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
119 /* userspace buffer address from io cmd */
124 struct io_uring_cmd
*cmd
;
132 struct task_struct
*ubq_daemon
;
135 struct llist_head io_cmds
;
137 unsigned long io_addr
; /* mapped vm address */
138 unsigned int max_io_sz
;
141 unsigned short nr_io_ready
; /* how many ios setup */
142 struct ublk_device
*dev
;
143 struct ublk_io ios
[];
146 #define UBLK_DAEMON_MONITOR_PERIOD (5 * HZ)
149 struct gendisk
*ub_disk
;
153 unsigned int queue_size
;
154 struct ublksrv_ctrl_dev_info dev_info
;
156 struct blk_mq_tag_set tag_set
;
159 struct device cdev_dev
;
161 #define UB_STATE_OPEN 0
162 #define UB_STATE_USED 1
163 #define UB_STATE_DELETED 2
170 struct mm_struct
*mm
;
172 struct ublk_params params
;
174 struct completion completion
;
175 unsigned int nr_queues_ready
;
176 unsigned int nr_privileged_daemon
;
179 * Our ubq->daemon may be killed without any notification, so
180 * monitor each queue's daemon periodically
182 struct delayed_work monitor_work
;
183 struct work_struct quiesce_work
;
184 struct work_struct stop_work
;
187 /* header of ublk_params */
188 struct ublk_params_header
{
193 static inline unsigned int ublk_req_build_flags(struct request
*req
);
194 static inline struct ublksrv_io_desc
*ublk_get_iod(struct ublk_queue
*ubq
,
197 static inline bool ublk_dev_is_user_copy(const struct ublk_device
*ub
)
199 return ub
->dev_info
.flags
& UBLK_F_USER_COPY
;
202 static inline bool ublk_dev_is_zoned(const struct ublk_device
*ub
)
204 return ub
->dev_info
.flags
& UBLK_F_ZONED
;
207 static inline bool ublk_queue_is_zoned(struct ublk_queue
*ubq
)
209 return ubq
->flags
& UBLK_F_ZONED
;
212 #ifdef CONFIG_BLK_DEV_ZONED
214 static int ublk_get_nr_zones(const struct ublk_device
*ub
)
216 const struct ublk_param_basic
*p
= &ub
->params
.basic
;
218 /* Zone size is a power of 2 */
219 return p
->dev_sectors
>> ilog2(p
->chunk_sectors
);
222 static int ublk_revalidate_disk_zones(struct ublk_device
*ub
)
224 return blk_revalidate_disk_zones(ub
->ub_disk
, NULL
);
227 static int ublk_dev_param_zoned_validate(const struct ublk_device
*ub
)
229 const struct ublk_param_zoned
*p
= &ub
->params
.zoned
;
232 if (!ublk_dev_is_zoned(ub
))
235 if (!p
->max_zone_append_sectors
)
238 nr_zones
= ublk_get_nr_zones(ub
);
240 if (p
->max_active_zones
> nr_zones
)
243 if (p
->max_open_zones
> nr_zones
)
249 static int ublk_dev_param_zoned_apply(struct ublk_device
*ub
)
251 const struct ublk_param_zoned
*p
= &ub
->params
.zoned
;
253 disk_set_zoned(ub
->ub_disk
, BLK_ZONED_HM
);
254 blk_queue_required_elevator_features(ub
->ub_disk
->queue
,
255 ELEVATOR_F_ZBD_SEQ_WRITE
);
256 disk_set_max_active_zones(ub
->ub_disk
, p
->max_active_zones
);
257 disk_set_max_open_zones(ub
->ub_disk
, p
->max_open_zones
);
258 blk_queue_max_zone_append_sectors(ub
->ub_disk
->queue
, p
->max_zone_append_sectors
);
260 ub
->ub_disk
->nr_zones
= ublk_get_nr_zones(ub
);
265 /* Based on virtblk_alloc_report_buffer */
266 static void *ublk_alloc_report_buffer(struct ublk_device
*ublk
,
267 unsigned int nr_zones
, size_t *buflen
)
269 struct request_queue
*q
= ublk
->ub_disk
->queue
;
273 nr_zones
= min_t(unsigned int, nr_zones
,
274 ublk
->ub_disk
->nr_zones
);
276 bufsize
= nr_zones
* sizeof(struct blk_zone
);
278 min_t(size_t, bufsize
, queue_max_hw_sectors(q
) << SECTOR_SHIFT
);
280 while (bufsize
>= sizeof(struct blk_zone
)) {
281 buf
= kvmalloc(bufsize
, GFP_KERNEL
| __GFP_NORETRY
);
293 static int ublk_report_zones(struct gendisk
*disk
, sector_t sector
,
294 unsigned int nr_zones
, report_zones_cb cb
, void *data
)
296 struct ublk_device
*ub
= disk
->private_data
;
297 unsigned int zone_size_sectors
= disk
->queue
->limits
.chunk_sectors
;
298 unsigned int first_zone
= sector
>> ilog2(zone_size_sectors
);
299 unsigned int done_zones
= 0;
300 unsigned int max_zones_per_request
;
302 struct blk_zone
*buffer
;
303 size_t buffer_length
;
305 nr_zones
= min_t(unsigned int, ub
->ub_disk
->nr_zones
- first_zone
,
308 buffer
= ublk_alloc_report_buffer(ub
, nr_zones
, &buffer_length
);
312 max_zones_per_request
= buffer_length
/ sizeof(struct blk_zone
);
314 while (done_zones
< nr_zones
) {
315 unsigned int remaining_zones
= nr_zones
- done_zones
;
316 unsigned int zones_in_request
=
317 min_t(unsigned int, remaining_zones
, max_zones_per_request
);
319 struct ublk_rq_data
*pdu
;
322 memset(buffer
, 0, buffer_length
);
324 req
= blk_mq_alloc_request(disk
->queue
, REQ_OP_DRV_IN
, 0);
330 pdu
= blk_mq_rq_to_pdu(req
);
331 pdu
->operation
= UBLK_IO_OP_REPORT_ZONES
;
332 pdu
->sector
= sector
;
333 pdu
->nr_zones
= zones_in_request
;
335 ret
= blk_rq_map_kern(disk
->queue
, req
, buffer
, buffer_length
,
338 blk_mq_free_request(req
);
342 status
= blk_execute_rq(req
, 0);
343 ret
= blk_status_to_errno(status
);
344 blk_mq_free_request(req
);
348 for (unsigned int i
= 0; i
< zones_in_request
; i
++) {
349 struct blk_zone
*zone
= buffer
+ i
;
351 /* A zero length zone means no more zones in this response */
355 ret
= cb(zone
, i
, data
);
360 sector
+= zone_size_sectors
;
372 static blk_status_t
ublk_setup_iod_zoned(struct ublk_queue
*ubq
,
375 struct ublksrv_io_desc
*iod
= ublk_get_iod(ubq
, req
->tag
);
376 struct ublk_io
*io
= &ubq
->ios
[req
->tag
];
377 struct ublk_rq_data
*pdu
= blk_mq_rq_to_pdu(req
);
380 switch (req_op(req
)) {
381 case REQ_OP_ZONE_OPEN
:
382 ublk_op
= UBLK_IO_OP_ZONE_OPEN
;
384 case REQ_OP_ZONE_CLOSE
:
385 ublk_op
= UBLK_IO_OP_ZONE_CLOSE
;
387 case REQ_OP_ZONE_FINISH
:
388 ublk_op
= UBLK_IO_OP_ZONE_FINISH
;
390 case REQ_OP_ZONE_RESET
:
391 ublk_op
= UBLK_IO_OP_ZONE_RESET
;
393 case REQ_OP_ZONE_APPEND
:
394 ublk_op
= UBLK_IO_OP_ZONE_APPEND
;
397 ublk_op
= pdu
->operation
;
399 case UBLK_IO_OP_REPORT_ZONES
:
400 iod
->op_flags
= ublk_op
| ublk_req_build_flags(req
);
401 iod
->nr_zones
= pdu
->nr_zones
;
402 iod
->start_sector
= pdu
->sector
;
405 return BLK_STS_IOERR
;
407 case REQ_OP_ZONE_RESET_ALL
:
409 /* We do not support reset_all and drv_out */
410 return BLK_STS_NOTSUPP
;
412 return BLK_STS_IOERR
;
415 iod
->op_flags
= ublk_op
| ublk_req_build_flags(req
);
416 iod
->nr_sectors
= blk_rq_sectors(req
);
417 iod
->start_sector
= blk_rq_pos(req
);
418 iod
->addr
= io
->addr
;
425 #define ublk_report_zones (NULL)
427 static int ublk_dev_param_zoned_validate(const struct ublk_device
*ub
)
432 static int ublk_dev_param_zoned_apply(struct ublk_device
*ub
)
437 static int ublk_revalidate_disk_zones(struct ublk_device
*ub
)
442 static blk_status_t
ublk_setup_iod_zoned(struct ublk_queue
*ubq
,
445 return BLK_STS_NOTSUPP
;
450 static inline void __ublk_complete_rq(struct request
*req
);
451 static void ublk_complete_rq(struct kref
*ref
);
453 static dev_t ublk_chr_devt
;
454 static const struct class ublk_chr_class
= {
458 static DEFINE_IDR(ublk_index_idr
);
459 static DEFINE_SPINLOCK(ublk_idr_lock
);
460 static wait_queue_head_t ublk_idr_wq
; /* wait until one idr is freed */
462 static DEFINE_MUTEX(ublk_ctl_mutex
);
465 * Max ublk devices allowed to add
467 * It can be extended to one per-user limit in future or even controlled
470 static unsigned int ublks_max
= 64;
471 static unsigned int ublks_added
; /* protected by ublk_ctl_mutex */
473 static struct miscdevice ublk_misc
;
475 static inline unsigned ublk_pos_to_hwq(loff_t pos
)
477 return ((pos
- UBLKSRV_IO_BUF_OFFSET
) >> UBLK_QID_OFF
) &
481 static inline unsigned ublk_pos_to_buf_off(loff_t pos
)
483 return (pos
- UBLKSRV_IO_BUF_OFFSET
) & UBLK_IO_BUF_BITS_MASK
;
486 static inline unsigned ublk_pos_to_tag(loff_t pos
)
488 return ((pos
- UBLKSRV_IO_BUF_OFFSET
) >> UBLK_TAG_OFF
) &
492 static void ublk_dev_param_basic_apply(struct ublk_device
*ub
)
494 struct request_queue
*q
= ub
->ub_disk
->queue
;
495 const struct ublk_param_basic
*p
= &ub
->params
.basic
;
497 blk_queue_logical_block_size(q
, 1 << p
->logical_bs_shift
);
