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- /*
- * Copyright (C) 2003 Sistina Software Limited.
- * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
- *
- * This file is released under the GPL.
- */
- #include <linux/device-mapper.h>
- #include "dm.h"
- #include "dm-path-selector.h"
- #include "dm-uevent.h"
- #include <linux/blkdev.h>
- #include <linux/ctype.h>
- #include <linux/init.h>
- #include <linux/mempool.h>
- #include <linux/module.h>
- #include <linux/pagemap.h>
- #include <linux/slab.h>
- #include <linux/time.h>
- #include <linux/workqueue.h>
- #include <linux/delay.h>
- #include <scsi/scsi_dh.h>
- #include <linux/atomic.h>
- #define DM_MSG_PREFIX "multipath"
- #define DM_PG_INIT_DELAY_MSECS 2000
- #define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1)
- /* Path properties */
- struct pgpath {
- struct list_head list;
- struct priority_group *pg; /* Owning PG */
- unsigned is_active; /* Path status */
- unsigned fail_count; /* Cumulative failure count */
- struct dm_path path;
- struct delayed_work activate_path;
- };
- #define path_to_pgpath(__pgp) container_of((__pgp), struct pgpath, path)
- /*
- * Paths are grouped into Priority Groups and numbered from 1 upwards.
- * Each has a path selector which controls which path gets used.
- */
- struct priority_group {
- struct list_head list;
- struct multipath *m; /* Owning multipath instance */
- struct path_selector ps;
- unsigned pg_num; /* Reference number */
- unsigned bypassed; /* Temporarily bypass this PG? */
- unsigned nr_pgpaths; /* Number of paths in PG */
- struct list_head pgpaths;
- };
- /* Multipath context */
- struct multipath {
- struct list_head list;
- struct dm_target *ti;
- const char *hw_handler_name;
- char *hw_handler_params;
- spinlock_t lock;
- unsigned nr_priority_groups;
- struct list_head priority_groups;
- wait_queue_head_t pg_init_wait; /* Wait for pg_init completion */
- unsigned pg_init_required; /* pg_init needs calling? */
- unsigned pg_init_in_progress; /* Only one pg_init allowed at once */
- unsigned pg_init_delay_retry; /* Delay pg_init retry? */
- unsigned nr_valid_paths; /* Total number of usable paths */
- struct pgpath *current_pgpath;
- struct priority_group *current_pg;
- struct priority_group *next_pg; /* Switch to this PG if set */
- unsigned repeat_count; /* I/Os left before calling PS again */
- unsigned queue_io:1; /* Must we queue all I/O? */
- unsigned queue_if_no_path:1; /* Queue I/O if last path fails? */
- unsigned saved_queue_if_no_path:1; /* Saved state during suspension */
- unsigned retain_attached_hw_handler:1; /* If there's already a hw_handler present, don't change it. */
- unsigned pg_init_disabled:1; /* pg_init is not currently allowed */
- unsigned pg_init_retries; /* Number of times to retry pg_init */
- unsigned pg_init_count; /* Number of times pg_init called */
- unsigned pg_init_delay_msecs; /* Number of msecs before pg_init retry */
- struct work_struct trigger_event;
- /*
- * We must use a mempool of dm_mpath_io structs so that we
- * can resubmit bios on error.
- */
- mempool_t *mpio_pool;
- struct mutex work_mutex;
- };
- /*
- * Context information attached to each bio we process.
- */
- struct dm_mpath_io {
- struct pgpath *pgpath;
- size_t nr_bytes;
- };
- typedef int (*action_fn) (struct pgpath *pgpath);
- static struct kmem_cache *_mpio_cache;
- static struct workqueue_struct *kmultipathd, *kmpath_handlerd;
- static void trigger_event(struct work_struct *work);
- static void activate_path(struct work_struct *work);
- static int __pgpath_busy(struct pgpath *pgpath);
- /*-----------------------------------------------
- * Allocation routines
- *-----------------------------------------------*/
- static struct pgpath *alloc_pgpath(void)
- {
- struct pgpath *pgpath = kzalloc(sizeof(*pgpath), GFP_KERNEL);
- if (pgpath) {
- pgpath->is_active = 1;
- INIT_DELAYED_WORK(&pgpath->activate_path, activate_path);
- }
- return pgpath;
- }
- static void free_pgpath(struct pgpath *pgpath)
- {
- kfree(pgpath);
- }
- static struct priority_group *alloc_priority_group(void)
- {
- struct priority_group *pg;
- pg = kzalloc(sizeof(*pg), GFP_KERNEL);
- if (pg)
- INIT_LIST_HEAD(&pg->pgpaths);
- return pg;
- }
- static void free_pgpaths(struct list_head *pgpaths, struct dm_target *ti)
- {
- struct pgpath *pgpath, *tmp;
- list_for_each_entry_safe(pgpath, tmp, pgpaths, list) {
- list_del(&pgpath->list);
- dm_put_device(ti, pgpath->path.dev);
- free_pgpath(pgpath);
- }
- }
- static void free_priority_group(struct priority_group *pg,
- struct dm_target *ti)
- {
- struct path_selector *ps = &pg->ps;
- if (ps->type) {
- ps->type->destroy(ps);
- dm_put_path_selector(ps->type);
- }
- free_pgpaths(&pg->pgpaths, ti);
- kfree(pg);
- }
- static struct multipath *alloc_multipath(struct dm_target *ti)
- {
- struct multipath *m;
- unsigned min_ios = dm_get_reserved_rq_based_ios();
- m = kzalloc(sizeof(*m), GFP_KERNEL);
- if (m) {
- INIT_LIST_HEAD(&m->priority_groups);
- spin_lock_init(&m->lock);
- m->queue_io = 1;
- m->pg_init_delay_msecs = DM_PG_INIT_DELAY_DEFAULT;
- INIT_WORK(&m->trigger_event, trigger_event);
- init_waitqueue_head(&m->pg_init_wait);
- mutex_init(&m->work_mutex);
- m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache);
- if (!m->mpio_pool) {
- kfree(m);
- return NULL;
- }
- m->ti = ti;
- ti->private = m;
- }
- return m;
- }
- static void free_multipath(struct multipath *m)
- {
- struct priority_group *pg, *tmp;
- list_for_each_entry_safe(pg, tmp, &m->priority_groups, list) {
- list_del(&pg->list);
- free_priority_group(pg, m->ti);
- }
- kfree(m->hw_handler_name);
- kfree(m->hw_handler_params);
- mempool_destroy(m->mpio_pool);
- kfree(m);
- }
- static int set_mapinfo(struct multipath *m, union map_info *info)
- {
- struct dm_mpath_io *mpio;
- mpio = mempool_alloc(m->mpio_pool, GFP_ATOMIC);
- if (!mpio)
- return -ENOMEM;
- memset(mpio, 0, sizeof(*mpio));
- info->ptr = mpio;
- return 0;
- }
- static void clear_mapinfo(struct multipath *m, union map_info *info)
- {
- struct dm_mpath_io *mpio = info->ptr;
- info->ptr = NULL;
- mempool_free(mpio, m->mpio_pool);
- }
- /*-----------------------------------------------
- * Path selection
- *-----------------------------------------------*/
- static int __pg_init_all_paths(struct multipath *m)
- {
- struct pgpath *pgpath;
- unsigned long pg_init_delay = 0;
- if (m->pg_init_in_progress || m->pg_init_disabled)
- return 0;
- m->pg_init_count++;
- m->pg_init_required = 0;
- /* Check here to reset pg_init_required */
- if (!m->current_pg)
- return 0;
- if (m->pg_init_delay_retry)
- pg_init_delay = msecs_to_jiffies(m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT ?
