1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * RDMA Network Block Driver
5 * Copyright (c) 2014 - 2018 ProfitBricks GmbH. All rights reserved.
6 * Copyright (c) 2018 - 2019 1&1 IONOS Cloud GmbH. All rights reserved.
7 * Copyright (c) 2019 - 2020 1&1 IONOS SE. All rights reserved.
11 #define pr_fmt(fmt) KBUILD_MODNAME " L" __stringify(__LINE__) ": " fmt
13 #include <linux/module.h>
14 #include <linux/blkdev.h>
15 #include <linux/hdreg.h>
16 #include <linux/scatterlist.h>
17 #include <linux/idr.h>
21 MODULE_DESCRIPTION("RDMA Network Block Device Client");
22 MODULE_LICENSE("GPL");
24 static int rnbd_client_major;
25 static DEFINE_IDA(index_ida);
26 static DEFINE_MUTEX(ida_lock);
27 static DEFINE_MUTEX(sess_lock);
28 static LIST_HEAD(sess_list);
31 * Maximum number of partitions an instance can have.
32 * 6 bits = 64 minors = 63 partitions (one minor is used for the device itself)
34 #define RNBD_PART_BITS 6
36 static inline bool rnbd_clt_get_sess(struct rnbd_clt_session *sess)
38 return refcount_inc_not_zero(&sess->refcount);
41 static void free_sess(struct rnbd_clt_session *sess);
43 static void rnbd_clt_put_sess(struct rnbd_clt_session *sess)
47 if (refcount_dec_and_test(&sess->refcount))
51 static void rnbd_clt_put_dev(struct rnbd_clt_dev *dev)
55 if (!refcount_dec_and_test(&dev->refcount))
58 mutex_lock(&ida_lock);
59 ida_simple_remove(&index_ida, dev->clt_device_id);
60 mutex_unlock(&ida_lock);
61 kfree(dev->hw_queues);
63 rnbd_clt_put_sess(dev->sess);
64 mutex_destroy(&dev->lock);
68 static inline bool rnbd_clt_get_dev(struct rnbd_clt_dev *dev)
70 return refcount_inc_not_zero(&dev->refcount);
73 static int rnbd_clt_set_dev_attr(struct rnbd_clt_dev *dev,
74 const struct rnbd_msg_open_rsp *rsp)
76 struct rnbd_clt_session *sess = dev->sess;
78 if (!rsp->logical_block_size)
81 dev->device_id = le32_to_cpu(rsp->device_id);
82 dev->nsectors = le64_to_cpu(rsp->nsectors);
83 dev->logical_block_size = le16_to_cpu(rsp->logical_block_size);
84 dev->physical_block_size = le16_to_cpu(rsp->physical_block_size);
85 dev->max_write_same_sectors = le32_to_cpu(rsp->max_write_same_sectors);
86 dev->max_discard_sectors = le32_to_cpu(rsp->max_discard_sectors);
87 dev->discard_granularity = le32_to_cpu(rsp->discard_granularity);
88 dev->discard_alignment = le32_to_cpu(rsp->discard_alignment);
89 dev->secure_discard = le16_to_cpu(rsp->secure_discard);
90 dev->rotational = rsp->rotational;
91 dev->wc = !!(rsp->cache_policy & RNBD_WRITEBACK);
92 dev->fua = !!(rsp->cache_policy & RNBD_FUA);
94 dev->max_hw_sectors = sess->max_io_size / SECTOR_SIZE;
95 dev->max_segments = sess->max_segments;
100 static int rnbd_clt_change_capacity(struct rnbd_clt_dev *dev,
103 rnbd_clt_info(dev, "Device size changed from %zu to %zu sectors\n",
104 dev->nsectors, new_nsectors);
105 dev->nsectors = new_nsectors;
106 set_capacity_and_notify(dev->gd, dev->nsectors);
110 static int process_msg_open_rsp(struct rnbd_clt_dev *dev,
111 struct rnbd_msg_open_rsp *rsp)
113 struct kobject *gd_kobj;
116 mutex_lock(&dev->lock);
117 if (dev->dev_state == DEV_STATE_UNMAPPED) {
119 "Ignoring Open-Response message from server for unmapped device\n");
123 if (dev->dev_state == DEV_STATE_MAPPED_DISCONNECTED) {
124 u64 nsectors = le64_to_cpu(rsp->nsectors);
127 * If the device was remapped and the size changed in the
128 * meantime we need to revalidate it
130 if (dev->nsectors != nsectors)
131 rnbd_clt_change_capacity(dev, nsectors);
132 gd_kobj = &disk_to_dev(dev->gd)->kobj;
133 kobject_uevent(gd_kobj, KOBJ_ONLINE);
134 rnbd_clt_info(dev, "Device online, device remapped successfully\n");
136 err = rnbd_clt_set_dev_attr(dev, rsp);
139 dev->dev_state = DEV_STATE_MAPPED;
142 mutex_unlock(&dev->lock);
147 int rnbd_clt_resize_disk(struct rnbd_clt_dev *dev, size_t newsize)
151 mutex_lock(&dev->lock);
152 if (dev->dev_state != DEV_STATE_MAPPED) {
153 pr_err("Failed to set new size of the device, device is not opened\n");
157 ret = rnbd_clt_change_capacity(dev, newsize);
160 mutex_unlock(&dev->lock);
165 static inline void rnbd_clt_dev_requeue(struct rnbd_queue *q)
167 if (WARN_ON(!q->hctx))
170 /* We can come here from interrupt, thus async=true */
171 blk_mq_run_hw_queue(q->hctx, true);
175 RNBD_DELAY_IFBUSY = -1,
179 * rnbd_get_cpu_qlist() - finds a list with HW queues to be rerun
180 * @sess: Session to find a queue for
181 * @cpu: Cpu to start the search from
184 * Each CPU has a list of HW queues, which needs to be rerun. If a list
185 * is not empty - it is marked with a bit. This function finds first
186 * set bit in a bitmap and returns corresponding CPU list.
188 static struct rnbd_cpu_qlist *
189 rnbd_get_cpu_qlist(struct rnbd_clt_session *sess, int cpu)
193 /* Search from cpu to nr_cpu_ids */
194 bit = find_next_bit(sess->cpu_queues_bm, nr_cpu_ids, cpu);
195 if (bit < nr_cpu_ids) {
196 return per_cpu_ptr(sess->cpu_queues, bit);
197 } else if (cpu != 0) {
198 /* Search from 0 to cpu */
199 bit = find_next_bit(sess->cpu_queues_bm, cpu, 0);
201 return per_cpu_ptr(sess->cpu_queues, bit);
207 static inline int nxt_cpu(int cpu)
209 return (cpu + 1) % nr_cpu_ids;
213 * rnbd_rerun_if_needed() - rerun next queue marked as stopped
214 * @sess: Session to rerun a queue on
217 * Each CPU has it's own list of HW queues, which should be rerun.