498 blk_queue_physical_block_size(q
, 1 << p
->physical_bs_shift
);
499 blk_queue_io_min(q
, 1 << p
->io_min_shift
);
500 blk_queue_io_opt(q
, 1 << p
->io_opt_shift
);
502 blk_queue_write_cache(q
, p
->attrs
& UBLK_ATTR_VOLATILE_CACHE
,
503 p
->attrs
& UBLK_ATTR_FUA
);
504 if (p
->attrs
& UBLK_ATTR_ROTATIONAL
)
505 blk_queue_flag_clear(QUEUE_FLAG_NONROT
, q
);
507 blk_queue_flag_set(QUEUE_FLAG_NONROT
, q
);
509 blk_queue_max_hw_sectors(q
, p
->max_sectors
);
510 blk_queue_chunk_sectors(q
, p
->chunk_sectors
);
511 blk_queue_virt_boundary(q
, p
->virt_boundary_mask
);
513 if (p
->attrs
& UBLK_ATTR_READ_ONLY
)
514 set_disk_ro(ub
->ub_disk
, true);
516 set_capacity(ub
->ub_disk
, p
->dev_sectors
);
519 static void ublk_dev_param_discard_apply(struct ublk_device
*ub
)
521 struct request_queue
*q
= ub
->ub_disk
->queue
;
522 const struct ublk_param_discard
*p
= &ub
->params
.discard
;
524 q
->limits
.discard_alignment
= p
->discard_alignment
;
525 q
->limits
.discard_granularity
= p
->discard_granularity
;
526 blk_queue_max_discard_sectors(q
, p
->max_discard_sectors
);
527 blk_queue_max_write_zeroes_sectors(q
,
528 p
->max_write_zeroes_sectors
);
529 blk_queue_max_discard_segments(q
, p
->max_discard_segments
);
532 static int ublk_validate_params(const struct ublk_device
*ub
)
534 /* basic param is the only one which must be set */
535 if (ub
->params
.types
& UBLK_PARAM_TYPE_BASIC
) {
536 const struct ublk_param_basic
*p
= &ub
->params
.basic
;
538 if (p
->logical_bs_shift
> PAGE_SHIFT
|| p
->logical_bs_shift
< 9)
541 if (p
->logical_bs_shift
> p
->physical_bs_shift
)
544 if (p
->max_sectors
> (ub
->dev_info
.max_io_buf_bytes
>> 9))
547 if (ublk_dev_is_zoned(ub
) && !p
->chunk_sectors
)
552 if (ub
->params
.types
& UBLK_PARAM_TYPE_DISCARD
) {
553 const struct ublk_param_discard
*p
= &ub
->params
.discard
;
555 /* So far, only support single segment discard */
556 if (p
->max_discard_sectors
&& p
->max_discard_segments
!= 1)
559 if (!p
->discard_granularity
)
563 /* dev_t is read-only */
564 if (ub
->params
.types
& UBLK_PARAM_TYPE_DEVT
)
567 if (ub
->params
.types
& UBLK_PARAM_TYPE_ZONED
)
568 return ublk_dev_param_zoned_validate(ub
);
569 else if (ublk_dev_is_zoned(ub
))
575 static int ublk_apply_params(struct ublk_device
*ub
)
577 if (!(ub
->params
.types
& UBLK_PARAM_TYPE_BASIC
))
580 ublk_dev_param_basic_apply(ub
);
582 if (ub
->params
.types
& UBLK_PARAM_TYPE_DISCARD
)
583 ublk_dev_param_discard_apply(ub
);
585 if (ub
->params
.types
& UBLK_PARAM_TYPE_ZONED
)
586 return ublk_dev_param_zoned_apply(ub
);
591 static inline bool ublk_support_user_copy(const struct ublk_queue
*ubq
)
593 return ubq
->flags
& UBLK_F_USER_COPY
;
596 static inline bool ublk_need_req_ref(const struct ublk_queue
*ubq
)
599 * read()/write() is involved in user copy, so request reference
602 return ublk_support_user_copy(ubq
);
605 static inline void ublk_init_req_ref(const struct ublk_queue
*ubq
,
608 if (ublk_need_req_ref(ubq
)) {
609 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(req
);
611 kref_init(&data
->ref
);
615 static inline bool ublk_get_req_ref(const struct ublk_queue
*ubq
,
618 if (ublk_need_req_ref(ubq
)) {
619 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(req
);
621 return kref_get_unless_zero(&data
->ref
);
627 static inline void ublk_put_req_ref(const struct ublk_queue
*ubq
,
630 if (ublk_need_req_ref(ubq
)) {
631 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(req
);
633 kref_put(&data
->ref
, ublk_complete_rq
);
635 __ublk_complete_rq(req
);
639 static inline bool ublk_need_get_data(const struct ublk_queue
*ubq
)
641 return ubq
->flags
& UBLK_F_NEED_GET_DATA
;
644 static struct ublk_device
*ublk_get_device(struct ublk_device
*ub
)
646 if (kobject_get_unless_zero(&ub
->cdev_dev
.kobj
))
651 static void ublk_put_device(struct ublk_device
*ub
)
653 put_device(&ub
->cdev_dev
);
656 static inline struct ublk_queue
*ublk_get_queue(struct ublk_device
*dev
,
659 return (struct ublk_queue
*)&(dev
->__queues
[qid
* dev
->queue_size
]);
662 static inline bool ublk_rq_has_data(const struct request
*rq
)
664 return bio_has_data(rq
->bio
);
667 static inline struct ublksrv_io_desc
*ublk_get_iod(struct ublk_queue
*ubq
,
670 return (struct ublksrv_io_desc
*)
671 &(ubq
->io_cmd_buf
[tag
* sizeof(struct ublksrv_io_desc
)]);
674 static inline char *ublk_queue_cmd_buf(struct ublk_device
*ub
, int q_id
)
676 return ublk_get_queue(ub
, q_id
)->io_cmd_buf
;
679 static inline int ublk_queue_cmd_buf_size(struct ublk_device
*ub
, int q_id
)
681 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
683 return round_up(ubq
->q_depth
* sizeof(struct ublksrv_io_desc
),
687 static inline bool ublk_queue_can_use_recovery_reissue(
688 struct ublk_queue
*ubq
)
690 return (ubq
->flags
& UBLK_F_USER_RECOVERY
) &&
691 (ubq
->flags
& UBLK_F_USER_RECOVERY_REISSUE
);
694 static inline bool ublk_queue_can_use_recovery(
695 struct ublk_queue
*ubq
)
697 return ubq
->flags
& UBLK_F_USER_RECOVERY
;
700 static inline bool ublk_can_use_recovery(struct ublk_device
*ub
)
702 return ub
->dev_info
.flags
& UBLK_F_USER_RECOVERY
;
705 static void ublk_free_disk(struct gendisk
*disk
)
707 struct ublk_device
*ub
= disk
->private_data
;
709 clear_bit(UB_STATE_USED
, &ub
->state
);
710 put_device(&ub
->cdev_dev
);
713 static void ublk_store_owner_uid_gid(unsigned int *owner_uid
,
714 unsigned int *owner_gid
)
719 current_uid_gid(&uid
, &gid
);
721 *owner_uid
= from_kuid(&init_user_ns
, uid
);
722 *owner_gid
= from_kgid(&init_user_ns
, gid
);
725 static int ublk_open(struct gendisk
*disk
, blk_mode_t mode
)
727 struct ublk_device
*ub
= disk
->private_data
;
729 if (capable(CAP_SYS_ADMIN
))
733 * If it is one unprivileged device, only owner can open
734 * the disk. Otherwise it could be one trap made by one
735 * evil user who grants this disk's privileges to other
736 * users deliberately.
738 * This way is reasonable too given anyone can create
739 * unprivileged device, and no need other's grant.
741 if (ub
->dev_info
.flags
& UBLK_F_UNPRIVILEGED_DEV
) {
742 unsigned int curr_uid
, curr_gid
;
744 ublk_store_owner_uid_gid(&curr_uid
, &curr_gid
);
746 if (curr_uid
!= ub
->dev_info
.owner_uid
|| curr_gid
!=
747 ub
->dev_info
.owner_gid
)
754 static const struct block_device_operations ub_fops
= {
755 .owner
= THIS_MODULE
,
757 .free_disk
= ublk_free_disk
,
758 .report_zones
= ublk_report_zones
,
761 #define UBLK_MAX_PIN_PAGES 32
763 struct ublk_io_iter
{
764 struct page
*pages
[UBLK_MAX_PIN_PAGES
];
766 struct bvec_iter iter
;
769 /* return how many pages are copied */
770 static void ublk_copy_io_pages(struct ublk_io_iter
*data
,
771 size_t total
, size_t pg_off
, int dir
)
776 while (done
< total
) {
777 struct bio_vec bv
= bio_iter_iovec(data
->bio
, data
->iter
);
778 unsigned int bytes
= min3(bv
.bv_len
, (unsigned)total
- done
,
779 (unsigned)(PAGE_SIZE
- pg_off
));
780 void *bv_buf
= bvec_kmap_local(&bv
);
781 void *pg_buf
= kmap_local_page(data
->pages
[pg_idx
]);
783 if (dir
== ITER_DEST
)
784 memcpy(pg_buf
+ pg_off
, bv_buf
, bytes
);
786 memcpy(bv_buf
, pg_buf
+ pg_off
, bytes
);
788 kunmap_local(pg_buf
);
789 kunmap_local(bv_buf
);
791 /* advance page array */
793 if (pg_off
== PAGE_SIZE
) {
801 bio_advance_iter_single(data
->bio
, &data
->iter
, bytes
);
802 if (!data
->iter
.bi_size
) {
803 data
->bio
= data
->bio
->bi_next
;
804 if (data
->bio
== NULL
)
806 data
->iter
= data
->bio
->bi_iter
;
811 static bool ublk_advance_io_iter(const struct request
*req
,
812 struct ublk_io_iter
*iter
, unsigned int offset
)
814 struct bio
*bio
= req
->bio
;
817 if (bio
->bi_iter
.bi_size
> offset
) {
819 iter
->iter
= bio
->bi_iter
;
820 bio_advance_iter(iter
->bio
, &iter
->iter
, offset
);
823 offset
-= bio
->bi_iter
.bi_size
;
829 * Copy data between request pages and io_iter, and 'offset'
830 * is the start point of linear offset of request.
