diff options
Diffstat (limited to 'drivers/md/dm-queue-length.c')
| -rw-r--r-- | drivers/md/dm-queue-length.c | 37 |
1 files changed, 28 insertions, 9 deletions
diff --git a/drivers/md/dm-queue-length.c b/drivers/md/dm-queue-length.c index 3941fae0de9f..23f178641794 100644 --- a/drivers/md/dm-queue-length.c +++ b/drivers/md/dm-queue-length.c @@ -23,12 +23,13 @@ #include <linux/atomic.h> #define DM_MSG_PREFIX "multipath queue-length" -#define QL_MIN_IO 128 -#define QL_VERSION "0.1.0" +#define QL_MIN_IO 1 +#define QL_VERSION "0.2.0" 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: [<repeat_count>] @@ -129,6 +132,11 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path, return -EINVAL; } + if (repeat_count > 1) { + DMWARN_LIMIT("repeat_count > 1 is deprecated, using 1 instead"); + repeat_count = 1; + } + /* Allocate the path information structure */ pi = kmalloc(sizeof(*pi), GFP_KERNEL); if (!pi) { @@ -142,7 +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; } @@ -151,16 +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; } @@ -168,14 +184,16 @@ static int ql_reinstate_path(struct path_selector *ps, struct dm_path *path) /* * Select a path having the minimum number of in-flight I/Os */ -static struct dm_path *ql_select_path(struct path_selector *ps, - unsigned *repeat_count, size_t nr_bytes) +static struct dm_path *ql_select_path(struct path_selector *ps, size_t nr_bytes) { 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); @@ -190,11 +208,12 @@ static struct dm_path *ql_select_path(struct path_selector *ps, } if (!best) - return NULL; - - *repeat_count = best->repeat_count; + goto out; - 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, |