218 * Function finds such list with HW queues, takes a list lock, picks up
219 * the first HW queue out of the list and requeues it.
222 * True if the queue was requeued, false otherwise.
227 static bool rnbd_rerun_if_needed(struct rnbd_clt_session *sess)
229 struct rnbd_queue *q = NULL;
230 struct rnbd_cpu_qlist *cpu_q;
235 * To keep fairness and not to let other queues starve we always
236 * try to wake up someone else in round-robin manner. That of course
237 * increases latency but queues always have a chance to be executed.
239 cpup = get_cpu_ptr(sess->cpu_rr);
240 for (cpu_q = rnbd_get_cpu_qlist(sess, nxt_cpu(*cpup)); cpu_q;
241 cpu_q = rnbd_get_cpu_qlist(sess, nxt_cpu(cpu_q->cpu))) {
242 if (!spin_trylock_irqsave(&cpu_q->requeue_lock, flags))
244 if (!test_bit(cpu_q->cpu, sess->cpu_queues_bm))
246 q = list_first_entry_or_null(&cpu_q->requeue_list,
247 typeof(*q), requeue_list);
250 list_del_init(&q->requeue_list);
251 clear_bit_unlock(0, &q->in_list);
253 if (list_empty(&cpu_q->requeue_list)) {
254 /* Clear bit if nothing is left */
256 clear_bit(cpu_q->cpu, sess->cpu_queues_bm);
259 spin_unlock_irqrestore(&cpu_q->requeue_lock, flags);
266 * Saves the CPU that is going to be requeued on the per-cpu var. Just
267 * incrementing it doesn't work because rnbd_get_cpu_qlist() will
268 * always return the first CPU with something on the queue list when the
269 * value stored on the var is greater than the last CPU with something
274 put_cpu_var(sess->cpu_rr);
277 rnbd_clt_dev_requeue(q);
283 * rnbd_rerun_all_if_idle() - rerun all queues left in the list if
284 * session is idling (there are no requests
286 * @sess: Session to rerun the queues on
289 * This function tries to rerun all stopped queues if there are no
290 * requests in-flight anymore. This function tries to solve an obvious
291 * problem, when number of tags < than number of queues (hctx), which
292 * are stopped and put to sleep. If last permit, which has been just put,
293 * does not wake up all left queues (hctxs), IO requests hang forever.
295 * That can happen when all number of permits, say N, have been exhausted
296 * from one CPU, and we have many block devices per session, say M.
297 * Each block device has it's own queue (hctx) for each CPU, so eventually
298 * we can put that number of queues (hctxs) to sleep: M x nr_cpu_ids.
299 * If number of permits N < M x nr_cpu_ids finally we will get an IO hang.
301 * To avoid this hang last caller of rnbd_put_permit() (last caller is the
302 * one who observes sess->busy == 0) must wake up all remaining queues.
307 static void rnbd_rerun_all_if_idle(struct rnbd_clt_session *sess)
312 requeued = rnbd_rerun_if_needed(sess);
313 } while (atomic_read(&sess->busy) == 0 && requeued);
316 static struct rtrs_permit *rnbd_get_permit(struct rnbd_clt_session *sess,
317 enum rtrs_clt_con_type con_type,
320 struct rtrs_permit *permit;
322 permit = rtrs_clt_get_permit(sess->rtrs, con_type, wait);
324 /* We have a subtle rare case here, when all permits can be
325 * consumed before busy counter increased. This is safe,
326 * because loser will get NULL as a permit, observe 0 busy
327 * counter and immediately restart the queue himself.
329 atomic_inc(&sess->busy);
334 static void rnbd_put_permit(struct rnbd_clt_session *sess,
335 struct rtrs_permit *permit)
337 rtrs_clt_put_permit(sess->rtrs, permit);
338 atomic_dec(&sess->busy);
339 /* Paired with rnbd_clt_dev_add_to_requeue(). Decrement first
340 * and then check queue bits.
342 smp_mb__after_atomic();
343 rnbd_rerun_all_if_idle(sess);
346 static struct rnbd_iu *rnbd_get_iu(struct rnbd_clt_session *sess,
347 enum rtrs_clt_con_type con_type,
351 struct rtrs_permit *permit;
353 iu = kzalloc(sizeof(*iu), GFP_KERNEL);
357 permit = rnbd_get_permit(sess, con_type, wait);
365 * 1st reference is dropped after finishing sending a "user" message,
366 * 2nd reference is dropped after confirmation with the response is
368 * 1st and 2nd can happen in any order, so the rnbd_iu should be
369 * released (rtrs_permit returned to rtrs) only after both
372 atomic_set(&iu->refcount, 2);
373 init_waitqueue_head(&iu->comp.wait);
374 iu->comp.errno = INT_MAX;
376 if (sg_alloc_table(&iu->sgt, 1, GFP_KERNEL)) {
377 rnbd_put_permit(sess, permit);
385 static void rnbd_put_iu(struct rnbd_clt_session *sess, struct rnbd_iu *iu)
387 if (atomic_dec_and_test(&iu->refcount)) {
388 sg_free_table(&iu->sgt);
389 rnbd_put_permit(sess, iu->permit);
394 static void rnbd_softirq_done_fn(struct request *rq)
396 struct rnbd_clt_dev *dev = rq->rq_disk->private_data;
397 struct rnbd_clt_session *sess = dev->sess;
400 iu = blk_mq_rq_to_pdu(rq);
401 sg_free_table_chained(&iu->sgt, RNBD_INLINE_SG_CNT);
402 rnbd_put_permit(sess, iu->permit);
403 blk_mq_end_request(rq, errno_to_blk_status(iu->errno));
406 static void msg_io_conf(void *priv, int errno)
408 struct rnbd_iu *iu = priv;
409 struct rnbd_clt_dev *dev = iu->dev;
410 struct request *rq = iu->rq;
411 int rw = rq_data_dir(rq);
415 blk_mq_complete_request(rq);
418 rnbd_clt_info_rl(dev, "%s I/O failed with err: %d\n",
419 rw == READ ? "read" : "write", errno);
422 static void wake_up_iu_comp(struct rnbd_iu *iu, int errno)
424 iu->comp.errno = errno;
425 wake_up(&iu->comp.wait);
428 static void msg_conf(void *priv, int errno)
430 struct rnbd_iu *iu = priv;
433 schedule_work(&iu->work);
436 static int send_usr_msg(struct rtrs_clt *rtrs, int dir,
437 struct rnbd_iu *iu, struct kvec *vec,
438 size_t len, struct scatterlist *sg, unsigned int sg_len,
439 void (*conf)(struct work_struct *work),
440 int *errno, int wait)
443 struct rtrs_clt_req_ops req_ops;
445 INIT_WORK(&iu->work, conf);
446 req_ops = (struct rtrs_clt_req_ops) {
450 err = rtrs_clt_request(dir, &req_ops, rtrs, iu->permit,
451 vec, 1, len, sg, sg_len);
453 wait_event(iu->comp.wait, iu->comp.errno != INT_MAX);
454 *errno = iu->comp.errno;
462 static void msg_close_conf(struct work_struct *work)
464 struct rnbd_iu *iu = container_of(work, struct rnbd_iu, work);
465 struct rnbd_clt_dev *dev = iu->dev;
467 wake_up_iu_comp(iu, iu->errno);
468 rnbd_put_iu(dev->sess, iu);
469 rnbd_clt_put_dev(dev);
472 static int send_msg_close(struct rnbd_clt_dev *dev, u32 device_id,
475 struct rnbd_clt_session *sess = dev->sess;
476 struct rnbd_msg_close msg;
480 .iov_len = sizeof(msg)
484 iu = rnbd_get_iu(sess, RTRS_ADMIN_CON, RTRS_PERMIT_WAIT);
491 msg.hdr.type = cpu_to_le16(RNBD_MSG_CLOSE);
492 msg.device_id = cpu_to_le32(device_id);
494 WARN_ON(!rnbd_clt_get_dev(dev));
495 err = send_usr_msg(sess->rtrs, WRITE, iu, &vec, 0, NULL, 0,
496 msg_close_conf, &errno, wait);
498 rnbd_clt_put_dev(dev);
499 rnbd_put_iu(sess, iu);
504 rnbd_put_iu(sess, iu);
508 static void msg_open_conf(struct work_struct *work)
510 struct rnbd_iu *iu = container_of(work, struct rnbd_iu, work);
511 struct rnbd_msg_open_rsp *rsp = iu->buf;
512 struct rnbd_clt_dev *dev = iu->dev;
513 int errno = iu->errno;
517 "Opening failed, server responded: %d\n",
520 errno = process_msg_open_rsp(dev, rsp);
522 u32 device_id = le32_to_cpu(rsp->device_id);
524 * If server thinks its fine, but we fail to process
525 * then be nice and send a close to server.