832 static size_t ublk_copy_user_pages(const struct request
*req
,
833 unsigned offset
, struct iov_iter
*uiter
, int dir
)
835 struct ublk_io_iter iter
;
838 if (!ublk_advance_io_iter(req
, &iter
, offset
))
841 while (iov_iter_count(uiter
) && iter
.bio
) {
847 len
= iov_iter_get_pages2(uiter
, iter
.pages
,
848 iov_iter_count(uiter
),
849 UBLK_MAX_PIN_PAGES
, &off
);
853 ublk_copy_io_pages(&iter
, len
, off
, dir
);
854 nr_pages
= DIV_ROUND_UP(len
+ off
, PAGE_SIZE
);
855 for (i
= 0; i
< nr_pages
; i
++) {
856 if (dir
== ITER_DEST
)
857 set_page_dirty(iter
.pages
[i
]);
858 put_page(iter
.pages
[i
]);
866 static inline bool ublk_need_map_req(const struct request
*req
)
868 return ublk_rq_has_data(req
) && req_op(req
) == REQ_OP_WRITE
;
871 static inline bool ublk_need_unmap_req(const struct request
*req
)
873 return ublk_rq_has_data(req
) &&
874 (req_op(req
) == REQ_OP_READ
|| req_op(req
) == REQ_OP_DRV_IN
);
877 static int ublk_map_io(const struct ublk_queue
*ubq
, const struct request
*req
,
880 const unsigned int rq_bytes
= blk_rq_bytes(req
);
882 if (ublk_support_user_copy(ubq
))
886 * no zero copy, we delay copy WRITE request data into ublksrv
887 * context and the big benefit is that pinning pages in current
888 * context is pretty fast, see ublk_pin_user_pages
890 if (ublk_need_map_req(req
)) {
891 struct iov_iter iter
;
893 const int dir
= ITER_DEST
;
895 import_single_range(dir
, u64_to_user_ptr(io
->addr
), rq_bytes
,
898 return ublk_copy_user_pages(req
, 0, &iter
, dir
);
903 static int ublk_unmap_io(const struct ublk_queue
*ubq
,
904 const struct request
*req
,
907 const unsigned int rq_bytes
= blk_rq_bytes(req
);
909 if (ublk_support_user_copy(ubq
))
912 if (ublk_need_unmap_req(req
)) {
913 struct iov_iter iter
;
915 const int dir
= ITER_SOURCE
;
917 WARN_ON_ONCE(io
->res
> rq_bytes
);
919 import_single_range(dir
, u64_to_user_ptr(io
->addr
), io
->res
,
921 return ublk_copy_user_pages(req
, 0, &iter
, dir
);
926 static inline unsigned int ublk_req_build_flags(struct request
*req
)
930 if (req
->cmd_flags
& REQ_FAILFAST_DEV
)
931 flags
|= UBLK_IO_F_FAILFAST_DEV
;
933 if (req
->cmd_flags
& REQ_FAILFAST_TRANSPORT
)
934 flags
|= UBLK_IO_F_FAILFAST_TRANSPORT
;
936 if (req
->cmd_flags
& REQ_FAILFAST_DRIVER
)
937 flags
|= UBLK_IO_F_FAILFAST_DRIVER
;
939 if (req
->cmd_flags
& REQ_META
)
940 flags
|= UBLK_IO_F_META
;
942 if (req
->cmd_flags
& REQ_FUA
)
943 flags
|= UBLK_IO_F_FUA
;
945 if (req
->cmd_flags
& REQ_NOUNMAP
)
946 flags
|= UBLK_IO_F_NOUNMAP
;
948 if (req
->cmd_flags
& REQ_SWAP
)
949 flags
|= UBLK_IO_F_SWAP
;
954 static blk_status_t
ublk_setup_iod(struct ublk_queue
*ubq
, struct request
*req
)
956 struct ublksrv_io_desc
*iod
= ublk_get_iod(ubq
, req
->tag
);
957 struct ublk_io
*io
= &ubq
->ios
[req
->tag
];
958 enum req_op op
= req_op(req
);
961 if (!ublk_queue_is_zoned(ubq
) &&
962 (op_is_zone_mgmt(op
) || op
== REQ_OP_ZONE_APPEND
))
963 return BLK_STS_IOERR
;
965 switch (req_op(req
)) {
967 ublk_op
= UBLK_IO_OP_READ
;
970 ublk_op
= UBLK_IO_OP_WRITE
;
973 ublk_op
= UBLK_IO_OP_FLUSH
;
976 ublk_op
= UBLK_IO_OP_DISCARD
;
978 case REQ_OP_WRITE_ZEROES
:
979 ublk_op
= UBLK_IO_OP_WRITE_ZEROES
;
982 if (ublk_queue_is_zoned(ubq
))
983 return ublk_setup_iod_zoned(ubq
, req
);
984 return BLK_STS_IOERR
;
987 /* need to translate since kernel may change */
988 iod
->op_flags
= ublk_op
| ublk_req_build_flags(req
);
989 iod
->nr_sectors
= blk_rq_sectors(req
);
990 iod
->start_sector
= blk_rq_pos(req
);
991 iod
->addr
= io
->addr
;
996 static inline struct ublk_uring_cmd_pdu
*ublk_get_uring_cmd_pdu(
997 struct io_uring_cmd
*ioucmd
)
999 return (struct ublk_uring_cmd_pdu
*)&ioucmd
->pdu
;
1002 static inline bool ubq_daemon_is_dying(struct ublk_queue
*ubq
)
1004 return ubq
->ubq_daemon
->flags
& PF_EXITING
;
1007 /* todo: handle partial completion */
1008 static inline void __ublk_complete_rq(struct request
*req
)
1010 struct ublk_queue
*ubq
= req
->mq_hctx
->driver_data
;
1011 struct ublk_io
*io
= &ubq
->ios
[req
->tag
];
1012 unsigned int unmapped_bytes
;
1013 blk_status_t res
= BLK_STS_OK
;
1015 /* called from ublk_abort_queue() code path */
1016 if (io
->flags
& UBLK_IO_FLAG_ABORTED
) {
1017 res
= BLK_STS_IOERR
;
1021 /* failed read IO if nothing is read */
1022 if (!io
->res
&& req_op(req
) == REQ_OP_READ
)
1026 res
= errno_to_blk_status(io
->res
);
1031 * FLUSH, DISCARD or WRITE_ZEROES usually won't return bytes returned, so end them
1034 * Both the two needn't unmap.
1036 if (req_op(req
) != REQ_OP_READ
&& req_op(req
) != REQ_OP_WRITE
&&
1037 req_op(req
) != REQ_OP_DRV_IN
)
1040 /* for READ request, writing data in iod->addr to rq buffers */
1041 unmapped_bytes
= ublk_unmap_io(ubq
, req
, io
);
1044 * Extremely impossible since we got data filled in just before
1046 * Re-read simply for this unlikely case.
1048 if (unlikely(unmapped_bytes
< io
->res
))
1049 io
->res
= unmapped_bytes
;
1051 if (blk_update_request(req
, BLK_STS_OK
, io
->res
))
1052 blk_mq_requeue_request(req
, true);
1054 __blk_mq_end_request(req
, BLK_STS_OK
);
1058 blk_mq_end_request(req
, res
);
1061 static void ublk_complete_rq(struct kref
*ref
)
1063 struct ublk_rq_data
*data
= container_of(ref
, struct ublk_rq_data
,
1065 struct request
*req
= blk_mq_rq_from_pdu(data
);
1067 __ublk_complete_rq(req
);
1071 * Since __ublk_rq_task_work always fails requests immediately during
1072 * exiting, __ublk_fail_req() is only called from abort context during
1073 * exiting. So lock is unnecessary.
1075 * Also aborting may not be started yet, keep in mind that one failed
1076 * request may be issued by block layer again.
1078 static void __ublk_fail_req(struct ublk_queue
*ubq
, struct ublk_io
*io
,
1079 struct request
*req
)
1081 WARN_ON_ONCE(io
->flags
& UBLK_IO_FLAG_ACTIVE
);
1083 if (!(io
->flags
& UBLK_IO_FLAG_ABORTED
)) {
1084 io
->flags
|= UBLK_IO_FLAG_ABORTED
;
1085 if (ublk_queue_can_use_recovery_reissue(ubq
))
1086 blk_mq_requeue_request(req
, false);
1088 ublk_put_req_ref(ubq
, req
);
1092 static void ubq_complete_io_cmd(struct ublk_io
*io
, int res
,
1093 unsigned issue_flags
)
1095 /* mark this cmd owned by ublksrv */
1096 io
->flags
|= UBLK_IO_FLAG_OWNED_BY_SRV
;
1099 * clear ACTIVE since we are done with this sqe/cmd slot
1100 * We can only accept io cmd in case of being not active.
1102 io
->flags
&= ~UBLK_IO_FLAG_ACTIVE
;
1104 /* tell ublksrv one io request is coming */
1105 io_uring_cmd_done(io
->cmd
, res
, 0, issue_flags
);
1108 #define UBLK_REQUEUE_DELAY_MS 3
1110 static inline void __ublk_abort_rq(struct ublk_queue
*ubq
,
1113 /* We cannot process this rq so just requeue it. */
1114 if (ublk_queue_can_use_recovery(ubq
))
1115 blk_mq_requeue_request(rq
, false);
1117 blk_mq_end_request(rq
, BLK_STS_IOERR
);
1119 mod_delayed_work(system_wq
, &ubq
->dev
->monitor_work
, 0);
1122 static inline void __ublk_rq_task_work(struct request
*req
,
1123 unsigned issue_flags
)
1125 struct ublk_queue
*ubq
= req
->mq_hctx
->driver_data
;
1127 struct ublk_io
*io
= &ubq
->ios
[tag
];
1128 unsigned int mapped_bytes
;
1130 pr_devel("%s: complete: op %d, qid %d tag %d io_flags %x addr %llx\n",
1131 __func__
, io
->cmd
->cmd_op
, ubq
->q_id
, req
->tag
, io
->flags
,
1132 ublk_get_iod(ubq
, req
->tag
)->addr
);
1135 * Task is exiting if either:
1137 * (1) current != ubq_daemon.
1138 * io_uring_cmd_complete_in_task() tries to run task_work
1139 * in a workqueue if ubq_daemon(cmd's task) is PF_EXITING.
1141 * (2) current->flags & PF_EXITING.
1143 if (unlikely(current
!= ubq
->ubq_daemon
|| current
->flags
& PF_EXITING
)) {
1144 __ublk_abort_rq(ubq
, req
);
1148 if (ublk_need_get_data(ubq
) && ublk_need_map_req(req
)) {
1150 * We have not handled UBLK_IO_NEED_GET_DATA command yet,
1151 * so immepdately pass UBLK_IO_RES_NEED_GET_DATA to ublksrv
1154 if (!(io
->flags
& UBLK_IO_FLAG_NEED_GET_DATA
)) {
1155 io
->flags
|= UBLK_IO_FLAG_NEED_GET_DATA
;
1156 pr_devel("%s: need get data. op %d, qid %d tag %d io_flags %x\n",
1157 __func__
, io
->cmd
->cmd_op
, ubq
->q_id
,
1158 req
->tag
, io
->flags
);
1159 ubq_complete_io_cmd(io
, UBLK_IO_RES_NEED_GET_DATA
, issue_flags
);
1163 * We have handled UBLK_IO_NEED_GET_DATA command,
1164 * so clear UBLK_IO_FLAG_NEED_GET_DATA now and just
1167 io
->flags
&= ~UBLK_IO_FLAG_NEED_GET_DATA
;
1168 /* update iod->addr because ublksrv may have passed a new io buffer */
1169 ublk_get_iod(ubq
, req
->tag
)->addr
= io
->addr
;
1170 pr_devel("%s: update iod->addr: op %d, qid %d tag %d io_flags %x addr %llx\n",
1171 __func__
, io
->cmd
->cmd_op
, ubq
->q_id
, req
->tag
, io
->flags
,
1172 ublk_get_iod(ubq
, req
->tag
)->addr
);
1175 mapped_bytes
= ublk_map_io(ubq
, req
, io
);
1177 /* partially mapped, update io descriptor */
1178 if (unlikely(mapped_bytes
!= blk_rq_bytes(req
))) {
1180 * Nothing mapped, retry until we succeed.
1182 * We may never succeed in mapping any bytes here because
1183 * of OOM. TODO: reserve one buffer with single page pinned
1184 * for providing forward progress guarantee.
1186 if (unlikely(!mapped_bytes
)) {
1187 blk_mq_requeue_request(req
, false);
1188 blk_mq_delay_kick_requeue_list(req
->q
,
1189 UBLK_REQUEUE_DELAY_MS
);
1193 ublk_get_iod(ubq
, req
->tag
)->nr_sectors
=
1197 ublk_init_req_ref(ubq
, req
);
1198 ubq_complete_io_cmd(io
, UBLK_IO_RES_OK
, issue_flags
);
1201 static inline void ublk_forward_io_cmds(struct ublk_queue
*ubq
,
1202 unsigned issue_flags
)
1204 struct llist_node
*io_cmds
= llist_del_all(&ubq
->io_cmds
);
1205 struct ublk_rq_data
*data
, *tmp
;
1207 io_cmds
= llist_reverse_order(io_cmds
);
1208 llist_for_each_entry_safe(data
, tmp
, io_cmds
, node
)
1209 __ublk_rq_task_work(blk_mq_rq_from_pdu(data
), issue_flags
);
1212 static inline void ublk_abort_io_cmds(struct ublk_queue
*ubq
)
1214 struct llist_node
*io_cmds
= llist_del_all(&ubq
->io_cmds
);
1215 struct ublk_rq_data
*data
, *tmp
;
1217 llist_for_each_entry_safe(data
, tmp
, io_cmds
, node
)
1218 __ublk_abort_rq(ubq
, blk_mq_rq_from_pdu(data
));
1221 static void ublk_rq_task_work_cb(struct io_uring_cmd
*cmd
, unsigned issue_flags
)
1223 struct ublk_uring_cmd_pdu
*pdu
= ublk_get_uring_cmd_pdu(cmd
);
1224 struct ublk_queue
*ubq
= pdu
->ubq
;
1226 ublk_forward_io_cmds(ubq
, issue_flags
);
1229 static void ublk_queue_cmd(struct ublk_queue
*ubq
, struct request
*rq
)
1231 struct ublk_rq_data
*data
= blk_mq_rq_to_pdu(rq
);
1234 if (!llist_add(&data
->node
, &ubq
->io_cmds
))
1237 io
= &ubq
->ios
[rq
->tag
];
1239 * If the check pass, we know that this is a re-issued request aborted
1240 * previously in monitor_work because the ubq_daemon(cmd's task) is
1241 * PF_EXITING. We cannot call io_uring_cmd_complete_in_task() anymore
1242 * because this ioucmd's io_uring context may be freed now if no inflight
1243 * ioucmd exists. Otherwise we may cause null-deref in ctx->fallback_work.