- m->pg_init_delay_msecs : DM_PG_INIT_DELAY_MSECS);
- list_for_each_entry(pgpath, &m->current_pg->pgpaths, list) {
- /* Skip failed paths */
- if (!pgpath->is_active)
- continue;
- if (queue_delayed_work(kmpath_handlerd, &pgpath->activate_path,
- pg_init_delay))
- m->pg_init_in_progress++;
- }
- return m->pg_init_in_progress;
- }
- static void __switch_pg(struct multipath *m, struct pgpath *pgpath)
- {
- m->current_pg = pgpath->pg;
- /* Must we initialise the PG first, and queue I/O till it's ready? */
- if (m->hw_handler_name) {
- m->pg_init_required = 1;
- m->queue_io = 1;
- } else {
- m->pg_init_required = 0;
- m->queue_io = 0;
- }
- m->pg_init_count = 0;
- }
- static int __choose_path_in_pg(struct multipath *m, struct priority_group *pg,
- size_t nr_bytes)
- {
- struct dm_path *path;
- path = pg->ps.type->select_path(&pg->ps, &m->repeat_count, nr_bytes);
- if (!path)
- return -ENXIO;
- m->current_pgpath = path_to_pgpath(path);
- if (m->current_pg != pg)
- __switch_pg(m, m->current_pgpath);
- return 0;
- }
- static void __choose_pgpath(struct multipath *m, size_t nr_bytes)
- {
- struct priority_group *pg;
- unsigned bypassed = 1;
- if (!m->nr_valid_paths) {
- m->queue_io = 0;
- goto failed;
- }
- /* Were we instructed to switch PG? */
- if (m->next_pg) {
- pg = m->next_pg;
- m->next_pg = NULL;
- if (!__choose_path_in_pg(m, pg, nr_bytes))
- return;
- }
- /* Don't change PG until it has no remaining paths */
- if (m->current_pg && !__choose_path_in_pg(m, m->current_pg, nr_bytes))
- return;
- /*
- * Loop through priority groups until we find a valid path.
- * First time we skip PGs marked 'bypassed'.
- * Second time we only try the ones we skipped, but set
- * pg_init_delay_retry so we do not hammer controllers.
- */
- do {
- list_for_each_entry(pg, &m->priority_groups, list) {
- if (pg->bypassed == bypassed)
- continue;
- if (!__choose_path_in_pg(m, pg, nr_bytes)) {
- if (!bypassed)
- m->pg_init_delay_retry = 1;
- return;
- }
- }
- } while (bypassed--);
- failed:
- m->current_pgpath = NULL;
- m->current_pg = NULL;
- }
- /*
- * Check whether bios must be queued in the device-mapper core rather
- * than here in the target.
- *
- * m->lock must be held on entry.
- *
- * If m->queue_if_no_path and m->saved_queue_if_no_path hold the
- * same value then we are not between multipath_presuspend()
- * and multipath_resume() calls and we have no need to check
- * for the DMF_NOFLUSH_SUSPENDING flag.
- */
- static int __must_push_back(struct multipath *m)
- {
- return (m->queue_if_no_path ||
- (m->queue_if_no_path != m->saved_queue_if_no_path &&
- dm_noflush_suspending(m->ti)));
- }
- /*
- * Map cloned requests
- */
- static int __multipath_map(struct dm_target *ti, struct request *clone,
- union map_info *map_context,
- struct request *rq, struct request **__clone)
- {
- struct multipath *m = (struct multipath *) ti->private;
- int r = DM_MAPIO_REQUEUE;
- size_t nr_bytes = clone ? blk_rq_bytes(clone) : blk_rq_bytes(rq);
- struct pgpath *pgpath;
- struct block_device *bdev;
- struct dm_mpath_io *mpio;
- spin_lock_irq(&m->lock);
- /* Do we need to select a new pgpath? */
- if (!m->current_pgpath ||
- (!m->queue_io && (m->repeat_count && --m->repeat_count == 0)))
- __choose_pgpath(m, nr_bytes);
- pgpath = m->current_pgpath;
- if (!pgpath) {
- if (!__must_push_back(m))
- r = -EIO; /* Failed */
- goto out_unlock;
- } else if (m->queue_io || m->pg_init_required) {
- __pg_init_all_paths(m);
- goto out_unlock;
- }
- if (set_mapinfo(m, map_context) < 0)
- /* ENOMEM, requeue */
- goto out_unlock;
- mpio = map_context->ptr;
- mpio->pgpath = pgpath;
- mpio->nr_bytes = nr_bytes;
- bdev = pgpath->path.dev->bdev;
- spin_unlock_irq(&m->lock);
- if (clone) {
- /* Old request-based interface: allocated clone is passed in */
- clone->q = bdev_get_queue(bdev);
- clone->rq_disk = bdev->bd_disk;
- clone->cmd_flags |= REQ_FAILFAST_TRANSPORT;
- } else {
- /* blk-mq request-based interface */
- *__clone = blk_get_request(bdev_get_queue(bdev),
- rq_data_dir(rq), GFP_ATOMIC);
- if (IS_ERR(*__clone)) {
- /* ENOMEM, requeue */
- clear_mapinfo(m, map_context);
- return r;
- }
- (*__clone)->bio = (*__clone)->biotail = NULL;
- (*__clone)->rq_disk = bdev->bd_disk;
- (*__clone)->cmd_flags |= REQ_FAILFAST_TRANSPORT;
- }
- if (pgpath->pg->ps.type->start_io)
- pgpath->pg->ps.type->start_io(&pgpath->pg->ps,
- &pgpath->path,
- nr_bytes);
- return DM_MAPIO_REMAPPED;
- out_unlock:
- spin_unlock_irq(&m->lock);
- return r;
- }
- static int multipath_map(struct dm_target *ti, struct request *clone,
- union map_info *map_context)
- {
- return __multipath_map(ti, clone, map_context, NULL, NULL);
- }
- static int multipath_clone_and_map(struct dm_target *ti, struct request *rq,
- union map_info *map_context,
- struct request **clone)
- {
- return __multipath_map(ti, NULL, map_context, rq, clone);
- }
- static void multipath_release_clone(struct request *clone)
- {
- blk_put_request(clone);
- }
- /*
- * If we run out of usable paths, should we queue I/O or error it?