527 send_msg_close(dev, device_id, RTRS_PERMIT_NOWAIT);
531 wake_up_iu_comp(iu, errno);
532 rnbd_put_iu(dev->sess, iu);
533 rnbd_clt_put_dev(dev);
536 static void msg_sess_info_conf(struct work_struct *work)
538 struct rnbd_iu *iu = container_of(work, struct rnbd_iu, work);
539 struct rnbd_msg_sess_info_rsp *rsp = iu->buf;
540 struct rnbd_clt_session *sess = iu->sess;
543 sess->ver = min_t(u8, rsp->ver, RNBD_PROTO_VER_MAJOR);
546 wake_up_iu_comp(iu, iu->errno);
547 rnbd_put_iu(sess, iu);
548 rnbd_clt_put_sess(sess);
551 static int send_msg_open(struct rnbd_clt_dev *dev, enum wait_type wait)
553 struct rnbd_clt_session *sess = dev->sess;
554 struct rnbd_msg_open_rsp *rsp;
555 struct rnbd_msg_open msg;
559 .iov_len = sizeof(msg)
563 rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
567 iu = rnbd_get_iu(sess, RTRS_ADMIN_CON, RTRS_PERMIT_WAIT);
576 sg_init_one(iu->sgt.sgl, rsp, sizeof(*rsp));
578 msg.hdr.type = cpu_to_le16(RNBD_MSG_OPEN);
579 msg.access_mode = dev->access_mode;
580 strscpy(msg.dev_name, dev->pathname, sizeof(msg.dev_name));
582 WARN_ON(!rnbd_clt_get_dev(dev));
583 err = send_usr_msg(sess->rtrs, READ, iu,
584 &vec, sizeof(*rsp), iu->sgt.sgl, 1,
585 msg_open_conf, &errno, wait);
587 rnbd_clt_put_dev(dev);
588 rnbd_put_iu(sess, iu);
594 rnbd_put_iu(sess, iu);
598 static int send_msg_sess_info(struct rnbd_clt_session *sess, enum wait_type wait)
600 struct rnbd_msg_sess_info_rsp *rsp;
601 struct rnbd_msg_sess_info msg;
605 .iov_len = sizeof(msg)
609 rsp = kzalloc(sizeof(*rsp), GFP_KERNEL);
613 iu = rnbd_get_iu(sess, RTRS_ADMIN_CON, RTRS_PERMIT_WAIT);
621 sg_init_one(iu->sgt.sgl, rsp, sizeof(*rsp));
623 msg.hdr.type = cpu_to_le16(RNBD_MSG_SESS_INFO);
624 msg.ver = RNBD_PROTO_VER_MAJOR;
626 if (!rnbd_clt_get_sess(sess)) {
628 * That can happen only in one case, when RTRS has restablished
629 * the connection and link_ev() is called, but session is almost
630 * dead, last reference on session is put and caller is waiting
631 * for RTRS to close everything.
636 err = send_usr_msg(sess->rtrs, READ, iu,
637 &vec, sizeof(*rsp), iu->sgt.sgl, 1,
638 msg_sess_info_conf, &errno, wait);
640 rnbd_clt_put_sess(sess);
642 rnbd_put_iu(sess, iu);
647 rnbd_put_iu(sess, iu);
651 static void set_dev_states_to_disconnected(struct rnbd_clt_session *sess)
653 struct rnbd_clt_dev *dev;
654 struct kobject *gd_kobj;
656 mutex_lock(&sess->lock);
657 list_for_each_entry(dev, &sess->devs_list, list) {
658 rnbd_clt_err(dev, "Device disconnected.\n");
660 mutex_lock(&dev->lock);
661 if (dev->dev_state == DEV_STATE_MAPPED) {
662 dev->dev_state = DEV_STATE_MAPPED_DISCONNECTED;
663 gd_kobj = &disk_to_dev(dev->gd)->kobj;
664 kobject_uevent(gd_kobj, KOBJ_OFFLINE);
666 mutex_unlock(&dev->lock);
668 mutex_unlock(&sess->lock);
671 static void remap_devs(struct rnbd_clt_session *sess)
673 struct rnbd_clt_dev *dev;
674 struct rtrs_attrs attrs;
678 * Careful here: we are called from RTRS link event directly,
679 * thus we can't send any RTRS request and wait for response
680 * or RTRS will not be able to complete request with failure
681 * if something goes wrong (failing of outstanding requests
682 * happens exactly from the context where we are blocking now).
684 * So to avoid deadlocks each usr message sent from here must
688 err = send_msg_sess_info(sess, RTRS_PERMIT_NOWAIT);
690 pr_err("send_msg_sess_info(\"%s\"): %d\n", sess->sessname, err);
694 err = rtrs_clt_query(sess->rtrs, &attrs);
696 pr_err("rtrs_clt_query(\"%s\"): %d\n", sess->sessname, err);
699 mutex_lock(&sess->lock);
700 sess->max_io_size = attrs.max_io_size;
702 list_for_each_entry(dev, &sess->devs_list, list) {
705 mutex_lock(&dev->lock);
706 skip = (dev->dev_state == DEV_STATE_INIT);
707 mutex_unlock(&dev->lock);
710 * When device is establishing connection for the first
711 * time - do not remap, it will be closed soon.
