md: remove md_mutex locking.

lock_kernel calls were recently pushed down into open/release
functions.
md doesn't need that protection.
Then the BKL calls were change to md_mutex.  We don't need those
either.
So remove it all.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 64f97168cefa5a846666c3a54b6c75638020dc66..2399168b631560e03d6307c1d8eed1b180888cd0 100644 (file)
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -57,8 +57,6 @@
 #define DEBUG 0
 #define dprintk(x...) ((void)(DEBUG && printk(x)))
 
-static DEFINE_MUTEX(md_mutex);
-
 #ifndef MODULE
 static void autostart_arrays(int part);
 #endif
@@ -5887,7 +5885,6 @@ static int md_open(struct block_device *bdev, fmode_t mode)
        mddev_t *mddev = mddev_find(bdev->bd_dev);
        int err;
 
-       mutex_lock(&md_mutex);
        if (mddev->gendisk != bdev->bd_disk) {
                /* we are racing with mddev_put which is discarding this
                 * bd_disk.
@@ -5896,7 +5893,6 @@ static int md_open(struct block_device *bdev, fmode_t mode)
                /* Wait until bdev->bd_disk is definitely gone */
                flush_scheduled_work();
                /* Then retry the open from the top */
-               mutex_unlock(&md_mutex);
                return -ERESTARTSYS;
        }
        BUG_ON(mddev != bdev->bd_disk->private_data);
@@ -5910,7 +5906,6 @@ static int md_open(struct block_device *bdev, fmode_t mode)
 
        check_disk_size_change(mddev->gendisk, bdev);
  out:
-       mutex_unlock(&md_mutex);
        return err;
 }
 
@@ -5919,10 +5914,8 @@ static int md_release(struct gendisk *disk, fmode_t mode)
        mddev_t *mddev = disk->private_data;
 
        BUG_ON(!mddev);
-       mutex_lock(&md_mutex);
        atomic_dec(&mddev->openers);
        mddev_put(mddev);
-       mutex_unlock(&md_mutex);
 
        return 0;
 }