dm mpath: push path selector locking down to path selectors
[cascardo/linux.git] / drivers / md / dm-round-robin.c
index 65ffdc3..be9aa7f 100644 (file)
@@ -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;
 }