From 9659f811446a67951127d4e81576204ffce9c86e Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Mon, 15 Feb 2016 14:25:00 -0500 Subject: [PATCH] dm mpath: push path selector locking down to path selectors Proper locking of the lists used by the path selectors should be handled within the selectors (relying on dm-mpath.c code's use of the m->lock spinlock was reckless). Signed-off-by: Mike Snitzer --- drivers/md/dm-queue-length.c | 23 ++++++++++++++++++++--- drivers/md/dm-round-robin.c | 24 +++++++++++++++++++----- drivers/md/dm-service-time.c | 23 ++++++++++++++++++++--- 3 files changed, 59 insertions(+), 11 deletions(-) diff --git a/drivers/md/dm-queue-length.c b/drivers/md/dm-queue-length.c index 51d82290ad4c..aeea3b7f3d5e 100644 --- a/drivers/md/dm-queue-length.c +++ b/drivers/md/dm-queue-length.c @@ -29,6 +29,7 @@ struct selector { struct list_head valid_paths; struct list_head failed_paths; + spinlock_t lock; }; struct path_info { @@ -45,6 +46,7 @@ static struct selector *alloc_selector(void) if (s) { INIT_LIST_HEAD(&s->valid_paths); INIT_LIST_HEAD(&s->failed_paths); + spin_lock_init(&s->lock); } return s; @@ -113,6 +115,7 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path, struct path_info *pi; unsigned repeat_count = QL_MIN_IO; char dummy; + unsigned long flags; /* * Arguments: [] @@ -147,7 +150,9 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path, path->pscontext = pi; + spin_lock_irqsave(&s->lock, flags); list_add_tail(&pi->list, &s->valid_paths); + spin_unlock_irqrestore(&s->lock, flags); return 0; } @@ -156,16 +161,22 @@ static void ql_fail_path(struct path_selector *ps, struct dm_path *path) { struct selector *s = ps->context; struct path_info *pi = path->pscontext; + unsigned long flags; + spin_lock_irqsave(&s->lock, flags); list_move(&pi->list, &s->failed_paths); + spin_unlock_irqrestore(&s->lock, flags); } static int ql_reinstate_path(struct path_selector *ps, struct dm_path *path) { struct selector *s = ps->context; struct path_info *pi = path->pscontext; + unsigned long flags; + spin_lock_irqsave(&s->lock, flags); list_move_tail(&pi->list, &s->valid_paths); + spin_unlock_irqrestore(&s->lock, flags); return 0; } @@ -178,9 +189,12 @@ static struct dm_path *ql_select_path(struct path_selector *ps, { struct selector *s = ps->context; struct path_info *pi = NULL, *best = NULL; + struct dm_path *ret = NULL; + unsigned long flags; + spin_lock_irqsave(&s->lock, flags); if (list_empty(&s->valid_paths)) - return NULL; + goto out; /* Change preferred (first in list) path to evenly balance. */ list_move_tail(s->valid_paths.next, &s->valid_paths); @@ -195,11 +209,14 @@ static struct dm_path *ql_select_path(struct path_selector *ps, } if (!best) - return NULL; + goto out; *repeat_count = best->repeat_count; - return best->path; + ret = best->path; +out: + spin_unlock_irqrestore(&s->lock, flags); + return ret; } static int ql_start_io(struct path_selector *ps, struct dm_path *path, diff --git a/drivers/md/dm-round-robin.c b/drivers/md/dm-round-robin.c index 65ffdc3403b6..be9aa7f30b61 100644 --- a/drivers/md/dm-round-robin.c +++ b/drivers/md/dm-round-robin.c @@ -46,6 +46,7 @@ static void free_paths(struct list_head *paths) struct selector { struct list_head valid_paths; struct list_head invalid_paths; + spinlock_t lock; }; static struct selector *alloc_selector(void) @@ -55,6 +56,7 @@ static struct selector *alloc_selector(void) if (s) { INIT_LIST_HEAD(&s->valid_paths); INIT_LIST_HEAD(&s->invalid_paths); + spin_lock_init(&s->lock); } return s; @@ -74,7 +76,7 @@ static int rr_create(struct path_selector *ps, unsigned argc, char **argv) static void rr_destroy(struct path_selector *ps) { - struct selector *s = (struct selector *) ps->context; + struct selector *s = ps->context; free_paths(&s->valid_paths); free_paths(&s->invalid_paths); @@ -111,10 +113,11 @@ static int rr_status(struct path_selector *ps, struct dm_path *path, static int rr_add_path(struct path_selector *ps, struct dm_path *path, int argc, char **argv, char **error) { - struct selector *s = (struct selector *) ps->context; + struct selector *s = ps->context; struct path_info *pi; unsigned repeat_count = RR_MIN_IO; char dummy; + unsigned long flags; if (argc > 1) { *error = "round-robin ps: incorrect number of arguments"; @@ -144,25 +147,33 @@ static int rr_add_path(struct path_selector *ps, struct dm_path *path, path->pscontext = pi; + spin_lock_irqsave(&s->lock, flags); list_add_tail(&pi->list, &s->valid_paths); + spin_unlock_irqrestore(&s->lock, flags); return 0; } static void rr_fail_path(struct path_selector *ps, struct dm_path *p) { - struct selector *s = (struct selector *) ps->context; + unsigned long flags; + struct selector *s = ps->context; struct path_info *pi = p->pscontext; + spin_lock_irqsave(&s->lock, flags); list_move(&pi->list, &s->invalid_paths); + spin_unlock_irqrestore(&s->lock, flags); } static int rr_reinstate_path(struct path_selector *ps, struct dm_path *p) { - struct selector *s = (struct selector *) ps->context; + unsigned long flags; + struct selector *s = ps->context; struct path_info *pi = p->pscontext; + spin_lock_irqsave(&s->lock, flags); list_move(&pi->list, &s->valid_paths); + spin_unlock_irqrestore(&s->lock, flags); return 0; } @@ -170,14 +181,17 @@ static int rr_reinstate_path(struct path_selector *ps, struct dm_path *p) static struct dm_path *rr_select_path(struct path_selector *ps, unsigned *repeat_count, size_t nr_bytes) { - struct selector *s = (struct selector *) ps->context; + unsigned long flags; + struct selector *s = ps->context; struct path_info *pi = NULL; + spin_lock_irqsave(&s->lock, flags); if (!list_empty(&s->valid_paths)) { pi = list_entry(s->valid_paths.next, struct path_info, list); list_move_tail(&pi->list, &s->valid_paths); *repeat_count = pi->repeat_count; } + spin_unlock_irqrestore(&s->lock, flags); return pi ? pi->path : NULL; } diff --git a/drivers/md/dm-service-time.c b/drivers/md/dm-service-time.c index 0370eaf3d949..d09bcbe3655d 100644 --- a/drivers/md/dm-service-time.c +++ b/drivers/md/dm-service-time.c @@ -24,6 +24,7 @@ struct selector { struct list_head valid_paths; struct list_head failed_paths; + spinlock_t lock; }; struct path_info { @@ -41,6 +42,7 @@ static struct selector *alloc_selector(void) if (s) { INIT_LIST_HEAD(&s->valid_paths); INIT_LIST_HEAD(&s->failed_paths); + spin_lock_init(&s->lock); } return s; @@ -111,6 +113,7 @@ static int st_add_path(struct path_selector *ps, struct dm_path *path, unsigned repeat_count = ST_MIN_IO; unsigned relative_throughput = 1; char dummy; + unsigned long flags; /* * Arguments: [ []] @@ -160,7 +163,9 @@ static int st_add_path(struct path_selector *ps, struct dm_path *path, path->pscontext = pi; + spin_lock_irqsave(&s->lock, flags); list_add_tail(&pi->list, &s->valid_paths); + spin_unlock_irqrestore(&s->lock, flags); return 0; } @@ -169,16 +174,22 @@ static void st_fail_path(struct path_selector *ps, struct dm_path *path) { struct selector *s = ps->context; struct path_info *pi = path->pscontext; + unsigned long flags; + spin_lock_irqsave(&s->lock, flags); list_move(&pi->list, &s->failed_paths); + spin_unlock_irqrestore(&s->lock, flags); } static int st_reinstate_path(struct path_selector *ps, struct dm_path *path) { struct selector *s = ps->context; struct path_info *pi = path->pscontext; + unsigned long flags; + spin_lock_irqsave(&s->lock, flags); list_move_tail(&pi->list, &s->valid_paths); + spin_unlock_irqrestore(&s->lock, flags); return 0; } @@ -265,9 +276,12 @@ static struct dm_path *st_select_path(struct path_selector *ps, { struct selector *s = ps->context; struct path_info *pi = NULL, *best = NULL; + struct dm_path *ret = NULL; + unsigned long flags; + spin_lock_irqsave(&s->lock, flags); if (list_empty(&s->valid_paths)) - return NULL; + goto out; /* Change preferred (first in list) path to evenly balance. */ list_move_tail(s->valid_paths.next, &s->valid_paths); @@ -277,11 +291,14 @@ static struct dm_path *st_select_path(struct path_selector *ps, best = pi; if (!best) - return NULL; + goto out; *repeat_count = best->repeat_count; - return best->path; + ret = best->path; +out: + spin_unlock_irqrestore(&s->lock, flags); + return ret; } static int st_start_io(struct path_selector *ps, struct dm_path *path, -- 2.39.5