kcopyd use mutex instead of semaphore

Kcopyd uses a semaphore as mutex.  Use the mutex API instead of the (binary)
semaphore,

Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

drivers/md/kcopyd.c

@@ -198,7 +198,7 @@ struct kcopyd_job {
 	 * These fields are only used if the job has been split
 	 * into more manageable parts.
 	 */
-	struct semaphore lock;
+	struct mutex lock;
 	atomic_t sub_jobs;
 	sector_t progress;
 };
@@ -456,7 +456,7 @@ static void segment_complete(int read_err,
 	sector_t count = 0;
 	struct kcopyd_job *job = (struct kcopyd_job *) context;
 
-	down(&job->lock);
+	mutex_lock(&job->lock);
 
 	/* update the error */
 	if (read_err)
@@ -480,7 +480,7 @@ static void segment_complete(int read_err,
 			job->progress += count;
 		}
 	}
-	up(&job->lock);
+	mutex_unlock(&job->lock);
 
 	if (count) {
 		int i;
@@ -562,7 +562,7 @@ int kcopyd_copy(struct kcopyd_client *kc, struct io_region *from,
 		dispatch_job(job);
 
 	else {
-		init_MUTEX(&job->lock);
+		mutex_init(&job->lock);
 		job->progress = 0;
 		split_job(job);
 	}