- */
- static int queue_if_no_path(struct multipath *m, unsigned queue_if_no_path,
- unsigned save_old_value)
- {
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- if (save_old_value)
- m->saved_queue_if_no_path = m->queue_if_no_path;
- else
- m->saved_queue_if_no_path = queue_if_no_path;
- m->queue_if_no_path = queue_if_no_path;
- spin_unlock_irqrestore(&m->lock, flags);
- if (!queue_if_no_path)
- dm_table_run_md_queue_async(m->ti->table);
- return 0;
- }
- /*
- * An event is triggered whenever a path is taken out of use.
- * Includes path failure and PG bypass.
- */
- static void trigger_event(struct work_struct *work)
- {
- struct multipath *m =
- container_of(work, struct multipath, trigger_event);
- dm_table_event(m->ti->table);
- }
- /*-----------------------------------------------------------------
- * Constructor/argument parsing:
- * <#multipath feature args> [<arg>]*
- * <#hw_handler args> [hw_handler [<arg>]*]
- * <#priority groups>
- * <initial priority group>
- * [<selector> <#selector args> [<arg>]*
- * <#paths> <#per-path selector args>
- * [<path> [<arg>]* ]+ ]+
- *---------------------------------------------------------------*/
- static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg,
- struct dm_target *ti)
- {
- int r;
- struct path_selector_type *pst;
- unsigned ps_argc;
- static struct dm_arg _args[] = {
- {0, 1024, "invalid number of path selector args"},
- };
- pst = dm_get_path_selector(dm_shift_arg(as));
- if (!pst) {
- ti->error = "unknown path selector type";
- return -EINVAL;
- }
- r = dm_read_arg_group(_args, as, &ps_argc, &ti->error);
- if (r) {
- dm_put_path_selector(pst);
- return -EINVAL;
- }
- r = pst->create(&pg->ps, ps_argc, as->argv);
- if (r) {
- dm_put_path_selector(pst);
- ti->error = "path selector constructor failed";
- return r;
- }
- pg->ps.type = pst;
- dm_consume_args(as, ps_argc);
- return 0;
- }
- static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps,
- struct dm_target *ti)
- {
- int r;
- struct pgpath *p;
- struct multipath *m = ti->private;
- struct request_queue *q = NULL;
- const char *attached_handler_name;
- /* we need at least a path arg */
- if (as->argc < 1) {
- ti->error = "no device given";
- return ERR_PTR(-EINVAL);
- }
- p = alloc_pgpath();
- if (!p)
- return ERR_PTR(-ENOMEM);
- r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table),
- &p->path.dev);
- if (r) {
- ti->error = "error getting device";
- goto bad;
- }
- if (m->retain_attached_hw_handler || m->hw_handler_name)
- q = bdev_get_queue(p->path.dev->bdev);
- if (m->retain_attached_hw_handler) {
- retain:
- attached_handler_name = scsi_dh_attached_handler_name(q, GFP_KERNEL);
- if (attached_handler_name) {
- /*
- * Reset hw_handler_name to match the attached handler
- * and clear any hw_handler_params associated with the
- * ignored handler.
- *
- * NB. This modifies the table line to show the actual
- * handler instead of the original table passed in.
