diff options
| -rw-r--r-- | drivers/md/md.c | 73 | ||||
| -rw-r--r-- | include/linux/raid/md_k.h | 10 |
2 files changed, 55 insertions, 28 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 1fccd7c3a4aa..825c78d16c44 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -127,8 +127,33 @@ static struct gendisk md_gendisk= /* * Enables to iterate over all existing md arrays + * all_mddevs_lock protects this list as well as mddev_map. */ static LIST_HEAD(all_mddevs); +static spinlock_t all_mddevs_lock = SPIN_LOCK_UNLOCKED; + + +/* + * iterates through all used mddevs in the system. + * We take care to grab the all_mddevs_lock whenever navigating + * the list, and to always hold a refcount when unlocked. + * Any code which breaks out of this loop while own + * a reference to the current mddev and must mddev_put it. + */ +#define ITERATE_MDDEV(mddev,tmp) \ + \ + for (spin_lock(&all_mddevs_lock), \ + (tmp = all_mddevs.next), \ + (mddev = NULL); \ + (void)(tmp != &all_mddevs && \ + mddev_get(list_entry(tmp, mddev_t, all_mddevs))),\ + spin_unlock(&all_mddevs_lock), \ + (mddev ? mddev_put(mddev):(void)NULL), \ + (mddev = list_entry(tmp, mddev_t, all_mddevs)), \ + (tmp != &all_mddevs); \ + spin_lock(&all_mddevs_lock), \ + (tmp = tmp->next) \ + ) static mddev_t *mddev_map[MAX_MD_DEVS]; @@ -146,7 +171,7 @@ static inline mddev_t *mddev_get(mddev_t *mddev) static void mddev_put(mddev_t *mddev) { - if (!atomic_dec_and_test(&mddev->active)) + if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock)) return; if (!mddev->sb && list_empty(&mddev->disks)) { list_del(&mddev->all_mddevs); @@ -154,33 +179,44 @@ static void mddev_put(mddev_t *mddev) kfree(mddev); MOD_DEC_USE_COUNT; } + spin_unlock(&all_mddevs_lock); } static mddev_t * mddev_find(int unit) { - mddev_t *mddev; + mddev_t *mddev, *new = NULL; - if ((mddev = mddev_map[unit])) { - return mddev_get(mddev); + retry: + spin_lock(&all_mddevs_lock); + if (mddev_map[unit]) { + mddev = mddev_get(mddev_map[unit]); + spin_unlock(&all_mddevs_lock); + if (new) + kfree(new); + return mddev; } - mddev = (mddev_t *) kmalloc(sizeof(*mddev), GFP_KERNEL); - if (!mddev) - return NULL; - - memset(mddev, 0, sizeof(*mddev)); + if (new) { + mddev_map[unit] = new; + list_add(&new->all_mddevs, &all_mddevs); + spin_unlock(&all_mddevs_lock); + MOD_INC_USE_COUNT; + return new; + } + spin_unlock(&all_mddevs_lock); - mddev->__minor = unit; - init_MUTEX(&mddev->reconfig_sem); - INIT_LIST_HEAD(&mddev->disks); - INIT_LIST_HEAD(&mddev->all_mddevs); - atomic_set(&mddev->active, 1); + new = (mddev_t *) kmalloc(sizeof(*new), GFP_KERNEL); + if (!new) + return NULL; - mddev_map[unit] = mddev; - list_add(&mddev->all_mddevs, &all_mddevs); + memset(new, 0, sizeof(*new)); - MOD_INC_USE_COUNT; + new->__minor = unit; + init_MUTEX(&new->reconfig_sem); + INIT_LIST_HEAD(&new->disks); + INIT_LIST_HEAD(&new->all_mddevs); + atomic_set(&new->active, 1); - return mddev; + goto retry; } static inline int mddev_lock(mddev_t * mddev) @@ -3192,6 +3228,7 @@ int md_do_sync(mddev_t *mddev, mdp_disk_t *spare) mddev2->curr_resync < 2)) { flush_curr_signals(); err = -EINTR; + mddev_put(mddev2); goto out; } } diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h index 3352cbca5308..c1db880110c0 100644 --- a/include/linux/raid/md_k.h +++ b/include/linux/raid/md_k.h @@ -277,16 +277,6 @@ extern mdp_disk_t *get_spare(mddev_t *mddev); #define ITERATE_RDEV_PENDING(rdev,tmp) \ ITERATE_RDEV_GENERIC(pending_raid_disks,pending,rdev,tmp) -/* - * iterates through all used mddevs in the system. - */ -#define ITERATE_MDDEV(mddev,tmp) \ - \ - for (tmp = all_mddevs.next; \ - mddev = list_entry(tmp, mddev_t, all_mddevs), \ - tmp = tmp->next, tmp->prev != &all_mddevs \ - ; ) - #define xchg_values(x,y) do { __typeof__(x) __tmp = x; \ x = y; y = __tmp; } while (0) |