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 <snitzer@redhat.com>
This commit is contained in:
parent
21136f89d7
commit
9659f81144
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@ -29,6 +29,7 @@
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struct selector {
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struct list_head valid_paths;
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struct list_head failed_paths;
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spinlock_t lock;
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};
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struct path_info {
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@ -45,6 +46,7 @@ static struct selector *alloc_selector(void)
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if (s) {
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INIT_LIST_HEAD(&s->valid_paths);
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INIT_LIST_HEAD(&s->failed_paths);
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spin_lock_init(&s->lock);
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}
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return s;
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@ -113,6 +115,7 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path,
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struct path_info *pi;
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unsigned repeat_count = QL_MIN_IO;
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char dummy;
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unsigned long flags;
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/*
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* Arguments: [<repeat_count>]
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@ -147,7 +150,9 @@ static int ql_add_path(struct path_selector *ps, struct dm_path *path,
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path->pscontext = pi;
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spin_lock_irqsave(&s->lock, flags);
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list_add_tail(&pi->list, &s->valid_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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return 0;
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}
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@ -156,16 +161,22 @@ static void ql_fail_path(struct path_selector *ps, struct dm_path *path)
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{
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struct selector *s = ps->context;
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struct path_info *pi = path->pscontext;
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unsigned long flags;
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spin_lock_irqsave(&s->lock, flags);
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list_move(&pi->list, &s->failed_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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}
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static int ql_reinstate_path(struct path_selector *ps, struct dm_path *path)
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{
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struct selector *s = ps->context;
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struct path_info *pi = path->pscontext;
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unsigned long flags;
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spin_lock_irqsave(&s->lock, flags);
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list_move_tail(&pi->list, &s->valid_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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return 0;
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}
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@ -178,9 +189,12 @@ static struct dm_path *ql_select_path(struct path_selector *ps,
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{
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struct selector *s = ps->context;
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struct path_info *pi = NULL, *best = NULL;
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struct dm_path *ret = NULL;
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unsigned long flags;
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spin_lock_irqsave(&s->lock, flags);
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if (list_empty(&s->valid_paths))
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return NULL;
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goto out;
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/* Change preferred (first in list) path to evenly balance. */
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list_move_tail(s->valid_paths.next, &s->valid_paths);
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@ -195,11 +209,14 @@ static struct dm_path *ql_select_path(struct path_selector *ps,
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}
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if (!best)
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return NULL;
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goto out;
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*repeat_count = best->repeat_count;
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return best->path;
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ret = best->path;
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out:
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spin_unlock_irqrestore(&s->lock, flags);
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return ret;
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}
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static int ql_start_io(struct path_selector *ps, struct dm_path *path,
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@ -46,6 +46,7 @@ static void free_paths(struct list_head *paths)
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struct selector {
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struct list_head valid_paths;
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struct list_head invalid_paths;
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spinlock_t lock;
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};
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static struct selector *alloc_selector(void)
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@ -55,6 +56,7 @@ static struct selector *alloc_selector(void)
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if (s) {
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INIT_LIST_HEAD(&s->valid_paths);
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INIT_LIST_HEAD(&s->invalid_paths);
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spin_lock_init(&s->lock);
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}
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return s;
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@ -74,7 +76,7 @@ static int rr_create(struct path_selector *ps, unsigned argc, char **argv)
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static void rr_destroy(struct path_selector *ps)
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{
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struct selector *s = (struct selector *) ps->context;
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struct selector *s = ps->context;
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free_paths(&s->valid_paths);
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free_paths(&s->invalid_paths);
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@ -111,10 +113,11 @@ static int rr_status(struct path_selector *ps, struct dm_path *path,
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static int rr_add_path(struct path_selector *ps, struct dm_path *path,
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int argc, char **argv, char **error)
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{
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struct selector *s = (struct selector *) ps->context;
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struct selector *s = ps->context;
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struct path_info *pi;
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unsigned repeat_count = RR_MIN_IO;
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char dummy;
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unsigned long flags;
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if (argc > 1) {
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*error = "round-robin ps: incorrect number of arguments";
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@ -144,25 +147,33 @@ static int rr_add_path(struct path_selector *ps, struct dm_path *path,
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path->pscontext = pi;
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spin_lock_irqsave(&s->lock, flags);
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list_add_tail(&pi->list, &s->valid_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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return 0;