- */
- kfree(m->hw_handler_name);
- m->hw_handler_name = attached_handler_name;
- kfree(m->hw_handler_params);
- m->hw_handler_params = NULL;
- }
- }
- if (m->hw_handler_name) {
- r = scsi_dh_attach(q, m->hw_handler_name);
- if (r == -EBUSY) {
- char b[BDEVNAME_SIZE];
- printk(KERN_INFO "dm-mpath: retaining handler on device %s\n",
- bdevname(p->path.dev->bdev, b));
- goto retain;
- }
- if (r < 0) {
- ti->error = "error attaching hardware handler";
- dm_put_device(ti, p->path.dev);
- goto bad;
- }
- if (m->hw_handler_params) {
- r = scsi_dh_set_params(q, m->hw_handler_params);
- if (r < 0) {
- ti->error = "unable to set hardware "
- "handler parameters";
- dm_put_device(ti, p->path.dev);
- goto bad;
- }
- }
- }
- r = ps->type->add_path(ps, &p->path, as->argc, as->argv, &ti->error);
- if (r) {
- dm_put_device(ti, p->path.dev);
- goto bad;
- }
- return p;
- bad:
- free_pgpath(p);
- return ERR_PTR(r);
- }
- static struct priority_group *parse_priority_group(struct dm_arg_set *as,
- struct multipath *m)
- {
- static struct dm_arg _args[] = {
- {1, 1024, "invalid number of paths"},
- {0, 1024, "invalid number of selector args"}
- };
- int r;
- unsigned i, nr_selector_args, nr_args;
- struct priority_group *pg;
- struct dm_target *ti = m->ti;
- if (as->argc < 2) {
- as->argc = 0;
- ti->error = "not enough priority group arguments";
- return ERR_PTR(-EINVAL);
- }
- pg = alloc_priority_group();
- if (!pg) {
- ti->error = "couldn't allocate priority group";
- return ERR_PTR(-ENOMEM);
- }
- pg->m = m;
- r = parse_path_selector(as, pg, ti);
- if (r)
- goto bad;
- /*
- * read the paths
- */
- r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error);
- if (r)
- goto bad;
- r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error);
- if (r)
- goto bad;
- nr_args = 1 + nr_selector_args;
- for (i = 0; i < pg->nr_pgpaths; i++) {
- struct pgpath *pgpath;
- struct dm_arg_set path_args;
- if (as->argc < nr_args) {
- ti->error = "not enough path parameters";
- r = -EINVAL;
- goto bad;
- }
- path_args.argc = nr_args;
- path_args.argv = as->argv;
- pgpath = parse_path(&path_args, &pg->ps, ti);
- if (IS_ERR(pgpath)) {
- r = PTR_ERR(pgpath);
- goto bad;
- }
- pgpath->pg = pg;
- list_add_tail(&pgpath->list, &pg->pgpaths);
- dm_consume_args(as, nr_args);
- }
- return pg;
- bad:
- free_priority_group(pg, ti);
- return ERR_PTR(r);
- }
- static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m)
- {
- unsigned hw_argc;
- int ret;
- struct dm_target *ti = m->ti;
- static struct dm_arg _args[] = {
- {0, 1024, "invalid number of hardware handler args"},
- };
- if (dm_read_arg_group(_args, as, &hw_argc, &ti->error))
- return -EINVAL;
- if (!hw_argc)
- return 0;
- m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL);
- if (hw_argc > 1) {
- char *p;
- int i, j, len = 4;
- for (i = 0; i <= hw_argc - 2; i++)
- len += strlen(as->argv[i]) + 1;
- p = m->hw_handler_params = kzalloc(len, GFP_KERNEL);
- if (!p) {
- ti->error = "memory allocation failed";
- ret = -ENOMEM;
- goto fail;
- }
- j = sprintf(p, "%d", hw_argc - 1);
- for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1)
- j = sprintf(p, "%s", as->argv[i]);
- }
- dm_consume_args(as, hw_argc - 1);
- return 0;
- fail:
- kfree(m->hw_handler_name);
- m->hw_handler_name = NULL;
- return ret;
- }
- static int parse_features(struct dm_arg_set *as, struct multipath *m)
- {
- int r;
- unsigned argc;
- struct dm_target *ti = m->ti;
- const char *arg_name;
- static struct dm_arg _args[] = {
- {0, 6, "invalid number of feature args"},
- {1, 50, "pg_init_retries must be between 1 and 50"},
- {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"},
- };
- r = dm_read_arg_group(_args, as, &argc, &ti->error);
- if (r)
- return -EINVAL;
- if (!argc)
- return 0;
- do {
- arg_name = dm_shift_arg(as);
- argc--;
- if (!strcasecmp(arg_name, "queue_if_no_path")) {
- r = queue_if_no_path(m, 1, 0);
- continue;
- }
- if (!strcasecmp(arg_name, "retain_attached_hw_handler")) {
- m->retain_attached_hw_handler = 1;
- continue;
- }
- if (!strcasecmp(arg_name, "pg_init_retries") &&
- (argc >= 1)) {
- r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error);
- argc--;
- continue;
- }
- if (!strcasecmp(arg_name, "pg_init_delay_msecs") &&
- (argc >= 1)) {
- r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error);
- argc--;
- continue;
- }
- ti->error = "Unrecognised multipath feature request";
- r = -EINVAL;
- } while (argc && !r);
- return r;
- }
- static int multipath_ctr(struct dm_target *ti, unsigned int argc,
- char **argv)
- {
- /* target arguments */
- static struct dm_arg _args[] = {
- {0, 1024, "invalid number of priority groups"},
- {0, 1024, "invalid initial priority group number"},
- };
- int r;
- struct multipath *m;
- struct dm_arg_set as;
- unsigned pg_count = 0;
- unsigned next_pg_num;
- as.argc = argc;
- as.argv = argv;
- m = alloc_multipath(ti);
- if (!m) {
- ti->error = "can't allocate multipath";
- return -EINVAL;
- }
- r = parse_features(&as, m);
- if (r)
- goto bad;
- r = parse_hw_handler(&as, m);
- if (r)
- goto bad;
- r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error);
- if (r)
- goto bad;
- r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error);
- if (r)
- goto bad;
- if ((!m->nr_priority_groups && next_pg_num) ||
- (m->nr_priority_groups && !next_pg_num)) {
- ti->error = "invalid initial priority group";
- r = -EINVAL;
- goto bad;
- }
- /* parse the priority groups */
- while (as.argc) {
- struct priority_group *pg;
- pg = parse_priority_group(&as, m);
- if (IS_ERR(pg)) {
- r = PTR_ERR(pg);
- goto bad;
- }
- m->nr_valid_paths += pg->nr_pgpaths;
- list_add_tail(&pg->list, &m->priority_groups);
- pg_count++;
- pg->pg_num = pg_count;
- if (!--next_pg_num)
- m->next_pg = pg;
- }
- if (pg_count != m->nr_priority_groups) {
- ti->error = "priority group count mismatch";
- r = -EINVAL;
- goto bad;
- }
- ti->num_flush_bios = 1;
- ti->num_discard_bios = 1;
- ti->num_write_same_bios = 1;
- return 0;
- bad:
- free_multipath(m);
- return r;
- }
- static void multipath_wait_for_pg_init_completion(struct multipath *m)
- {
- DECLARE_WAITQUEUE(wait, current);
- unsigned long flags;
- add_wait_queue(&m->pg_init_wait, &wait);
- while (1) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- spin_lock_irqsave(&m->lock, flags);
- if (!m->pg_init_in_progress) {
- spin_unlock_irqrestore(&m->lock, flags);
- break;
- }
- spin_unlock_irqrestore(&m->lock, flags);
- io_schedule();
- }
- set_current_state(TASK_RUNNING);
- remove_wait_queue(&m->pg_init_wait, &wait);
- }
- static void flush_multipath_work(struct multipath *m)
- {
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- m->pg_init_disabled = 1;
- spin_unlock_irqrestore(&m->lock, flags);
- flush_workqueue(kmpath_handlerd);
- multipath_wait_for_pg_init_completion(m);
- flush_workqueue(kmultipathd);
- flush_work(&m->trigger_event);
- spin_lock_irqsave(&m->lock, flags);
- m->pg_init_disabled = 0;
- spin_unlock_irqrestore(&m->lock, flags);
- }
- static void multipath_dtr(struct dm_target *ti)
- {
- struct multipath *m = ti->private;
- flush_multipath_work(m);
- free_multipath(m);
- }
- /*
- * Take a path out of use.