1245 * Note: monitor_work sets UBLK_IO_FLAG_ABORTED and ends this request(releasing
1246 * the tag). Then the request is re-started(allocating the tag) and we are here.
1247 * Since releasing/allocating a tag implies smp_mb(), finding UBLK_IO_FLAG_ABORTED
1248 * guarantees that here is a re-issued request aborted previously.
1250 if (unlikely(io
->flags
& UBLK_IO_FLAG_ABORTED
)) {
1251 ublk_abort_io_cmds(ubq
);
1253 struct io_uring_cmd
*cmd
= io
->cmd
;
1254 struct ublk_uring_cmd_pdu
*pdu
= ublk_get_uring_cmd_pdu(cmd
);
1257 io_uring_cmd_complete_in_task(cmd
, ublk_rq_task_work_cb
);
1261 static enum blk_eh_timer_return
ublk_timeout(struct request
*rq
)
1263 struct ublk_queue
*ubq
= rq
->mq_hctx
->driver_data
;
1265 if (ubq
->flags
& UBLK_F_UNPRIVILEGED_DEV
) {
1266 if (!ubq
->timeout
) {
1267 send_sig(SIGKILL
, ubq
->ubq_daemon
, 0);
1268 ubq
->timeout
= true;
1274 return BLK_EH_RESET_TIMER
;
1277 static blk_status_t
ublk_queue_rq(struct blk_mq_hw_ctx
*hctx
,
1278 const struct blk_mq_queue_data
*bd
)
1280 struct ublk_queue
*ubq
= hctx
->driver_data
;
1281 struct request
*rq
= bd
->rq
;
1284 /* fill iod to slot in io cmd buffer */
1285 res
= ublk_setup_iod(ubq
, rq
);
1286 if (unlikely(res
!= BLK_STS_OK
))
1287 return BLK_STS_IOERR
;
1289 /* With recovery feature enabled, force_abort is set in
1290 * ublk_stop_dev() before calling del_gendisk(). We have to
1291 * abort all requeued and new rqs here to let del_gendisk()
1292 * move on. Besides, we cannot not call io_uring_cmd_complete_in_task()
1293 * to avoid UAF on io_uring ctx.
1295 * Note: force_abort is guaranteed to be seen because it is set
1296 * before request queue is unqiuesced.
1298 if (ublk_queue_can_use_recovery(ubq
) && unlikely(ubq
->force_abort
))
1299 return BLK_STS_IOERR
;
1301 blk_mq_start_request(bd
->rq
);
1303 if (unlikely(ubq_daemon_is_dying(ubq
))) {
1304 __ublk_abort_rq(ubq
, rq
);
1308 ublk_queue_cmd(ubq
, rq
);
1313 static int ublk_init_hctx(struct blk_mq_hw_ctx
*hctx
, void *driver_data
,
1314 unsigned int hctx_idx
)
1316 struct ublk_device
*ub
= driver_data
;
1317 struct ublk_queue
*ubq
= ublk_get_queue(ub
, hctx
->queue_num
);
1319 hctx
->driver_data
= ubq
;
1323 static const struct blk_mq_ops ublk_mq_ops
= {
1324 .queue_rq
= ublk_queue_rq
,
1325 .init_hctx
= ublk_init_hctx
,
1326 .timeout
= ublk_timeout
,
1329 static int ublk_ch_open(struct inode
*inode
, struct file
*filp
)
1331 struct ublk_device
*ub
= container_of(inode
->i_cdev
,
1332 struct ublk_device
, cdev
);
1334 if (test_and_set_bit(UB_STATE_OPEN
, &ub
->state
))
1336 filp
->private_data
= ub
;
1340 static int ublk_ch_release(struct inode
*inode
, struct file
*filp
)
1342 struct ublk_device
*ub
= filp
->private_data
;
1344 clear_bit(UB_STATE_OPEN
, &ub
->state
);
1348 /* map pre-allocated per-queue cmd buffer to ublksrv daemon */
1349 static int ublk_ch_mmap(struct file
*filp
, struct vm_area_struct
*vma
)
1351 struct ublk_device
*ub
= filp
->private_data
;
1352 size_t sz
= vma
->vm_end
- vma
->vm_start
;
1353 unsigned max_sz
= UBLK_MAX_QUEUE_DEPTH
* sizeof(struct ublksrv_io_desc
);
1354 unsigned long pfn
, end
, phys_off
= vma
->vm_pgoff
<< PAGE_SHIFT
;
1357 spin_lock(&ub
->mm_lock
);
1359 ub
->mm
= current
->mm
;
1360 if (current
->mm
!= ub
->mm
)
1362 spin_unlock(&ub
->mm_lock
);
1367 if (vma
->vm_flags
& VM_WRITE
)
1370 end
= UBLKSRV_CMD_BUF_OFFSET
+ ub
->dev_info
.nr_hw_queues
* max_sz
;
1371 if (phys_off
< UBLKSRV_CMD_BUF_OFFSET
|| phys_off
>= end
)
1374 q_id
= (phys_off
- UBLKSRV_CMD_BUF_OFFSET
) / max_sz
;
1375 pr_devel("%s: qid %d, pid %d, addr %lx pg_off %lx sz %lu\n",
1376 __func__
, q_id
, current
->pid
, vma
->vm_start
,
1377 phys_off
, (unsigned long)sz
);
1379 if (sz
!= ublk_queue_cmd_buf_size(ub
, q_id
))
1382 pfn
= virt_to_phys(ublk_queue_cmd_buf(ub
, q_id
)) >> PAGE_SHIFT
;
1383 return remap_pfn_range(vma
, vma
->vm_start
, pfn
, sz
, vma
->vm_page_prot
);
1386 static void ublk_commit_completion(struct ublk_device
*ub
,
1387 const struct ublksrv_io_cmd
*ub_cmd
)
1389 u32 qid
= ub_cmd
->q_id
, tag
= ub_cmd
->tag
;
1390 struct ublk_queue
*ubq
= ublk_get_queue(ub
, qid
);
1391 struct ublk_io
*io
= &ubq
->ios
[tag
];
1392 struct request
*req
;
1394 /* now this cmd slot is owned by nbd driver */
1395 io
->flags
&= ~UBLK_IO_FLAG_OWNED_BY_SRV
;
1396 io
->res
= ub_cmd
->result
;
1398 /* find the io request and complete */
1399 req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[qid
], tag
);
1400 if (WARN_ON_ONCE(unlikely(!req
)))
1403 if (req_op(req
) == REQ_OP_ZONE_APPEND
)
1404 req
->__sector
= ub_cmd
->zone_append_lba
;
1406 if (likely(!blk_should_fake_timeout(req
->q
)))
1407 ublk_put_req_ref(ubq
, req
);
1411 * When ->ubq_daemon is exiting, either new request is ended immediately,
1412 * or any queued io command is drained, so it is safe to abort queue
1415 static void ublk_abort_queue(struct ublk_device
*ub
, struct ublk_queue
*ubq
)
1419 if (!ublk_get_device(ub
))
1422 for (i
= 0; i
< ubq
->q_depth
; i
++) {
1423 struct ublk_io
*io
= &ubq
->ios
[i
];
1425 if (!(io
->flags
& UBLK_IO_FLAG_ACTIVE
)) {
1429 * Either we fail the request or ublk_rq_task_work_fn
1432 rq
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[ubq
->q_id
], i
);
1434 __ublk_fail_req(ubq
, io
, rq
);
1437 ublk_put_device(ub
);
1440 static void ublk_daemon_monitor_work(struct work_struct
*work
)
1442 struct ublk_device
*ub
=
1443 container_of(work
, struct ublk_device
, monitor_work
.work
);
1446 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++) {
1447 struct ublk_queue
*ubq
= ublk_get_queue(ub
, i
);
1449 if (ubq_daemon_is_dying(ubq
)) {
1450 if (ublk_queue_can_use_recovery(ubq
))
1451 schedule_work(&ub
->quiesce_work
);
1453 schedule_work(&ub
->stop_work
);
1455 /* abort queue is for making forward progress */
1456 ublk_abort_queue(ub
, ubq
);
1461 * We can't schedule monitor work after ub's state is not UBLK_S_DEV_LIVE.
1462 * after ublk_remove() or __ublk_quiesce_dev() is started.
1464 * No need ub->mutex, monitor work are canceled after state is marked
1465 * as not LIVE, so new state is observed reliably.
1467 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
)
1468 schedule_delayed_work(&ub
->monitor_work
,
1469 UBLK_DAEMON_MONITOR_PERIOD
);
1472 static inline bool ublk_queue_ready(struct ublk_queue
*ubq
)
1474 return ubq
->nr_io_ready
== ubq
->q_depth
;
1477 static void ublk_cmd_cancel_cb(struct io_uring_cmd
*cmd
, unsigned issue_flags
)
1479 io_uring_cmd_done(cmd
, UBLK_IO_RES_ABORT
, 0, issue_flags
);
1482 static void ublk_cancel_queue(struct ublk_queue
*ubq
)
1486 if (!ublk_queue_ready(ubq
))
1489 for (i
= 0; i
< ubq
->q_depth
; i
++) {
1490 struct ublk_io
*io
= &ubq
->ios
[i
];
1492 if (io
->flags
& UBLK_IO_FLAG_ACTIVE
)
1493 io_uring_cmd_complete_in_task(io
->cmd
,
1494 ublk_cmd_cancel_cb
);
1497 /* all io commands are canceled */
1498 ubq
->nr_io_ready
= 0;
1501 /* Cancel all pending commands, must be called after del_gendisk() returns */
1502 static void ublk_cancel_dev(struct ublk_device
*ub
)
1506 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++)
1507 ublk_cancel_queue(ublk_get_queue(ub
, i
));
1510 static bool ublk_check_inflight_rq(struct request
*rq
, void *data
)
1514 if (blk_mq_request_started(rq
)) {
1521 static void ublk_wait_tagset_rqs_idle(struct ublk_device
*ub
)
1525 WARN_ON_ONCE(!blk_queue_quiesced(ub
->ub_disk
->queue
));
1528 blk_mq_tagset_busy_iter(&ub
->tag_set
,
1529 ublk_check_inflight_rq
, &idle
);
1532 msleep(UBLK_REQUEUE_DELAY_MS
);
1536 static void __ublk_quiesce_dev(struct ublk_device
*ub
)
1538 pr_devel("%s: quiesce ub: dev_id %d state %s\n",
1539 __func__
, ub
->dev_info
.dev_id
,
1540 ub
->dev_info
.state
== UBLK_S_DEV_LIVE
?