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}
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static void rr_fail_path(struct path_selector *ps, struct dm_path *p)
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{
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struct selector *s = (struct selector *) ps->context;
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unsigned long flags;
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struct selector *s = ps->context;
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struct path_info *pi = p->pscontext;
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spin_lock_irqsave(&s->lock, flags);
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list_move(&pi->list, &s->invalid_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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}
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static int rr_reinstate_path(struct path_selector *ps, struct dm_path *p)
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{
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struct selector *s = (struct selector *) ps->context;
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unsigned long flags;
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struct selector *s = ps->context;
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struct path_info *pi = p->pscontext;
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spin_lock_irqsave(&s->lock, flags);
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list_move(&pi->list, &s->valid_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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return 0;
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}
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@ -170,14 +181,17 @@ static int rr_reinstate_path(struct path_selector *ps, struct dm_path *p)
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static struct dm_path *rr_select_path(struct path_selector *ps,
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unsigned *repeat_count, size_t nr_bytes)
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{
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struct selector *s = (struct selector *) ps->context;
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unsigned long flags;
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struct selector *s = ps->context;
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struct path_info *pi = NULL;
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spin_lock_irqsave(&s->lock, flags);
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if (!list_empty(&s->valid_paths)) {
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pi = list_entry(s->valid_paths.next, struct path_info, list);
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list_move_tail(&pi->list, &s->valid_paths);
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*repeat_count = pi->repeat_count;
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}
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spin_unlock_irqrestore(&s->lock, flags);
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return pi ? pi->path : NULL;
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}
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@ -24,6 +24,7 @@
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struct selector {
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struct list_head valid_paths;
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struct list_head failed_paths;
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spinlock_t lock;
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};
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struct path_info {
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@ -41,6 +42,7 @@ static struct selector *alloc_selector(void)
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if (s) {
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INIT_LIST_HEAD(&s->valid_paths);
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INIT_LIST_HEAD(&s->failed_paths);
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spin_lock_init(&s->lock);
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}
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return s;
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@ -111,6 +113,7 @@ static int st_add_path(struct path_selector *ps, struct dm_path *path,
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unsigned repeat_count = ST_MIN_IO;
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unsigned relative_throughput = 1;
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char dummy;
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unsigned long flags;
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/*
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* Arguments: [<repeat_count> [<relative_throughput>]]
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@ -160,7 +163,9 @@ static int st_add_path(struct path_selector *ps, struct dm_path *path,
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path->pscontext = pi;
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spin_lock_irqsave(&s->lock, flags);
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list_add_tail(&pi->list, &s->valid_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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return 0;
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}
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@ -169,16 +174,22 @@ static void st_fail_path(struct path_selector *ps, struct dm_path *path)
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{
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struct selector *s = ps->context;
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struct path_info *pi = path->pscontext;
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unsigned long flags;
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spin_lock_irqsave(&s->lock, flags);
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list_move(&pi->list, &s->failed_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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}
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static int st_reinstate_path(struct path_selector *ps, struct dm_path *path)
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{
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struct selector *s = ps->context;
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struct path_info *pi = path->pscontext;
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unsigned long flags;
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spin_lock_irqsave(&s->lock, flags);
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list_move_tail(&pi->list, &s->valid_paths);
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spin_unlock_irqrestore(&s->lock, flags);
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return 0;
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}
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@ -265,9 +276,12 @@ static struct dm_path *st_select_path(struct path_selector *ps,
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{
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struct selector *s = ps->context;
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struct path_info *pi = NULL, *best = NULL;
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struct dm_path *ret = NULL;
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unsigned long flags;
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spin_lock_irqsave(&s->lock, flags);
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if (list_empty(&s->valid_paths))
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return NULL;
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goto out;
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/* Change preferred (first in list) path to evenly balance. */
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list_move_tail(s->valid_paths.next, &s->valid_paths);
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@ -277,11 +291,14 @@ static struct dm_path *st_select_path(struct path_selector *ps,
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best = pi;
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if (!best)
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return NULL;
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goto out;
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*repeat_count = best->repeat_count;
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return best->path;
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ret = best->path;
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out:
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spin_unlock_irqrestore(&s->lock, flags);
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return ret;
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}
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static int st_start_io(struct path_selector *ps, struct dm_path *path,
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