- */
- static int fail_path(struct pgpath *pgpath)
- {
- unsigned long flags;
- struct multipath *m = pgpath->pg->m;
- spin_lock_irqsave(&m->lock, flags);
- if (!pgpath->is_active)
- goto out;
- DMWARN("Failing path %s.", pgpath->path.dev->name);
- pgpath->pg->ps.type->fail_path(&pgpath->pg->ps, &pgpath->path);
- pgpath->is_active = 0;
- pgpath->fail_count++;
- m->nr_valid_paths--;
- if (pgpath == m->current_pgpath)
- m->current_pgpath = NULL;
- dm_path_uevent(DM_UEVENT_PATH_FAILED, m->ti,
- pgpath->path.dev->name, m->nr_valid_paths);
- schedule_work(&m->trigger_event);
- out:
- spin_unlock_irqrestore(&m->lock, flags);
- return 0;
- }
- /*
- * Reinstate a previously-failed path
- */
- static int reinstate_path(struct pgpath *pgpath)
- {
- int r = 0, run_queue = 0;
- unsigned long flags;
- struct multipath *m = pgpath->pg->m;
- spin_lock_irqsave(&m->lock, flags);
- if (pgpath->is_active)
- goto out;
- if (!pgpath->pg->ps.type->reinstate_path) {
- DMWARN("Reinstate path not supported by path selector %s",
- pgpath->pg->ps.type->name);
- r = -EINVAL;
- goto out;
- }
- r = pgpath->pg->ps.type->reinstate_path(&pgpath->pg->ps, &pgpath->path);
- if (r)
- goto out;
- pgpath->is_active = 1;
- if (!m->nr_valid_paths++) {
- m->current_pgpath = NULL;
- run_queue = 1;
- } else if (m->hw_handler_name && (m->current_pg == pgpath->pg)) {
- if (queue_work(kmpath_handlerd, &pgpath->activate_path.work))
- m->pg_init_in_progress++;
- }
- dm_path_uevent(DM_UEVENT_PATH_REINSTATED, m->ti,
- pgpath->path.dev->name, m->nr_valid_paths);
- schedule_work(&m->trigger_event);
- out:
- spin_unlock_irqrestore(&m->lock, flags);
- if (run_queue)
- dm_table_run_md_queue_async(m->ti->table);
- return r;
- }
- /*
- * Fail or reinstate all paths that match the provided struct dm_dev.
- */
- static int action_dev(struct multipath *m, struct dm_dev *dev,
- action_fn action)
- {
- int r = -EINVAL;
- struct pgpath *pgpath;
- struct priority_group *pg;
- list_for_each_entry(pg, &m->priority_groups, list) {
- list_for_each_entry(pgpath, &pg->pgpaths, list) {
- if (pgpath->path.dev == dev)
- r = action(pgpath);
- }
- }
- return r;
- }
- /*
- * Temporarily try to avoid having to use the specified PG
- */
- static void bypass_pg(struct multipath *m, struct priority_group *pg,
- int bypassed)
- {
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- pg->bypassed = bypassed;
- m->current_pgpath = NULL;
- m->current_pg = NULL;
- spin_unlock_irqrestore(&m->lock, flags);
- schedule_work(&m->trigger_event);
- }
- /*
- * Switch to using the specified PG from the next I/O that gets mapped
- */
- static int switch_pg_num(struct multipath *m, const char *pgstr)
- {
- struct priority_group *pg;
- unsigned pgnum;
- unsigned long flags;
- char dummy;
- if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
- (pgnum > m->nr_priority_groups)) {
- DMWARN("invalid PG number supplied to switch_pg_num");
- return -EINVAL;
- }
- spin_lock_irqsave(&m->lock, flags);
- list_for_each_entry(pg, &m->priority_groups, list) {
- pg->bypassed = 0;
- if (--pgnum)
- continue;
- m->current_pgpath = NULL;
- m->current_pg = NULL;
- m->next_pg = pg;
- }
- spin_unlock_irqrestore(&m->lock, flags);
- schedule_work(&m->trigger_event);
- return 0;
- }
- /*
- * Set/clear bypassed status of a PG.
- * PGs are numbered upwards from 1 in the order they were declared.
- */
- static int bypass_pg_num(struct multipath *m, const char *pgstr, int bypassed)
- {
- struct priority_group *pg;
- unsigned pgnum;
- char dummy;
- if (!pgstr || (sscanf(pgstr, "%u%c", &pgnum, &dummy) != 1) || !pgnum ||
- (pgnum > m->nr_priority_groups)) {
- DMWARN("invalid PG number supplied to bypass_pg");
- return -EINVAL;
- }
- list_for_each_entry(pg, &m->priority_groups, list) {
- if (!--pgnum)
- break;
- }
- bypass_pg(m, pg, bypassed);
- return 0;
- }
- /*
- * Should we retry pg_init immediately?