1541 "LIVE" : "QUIESCED");
1542 blk_mq_quiesce_queue(ub
->ub_disk
->queue
);
1543 ublk_wait_tagset_rqs_idle(ub
);
1544 ub
->dev_info
.state
= UBLK_S_DEV_QUIESCED
;
1545 ublk_cancel_dev(ub
);
1546 /* we are going to release task_struct of ubq_daemon and resets
1547 * ->ubq_daemon to NULL. So in monitor_work, check on ubq_daemon causes UAF.
1548 * Besides, monitor_work is not necessary in QUIESCED state since we have
1549 * already scheduled quiesce_work and quiesced all ubqs.
1551 * Do not let monitor_work schedule itself if state it QUIESCED. And we cancel
1552 * it here and re-schedule it in END_USER_RECOVERY to avoid UAF.
1554 cancel_delayed_work_sync(&ub
->monitor_work
);
1557 static void ublk_quiesce_work_fn(struct work_struct
*work
)
1559 struct ublk_device
*ub
=
1560 container_of(work
, struct ublk_device
, quiesce_work
);
1562 mutex_lock(&ub
->mutex
);
1563 if (ub
->dev_info
.state
!= UBLK_S_DEV_LIVE
)
1565 __ublk_quiesce_dev(ub
);
1567 mutex_unlock(&ub
->mutex
);
1570 static void ublk_unquiesce_dev(struct ublk_device
*ub
)
1574 pr_devel("%s: unquiesce ub: dev_id %d state %s\n",
1575 __func__
, ub
->dev_info
.dev_id
,
1576 ub
->dev_info
.state
== UBLK_S_DEV_LIVE
?
1577 "LIVE" : "QUIESCED");
1578 /* quiesce_work has run. We let requeued rqs be aborted
1579 * before running fallback_wq. "force_abort" must be seen
1580 * after request queue is unqiuesced. Then del_gendisk()
1583 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++)
1584 ublk_get_queue(ub
, i
)->force_abort
= true;
1586 blk_mq_unquiesce_queue(ub
->ub_disk
->queue
);
1587 /* We may have requeued some rqs in ublk_quiesce_queue() */
1588 blk_mq_kick_requeue_list(ub
->ub_disk
->queue
);
1591 static void ublk_stop_dev(struct ublk_device
*ub
)
1593 mutex_lock(&ub
->mutex
);
1594 if (ub
->dev_info
.state
== UBLK_S_DEV_DEAD
)
1596 if (ublk_can_use_recovery(ub
)) {
1597 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
)
1598 __ublk_quiesce_dev(ub
);
1599 ublk_unquiesce_dev(ub
);
1601 del_gendisk(ub
->ub_disk
);
1602 ub
->dev_info
.state
= UBLK_S_DEV_DEAD
;
1603 ub
->dev_info
.ublksrv_pid
= -1;
1604 put_disk(ub
->ub_disk
);
1607 ublk_cancel_dev(ub
);
1608 mutex_unlock(&ub
->mutex
);
1609 cancel_delayed_work_sync(&ub
->monitor_work
);
1612 /* device can only be started after all IOs are ready */
1613 static void ublk_mark_io_ready(struct ublk_device
*ub
, struct ublk_queue
*ubq
)
1615 mutex_lock(&ub
->mutex
);
1617 if (ublk_queue_ready(ubq
)) {
1618 ubq
->ubq_daemon
= current
;
1619 get_task_struct(ubq
->ubq_daemon
);
1620 ub
->nr_queues_ready
++;
1622 if (capable(CAP_SYS_ADMIN
))
1623 ub
->nr_privileged_daemon
++;
1625 if (ub
->nr_queues_ready
== ub
->dev_info
.nr_hw_queues
)
1626 complete_all(&ub
->completion
);
1627 mutex_unlock(&ub
->mutex
);
1630 static void ublk_handle_need_get_data(struct ublk_device
*ub
, int q_id
,
1633 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
1634 struct request
*req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[q_id
], tag
);
1636 ublk_queue_cmd(ubq
, req
);
1639 static inline int ublk_check_cmd_op(u32 cmd_op
)
1641 u32 ioc_type
= _IOC_TYPE(cmd_op
);
1643 if (!IS_ENABLED(CONFIG_BLKDEV_UBLK_LEGACY_OPCODES
) && ioc_type
!= 'u')
1646 if (ioc_type
!= 'u' && ioc_type
!= 0)
1652 static inline void ublk_fill_io_cmd(struct ublk_io
*io
,
1653 struct io_uring_cmd
*cmd
, unsigned long buf_addr
)
1656 io
->flags
|= UBLK_IO_FLAG_ACTIVE
;
1657 io
->addr
= buf_addr
;
1660 static int __ublk_ch_uring_cmd(struct io_uring_cmd
*cmd
,
1661 unsigned int issue_flags
,
1662 const struct ublksrv_io_cmd
*ub_cmd
)
1664 struct ublk_device
*ub
= cmd
->file
->private_data
;
1665 struct ublk_queue
*ubq
;
1667 u32 cmd_op
= cmd
->cmd_op
;
1668 unsigned tag
= ub_cmd
->tag
;
1670 struct request
*req
;
1672 pr_devel("%s: received: cmd op %d queue %d tag %d result %d\n",
1673 __func__
, cmd
->cmd_op
, ub_cmd
->q_id
, tag
,
1676 if (ub_cmd
->q_id
>= ub
->dev_info
.nr_hw_queues
)
1679 ubq
= ublk_get_queue(ub
, ub_cmd
->q_id
);
1680 if (!ubq
|| ub_cmd
->q_id
!= ubq
->q_id
)
1683 if (ubq
->ubq_daemon
&& ubq
->ubq_daemon
!= current
)
1686 if (tag
>= ubq
->q_depth
)
1689 io
= &ubq
->ios
[tag
];
1691 /* there is pending io cmd, something must be wrong */
1692 if (io
->flags
& UBLK_IO_FLAG_ACTIVE
) {
1698 * ensure that the user issues UBLK_IO_NEED_GET_DATA
1699 * iff the driver have set the UBLK_IO_FLAG_NEED_GET_DATA.
1701 if ((!!(io
->flags
& UBLK_IO_FLAG_NEED_GET_DATA
))
1702 ^ (_IOC_NR(cmd_op
) == UBLK_IO_NEED_GET_DATA
))
1705 ret
= ublk_check_cmd_op(cmd_op
);
1710 switch (_IOC_NR(cmd_op
)) {
1711 case UBLK_IO_FETCH_REQ
:
1712 /* UBLK_IO_FETCH_REQ is only allowed before queue is setup */
1713 if (ublk_queue_ready(ubq
)) {
1718 * The io is being handled by server, so COMMIT_RQ is expected
1719 * instead of FETCH_REQ
1721 if (io
->flags
& UBLK_IO_FLAG_OWNED_BY_SRV
)
1724 if (!ublk_support_user_copy(ubq
)) {
1726 * FETCH_RQ has to provide IO buffer if NEED GET
1727 * DATA is not enabled
1729 if (!ub_cmd
->addr
&& !ublk_need_get_data(ubq
))
1731 } else if (ub_cmd
->addr
) {
1732 /* User copy requires addr to be unset */
1737 ublk_fill_io_cmd(io
, cmd
, ub_cmd
->addr
);
1738 ublk_mark_io_ready(ub
, ubq
);
1740 case UBLK_IO_COMMIT_AND_FETCH_REQ
:
1741 req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[ub_cmd
->q_id
], tag
);
1743 if (!(io
->flags
& UBLK_IO_FLAG_OWNED_BY_SRV
))
1746 if (!ublk_support_user_copy(ubq
)) {
1748 * COMMIT_AND_FETCH_REQ has to provide IO buffer if
1749 * NEED GET DATA is not enabled or it is Read IO.
1751 if (!ub_cmd
->addr
&& (!ublk_need_get_data(ubq
) ||
1752 req_op(req
) == REQ_OP_READ
))
1754 } else if (req_op(req
) != REQ_OP_ZONE_APPEND
&& ub_cmd
->addr
) {
1756 * User copy requires addr to be unset when command is
1763 ublk_fill_io_cmd(io
, cmd
, ub_cmd
->addr
);
1764 ublk_commit_completion(ub
, ub_cmd
);
1766 case UBLK_IO_NEED_GET_DATA
:
1767 if (!(io
->flags
& UBLK_IO_FLAG_OWNED_BY_SRV
))
1769 ublk_fill_io_cmd(io
, cmd
, ub_cmd
->addr
);
1770 ublk_handle_need_get_data(ub
, ub_cmd
->q_id
, ub_cmd
->tag
);
1775 return -EIOCBQUEUED
;
1778 io_uring_cmd_done(cmd
, ret
, 0, issue_flags
);
1779 pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n",
1780 __func__
, cmd_op
, tag
, ret
, io
->flags
);
1781 return -EIOCBQUEUED
;
1784 static inline struct request
*__ublk_check_and_get_req(struct ublk_device
*ub
,
1785 struct ublk_queue
*ubq
, int tag
, size_t offset
)
1787 struct request
*req
;
1789 if (!ublk_need_req_ref(ubq
))
1792 req
= blk_mq_tag_to_rq(ub
->tag_set
.tags
[ubq
->q_id
], tag
);
1796 if (!ublk_get_req_ref(ubq
, req
))
1799 if (unlikely(!blk_mq_request_started(req
) || req
->tag
!= tag
))
1802 if (!ublk_rq_has_data(req
))
1805 if (offset
> blk_rq_bytes(req
))
1810 ublk_put_req_ref(ubq
, req
);
1814 static int ublk_ch_uring_cmd(struct io_uring_cmd
*cmd
, unsigned int issue_flags
)
1817 * Not necessary for async retry, but let's keep it simple and always
1818 * copy the values to avoid any potential reuse.