715 rnbd_clt_info(dev, "session reconnected, remapping device\n");
716 err = send_msg_open(dev, RTRS_PERMIT_NOWAIT);
718 rnbd_clt_err(dev, "send_msg_open(): %d\n", err);
722 mutex_unlock(&sess->lock);
725 static void rnbd_clt_link_ev(void *priv, enum rtrs_clt_link_ev ev)
727 struct rnbd_clt_session *sess = priv;
730 case RTRS_CLT_LINK_EV_DISCONNECTED:
731 set_dev_states_to_disconnected(sess);
733 case RTRS_CLT_LINK_EV_RECONNECTED:
737 pr_err("Unknown session event received (%d), session: %s\n",
742 static void rnbd_init_cpu_qlists(struct rnbd_cpu_qlist __percpu *cpu_queues)
745 struct rnbd_cpu_qlist *cpu_q;
747 for_each_possible_cpu(cpu) {
748 cpu_q = per_cpu_ptr(cpu_queues, cpu);
751 INIT_LIST_HEAD(&cpu_q->requeue_list);
752 spin_lock_init(&cpu_q->requeue_lock);
756 static void destroy_mq_tags(struct rnbd_clt_session *sess)
758 if (sess->tag_set.tags)
759 blk_mq_free_tag_set(&sess->tag_set);
762 static inline void wake_up_rtrs_waiters(struct rnbd_clt_session *sess)
764 sess->rtrs_ready = true;
765 wake_up_all(&sess->rtrs_waitq);
768 static void close_rtrs(struct rnbd_clt_session *sess)
772 if (!IS_ERR_OR_NULL(sess->rtrs)) {
773 rtrs_clt_close(sess->rtrs);
775 wake_up_rtrs_waiters(sess);
779 static void free_sess(struct rnbd_clt_session *sess)
781 WARN_ON(!list_empty(&sess->devs_list));
786 destroy_mq_tags(sess);
787 if (!list_empty(&sess->list)) {
788 mutex_lock(&sess_lock);
789 list_del(&sess->list);
790 mutex_unlock(&sess_lock);
792 free_percpu(sess->cpu_queues);
793 free_percpu(sess->cpu_rr);
794 mutex_destroy(&sess->lock);
798 static struct rnbd_clt_session *alloc_sess(const char *sessname)
800 struct rnbd_clt_session *sess;
803 sess = kzalloc_node(sizeof(*sess), GFP_KERNEL, NUMA_NO_NODE);
805 return ERR_PTR(-ENOMEM);
806 strscpy(sess->sessname, sessname, sizeof(sess->sessname));
807 atomic_set(&sess->busy, 0);
808 mutex_init(&sess->lock);
809 INIT_LIST_HEAD(&sess->devs_list);
810 INIT_LIST_HEAD(&sess->list);
811 bitmap_zero(sess->cpu_queues_bm, num_possible_cpus());
812 init_waitqueue_head(&sess->rtrs_waitq);
813 refcount_set(&sess->refcount, 1);
815 sess->cpu_queues = alloc_percpu(struct rnbd_cpu_qlist);
816 if (!sess->cpu_queues) {
820 rnbd_init_cpu_qlists(sess->cpu_queues);
823 * That is simple percpu variable which stores cpu indices, which are
824 * incremented on each access. We need that for the sake of fairness
825 * to wake up queues in a round-robin manner.
827 sess->cpu_rr = alloc_percpu(int);
832 for_each_possible_cpu(cpu)
833 * per_cpu_ptr(sess->cpu_rr, cpu) = cpu;
843 static int wait_for_rtrs_connection(struct rnbd_clt_session *sess)
845 wait_event(sess->rtrs_waitq, sess->rtrs_ready);
846 if (IS_ERR_OR_NULL(sess->rtrs))
852 static void wait_for_rtrs_disconnection(struct rnbd_clt_session *sess)
853 __releases(&sess_lock)
854 __acquires(&sess_lock)
858 prepare_to_wait(&sess->rtrs_waitq, &wait, TASK_UNINTERRUPTIBLE);
859 if (IS_ERR_OR_NULL(sess->rtrs)) {
860 finish_wait(&sess->rtrs_waitq, &wait);
863 mutex_unlock(&sess_lock);
864 /* loop in caller, see __find_and_get_sess().
865 * You can't leave mutex locked and call schedule(), you will catch a
866 * deadlock with a caller of free_sess(), which has just put the last
867 * reference and is about to take the sess_lock in order to delete
868 * the session from the list.
871 mutex_lock(&sess_lock);
874 static struct rnbd_clt_session *__find_and_get_sess(const char *sessname)
875 __releases(&sess_lock)
876 __acquires(&sess_lock)
878 struct rnbd_clt_session *sess, *sn;
882 list_for_each_entry_safe(sess, sn, &sess_list, list) {
883 if (strcmp(sessname, sess->sessname))
886 if (sess->rtrs_ready && IS_ERR_OR_NULL(sess->rtrs))
888 * No RTRS connection, session is dying.
892 if (rnbd_clt_get_sess(sess)) {
894 * Alive session is found, wait for RTRS connection.
896 mutex_unlock(&sess_lock);
897 err = wait_for_rtrs_connection(sess);
899 rnbd_clt_put_sess(sess);
900 mutex_lock(&sess_lock);
903 /* Session is dying, repeat the loop */
909 * Ref is 0, session is dying, wait for RTRS disconnect
910 * in order to avoid session names clashes.
912 wait_for_rtrs_disconnection(sess);
914 * RTRS is disconnected and soon session will be freed,
923 /* caller is responsible for initializing 'first' to false */
925 rnbd_clt_session *find_or_create_sess(const char *sessname, bool *first)
927 struct rnbd_clt_session *sess = NULL;
929 mutex_lock(&sess_lock);
930 sess = __find_and_get_sess(sessname);
932 sess = alloc_sess(sessname);
934 mutex_unlock(&sess_lock);
937 list_add(&sess->list, &sess_list);
940 mutex_unlock(&sess_lock);
945 static int rnbd_client_open(struct block_device *block_device, fmode_t mode)
947 struct rnbd_clt_dev *dev = block_device->bd_disk->private_data;
949 if (dev->read_only && (mode & FMODE_WRITE))
952 if (dev->dev_state == DEV_STATE_UNMAPPED ||
953 !rnbd_clt_get_dev(dev))
959 static void rnbd_client_release(struct gendisk *gen, fmode_t mode)
961 struct rnbd_clt_dev *dev = gen->private_data;
963 rnbd_clt_put_dev(dev);
966 static int rnbd_client_getgeo(struct block_device *block_device,
967 struct hd_geometry *geo)
970 struct rnbd_clt_dev *dev;
972 dev = block_device->bd_disk->private_data;
973 size = dev->size * (dev->logical_block_size / SECTOR_SIZE);
974 geo->cylinders = size >> 6; /* size/64 */
982 static const struct block_device_operations rnbd_client_ops = {
983 .owner = THIS_MODULE,
984 .open = rnbd_client_open,
985 .release = rnbd_client_release,
986 .getgeo = rnbd_client_getgeo
989 /* The amount of data that belongs to an I/O and the amount of data that
990 * should be read or written to the disk (bi_size) can differ.
