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dm mpath: push path selector locking down to path selectors

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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 <snitzer@redhat.com>
This commit is contained in:
Mike Snitzer 2016-02-15 14:25:00 -05:00
parent 21136f89d7
commit 9659f81144
3 changed files with 59 additions and 11 deletions
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23
drivers/md/dm-queue-length.c
View File

@ -29,6 +29,7 @@
struct selector { struct selector {
struct list_head valid_paths; struct list_head valid_paths;
struct list_head failed_paths; struct list_head failed_paths;
spinlock_t lock;
}; };
struct path_info { struct path_info {
@ -45,6 +46,7 @@ static struct selector *alloc_selector(void)
if (s) { if (s) {
INIT_LIST_HEAD(&s->valid_paths); INIT_LIST_HEAD(&s->valid_paths);
INIT_LIST_HEAD(&s->failed_paths); INIT_LIST_HEAD(&s->failed_paths);
spin_lock_init(&s->lock);
} }
return s; return s;
@ -113,6 +115,7 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path,
struct path_info *pi; struct path_info *pi;
unsigned repeat_count = QL_MIN_IO; unsigned repeat_count = QL_MIN_IO;
char dummy; char dummy;
unsigned long flags;
/* /*
* Arguments: [<repeat_count>] * Arguments: [<repeat_count>]
@ -147,7 +150,9 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path,
path->pscontext = pi; path->pscontext = pi;
spin_lock_irqsave(&s->lock, flags);
list_add_tail(&pi->list, &s->valid_paths); list_add_tail(&pi->list, &s->valid_paths);
spin_unlock_irqrestore(&s->lock, flags);
return 0; 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 selector *s = ps->context;
struct path_info *pi = path->pscontext; struct path_info *pi = path->pscontext;
unsigned long flags;
spin_lock_irqsave(&s->lock, flags);
list_move(&pi->list, &s->failed_paths); 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) static int ql_reinstate_path(struct path_selector *ps, struct dm_path *path)
{ {
struct selector *s = ps->context; struct selector *s = ps->context;
struct path_info *pi = path->pscontext; struct path_info *pi = path->pscontext;
unsigned long flags;
spin_lock_irqsave(&s->lock, flags);
list_move_tail(&pi->list, &s->valid_paths); list_move_tail(&pi->list, &s->valid_paths);
spin_unlock_irqrestore(&s->lock, flags);
return 0; return 0;
} }
@ -178,9 +189,12 @@ static struct dm_path *ql_select_path(struct path_selector *ps,
{ {
struct selector *s = ps->context; struct selector *s = ps->context;
struct path_info *pi = NULL, *best = NULL; 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)) if (list_empty(&s->valid_paths))
return NULL; goto out;
/* Change preferred (first in list) path to evenly balance. */ /* Change preferred (first in list) path to evenly balance. */
list_move_tail(s->valid_paths.next, &s->valid_paths); 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) if (!best)
return NULL; goto out;
*repeat_count = best->repeat_count; *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, static int ql_start_io(struct path_selector *ps, struct dm_path *path,