1820 const struct ublksrv_io_cmd
*ub_src
= io_uring_sqe_cmd(cmd
->sqe
);
1821 const struct ublksrv_io_cmd ub_cmd
= {
1822 .q_id
= READ_ONCE(ub_src
->q_id
),
1823 .tag
= READ_ONCE(ub_src
->tag
),
1824 .result
= READ_ONCE(ub_src
->result
),
1825 .addr
= READ_ONCE(ub_src
->addr
)
1828 return __ublk_ch_uring_cmd(cmd
, issue_flags
, &ub_cmd
);
1831 static inline bool ublk_check_ubuf_dir(const struct request
*req
,
1834 /* copy ubuf to request pages */
1835 if ((req_op(req
) == REQ_OP_READ
|| req_op(req
) == REQ_OP_DRV_IN
) &&
1836 ubuf_dir
== ITER_SOURCE
)
1839 /* copy request pages to ubuf */
1840 if ((req_op(req
) == REQ_OP_WRITE
||
1841 req_op(req
) == REQ_OP_ZONE_APPEND
) &&
1842 ubuf_dir
== ITER_DEST
)
1848 static struct request
*ublk_check_and_get_req(struct kiocb
*iocb
,
1849 struct iov_iter
*iter
, size_t *off
, int dir
)
1851 struct ublk_device
*ub
= iocb
->ki_filp
->private_data
;
1852 struct ublk_queue
*ubq
;
1853 struct request
*req
;
1858 return ERR_PTR(-EACCES
);
1860 if (!user_backed_iter(iter
))
1861 return ERR_PTR(-EACCES
);
1863 if (ub
->dev_info
.state
== UBLK_S_DEV_DEAD
)
1864 return ERR_PTR(-EACCES
);
1866 tag
= ublk_pos_to_tag(iocb
->ki_pos
);
1867 q_id
= ublk_pos_to_hwq(iocb
->ki_pos
);
1868 buf_off
= ublk_pos_to_buf_off(iocb
->ki_pos
);
1870 if (q_id
>= ub
->dev_info
.nr_hw_queues
)
1871 return ERR_PTR(-EINVAL
);
1873 ubq
= ublk_get_queue(ub
, q_id
);
1875 return ERR_PTR(-EINVAL
);
1877 if (tag
>= ubq
->q_depth
)
1878 return ERR_PTR(-EINVAL
);
1880 req
= __ublk_check_and_get_req(ub
, ubq
, tag
, buf_off
);
1882 return ERR_PTR(-EINVAL
);
1884 if (!req
->mq_hctx
|| !req
->mq_hctx
->driver_data
)
1887 if (!ublk_check_ubuf_dir(req
, dir
))
1893 ublk_put_req_ref(ubq
, req
);
1894 return ERR_PTR(-EACCES
);
1897 static ssize_t
ublk_ch_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
1899 struct ublk_queue
*ubq
;
1900 struct request
*req
;
1904 req
= ublk_check_and_get_req(iocb
, to
, &buf_off
, ITER_DEST
);
1906 return PTR_ERR(req
);
1908 ret
= ublk_copy_user_pages(req
, buf_off
, to
, ITER_DEST
);
1909 ubq
= req
->mq_hctx
->driver_data
;
1910 ublk_put_req_ref(ubq
, req
);
1915 static ssize_t
ublk_ch_write_iter(struct kiocb
*iocb
, struct iov_iter
*from
)
1917 struct ublk_queue
*ubq
;
1918 struct request
*req
;
1922 req
= ublk_check_and_get_req(iocb
, from
, &buf_off
, ITER_SOURCE
);
1924 return PTR_ERR(req
);
1926 ret
= ublk_copy_user_pages(req
, buf_off
, from
, ITER_SOURCE
);
1927 ubq
= req
->mq_hctx
->driver_data
;
1928 ublk_put_req_ref(ubq
, req
);
1933 static const struct file_operations ublk_ch_fops
= {
1934 .owner
= THIS_MODULE
,
1935 .open
= ublk_ch_open
,
1936 .release
= ublk_ch_release
,
1937 .llseek
= no_llseek
,
1938 .read_iter
= ublk_ch_read_iter
,
1939 .write_iter
= ublk_ch_write_iter
,
1940 .uring_cmd
= ublk_ch_uring_cmd
,
1941 .mmap
= ublk_ch_mmap
,
1944 static void ublk_deinit_queue(struct ublk_device
*ub
, int q_id
)
1946 int size
= ublk_queue_cmd_buf_size(ub
, q_id
);
1947 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
1949 if (ubq
->ubq_daemon
)
1950 put_task_struct(ubq
->ubq_daemon
);
1951 if (ubq
->io_cmd_buf
)
1952 free_pages((unsigned long)ubq
->io_cmd_buf
, get_order(size
));
1955 static int ublk_init_queue(struct ublk_device
*ub
, int q_id
)
1957 struct ublk_queue
*ubq
= ublk_get_queue(ub
, q_id
);
1958 gfp_t gfp_flags
= GFP_KERNEL
| __GFP_ZERO
;
1962 ubq
->flags
= ub
->dev_info
.flags
;
1964 ubq
->q_depth
= ub
->dev_info
.queue_depth
;
1965 size
= ublk_queue_cmd_buf_size(ub
, q_id
);
1967 ptr
= (void *) __get_free_pages(gfp_flags
, get_order(size
));
1971 ubq
->io_cmd_buf
= ptr
;
1976 static void ublk_deinit_queues(struct ublk_device
*ub
)
1978 int nr_queues
= ub
->dev_info
.nr_hw_queues
;
1984 for (i
= 0; i
< nr_queues
; i
++)
1985 ublk_deinit_queue(ub
, i
);
1986 kfree(ub
->__queues
);
1989 static int ublk_init_queues(struct ublk_device
*ub
)
1991 int nr_queues
= ub
->dev_info
.nr_hw_queues
;
1992 int depth
= ub
->dev_info
.queue_depth
;
1993 int ubq_size
= sizeof(struct ublk_queue
) + depth
* sizeof(struct ublk_io
);
1994 int i
, ret
= -ENOMEM
;
1996 ub
->queue_size
= ubq_size
;
1997 ub
->__queues
= kcalloc(nr_queues
, ubq_size
, GFP_KERNEL
);
2001 for (i
= 0; i
< nr_queues
; i
++) {
2002 if (ublk_init_queue(ub
, i
))
2006 init_completion(&ub
->completion
);
2010 ublk_deinit_queues(ub
);
2014 static int ublk_alloc_dev_number(struct ublk_device
*ub
, int idx
)
2019 spin_lock(&ublk_idr_lock
);
2020 /* allocate id, if @id >= 0, we're requesting that specific id */
2022 err
= idr_alloc(&ublk_index_idr
, ub
, i
, i
+ 1, GFP_NOWAIT
);
2026 err
= idr_alloc(&ublk_index_idr
, ub
, 0, 0, GFP_NOWAIT
);
2028 spin_unlock(&ublk_idr_lock
);
2031 ub
->ub_number
= err
;
2036 static void ublk_free_dev_number(struct ublk_device
*ub
)
2038 spin_lock(&ublk_idr_lock
);
2039 idr_remove(&ublk_index_idr
, ub
->ub_number
);
2040 wake_up_all(&ublk_idr_wq
);
2041 spin_unlock(&ublk_idr_lock
);
2044 static void ublk_cdev_rel(struct device
*dev
)
2046 struct ublk_device
*ub
= container_of(dev
, struct ublk_device
, cdev_dev
);
2048 blk_mq_free_tag_set(&ub
->tag_set
);
2049 ublk_deinit_queues(ub
);
2050 ublk_free_dev_number(ub
);
2051 mutex_destroy(&ub
->mutex
);
2055 static int ublk_add_chdev(struct ublk_device
*ub
)
2057 struct device
*dev
= &ub
->cdev_dev
;
2058 int minor
= ub
->ub_number
;
2061 dev
->parent
= ublk_misc
.this_device
;
2062 dev
->devt
= MKDEV(MAJOR(ublk_chr_devt
), minor
);
2063 dev
->class = &ublk_chr_class
;
2064 dev
->release
= ublk_cdev_rel
;
2065 device_initialize(dev
);
2067 ret
= dev_set_name(dev
, "ublkc%d", minor
);
2071 cdev_init(&ub
->cdev
, &ublk_ch_fops
);
2072 ret
= cdev_device_add(&ub
->cdev
, dev
);
2083 static void ublk_stop_work_fn(struct work_struct
*work
)
2085 struct ublk_device
*ub
=
2086 container_of(work
, struct ublk_device
, stop_work
);
2091 /* align max io buffer size with PAGE_SIZE */
2092 static void ublk_align_max_io_size(struct ublk_device
*ub
)
2094 unsigned int max_io_bytes
= ub
->dev_info
.max_io_buf_bytes
;
2096 ub
->dev_info
.max_io_buf_bytes
=
2097 round_down(max_io_bytes
, PAGE_SIZE
);
2100 static int ublk_add_tag_set(struct ublk_device
*ub
)
2102 ub
->tag_set
.ops
= &ublk_mq_ops
;
2103 ub
->tag_set
.nr_hw_queues
= ub
->dev_info
.nr_hw_queues
;
2104 ub
->tag_set
.queue_depth
= ub
->dev_info
.queue_depth
;
2105 ub
->tag_set
.numa_node
= NUMA_NO_NODE
;
2106 ub
->tag_set
.cmd_size
= sizeof(struct ublk_rq_data
);
2107 ub
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
;
2108 ub
->tag_set
.driver_data
= ub
;
2109 return blk_mq_alloc_tag_set(&ub
->tag_set
);
2112 static void ublk_remove(struct ublk_device
*ub
)
2115 cancel_work_sync(&ub
->stop_work
);
2116 cancel_work_sync(&ub
->quiesce_work
);
2117 cdev_device_del(&ub
->cdev
, &ub
->cdev_dev
);
2118 put_device(&ub
->cdev_dev
);
2122 static struct ublk_device
*ublk_get_device_from_id(int idx
)
2124 struct ublk_device
*ub
= NULL
;
2129 spin_lock(&ublk_idr_lock
);
2130 ub
= idr_find(&ublk_index_idr
, idx
);
2132 ub
= ublk_get_device(ub
);
2133 spin_unlock(&ublk_idr_lock
);
2138 static int ublk_ctrl_start_dev(struct ublk_device
*ub
, struct io_uring_cmd
*cmd
)
2140 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2141 int ublksrv_pid
= (int)header
->data
[0];
2142 struct gendisk
*disk
;
2145 if (ublksrv_pid
<= 0)
2148 wait_for_completion_interruptible(&ub
->completion
);
2150 schedule_delayed_work(&ub
->monitor_work
, UBLK_DAEMON_MONITOR_PERIOD
);
2152 mutex_lock(&ub
->mutex
);
2153 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
||
2154 test_bit(UB_STATE_USED
, &ub
->state
)) {
2159 disk
= blk_mq_alloc_disk(&ub
->tag_set
, NULL
);
2161 ret
= PTR_ERR(disk
);
2164 sprintf(disk
->disk_name
, "ublkb%d", ub
->ub_number
);
2165 disk
->fops
= &ub_fops
;
2166 disk
->private_data
= ub
;
2168 ub
->dev_info
.ublksrv_pid
= ublksrv_pid
;
2171 ret
= ublk_apply_params(ub
);
2175 /* don't probe partitions if any one ubq daemon is un-trusted */
2176 if (ub
->nr_privileged_daemon
!= ub
->nr_queues_ready
)
2177 set_bit(GD_SUPPRESS_PART_SCAN
, &disk
->state
);
2179 get_device(&ub
->cdev_dev
);
2180 ub
->dev_info
.state
= UBLK_S_DEV_LIVE
;
2182 if (ublk_dev_is_zoned(ub
)) {
2183 ret
= ublk_revalidate_disk_zones(ub
);
2188 ret
= add_disk(disk
);
2192 set_bit(UB_STATE_USED
, &ub
->state
);
2196 ub
->dev_info
.state
= UBLK_S_DEV_DEAD
;
2197 ublk_put_device(ub
);
2203 mutex_unlock(&ub
->mutex
);
2207 static int ublk_ctrl_get_queue_affinity(struct ublk_device
*ub
,
2208 struct io_uring_cmd
*cmd
)
2210 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2211 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2212 cpumask_var_t cpumask
;
2213 unsigned long queue
;
2214 unsigned int retlen
;
2218 if (header
->len
* BITS_PER_BYTE
< nr_cpu_ids
)
2220 if (header
->len
& (sizeof(unsigned long)-1))
2225 queue
= header
->data
[0];
2226 if (queue
>= ub
->dev_info
.nr_hw_queues
)
2229 if (!zalloc_cpumask_var(&cpumask
, GFP_KERNEL
))
2232 for_each_possible_cpu(i
) {
2233 if (ub
->tag_set
.map
[HCTX_TYPE_DEFAULT
].mq_map
[i
] == queue
)
2234 cpumask_set_cpu(i
, cpumask
);
2238 retlen
= min_t(unsigned short, header
->len
, cpumask_size());
2239 if (copy_to_user(argp
, cpumask
, retlen
))
2240 goto out_free_cpumask
;
2241 if (retlen
!= header
->len
&&
2242 clear_user(argp
+ retlen
, header
->len
- retlen
))
2243 goto out_free_cpumask
;
2247 free_cpumask_var(cpumask
);
2251 static inline void ublk_dump_dev_info(struct ublksrv_ctrl_dev_info
*info
)
2253 pr_devel("%s: dev id %d flags %llx\n", __func__
,
2254 info
->dev_id
, info
->flags
);
2255 pr_devel("\t nr_hw_queues %d queue_depth %d\n",
2256 info
->nr_hw_queues
, info
->queue_depth
);
2259 static int ublk_ctrl_add_dev(struct io_uring_cmd
*cmd
)
2261 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2262 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2263 struct ublksrv_ctrl_dev_info info
;
2264 struct ublk_device
*ub
;
2267 if (header
->len
< sizeof(info
) || !header
->addr
)
2269 if (header
->queue_id
!= (u16
)-1) {
2270 pr_warn("%s: queue_id is wrong %x\n",
2271 __func__
, header
->queue_id
);
2275 if (copy_from_user(&info
, argp
, sizeof(info
)))
2278 if (capable(CAP_SYS_ADMIN
))
2279 info
.flags
&= ~UBLK_F_UNPRIVILEGED_DEV
;
2280 else if (!(info
.flags
& UBLK_F_UNPRIVILEGED_DEV
))
2284 * unprivileged device can't be trusted, but RECOVERY and
2285 * RECOVERY_REISSUE still may hang error handling, so can't
2286 * support recovery features for unprivileged ublk now
2288 * TODO: provide forward progress for RECOVERY handler, so that
2289 * unprivileged device can benefit from it
2291 if (info
.flags
& UBLK_F_UNPRIVILEGED_DEV
)
2292 info
.flags
&= ~(UBLK_F_USER_RECOVERY_REISSUE
|
2293 UBLK_F_USER_RECOVERY
);
2295 /* the created device is always owned by current user */
2296 ublk_store_owner_uid_gid(&info
.owner_uid
, &info
.owner_gid
);
2298 if (header
->dev_id
!= info
.dev_id
) {
2299 pr_warn("%s: dev id not match %u %u\n",
2300 __func__
, header
->dev_id
, info
.dev_id
);
2304 ublk_dump_dev_info(&info
);
2306 ret
= mutex_lock_killable(&ublk_ctl_mutex
);
2311 if (ublks_added
>= ublks_max
)
2315 ub
= kzalloc(sizeof(*ub
), GFP_KERNEL
);
2318 mutex_init(&ub
->mutex
);
2319 spin_lock_init(&ub
->mm_lock
);
2320 INIT_WORK(&ub
->quiesce_work
, ublk_quiesce_work_fn
);
2321 INIT_WORK(&ub
->stop_work
, ublk_stop_work_fn
);
2322 INIT_DELAYED_WORK(&ub
->monitor_work
, ublk_daemon_monitor_work
);
2324 ret
= ublk_alloc_dev_number(ub
, header
->dev_id
);
2328 memcpy(&ub
->dev_info
, &info
, sizeof(info
));
2330 /* update device id */
2331 ub
->dev_info
.dev_id
= ub
->ub_number
;
2334 * 64bit flags will be copied back to userspace as feature
2335 * negotiation result, so have to clear flags which driver
2336 * doesn't support yet, then userspace can get correct flags
2337 * (features) to handle.