992 * E.g. When WRITE_SAME is used, only a small amount of data is
993 * transferred that is then written repeatedly over a lot of sectors.
995 * Get the size of data to be transferred via RTRS by summing up the size
996 * of the scather-gather list entries.
998 static size_t rnbd_clt_get_sg_size(struct scatterlist *sglist, u32 len)
1000 struct scatterlist *sg;
1004 for_each_sg(sglist, sg, len, i)
1005 tsize += sg->length;
1009 static int rnbd_client_xfer_request(struct rnbd_clt_dev *dev,
1013 struct rtrs_clt *rtrs = dev->sess->rtrs;
1014 struct rtrs_permit *permit = iu->permit;
1015 struct rnbd_msg_io msg;
1016 struct rtrs_clt_req_ops req_ops;
1017 unsigned int sg_cnt = 0;
1024 msg.sector = cpu_to_le64(blk_rq_pos(rq));
1025 msg.bi_size = cpu_to_le32(blk_rq_bytes(rq));
1026 msg.rw = cpu_to_le32(rq_to_rnbd_flags(rq));
1027 msg.prio = cpu_to_le16(req_get_ioprio(rq));
1030 * We only support discards with single segment for now.
1033 if (req_op(rq) != REQ_OP_DISCARD)
1034 sg_cnt = blk_rq_map_sg(dev->queue, rq, iu->sgt.sgl);
1037 sg_mark_end(&iu->sgt.sgl[0]);
1039 msg.hdr.type = cpu_to_le16(RNBD_MSG_IO);
1040 msg.device_id = cpu_to_le32(dev->device_id);
1042 vec = (struct kvec) {
1044 .iov_len = sizeof(msg)
1046 size = rnbd_clt_get_sg_size(iu->sgt.sgl, sg_cnt);
1047 req_ops = (struct rtrs_clt_req_ops) {
1049 .conf_fn = msg_io_conf,
1051 err = rtrs_clt_request(rq_data_dir(rq), &req_ops, rtrs, permit,
1052 &vec, 1, size, iu->sgt.sgl, sg_cnt);
1054 rnbd_clt_err_rl(dev, "RTRS failed to transfer IO, err: %d\n",
1063 * rnbd_clt_dev_add_to_requeue() - add device to requeue if session is busy
1064 * @dev: Device to be checked
1065 * @q: Queue to be added to the requeue list if required
1068 * If session is busy, that means someone will requeue us when resources
1069 * are freed. If session is not doing anything - device is not added to
1070 * the list and @false is returned.
1072 static bool rnbd_clt_dev_add_to_requeue(struct rnbd_clt_dev *dev,
1073 struct rnbd_queue *q)
1075 struct rnbd_clt_session *sess = dev->sess;
1076 struct rnbd_cpu_qlist *cpu_q;
1077 unsigned long flags;
1081 cpu_q = get_cpu_ptr(sess->cpu_queues);
1082 spin_lock_irqsave(&cpu_q->requeue_lock, flags);
1084 if (!test_and_set_bit_lock(0, &q->in_list)) {
1085 if (WARN_ON(!list_empty(&q->requeue_list)))
1088 need_set = !test_bit(cpu_q->cpu, sess->cpu_queues_bm);
1090 set_bit(cpu_q->cpu, sess->cpu_queues_bm);
1091 /* Paired with rnbd_put_permit(). Set a bit first
1092 * and then observe the busy counter.
1094 smp_mb__before_atomic();
1096 if (atomic_read(&sess->busy)) {
1097 list_add_tail(&q->requeue_list, &cpu_q->requeue_list);
1099 /* Very unlikely, but possible: busy counter was
1100 * observed as zero. Drop all bits and return
1101 * false to restart the queue by ourselves.
1104 clear_bit(cpu_q->cpu, sess->cpu_queues_bm);
1105 clear_bit_unlock(0, &q->in_list);
1110 spin_unlock_irqrestore(&cpu_q->requeue_lock, flags);
1111 put_cpu_ptr(sess->cpu_queues);
1116 static void rnbd_clt_dev_kick_mq_queue(struct rnbd_clt_dev *dev,
1117 struct blk_mq_hw_ctx *hctx,
1120 struct rnbd_queue *q = hctx->driver_data;
1122 if (delay != RNBD_DELAY_IFBUSY)
1123 blk_mq_delay_run_hw_queue(hctx, delay);
1124 else if (!rnbd_clt_dev_add_to_requeue(dev, q))
1126 * If session is not busy we have to restart
1127 * the queue ourselves.
1129 blk_mq_delay_run_hw_queue(hctx, 10/*ms*/);
1132 static blk_status_t rnbd_queue_rq(struct blk_mq_hw_ctx *hctx,
1133 const struct blk_mq_queue_data *bd)
1135 struct request *rq = bd->rq;
1136 struct rnbd_clt_dev *dev = rq->rq_disk->private_data;
1137 struct rnbd_iu *iu = blk_mq_rq_to_pdu(rq);
1139 blk_status_t ret = BLK_STS_IOERR;
1141 if (dev->dev_state != DEV_STATE_MAPPED)
1142 return BLK_STS_IOERR;
1144 iu->permit = rnbd_get_permit(dev->sess, RTRS_IO_CON,
1145 RTRS_PERMIT_NOWAIT);
1147 rnbd_clt_dev_kick_mq_queue(dev, hctx, RNBD_DELAY_IFBUSY);
1148 return BLK_STS_RESOURCE;
1151 iu->sgt.sgl = iu->first_sgl;
1152 err = sg_alloc_table_chained(&iu->sgt,
1153 /* Even-if the request has no segment,
1154 * sglist must have one entry at least.