- */
- static int pg_init_limit_reached(struct multipath *m, struct pgpath *pgpath)
- {
- unsigned long flags;
- int limit_reached = 0;
- spin_lock_irqsave(&m->lock, flags);
- if (m->pg_init_count <= m->pg_init_retries && !m->pg_init_disabled)
- m->pg_init_required = 1;
- else
- limit_reached = 1;
- spin_unlock_irqrestore(&m->lock, flags);
- return limit_reached;
- }
- static void pg_init_done(void *data, int errors)
- {
- struct pgpath *pgpath = data;
- struct priority_group *pg = pgpath->pg;
- struct multipath *m = pg->m;
- unsigned long flags;
- unsigned delay_retry = 0;
- /* device or driver problems */
- switch (errors) {
- case SCSI_DH_OK:
- break;
- case SCSI_DH_NOSYS:
- if (!m->hw_handler_name) {
- errors = 0;
- break;
- }
- DMERR("Could not failover the device: Handler scsi_dh_%s "
- "Error %d.", m->hw_handler_name, errors);
- /*
- * Fail path for now, so we do not ping pong
- */
- fail_path(pgpath);
- break;
- case SCSI_DH_DEV_TEMP_BUSY:
- /*
- * Probably doing something like FW upgrade on the
- * controller so try the other pg.
- */
- bypass_pg(m, pg, 1);
- break;
- case SCSI_DH_RETRY:
- /* Wait before retrying. */
- delay_retry = 1;
- case SCSI_DH_IMM_RETRY:
- case SCSI_DH_RES_TEMP_UNAVAIL:
- if (pg_init_limit_reached(m, pgpath))
- fail_path(pgpath);
- errors = 0;
- break;
- default:
- /*
- * We probably do not want to fail the path for a device
- * error, but this is what the old dm did. In future
- * patches we can do more advanced handling.
- */
- fail_path(pgpath);
- }
- spin_lock_irqsave(&m->lock, flags);
- if (errors) {
- if (pgpath == m->current_pgpath) {
- DMERR("Could not failover device. Error %d.", errors);
- m->current_pgpath = NULL;
- m->current_pg = NULL;
- }
- } else if (!m->pg_init_required)
- pg->bypassed = 0;
- if (--m->pg_init_in_progress)
- /* Activations of other paths are still on going */
- goto out;
- if (m->pg_init_required) {
- m->pg_init_delay_retry = delay_retry;
- if (__pg_init_all_paths(m))
- goto out;
- }
- m->queue_io = 0;
- /*
- * Wake up any thread waiting to suspend.
- */
- wake_up(&m->pg_init_wait);
- out:
- spin_unlock_irqrestore(&m->lock, flags);
- }
- static void activate_path(struct work_struct *work)
- {
- struct pgpath *pgpath =
- container_of(work, struct pgpath, activate_path.work);
- struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
- if (pgpath->is_active && !blk_queue_dying(q))
- scsi_dh_activate(q, pg_init_done, pgpath);
- else
- pg_init_done(pgpath, SCSI_DH_DEV_OFFLINED);
- }
- static int noretry_error(int error)
- {
- switch (error) {
- case -EOPNOTSUPP:
- case -EREMOTEIO:
- case -EILSEQ:
- case -ENODATA:
- case -ENOSPC:
- return 1;
- }
- /* Anything else could be a path failure, so should be retried */
- return 0;
- }
- /*
- * end_io handling
- */
- static int do_end_io(struct multipath *m, struct request *clone,
- int error, struct dm_mpath_io *mpio)
- {
- /*
- * We don't queue any clone request inside the multipath target
- * during end I/O handling, since those clone requests don't have
- * bio clones. If we queue them inside the multipath target,
- * we need to make bio clones, that requires memory allocation.
- * (See drivers/md/dm.c:end_clone_bio() about why the clone requests
- * don't have bio clones.)
- * Instead of queueing the clone request here, we queue the original
- * request into dm core, which will remake a clone request and
- * clone bios for it and resubmit it later.
- */
- int r = DM_ENDIO_REQUEUE;
- unsigned long flags;
- if (!error && !clone->errors)
- return 0; /* I/O complete */
- if (noretry_error(error))
- return error;
- if (mpio->pgpath)
- fail_path(mpio->pgpath);
- spin_lock_irqsave(&m->lock, flags);
- if (!m->nr_valid_paths) {
- if (!m->queue_if_no_path) {
- if (!__must_push_back(m))
- r = -EIO;
- } else {
- if (error == -EBADE)
- r = error;
- }
- }
- spin_unlock_irqrestore(&m->lock, flags);
- return r;
- }
- static int multipath_end_io(struct dm_target *ti, struct request *clone,
- int error, union map_info *map_context)
- {
- struct multipath *m = ti->private;
- struct dm_mpath_io *mpio = map_context->ptr;
- struct pgpath *pgpath;
- struct path_selector *ps;
- int r;
- BUG_ON(!mpio);
- r = do_end_io(m, clone, error, mpio);
- pgpath = mpio->pgpath;
- if (pgpath) {
- ps = &pgpath->pg->ps;
- if (ps->type->end_io)
- ps->type->end_io(ps, &pgpath->path, mpio->nr_bytes);
- }
- clear_mapinfo(m, map_context);
- return r;
- }
- /*
- * Suspend can't complete until all the I/O is processed so if
- * the last path fails we must error any remaining I/O.
- * Note that if the freeze_bdev fails while suspending, the
- * queue_if_no_path state is lost - userspace should reset it.
- */
- static void multipath_presuspend(struct dm_target *ti)
- {
- struct multipath *m = (struct multipath *) ti->private;
- queue_if_no_path(m, 0, 1);
- }
- static void multipath_postsuspend(struct dm_target *ti)
- {
- struct multipath *m = ti->private;
- mutex_lock(&m->work_mutex);
- flush_multipath_work(m);
- mutex_unlock(&m->work_mutex);
- }
- /*
- * Restore the queue_if_no_path setting.