2339 ub
->dev_info
.flags
&= UBLK_F_ALL
;
2341 ub
->dev_info
.flags
|= UBLK_F_CMD_IOCTL_ENCODE
|
2342 UBLK_F_URING_CMD_COMP_IN_TASK
;
2344 /* GET_DATA isn't needed any more with USER_COPY */
2345 if (ublk_dev_is_user_copy(ub
))
2346 ub
->dev_info
.flags
&= ~UBLK_F_NEED_GET_DATA
;
2348 /* Zoned storage support requires user copy feature */
2349 if (ublk_dev_is_zoned(ub
) &&
2350 (!IS_ENABLED(CONFIG_BLK_DEV_ZONED
) || !ublk_dev_is_user_copy(ub
))) {
2352 goto out_free_dev_number
;
2355 /* We are not ready to support zero copy */
2356 ub
->dev_info
.flags
&= ~UBLK_F_SUPPORT_ZERO_COPY
;
2358 ub
->dev_info
.nr_hw_queues
= min_t(unsigned int,
2359 ub
->dev_info
.nr_hw_queues
, nr_cpu_ids
);
2360 ublk_align_max_io_size(ub
);
2362 ret
= ublk_init_queues(ub
);
2364 goto out_free_dev_number
;
2366 ret
= ublk_add_tag_set(ub
);
2368 goto out_deinit_queues
;
2371 if (copy_to_user(argp
, &ub
->dev_info
, sizeof(info
)))
2372 goto out_free_tag_set
;
2375 * Add the char dev so that ublksrv daemon can be setup.
2376 * ublk_add_chdev() will cleanup everything if it fails.
2378 ret
= ublk_add_chdev(ub
);
2382 blk_mq_free_tag_set(&ub
->tag_set
);
2384 ublk_deinit_queues(ub
);
2385 out_free_dev_number
:
2386 ublk_free_dev_number(ub
);
2388 mutex_destroy(&ub
->mutex
);
2391 mutex_unlock(&ublk_ctl_mutex
);
2395 static inline bool ublk_idr_freed(int id
)
2399 spin_lock(&ublk_idr_lock
);
2400 ptr
= idr_find(&ublk_index_idr
, id
);
2401 spin_unlock(&ublk_idr_lock
);
2406 static int ublk_ctrl_del_dev(struct ublk_device
**p_ub
)
2408 struct ublk_device
*ub
= *p_ub
;
2409 int idx
= ub
->ub_number
;
2412 ret
= mutex_lock_killable(&ublk_ctl_mutex
);
2416 if (!test_bit(UB_STATE_DELETED
, &ub
->state
)) {
2418 set_bit(UB_STATE_DELETED
, &ub
->state
);
2421 /* Mark the reference as consumed */
2423 ublk_put_device(ub
);
2424 mutex_unlock(&ublk_ctl_mutex
);
2427 * Wait until the idr is removed, then it can be reused after
2428 * DEL_DEV command is returned.
2430 * If we returns because of user interrupt, future delete command
2433 * - the device number isn't freed, this device won't or needn't
2434 * be deleted again, since UB_STATE_DELETED is set, and device
2435 * will be released after the last reference is dropped
2437 * - the device number is freed already, we will not find this
2438 * device via ublk_get_device_from_id()
2440 wait_event_interruptible(ublk_idr_wq
, ublk_idr_freed(idx
));
2445 static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd
*cmd
)
2447 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2449 pr_devel("%s: cmd_op %x, dev id %d qid %d data %llx buf %llx len %u\n",
2450 __func__
, cmd
->cmd_op
, header
->dev_id
, header
->queue_id
,
2451 header
->data
[0], header
->addr
, header
->len
);
2454 static int ublk_ctrl_stop_dev(struct ublk_device
*ub
)
2457 cancel_work_sync(&ub
->stop_work
);
2458 cancel_work_sync(&ub
->quiesce_work
);
2463 static int ublk_ctrl_get_dev_info(struct ublk_device
*ub
,
2464 struct io_uring_cmd
*cmd
)
2466 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2467 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2469 if (header
->len
< sizeof(struct ublksrv_ctrl_dev_info
) || !header
->addr
)
2472 if (copy_to_user(argp
, &ub
->dev_info
, sizeof(ub
->dev_info
)))
2478 /* TYPE_DEVT is readonly, so fill it up before returning to userspace */
2479 static void ublk_ctrl_fill_params_devt(struct ublk_device
*ub
)
2481 ub
->params
.devt
.char_major
= MAJOR(ub
->cdev_dev
.devt
);
2482 ub
->params
.devt
.char_minor
= MINOR(ub
->cdev_dev
.devt
);
2485 ub
->params
.devt
.disk_major
= MAJOR(disk_devt(ub
->ub_disk
));
2486 ub
->params
.devt
.disk_minor
= MINOR(disk_devt(ub
->ub_disk
));
2488 ub
->params
.devt
.disk_major
= 0;
2489 ub
->params
.devt
.disk_minor
= 0;
2491 ub
->params
.types
|= UBLK_PARAM_TYPE_DEVT
;
2494 static int ublk_ctrl_get_params(struct ublk_device
*ub
,
2495 struct io_uring_cmd
*cmd
)
2497 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2498 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2499 struct ublk_params_header ph
;
2502 if (header
->len
<= sizeof(ph
) || !header
->addr
)
2505 if (copy_from_user(&ph
, argp
, sizeof(ph
)))
2508 if (ph
.len
> header
->len
|| !ph
.len
)
2511 if (ph
.len
> sizeof(struct ublk_params
))
2512 ph
.len
= sizeof(struct ublk_params
);
2514 mutex_lock(&ub
->mutex
);
2515 ublk_ctrl_fill_params_devt(ub
);
2516 if (copy_to_user(argp
, &ub
->params
, ph
.len
))
2520 mutex_unlock(&ub
->mutex
);
2525 static int ublk_ctrl_set_params(struct ublk_device
*ub
,
2526 struct io_uring_cmd
*cmd
)
2528 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2529 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2530 struct ublk_params_header ph
;
2533 if (header
->len
<= sizeof(ph
) || !header
->addr
)
2536 if (copy_from_user(&ph
, argp
, sizeof(ph
)))
2539 if (ph
.len
> header
->len
|| !ph
.len
|| !ph
.types
)
2542 if (ph
.len
> sizeof(struct ublk_params
))
2543 ph
.len
= sizeof(struct ublk_params
);
2545 /* parameters can only be changed when device isn't live */
2546 mutex_lock(&ub
->mutex
);
2547 if (ub
->dev_info
.state
== UBLK_S_DEV_LIVE
) {
2549 } else if (copy_from_user(&ub
->params
, argp
, ph
.len
)) {
2552 /* clear all we don't support yet */
2553 ub
->params
.types
&= UBLK_PARAM_TYPE_ALL
;
2554 ret
= ublk_validate_params(ub
);
2556 ub
->params
.types
= 0;
2558 mutex_unlock(&ub
->mutex
);
2563 static void ublk_queue_reinit(struct ublk_device
*ub
, struct ublk_queue
*ubq
)
2567 WARN_ON_ONCE(!(ubq
->ubq_daemon
&& ubq_daemon_is_dying(ubq
)));
2568 /* All old ioucmds have to be completed */
2569 WARN_ON_ONCE(ubq
->nr_io_ready
);
2570 /* old daemon is PF_EXITING, put it now */
2571 put_task_struct(ubq
->ubq_daemon
);
2572 /* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */
2573 ubq
->ubq_daemon
= NULL
;
2574 ubq
->timeout
= false;
2576 for (i
= 0; i
< ubq
->q_depth
; i
++) {
2577 struct ublk_io
*io
= &ubq
->ios
[i
];
2579 /* forget everything now and be ready for new FETCH_REQ */
2586 static int ublk_ctrl_start_recovery(struct ublk_device
*ub
,
2587 struct io_uring_cmd
*cmd
)
2589 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2593 mutex_lock(&ub
->mutex
);
2594 if (!ublk_can_use_recovery(ub
))
2597 * START_RECOVERY is only allowd after:
2599 * (1) UB_STATE_OPEN is not set, which means the dying process is exited
2600 * and related io_uring ctx is freed so file struct of /dev/ublkcX is
2603 * (2) UBLK_S_DEV_QUIESCED is set, which means the quiesce_work:
2604 * (a)has quiesced request queue
2605 * (b)has requeued every inflight rqs whose io_flags is ACTIVE
2606 * (c)has requeued/aborted every inflight rqs whose io_flags is NOT ACTIVE
2607 * (d)has completed/camceled all ioucmds owned by ther dying process
2609 if (test_bit(UB_STATE_OPEN
, &ub
->state
) ||
2610 ub
->dev_info
.state
!= UBLK_S_DEV_QUIESCED
) {
2614 pr_devel("%s: start recovery for dev id %d.\n", __func__
, header
->dev_id
);
2615 for (i
= 0; i
< ub
->dev_info
.nr_hw_queues
; i
++)
2616 ublk_queue_reinit(ub
, ublk_get_queue(ub
, i
));
2617 /* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */
2619 ub
->nr_queues_ready
= 0;
2620 ub
->nr_privileged_daemon
= 0;
2621 init_completion(&ub
->completion
);
2624 mutex_unlock(&ub
->mutex
);