1156 blk_rq_nr_phys_segments(rq) ? : 1,
1158 RNBD_INLINE_SG_CNT);
1160 rnbd_clt_err_rl(dev, "sg_alloc_table_chained ret=%d\n", err);
1161 rnbd_clt_dev_kick_mq_queue(dev, hctx, 10/*ms*/);
1162 rnbd_put_permit(dev->sess, iu->permit);
1163 return BLK_STS_RESOURCE;
1166 blk_mq_start_request(rq);
1167 err = rnbd_client_xfer_request(dev, rq, iu);
1170 if (err == -EAGAIN || err == -ENOMEM) {
1171 rnbd_clt_dev_kick_mq_queue(dev, hctx, 10/*ms*/);
1172 ret = BLK_STS_RESOURCE;
1174 sg_free_table_chained(&iu->sgt, RNBD_INLINE_SG_CNT);
1175 rnbd_put_permit(dev->sess, iu->permit);
1179 static int rnbd_rdma_poll(struct blk_mq_hw_ctx *hctx)
1181 struct rnbd_queue *q = hctx->driver_data;
1182 struct rnbd_clt_dev *dev = q->dev;
1185 cnt = rtrs_clt_rdma_cq_direct(dev->sess->rtrs, hctx->queue_num);
1189 static int rnbd_rdma_map_queues(struct blk_mq_tag_set *set)
1191 struct rnbd_clt_session *sess = set->driver_data;
1193 /* shared read/write queues */
1194 set->map[HCTX_TYPE_DEFAULT].nr_queues = num_online_cpus();
1195 set->map[HCTX_TYPE_DEFAULT].queue_offset = 0;
1196 set->map[HCTX_TYPE_READ].nr_queues = num_online_cpus();
1197 set->map[HCTX_TYPE_READ].queue_offset = 0;
1198 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1199 blk_mq_map_queues(&set->map[HCTX_TYPE_READ]);
1201 if (sess->nr_poll_queues) {
1202 /* dedicated queue for poll */
1203 set->map[HCTX_TYPE_POLL].nr_queues = sess->nr_poll_queues;
1204 set->map[HCTX_TYPE_POLL].queue_offset = set->map[HCTX_TYPE_READ].queue_offset +
1205 set->map[HCTX_TYPE_READ].nr_queues;
1206 blk_mq_map_queues(&set->map[HCTX_TYPE_POLL]);
1207 pr_info("[session=%s] mapped %d/%d/%d default/read/poll queues.\n",
1209 set->map[HCTX_TYPE_DEFAULT].nr_queues,
1210 set->map[HCTX_TYPE_READ].nr_queues,
1211 set->map[HCTX_TYPE_POLL].nr_queues);
1213 pr_info("[session=%s] mapped %d/%d default/read queues.\n",
1215 set->map[HCTX_TYPE_DEFAULT].nr_queues,
1216 set->map[HCTX_TYPE_READ].nr_queues);
1222 static struct blk_mq_ops rnbd_mq_ops = {
1223 .queue_rq = rnbd_queue_rq,
1224 .complete = rnbd_softirq_done_fn,
1225 .map_queues = rnbd_rdma_map_queues,
1226 .poll = rnbd_rdma_poll,
1229 static int setup_mq_tags(struct rnbd_clt_session *sess)
1231 struct blk_mq_tag_set *tag_set = &sess->tag_set;
1233 memset(tag_set, 0, sizeof(*tag_set));
1234 tag_set->ops = &rnbd_mq_ops;
1235 tag_set->queue_depth = sess->queue_depth;
1236 tag_set->numa_node = NUMA_NO_NODE;
1237 tag_set->flags = BLK_MQ_F_SHOULD_MERGE |
1238 BLK_MQ_F_TAG_QUEUE_SHARED;
1239 tag_set->cmd_size = sizeof(struct rnbd_iu) + RNBD_RDMA_SGL_SIZE;
1241 /* for HCTX_TYPE_DEFAULT, HCTX_TYPE_READ, HCTX_TYPE_POLL */
1242 tag_set->nr_maps = sess->nr_poll_queues ? HCTX_MAX_TYPES : 2;
1244 * HCTX_TYPE_DEFAULT and HCTX_TYPE_READ share one set of queues
1245 * others are for HCTX_TYPE_POLL
1247 tag_set->nr_hw_queues = num_online_cpus() + sess->nr_poll_queues;
1248 tag_set->driver_data = sess;
1250 return blk_mq_alloc_tag_set(tag_set);
1253 static struct rnbd_clt_session *
1254 find_and_get_or_create_sess(const char *sessname,
1255 const struct rtrs_addr *paths,
1256 size_t path_cnt, u16 port_nr, u32 nr_poll_queues)
1258 struct rnbd_clt_session *sess;
1259 struct rtrs_attrs attrs;
1262 struct rtrs_clt_ops rtrs_ops;
1264 sess = find_or_create_sess(sessname, &first);
1265 if (sess == ERR_PTR(-ENOMEM))
1266 return ERR_PTR(-ENOMEM);
1267 else if ((nr_poll_queues && !first) || (!nr_poll_queues && sess->nr_poll_queues)) {
1269 * A device MUST have its own session to use the polling-mode.
1270 * It must fail to map new device with the same session.
1280 pr_err("Session %s not found, and path parameter not given", sessname);
1285 rtrs_ops = (struct rtrs_clt_ops) {
1287 .link_ev = rnbd_clt_link_ev,
1290 * Nothing was found, establish rtrs connection and proceed further.
1292 sess->rtrs = rtrs_clt_open(&rtrs_ops, sessname,
1293 paths, path_cnt, port_nr,
1294 0, /* Do not use pdu of rtrs */
1296 MAX_RECONNECTS, nr_poll_queues);
1297 if (IS_ERR(sess->rtrs)) {
1298 err = PTR_ERR(sess->rtrs);
1299 goto wake_up_and_put;
1302 err = rtrs_clt_query(sess->rtrs, &attrs);
1306 sess->max_io_size = attrs.max_io_size;
1307 sess->queue_depth = attrs.queue_depth;
1308 sess->nr_poll_queues = nr_poll_queues;
1309 sess->max_segments = attrs.max_segments;
1311 err = setup_mq_tags(sess);
1315 err = send_msg_sess_info(sess, RTRS_PERMIT_WAIT);
1319 wake_up_rtrs_waiters(sess);
1326 rnbd_clt_put_sess(sess);
1328 return ERR_PTR(err);
1331 wake_up_rtrs_waiters(sess);
1335 static inline void rnbd_init_hw_queue(struct rnbd_clt_dev *dev,
1336 struct rnbd_queue *q,
1337 struct blk_mq_hw_ctx *hctx)
1339 INIT_LIST_HEAD(&q->requeue_list);
1344 static void rnbd_init_mq_hw_queues(struct rnbd_clt_dev *dev)
1347 struct blk_mq_hw_ctx *hctx;
1348 struct rnbd_queue *q;
1350 queue_for_each_hw_ctx(dev->queue, hctx, i) {
1351 q = &dev->hw_queues[i];
1352 rnbd_init_hw_queue(dev, q, hctx);
1353 hctx->driver_data = q;
1357 static void setup_request_queue(struct rnbd_clt_dev *dev)
1359 blk_queue_logical_block_size(dev->queue, dev->logical_block_size);
1360 blk_queue_physical_block_size(dev->queue, dev->physical_block_size);
1361 blk_queue_max_hw_sectors(dev->queue, dev->max_hw_sectors);
1362 blk_queue_max_write_same_sectors(dev->queue,
1363 dev->max_write_same_sectors);
1366 * we don't support discards to "discontiguous" segments
1369 blk_queue_max_discard_segments(dev->queue, 1);