- */
- static void multipath_resume(struct dm_target *ti)
- {
- struct multipath *m = (struct multipath *) ti->private;
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- m->queue_if_no_path = m->saved_queue_if_no_path;
- spin_unlock_irqrestore(&m->lock, flags);
- }
- /*
- * Info output has the following format:
- * num_multipath_feature_args [multipath_feature_args]*
- * num_handler_status_args [handler_status_args]*
- * num_groups init_group_number
- * [A|D|E num_ps_status_args [ps_status_args]*
- * num_paths num_selector_args
- * [path_dev A|F fail_count [selector_args]* ]+ ]+
- *
- * Table output has the following format (identical to the constructor string):
- * num_feature_args [features_args]*
- * num_handler_args hw_handler [hw_handler_args]*
- * num_groups init_group_number
- * [priority selector-name num_ps_args [ps_args]*
- * num_paths num_selector_args [path_dev [selector_args]* ]+ ]+
- */
- static void multipath_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
- {
- int sz = 0;
- unsigned long flags;
- struct multipath *m = (struct multipath *) ti->private;
- struct priority_group *pg;
- struct pgpath *p;
- unsigned pg_num;
- char state;
- spin_lock_irqsave(&m->lock, flags);
- /* Features */
- if (type == STATUSTYPE_INFO)
- DMEMIT("2 %u %u ", m->queue_io, m->pg_init_count);
- else {
- DMEMIT("%u ", m->queue_if_no_path +
- (m->pg_init_retries > 0) * 2 +
- (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT) * 2 +
- m->retain_attached_hw_handler);
- if (m->queue_if_no_path)
- DMEMIT("queue_if_no_path ");
- if (m->pg_init_retries)
- DMEMIT("pg_init_retries %u ", m->pg_init_retries);
- if (m->pg_init_delay_msecs != DM_PG_INIT_DELAY_DEFAULT)
- DMEMIT("pg_init_delay_msecs %u ", m->pg_init_delay_msecs);
- if (m->retain_attached_hw_handler)
- DMEMIT("retain_attached_hw_handler ");
- }
- if (!m->hw_handler_name || type == STATUSTYPE_INFO)
- DMEMIT("0 ");
- else
- DMEMIT("1 %s ", m->hw_handler_name);
- DMEMIT("%u ", m->nr_priority_groups);
- if (m->next_pg)
- pg_num = m->next_pg->pg_num;
- else if (m->current_pg)
- pg_num = m->current_pg->pg_num;
- else
- pg_num = (m->nr_priority_groups ? 1 : 0);
- DMEMIT("%u ", pg_num);
- switch (type) {
- case STATUSTYPE_INFO:
- list_for_each_entry(pg, &m->priority_groups, list) {
- if (pg->bypassed)
- state = 'D'; /* Disabled */
- else if (pg == m->current_pg)
- state = 'A'; /* Currently Active */
- else
- state = 'E'; /* Enabled */
- DMEMIT("%c ", state);
- if (pg->ps.type->status)
- sz += pg->ps.type->status(&pg->ps, NULL, type,
- result + sz,
- maxlen - sz);
- else
- DMEMIT("0 ");
- DMEMIT("%u %u ", pg->nr_pgpaths,
- pg->ps.type->info_args);
- list_for_each_entry(p, &pg->pgpaths, list) {
- DMEMIT("%s %s %u ", p->path.dev->name,
- p->is_active ? "A" : "F",
- p->fail_count);
- if (pg->ps.type->status)
- sz += pg->ps.type->status(&pg->ps,
- &p->path, type, result + sz,
- maxlen - sz);
- }
- }
- break;
- case STATUSTYPE_TABLE:
- list_for_each_entry(pg, &m->priority_groups, list) {
- DMEMIT("%s ", pg->ps.type->name);
- if (pg->ps.type->status)
- sz += pg->ps.type->status(&pg->ps, NULL, type,
- result + sz,
- maxlen - sz);
- else
- DMEMIT("0 ");
- DMEMIT("%u %u ", pg->nr_pgpaths,
- pg->ps.type->table_args);
- list_for_each_entry(p, &pg->pgpaths, list) {
- DMEMIT("%s ", p->path.dev->name);
- if (pg->ps.type->status)
- sz += pg->ps.type->status(&pg->ps,
- &p->path, type, result + sz,
- maxlen - sz);
- }
- }
- break;
- }
- spin_unlock_irqrestore(&m->lock, flags);
- }
- static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
- {
- int r = -EINVAL;
- struct dm_dev *dev;
- struct multipath *m = (struct multipath *) ti->private;
- action_fn action;
- mutex_lock(&m->work_mutex);
- if (dm_suspended(ti)) {
- r = -EBUSY;
- goto out;
- }
- if (argc == 1) {
- if (!strcasecmp(argv[0], "queue_if_no_path")) {
- r = queue_if_no_path(m, 1, 0);
- goto out;
- } else if (!strcasecmp(argv[0], "fail_if_no_path")) {
- r = queue_if_no_path(m, 0, 0);
- goto out;
- }
- }
- if (argc != 2) {
- DMWARN("Invalid multipath message arguments. Expected 2 arguments, got %d.", argc);
- goto out;
- }
- if (!strcasecmp(argv[0], "disable_group")) {
- r = bypass_pg_num(m, argv[1], 1);
- goto out;
- } else if (!strcasecmp(argv[0], "enable_group")) {
- r = bypass_pg_num(m, argv[1], 0);
- goto out;
- } else if (!strcasecmp(argv[0], "switch_group")) {
- r = switch_pg_num(m, argv[1]);
- goto out;
- } else if (!strcasecmp(argv[0], "reinstate_path"))
- action = reinstate_path;
- else if (!strcasecmp(argv[0], "fail_path"))
- action = fail_path;
- else {
- DMWARN("Unrecognised multipath message received: %s", argv[0]);
- goto out;
- }
- r = dm_get_device(ti, argv[1], dm_table_get_mode(ti->table), &dev);
- if (r) {
- DMWARN("message: error getting device %s",
- argv[1]);
- goto out;
- }
- r = action_dev(m, dev, action);
- dm_put_device(ti, dev);
- out:
- mutex_unlock(&m->work_mutex);
- return r;
- }
- static int multipath_prepare_ioctl(struct dm_target *ti,
- struct block_device **bdev, fmode_t *mode)
- {
- struct multipath *m = ti->private;
- unsigned long flags;
- int r;
- spin_lock_irqsave(&m->lock, flags);
- if (!m->current_pgpath)
- __choose_pgpath(m, 0);
- if (m->current_pgpath) {
- if (!m->queue_io) {
- *bdev = m->current_pgpath->path.dev->bdev;
- *mode = m->current_pgpath->path.dev->mode;
- r = 0;
- } else {
- /* pg_init has not started or completed */
- r = -ENOTCONN;
- }
- } else {
- /* No path is available */
- if (m->queue_if_no_path)
- r = -ENOTCONN;
- else
- r = -EIO;
- }
- spin_unlock_irqrestore(&m->lock, flags);
- if (r == -ENOTCONN) {
- spin_lock_irqsave(&m->lock, flags);
- if (!m->current_pg) {
- /* Path status changed, redo selection */
- __choose_pgpath(m, 0);
- }
- if (m->pg_init_required)
- __pg_init_all_paths(m);
- spin_unlock_irqrestore(&m->lock, flags);
- dm_table_run_md_queue_async(m->ti->table);
- }
- /*
- * Only pass ioctls through if the device sizes match exactly.