2628 static int ublk_ctrl_end_recovery(struct ublk_device
*ub
,
2629 struct io_uring_cmd
*cmd
)
2631 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2632 int ublksrv_pid
= (int)header
->data
[0];
2635 pr_devel("%s: Waiting for new ubq_daemons(nr: %d) are ready, dev id %d...\n",
2636 __func__
, ub
->dev_info
.nr_hw_queues
, header
->dev_id
);
2637 /* wait until new ubq_daemon sending all FETCH_REQ */
2638 wait_for_completion_interruptible(&ub
->completion
);
2639 pr_devel("%s: All new ubq_daemons(nr: %d) are ready, dev id %d\n",
2640 __func__
, ub
->dev_info
.nr_hw_queues
, header
->dev_id
);
2642 mutex_lock(&ub
->mutex
);
2643 if (!ublk_can_use_recovery(ub
))
2646 if (ub
->dev_info
.state
!= UBLK_S_DEV_QUIESCED
) {
2650 ub
->dev_info
.ublksrv_pid
= ublksrv_pid
;
2651 pr_devel("%s: new ublksrv_pid %d, dev id %d\n",
2652 __func__
, ublksrv_pid
, header
->dev_id
);
2653 blk_mq_unquiesce_queue(ub
->ub_disk
->queue
);
2654 pr_devel("%s: queue unquiesced, dev id %d.\n",
2655 __func__
, header
->dev_id
);
2656 blk_mq_kick_requeue_list(ub
->ub_disk
->queue
);
2657 ub
->dev_info
.state
= UBLK_S_DEV_LIVE
;
2658 schedule_delayed_work(&ub
->monitor_work
, UBLK_DAEMON_MONITOR_PERIOD
);
2661 mutex_unlock(&ub
->mutex
);
2665 static int ublk_ctrl_get_features(struct io_uring_cmd
*cmd
)
2667 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2668 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2669 u64 features
= UBLK_F_ALL
& ~UBLK_F_SUPPORT_ZERO_COPY
;
2671 if (header
->len
!= UBLK_FEATURES_LEN
|| !header
->addr
)
2674 if (copy_to_user(argp
, &features
, UBLK_FEATURES_LEN
))
2681 * All control commands are sent via /dev/ublk-control, so we have to check
2682 * the destination device's permission
2684 static int ublk_char_dev_permission(struct ublk_device
*ub
,
2685 const char *dev_path
, int mask
)
2691 err
= kern_path(dev_path
, LOOKUP_FOLLOW
, &path
);
2695 err
= vfs_getattr(&path
, &stat
, STATX_TYPE
, AT_STATX_SYNC_AS_STAT
);
2700 if (stat
.rdev
!= ub
->cdev_dev
.devt
|| !S_ISCHR(stat
.mode
))
2703 err
= inode_permission(&nop_mnt_idmap
,
2704 d_backing_inode(path
.dentry
), mask
);
2710 static int ublk_ctrl_uring_cmd_permission(struct ublk_device
*ub
,
2711 struct io_uring_cmd
*cmd
)
2713 struct ublksrv_ctrl_cmd
*header
= (struct ublksrv_ctrl_cmd
*)io_uring_sqe_cmd(cmd
->sqe
);
2714 bool unprivileged
= ub
->dev_info
.flags
& UBLK_F_UNPRIVILEGED_DEV
;
2715 void __user
*argp
= (void __user
*)(unsigned long)header
->addr
;
2716 char *dev_path
= NULL
;
2720 if (!unprivileged
) {
2721 if (!capable(CAP_SYS_ADMIN
))
2724 * The new added command of UBLK_CMD_GET_DEV_INFO2 includes
2725 * char_dev_path in payload too, since userspace may not
2726 * know if the specified device is created as unprivileged
2729 if (_IOC_NR(cmd
->cmd_op
) != UBLK_CMD_GET_DEV_INFO2
)
2734 * User has to provide the char device path for unprivileged ublk
2736 * header->addr always points to the dev path buffer, and
2737 * header->dev_path_len records length of dev path buffer.
2739 if (!header
->dev_path_len
|| header
->dev_path_len
> PATH_MAX
)
2742 if (header
->len
< header
->dev_path_len
)
2745 dev_path
= kmalloc(header
->dev_path_len
+ 1, GFP_KERNEL
);
2750 if (copy_from_user(dev_path
, argp
, header
->dev_path_len
))
2752 dev_path
[header
->dev_path_len
] = 0;
2755 switch (_IOC_NR(cmd
->cmd_op
)) {
2756 case UBLK_CMD_GET_DEV_INFO
:
2757 case UBLK_CMD_GET_DEV_INFO2
:
2758 case UBLK_CMD_GET_QUEUE_AFFINITY
:
2759 case UBLK_CMD_GET_PARAMS
:
2760 case (_IOC_NR(UBLK_U_CMD_GET_FEATURES
)):
2763 case UBLK_CMD_START_DEV
:
2764 case UBLK_CMD_STOP_DEV
:
2765 case UBLK_CMD_ADD_DEV
:
2766 case UBLK_CMD_DEL_DEV
:
2767 case UBLK_CMD_SET_PARAMS
:
2768 case UBLK_CMD_START_USER_RECOVERY
:
2769 case UBLK_CMD_END_USER_RECOVERY
:
2770 mask
= MAY_READ
| MAY_WRITE
;
2776 ret
= ublk_char_dev_permission(ub
, dev_path
, mask
);
2778 header
->len
-= header
->dev_path_len
;
2779 header
->addr
+= header
->dev_path_len
;
2781 pr_devel("%s: dev id %d cmd_op %x uid %d gid %d path %s ret %d\n",
2782 __func__
, ub
->ub_number
, cmd
->cmd_op
,
2783 ub
->dev_info
.owner_uid
, ub
->dev_info
.owner_gid
,
2790 static int ublk_ctrl_uring_cmd(struct io_uring_cmd
*cmd
,
2791 unsigned int issue_flags
)
2793 const struct ublksrv_ctrl_cmd
*header
= io_uring_sqe_cmd(cmd
->sqe
);
2794 struct ublk_device
*ub
= NULL
;
2795 u32 cmd_op
= cmd
->cmd_op
;
2798 if (issue_flags
& IO_URING_F_NONBLOCK
)
2801 ublk_ctrl_cmd_dump(cmd
);
2803 if (!(issue_flags
& IO_URING_F_SQE128
))
2806 ret
= ublk_check_cmd_op(cmd_op
);
2810 if (cmd_op
== UBLK_U_CMD_GET_FEATURES
) {
2811 ret
= ublk_ctrl_get_features(cmd
);
2815 if (_IOC_NR(cmd_op
) != UBLK_CMD_ADD_DEV
) {
2817 ub
= ublk_get_device_from_id(header
->dev_id
);
2821 ret
= ublk_ctrl_uring_cmd_permission(ub
, cmd
);
2826 switch (_IOC_NR(cmd_op
)) {
2827 case UBLK_CMD_START_DEV
:
2828 ret
= ublk_ctrl_start_dev(ub
, cmd
);
2830 case UBLK_CMD_STOP_DEV
:
2831 ret
= ublk_ctrl_stop_dev(ub
);
2833 case UBLK_CMD_GET_DEV_INFO
:
2834 case UBLK_CMD_GET_DEV_INFO2
:
2835 ret
= ublk_ctrl_get_dev_info(ub
, cmd
);
2837 case UBLK_CMD_ADD_DEV
:
2838 ret
= ublk_ctrl_add_dev(cmd
);
2840 case UBLK_CMD_DEL_DEV
:
2841 ret
= ublk_ctrl_del_dev(&ub
);
2843 case UBLK_CMD_GET_QUEUE_AFFINITY
:
2844 ret
= ublk_ctrl_get_queue_affinity(ub
, cmd
);
2846 case UBLK_CMD_GET_PARAMS
:
2847 ret
= ublk_ctrl_get_params(ub
, cmd
);
2849 case UBLK_CMD_SET_PARAMS
:
2850 ret
= ublk_ctrl_set_params(ub
, cmd
);
2852 case UBLK_CMD_START_USER_RECOVERY
:
2853 ret
= ublk_ctrl_start_recovery(ub
, cmd
);
2855 case UBLK_CMD_END_USER_RECOVERY
:
2856 ret
= ublk_ctrl_end_recovery(ub
, cmd
);
2865 ublk_put_device(ub
);
2867 io_uring_cmd_done(cmd
, ret
, 0, issue_flags
);
2868 pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n",
2869 __func__
, ret
, cmd
->cmd_op
, header
->dev_id
, header
->queue_id
);
2870 return -EIOCBQUEUED
;
2873 static const struct file_operations ublk_ctl_fops
= {
2874 .open
= nonseekable_open
,
2875 .uring_cmd
= ublk_ctrl_uring_cmd
,
2876 .owner
= THIS_MODULE
,
2877 .llseek
= noop_llseek
,
2880 static struct miscdevice ublk_misc
= {
2881 .minor
= MISC_DYNAMIC_MINOR
,
2882 .name
= "ublk-control",
2883 .fops
= &ublk_ctl_fops
,
2886 static int __init
ublk_init(void)
2890 BUILD_BUG_ON((u64
)UBLKSRV_IO_BUF_OFFSET
+
2891 UBLKSRV_IO_BUF_TOTAL_SIZE
< UBLKSRV_IO_BUF_OFFSET
);
2893 init_waitqueue_head(&ublk_idr_wq
);
2895 ret
= misc_register(&ublk_misc
);
2899 ret
= alloc_chrdev_region(&ublk_chr_devt
, 0, UBLK_MINORS
, "ublk-char");
2901 goto unregister_mis
;
2903 ret
= class_register(&ublk_chr_class
);
2905 goto free_chrdev_region
;
2910 unregister_chrdev_region(ublk_chr_devt
, UBLK_MINORS
);
2912 misc_deregister(&ublk_misc
);
2916 static void __exit
ublk_exit(void)
2918 struct ublk_device
*ub
;
2921 idr_for_each_entry(&ublk_index_idr
, ub
, id
)
2924 class_unregister(&ublk_chr_class
);
2925 misc_deregister(&ublk_misc
);
2927 idr_destroy(&ublk_index_idr
);
2928 unregister_chrdev_region(ublk_chr_devt
, UBLK_MINORS
);
2931 module_init(ublk_init
);
2932 module_exit(ublk_exit
);
2934 module_param(ublks_max
, int, 0444);
2935 MODULE_PARM_DESC(ublks_max
, "max number of ublk devices allowed to add(default: 64)");
2937 MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>");
2938 MODULE_LICENSE("GPL");