24
drivers/md/dm-round-robin.c
View File

@ -46,6 +46,7 @@ static void free_paths(struct list_head *paths)
struct selector { struct selector {
struct list_head valid_paths; struct list_head valid_paths;
struct list_head invalid_paths; struct list_head invalid_paths;
spinlock_t lock;
}; };
static struct selector *alloc_selector(void) static struct selector *alloc_selector(void)
@ -55,6 +56,7 @@ static struct selector *alloc_selector(void)
if (s) { if (s) {
INIT_LIST_HEAD(&s->valid_paths); INIT_LIST_HEAD(&s->valid_paths);
INIT_LIST_HEAD(&s->invalid_paths); INIT_LIST_HEAD(&s->invalid_paths);
spin_lock_init(&s->lock);
} }
return s; 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) 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->valid_paths);
free_paths(&s->invalid_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, static int rr_add_path(struct path_selector *ps, struct dm_path *path,
int argc, char **argv, char **error) int argc, char **argv, char **error)
{ {
struct selector *s = (struct selector *) ps->context; struct selector *s = ps->context;
struct path_info *pi; struct path_info *pi;
unsigned repeat_count = RR_MIN_IO; unsigned repeat_count = RR_MIN_IO;
char dummy; char dummy;
unsigned long flags;
if (argc > 1) { if (argc > 1) {
*error = "round-robin ps: incorrect number of arguments"; *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; path->pscontext = pi;
spin_lock_irqsave(&s->lock, flags);
list_add_tail(&pi->list, &s->valid_paths); list_add_tail(&pi->list, &s->valid_paths);
spin_unlock_irqrestore(&s->lock, flags);
return 0; return 0;
} }
static void rr_fail_path(struct path_selector *ps, struct dm_path *p) 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; struct path_info *pi = p->pscontext;
spin_lock_irqsave(&s->lock, flags);
list_move(&pi->list, &s->invalid_paths); 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) 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; struct path_info *pi = p->pscontext;
spin_lock_irqsave(&s->lock, flags);
list_move(&pi->list, &s->valid_paths); list_move(&pi->list, &s->valid_paths);
spin_unlock_irqrestore(&s->lock, flags);
return 0; 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, static struct dm_path *rr_select_path(struct path_selector *ps,
unsigned *repeat_count, size_t nr_bytes) 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; struct path_info *pi = NULL;
spin_lock_irqsave(&s->lock, flags);
if (!list_empty(&s->valid_paths)) { if (!list_empty(&s->valid_paths)) {
pi = list_entry(s->valid_paths.next, struct path_info, list); pi = list_entry(s->valid_paths.next, struct path_info, list);
list_move_tail(&pi->list, &s->valid_paths); list_move_tail(&pi->list, &s->valid_paths);
*repeat_count = pi->repeat_count; *repeat_count = pi->repeat_count;
} }
spin_unlock_irqrestore(&s->lock, flags);
return pi ? pi->path : NULL; return pi ? pi->path : NULL;
} }

23
drivers/md/dm-service-time.c
View File

@ -24,6 +24,7 @@
struct selector { struct selector {
struct list_head valid_paths; struct list_head valid_paths;
struct list_head failed_paths; struct list_head failed_paths;
spinlock_t lock;
}; };
struct path_info { struct path_info {
@ -41,6 +42,7 @@ static struct selector *alloc_selector(void)
if (s) { if (s) {
INIT_LIST_HEAD(&s->valid_paths); INIT_LIST_HEAD(&s->valid_paths);
INIT_LIST_HEAD(&s->failed_paths); INIT_LIST_HEAD(&s->failed_paths);
spin_lock_init(&s->lock);
} }
return s; 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 repeat_count = ST_MIN_IO;
unsigned relative_throughput = 1; unsigned relative_throughput = 1;
char dummy; char dummy;
unsigned long flags;
/* /*
* Arguments: [<repeat_count> [<relative_throughput>]] * Arguments: [<repeat_count> [<relative_throughput>]]
@ -160,7 +163,9 @@ static int st_add_path(struct path_selector *ps, struct dm_path *path,
path->pscontext = pi; path->pscontext = pi;
spin_lock_irqsave(&s->lock, flags);
list_add_tail(&pi->list, &s->valid_paths); list_add_tail(&pi->list, &s->valid_paths);
spin_unlock_irqrestore(&s->lock, flags);
return 0; 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 selector *s = ps->context;
struct path_info *pi = path->pscontext; struct path_info *pi = path->pscontext;
unsigned long flags;
spin_lock_irqsave(&s->lock, flags);
list_move(&pi->list, &s->failed_paths); 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) static int st_reinstate_path(struct path_selector *ps, struct dm_path *path)
{ {
struct selector *s = ps->context; struct selector *s = ps->context;
struct path_info *pi = path->pscontext; struct path_info *pi = path->pscontext;
unsigned long flags;
spin_lock_irqsave(&s->lock, flags);
list_move_tail(&pi->list, &s->valid_paths); list_move_tail(&pi->list, &s->valid_paths);
spin_unlock_irqrestore(&s->lock, flags);
return 0; return 0;
} }
@ -265,9 +276,12 @@ static struct dm_path *st_select_path(struct path_selector *ps,
{ {
struct selector *s = ps->context; struct selector *s = ps->context;
struct path_info *pi = NULL, *best = NULL; 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)) if (list_empty(&s->valid_paths))
return NULL; goto out;
/* Change preferred (first in list) path to evenly balance. */ /* Change preferred (first in list) path to evenly balance. */
list_move_tail(s->valid_paths.next, &s->valid_paths); 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; best = pi;
if (!best) if (!best)
return NULL; goto out;
*repeat_count = best->repeat_count; *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, static int st_start_io(struct path_selector *ps, struct dm_path *path,