block: drbd: Convert semaphore to mutex

The bm_change semaphore is semantically a mutex. Convert it to a real
mutex.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>

diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index b61057e7788219f6a574aa35df82d6e9d532c526..f58e76581c4b4c99e169310746c14465e7bedf82 100644 (file)
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -66,7 +66,7 @@ struct drbd_bitmap {
        size_t   bm_words;
        size_t   bm_number_of_pages;
        sector_t bm_dev_capacity;
-       struct semaphore bm_change; /* serializes resize operations */
+       struct mutex bm_change; /* serializes resize operations */
 
        atomic_t bm_async_io;
        wait_queue_head_t bm_io_wait;
@@ -114,7 +114,7 @@ void drbd_bm_lock(struct drbd_conf *mdev, char *why)
                return;
        }
 
-       trylock_failed = down_trylock(&b->bm_change);
+       trylock_failed = !mutex_trylock(&b->bm_change);
 
        if (trylock_failed) {
                dev_warn(DEV, "%s going to '%s' but bitmap already locked for '%s' by %s\n",
@@ -125,7 +125,7 @@ void drbd_bm_lock(struct drbd_conf *mdev, char *why)
                    b->bm_task == mdev->receiver.task ? "receiver" :
                    b->bm_task == mdev->asender.task  ? "asender"  :
                    b->bm_task == mdev->worker.task   ? "worker"   : "?");
-               down(&b->bm_change);
+               mutex_lock(&b->bm_change);
        }
        if (__test_and_set_bit(BM_LOCKED, &b->bm_flags))
                dev_err(DEV, "FIXME bitmap already locked in bm_lock\n");
@@ -147,7 +147,7 @@ void drbd_bm_unlock(struct drbd_conf *mdev)
 
        b->bm_why  = NULL;
        b->bm_task = NULL;
-       up(&b->bm_change);
+       mutex_unlock(&b->bm_change);
 }
 
 /* word offset to long pointer */
@@ -295,7 +295,7 @@ int drbd_bm_init(struct drbd_conf *mdev)
        if (!b)
                return -ENOMEM;
        spin_lock_init(&b->bm_lock);
-       init_MUTEX(&b->bm_change);
+       mutex_init(&b->bm_change);
        init_waitqueue_head(&b->bm_io_wait);
 
        mdev->bitmap = b;