1371 blk_queue_max_discard_sectors(dev->queue, dev->max_discard_sectors);
1372 dev->queue->limits.discard_granularity = dev->discard_granularity;
1373 dev->queue->limits.discard_alignment = dev->discard_alignment;
1374 if (dev->max_discard_sectors)
1375 blk_queue_flag_set(QUEUE_FLAG_DISCARD, dev->queue);
1376 if (dev->secure_discard)
1377 blk_queue_flag_set(QUEUE_FLAG_SECERASE, dev->queue);
1379 blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, dev->queue);
1380 blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, dev->queue);
1381 blk_queue_max_segments(dev->queue, dev->max_segments);
1382 blk_queue_io_opt(dev->queue, dev->sess->max_io_size);
1383 blk_queue_virt_boundary(dev->queue, SZ_4K - 1);
1384 blk_queue_write_cache(dev->queue, dev->wc, dev->fua);
1387 static void rnbd_clt_setup_gen_disk(struct rnbd_clt_dev *dev, int idx)
1389 dev->gd->major = rnbd_client_major;
1390 dev->gd->first_minor = idx << RNBD_PART_BITS;
1391 dev->gd->minors = 1 << RNBD_PART_BITS;
1392 dev->gd->fops = &rnbd_client_ops;
1393 dev->gd->queue = dev->queue;
1394 dev->gd->private_data = dev;
1395 snprintf(dev->gd->disk_name, sizeof(dev->gd->disk_name), "rnbd%d",
1397 pr_debug("disk_name=%s, capacity=%zu\n",
1399 dev->nsectors * (dev->logical_block_size / SECTOR_SIZE)
1402 set_capacity(dev->gd, dev->nsectors);
1404 if (dev->access_mode == RNBD_ACCESS_RO) {
1405 dev->read_only = true;
1406 set_disk_ro(dev->gd, true);
1408 dev->read_only = false;
1411 if (!dev->rotational)
1412 blk_queue_flag_set(QUEUE_FLAG_NONROT, dev->queue);
1416 static int rnbd_client_setup_device(struct rnbd_clt_dev *dev)
1418 int idx = dev->clt_device_id;
1420 dev->size = dev->nsectors * dev->logical_block_size;
1422 dev->gd = blk_mq_alloc_disk(&dev->sess->tag_set, dev);
1423 if (IS_ERR(dev->gd))
1424 return PTR_ERR(dev->gd);
1425 dev->queue = dev->gd->queue;
1426 rnbd_init_mq_hw_queues(dev);
1428 setup_request_queue(dev);
1429 rnbd_clt_setup_gen_disk(dev, idx);
1433 static struct rnbd_clt_dev *init_dev(struct rnbd_clt_session *sess,
1434 enum rnbd_access_mode access_mode,
1435 const char *pathname,
1438 struct rnbd_clt_dev *dev;
1441 dev = kzalloc_node(sizeof(*dev), GFP_KERNEL, NUMA_NO_NODE);
1443 return ERR_PTR(-ENOMEM);
1446 * nr_cpu_ids: the number of softirq queues
1447 * nr_poll_queues: the number of polling queues
1449 dev->hw_queues = kcalloc(nr_cpu_ids + nr_poll_queues,
1450 sizeof(*dev->hw_queues),
1452 if (!dev->hw_queues) {
1457 mutex_lock(&ida_lock);
1458 ret = ida_simple_get(&index_ida, 0, 1 << (MINORBITS - RNBD_PART_BITS),
1460 mutex_unlock(&ida_lock);
1462 pr_err("Failed to initialize device '%s' from session %s, allocating idr failed, err: %d\n",
1463 pathname, sess->sessname, ret);
1467 dev->pathname = kstrdup(pathname, GFP_KERNEL);
1468 if (!dev->pathname) {
1473 dev->clt_device_id = ret;
1475 dev->access_mode = access_mode;
1476 dev->nr_poll_queues = nr_poll_queues;
1477 mutex_init(&dev->lock);
1478 refcount_set(&dev->refcount, 1);
1479 dev->dev_state = DEV_STATE_INIT;
1482 * Here we called from sysfs entry, thus clt-sysfs is
1483 * responsible that session will not disappear.
1485 WARN_ON(!rnbd_clt_get_sess(sess));
1490 kfree(dev->hw_queues);
1493 return ERR_PTR(ret);
1496 static bool __exists_dev(const char *pathname, const char *sessname)
1498 struct rnbd_clt_session *sess;
1499 struct rnbd_clt_dev *dev;
1502 list_for_each_entry(sess, &sess_list, list) {
1503 if (sessname && strncmp(sess->sessname, sessname,
1504 sizeof(sess->sessname)))
1506 mutex_lock(&sess->lock);
1507 list_for_each_entry(dev, &sess->devs_list, list) {
1508 if (strlen(dev->pathname) == strlen(pathname) &&
1509 !strcmp(dev->pathname, pathname)) {
1514 mutex_unlock(&sess->lock);
1522 static bool exists_devpath(const char *pathname, const char *sessname)
1526 mutex_lock(&sess_lock);
1527 found = __exists_dev(pathname, sessname);
1528 mutex_unlock(&sess_lock);
1533 static bool insert_dev_if_not_exists_devpath(struct rnbd_clt_dev *dev)
1536 struct rnbd_clt_session *sess = dev->sess;
1538 mutex_lock(&sess_lock);
1539 found = __exists_dev(dev->pathname, sess->sessname);
1541 mutex_lock(&sess->lock);
1542 list_add_tail(&dev->list, &sess->devs_list);
1543 mutex_unlock(&sess->lock);
1545 mutex_unlock(&sess_lock);
1550 static void delete_dev(struct rnbd_clt_dev *dev)
1552 struct rnbd_clt_session *sess = dev->sess;
1554 mutex_lock(&sess->lock);
1555 list_del(&dev->list);
1556 mutex_unlock(&sess->lock);
1559 struct rnbd_clt_dev *rnbd_clt_map_device(const char *sessname,
1560 struct rtrs_addr *paths,
1561 size_t path_cnt, u16 port_nr,
1562 const char *pathname,
1563 enum rnbd_access_mode access_mode,
1566 struct rnbd_clt_session *sess;
1567 struct rnbd_clt_dev *dev;
1570 if (exists_devpath(pathname, sessname))
1571 return ERR_PTR(-EEXIST);
1573 sess = find_and_get_or_create_sess(sessname, paths, path_cnt, port_nr, nr_poll_queues);
1575 return ERR_CAST(sess);
1577 dev = init_dev(sess, access_mode, pathname, nr_poll_queues);
1579 pr_err("map_device: failed to map device '%s' from session %s, can't initialize device, err: %ld\n",
1580 pathname, sess->sessname, PTR_ERR(dev));
1584 if (insert_dev_if_not_exists_devpath(dev)) {
1588 ret = send_msg_open(dev, RTRS_PERMIT_WAIT);
1591 "map_device: failed, can't open remote device, err: %d\n",
1595 mutex_lock(&dev->lock);
1596 pr_debug("Opened remote device: session=%s, path='%s'\n",
1597 sess->sessname, pathname);
1598 ret = rnbd_client_setup_device(dev);