- */
- if (!r && ti->len != i_size_read((*bdev)->bd_inode) >> SECTOR_SHIFT)
- return 1;
- return r;
- }
- static int multipath_iterate_devices(struct dm_target *ti,
- iterate_devices_callout_fn fn, void *data)
- {
- struct multipath *m = ti->private;
- struct priority_group *pg;
- struct pgpath *p;
- int ret = 0;
- list_for_each_entry(pg, &m->priority_groups, list) {
- list_for_each_entry(p, &pg->pgpaths, list) {
- ret = fn(ti, p->path.dev, ti->begin, ti->len, data);
- if (ret)
- goto out;
- }
- }
- out:
- return ret;
- }
- static int __pgpath_busy(struct pgpath *pgpath)
- {
- struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
- return blk_lld_busy(q);
- }
- /*
- * We return "busy", only when we can map I/Os but underlying devices
- * are busy (so even if we map I/Os now, the I/Os will wait on
- * the underlying queue).
- * In other words, if we want to kill I/Os or queue them inside us
- * due to map unavailability, we don't return "busy". Otherwise,
- * dm core won't give us the I/Os and we can't do what we want.
- */
- static int multipath_busy(struct dm_target *ti)
- {
- int busy = 0, has_active = 0;
- struct multipath *m = ti->private;
- struct priority_group *pg;
- struct pgpath *pgpath;
- unsigned long flags;
- spin_lock_irqsave(&m->lock, flags);
- /* pg_init in progress or no paths available */
- if (m->pg_init_in_progress ||
- (!m->nr_valid_paths && m->queue_if_no_path)) {
- busy = 1;
- goto out;
- }
- /* Guess which priority_group will be used at next mapping time */
- if (unlikely(!m->current_pgpath && m->next_pg))
- pg = m->next_pg;
- else if (likely(m->current_pg))
- pg = m->current_pg;
- else
- /*
- * We don't know which pg will be used at next mapping time.
- * We don't call __choose_pgpath() here to avoid to trigger
- * pg_init just by busy checking.
- * So we don't know whether underlying devices we will be using
- * at next mapping time are busy or not. Just try mapping.
- */
- goto out;
- /*
- * If there is one non-busy active path at least, the path selector
- * will be able to select it. So we consider such a pg as not busy.
- */
- busy = 1;
- list_for_each_entry(pgpath, &pg->pgpaths, list)
- if (pgpath->is_active) {
- has_active = 1;
- if (!__pgpath_busy(pgpath)) {
- busy = 0;
- break;
- }
- }
- if (!has_active)
- /*
- * No active path in this pg, so this pg won't be used and
- * the current_pg will be changed at next mapping time.
- * We need to try mapping to determine it.
- */
- busy = 0;
- out:
- spin_unlock_irqrestore(&m->lock, flags);
- return busy;
- }
- /*-----------------------------------------------------------------
- * Module setup
- *---------------------------------------------------------------*/
- static struct target_type multipath_target = {
- .name = "multipath",
- .version = {1, 10, 0},
- .module = THIS_MODULE,
- .ctr = multipath_ctr,
- .dtr = multipath_dtr,
- .map_rq = multipath_map,
- .clone_and_map_rq = multipath_clone_and_map,
- .release_clone_rq = multipath_release_clone,
- .rq_end_io = multipath_end_io,
- .presuspend = multipath_presuspend,
- .postsuspend = multipath_postsuspend,
- .resume = multipath_resume,
- .status = multipath_status,
- .message = multipath_message,
- .prepare_ioctl = multipath_prepare_ioctl,
- .iterate_devices = multipath_iterate_devices,
- .busy = multipath_busy,
- };
- static int __init dm_multipath_init(void)
- {
- int r;
- /* allocate a slab for the dm_ios */
- _mpio_cache = KMEM_CACHE(dm_mpath_io, 0);
- if (!_mpio_cache)
- return -ENOMEM;
- r = dm_register_target(&multipath_target);
- if (r < 0) {
- DMERR("register failed %d", r);
- r = -EINVAL;
- goto bad_register_target;
- }
- kmultipathd = alloc_workqueue("kmpathd", WQ_MEM_RECLAIM, 0);
- if (!kmultipathd) {
- DMERR("failed to create workqueue kmpathd");
- r = -ENOMEM;
- goto bad_alloc_kmultipathd;
- }
- /*
- * A separate workqueue is used to handle the device handlers
- * to avoid overloading existing workqueue. Overloading the
- * old workqueue would also create a bottleneck in the
- * path of the storage hardware device activation.
- */
- kmpath_handlerd = alloc_ordered_workqueue("kmpath_handlerd",
- WQ_MEM_RECLAIM);
- if (!kmpath_handlerd) {
- DMERR("failed to create workqueue kmpath_handlerd");
- r = -ENOMEM;
- goto bad_alloc_kmpath_handlerd;
- }
- DMINFO("version %u.%u.%u loaded",
- multipath_target.version[0], multipath_target.version[1],
- multipath_target.version[2]);
- return 0;
- bad_alloc_kmpath_handlerd:
- destroy_workqueue(kmultipathd);
- bad_alloc_kmultipathd:
- dm_unregister_target(&multipath_target);
- bad_register_target:
- kmem_cache_destroy(_mpio_cache);
- return r;
- }
- static void __exit dm_multipath_exit(void)
- {
- destroy_workqueue(kmpath_handlerd);
- destroy_workqueue(kmultipathd);
- dm_unregister_target(&multipath_target);
- kmem_cache_destroy(_mpio_cache);
- }
- module_init(dm_multipath_init);
- module_exit(dm_multipath_exit);
- MODULE_DESCRIPTION(DM_NAME " multipath target");
- MODULE_AUTHOR("Sistina Software <dm-devel@redhat.com>");
- MODULE_LICENSE("GPL");
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