops ublk_max_ublks_ops
= {
2976 .set
= ublk_set_max_ublks
,
2977 .get
= ublk_get_max_ublks
,
2980 module_param_cb(ublks_max
, &ublk_max_ublks_ops
, &ublks_max
, 0644);
2981 MODULE_PARM_DESC(ublks_max
, "max number of ublk devices allowed to add(default: 64)");
2983 MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
2984 MODULE_LICENSE("GPL");