1601 "map_device: Failed to configure device, err: %d\n",
1603 mutex_unlock(&dev->lock);
1608 "map_device: Device mapped as %s (nsectors: %zu, logical_block_size: %d, physical_block_size: %d, max_write_same_sectors: %d, max_discard_sectors: %d, discard_granularity: %d, discard_alignment: %d, secure_discard: %d, max_segments: %d, max_hw_sectors: %d, rotational: %d, wc: %d, fua: %d)\n",
1609 dev->gd->disk_name, dev->nsectors,
1610 dev->logical_block_size, dev->physical_block_size,
1611 dev->max_write_same_sectors, dev->max_discard_sectors,
1612 dev->discard_granularity, dev->discard_alignment,
1613 dev->secure_discard, dev->max_segments,
1614 dev->max_hw_sectors, dev->rotational, dev->wc, dev->fua);
1616 mutex_unlock(&dev->lock);
1617 rnbd_clt_put_sess(sess);
1622 send_msg_close(dev, dev->device_id, RTRS_PERMIT_WAIT);
1626 rnbd_clt_put_dev(dev);
1628 rnbd_clt_put_sess(sess);
1630 return ERR_PTR(ret);
1633 static void destroy_gen_disk(struct rnbd_clt_dev *dev)
1635 del_gendisk(dev->gd);
1636 blk_cleanup_disk(dev->gd);
1639 static void destroy_sysfs(struct rnbd_clt_dev *dev,
1640 const struct attribute *sysfs_self)
1642 rnbd_clt_remove_dev_symlink(dev);
1643 if (dev->kobj.state_initialized) {
1645 /* To avoid deadlock firstly remove itself */
1646 sysfs_remove_file_self(&dev->kobj, sysfs_self);
1647 kobject_del(&dev->kobj);
1648 kobject_put(&dev->kobj);
1652 int rnbd_clt_unmap_device(struct rnbd_clt_dev *dev, bool force,
1653 const struct attribute *sysfs_self)
1655 struct rnbd_clt_session *sess = dev->sess;
1656 int refcount, ret = 0;
1659 mutex_lock(&dev->lock);
1660 if (dev->dev_state == DEV_STATE_UNMAPPED) {
1661 rnbd_clt_info(dev, "Device is already being unmapped\n");
1665 refcount = refcount_read(&dev->refcount);
1666 if (!force && refcount > 1) {
1668 "Closing device failed, device is in use, (%d device users)\n",
1673 was_mapped = (dev->dev_state == DEV_STATE_MAPPED);
1674 dev->dev_state = DEV_STATE_UNMAPPED;
1675 mutex_unlock(&dev->lock);
1678 destroy_sysfs(dev, sysfs_self);
1679 destroy_gen_disk(dev);
1680 if (was_mapped && sess->rtrs)
1681 send_msg_close(dev, dev->device_id, RTRS_PERMIT_WAIT);
1683 rnbd_clt_info(dev, "Device is unmapped\n");
1685 /* Likely last reference put */
1686 rnbd_clt_put_dev(dev);
1689 * Here device and session can be vanished!
1694 mutex_unlock(&dev->lock);
1699 int rnbd_clt_remap_device(struct rnbd_clt_dev *dev)
1703 mutex_lock(&dev->lock);
1704 if (dev->dev_state == DEV_STATE_MAPPED_DISCONNECTED)
1706 else if (dev->dev_state == DEV_STATE_UNMAPPED)
1708 else if (dev->dev_state == DEV_STATE_MAPPED)
1712 mutex_unlock(&dev->lock);
1714 rnbd_clt_info(dev, "Remapping device.\n");
1715 err = send_msg_open(dev, RTRS_PERMIT_WAIT);
1717 rnbd_clt_err(dev, "remap_device: %d\n", err);
1723 static void unmap_device_work(struct work_struct *work)
1725 struct rnbd_clt_dev *dev;
1727 dev = container_of(work, typeof(*dev), unmap_on_rmmod_work);
1728 rnbd_clt_unmap_device(dev, true, NULL);
1731 static void rnbd_destroy_sessions(void)
1733 struct rnbd_clt_session *sess, *sn;
1734 struct rnbd_clt_dev *dev, *tn;
1736 /* Firstly forbid access through sysfs interface */
1737 rnbd_clt_destroy_sysfs_files();
1740 * Here at this point there is no any concurrent access to sessions
1741 * list and devices list:
1742 * 1. New session or device can't be created - session sysfs files
1744 * 2. Device or session can't be removed - module reference is taken
1745 * into account in unmap device sysfs callback.
1746 * 3. No IO requests inflight - each file open of block_dev increases
1747 * module reference in get_disk().
1749 * But still there can be user requests inflights, which are sent by
1750 * asynchronous send_msg_*() functions, thus before unmapping devices
1751 * RTRS session must be explicitly closed.
1754 list_for_each_entry_safe(sess, sn, &sess_list, list) {
1755 if (!rnbd_clt_get_sess(sess))
1758 list_for_each_entry_safe(dev, tn, &sess->devs_list, list) {
1760 * Here unmap happens in parallel for only one reason:
1761 * blk_cleanup_queue() takes around half a second, so
1762 * on huge amount of devices the whole module unload
1763 * procedure takes minutes.
1765 INIT_WORK(&dev->unmap_on_rmmod_work, unmap_device_work);
1766 queue_work(system_long_wq, &dev->unmap_on_rmmod_work);
1768 rnbd_clt_put_sess(sess);
1770 /* Wait for all scheduled unmap works */
1771 flush_workqueue(system_long_wq);
1772 WARN_ON(!list_empty(&sess_list));
1775 static int __init rnbd_client_init(void)
1779 BUILD_BUG_ON(sizeof(struct rnbd_msg_hdr) != 4);
1780 BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info) != 36);
1781 BUILD_BUG_ON(sizeof(struct rnbd_msg_sess_info_rsp) != 36);
1782 BUILD_BUG_ON(sizeof(struct rnbd_msg_open) != 264);
1783 BUILD_BUG_ON(sizeof(struct rnbd_msg_close) != 8);
1784 BUILD_BUG_ON(sizeof(struct rnbd_msg_open_rsp) != 56);
1785 rnbd_client_major = register_blkdev(rnbd_client_major, "rnbd");
1786 if (rnbd_client_major <= 0) {
1787 pr_err("Failed to load module, block device registration failed\n");
1791 err = rnbd_clt_create_sysfs_files();
1793 pr_err("Failed to load module, creating sysfs device files failed, err: %d\n",
1795 unregister_blkdev(rnbd_client_major, "rnbd");
1801 static void __exit rnbd_client_exit(void)
1803 rnbd_destroy_sessions();
1804 unregister_blkdev(rnbd_client_major, "rnbd");
1805 ida_destroy(&index_ida);
1808 module_init(rnbd_client_init);
1809 module_exit(rnbd_client_exit);