1 files changed, 11 insertions, 60 deletions

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index 6ce4bc57f919..b8ae1ec14e17 100644
--- a/drivers/mtd/mtd_blkdevs.c
+++ b/drivers/mtd/mtd_blkdevs.c
@@ -23,7 +23,6 @@
 #include "mtdcore.h"
 
 static LIST_HEAD(blktrans_majors);
-static DEFINE_MUTEX(blktrans_ref_mutex);
 
 static void blktrans_dev_release(struct kref *kref)
 {
@@ -37,26 +36,9 @@ static void blktrans_dev_release(struct kref *kref)
 	kfree(dev);
 }
 
-static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
-{
-	struct mtd_blktrans_dev *dev;
-
-	mutex_lock(&blktrans_ref_mutex);
-	dev = disk->private_data;
-
-	if (!dev)
-		goto unlock;
-	kref_get(&dev->ref);
-unlock:
-	mutex_unlock(&blktrans_ref_mutex);
-	return dev;
-}
-
 static void blktrans_dev_put(struct mtd_blktrans_dev *dev)
 {
-	mutex_lock(&blktrans_ref_mutex);
 	kref_put(&dev->ref, blktrans_dev_release);
-	mutex_unlock(&blktrans_ref_mutex);
 }
 
 
@@ -201,19 +183,16 @@ static blk_status_t mtd_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 static int blktrans_open(struct block_device *bdev, fmode_t mode)
 {
-	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
+	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
 	int ret = 0;
 
-	if (!dev)
-		return -ERESTARTSYS; /* FIXME: busy loop! -arnd*/
+	kref_get(&dev->ref);
 
-	mutex_lock(&mtd_table_mutex);
 	mutex_lock(&dev->lock);
 
 	if (dev->open)
 		goto unlock;
 
-	kref_get(&dev->ref);
 	__module_get(dev->tr->owner);
 
 	if (!dev->mtd)
@@ -233,8 +212,6 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode)
 unlock:
 	dev->open++;
 	mutex_unlock(&dev->lock);
-	mutex_unlock(&mtd_table_mutex);
-	blktrans_dev_put(dev);
 	return ret;
 
 error_release:
@@ -242,27 +219,20 @@ error_release:
 		dev->tr->release(dev);
 error_put:
 	module_put(dev->tr->owner);
-	kref_put(&dev->ref, blktrans_dev_release);
 	mutex_unlock(&dev->lock);
-	mutex_unlock(&mtd_table_mutex);
 	blktrans_dev_put(dev);
 	return ret;
 }
 
 static void blktrans_release(struct gendisk *disk, fmode_t mode)
 {
-	struct mtd_blktrans_dev *dev = blktrans_dev_get(disk);
-
-	if (!dev)
-		return;
+	struct mtd_blktrans_dev *dev = disk->private_data;
 
-	mutex_lock(&mtd_table_mutex);
 	mutex_lock(&dev->lock);
 
 	if (--dev->open)
 		goto unlock;
 
-	kref_put(&dev->ref, blktrans_dev_release);
 	module_put(dev->tr->owner);
 
 	if (dev->mtd) {
@@ -272,18 +242,14 @@ static void blktrans_release(struct gendisk *disk, fmode_t mode)
 	}
 unlock:
 	mutex_unlock(&dev->lock);
-	mutex_unlock(&mtd_table_mutex);
 	blktrans_dev_put(dev);
 }
 
 static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 {
-	struct mtd_blktrans_dev *dev = blktrans_dev_get(bdev->bd_disk);
+	struct mtd_blktrans_dev *dev = bdev->bd_disk->private_data;
 	int ret = -ENXIO;
 
-	if (!dev)
-		return ret;
-
 	mutex_lock(&dev->lock);
 
 	if (!dev->mtd)
@@ -292,7 +258,6 @@ static int blktrans_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 	ret = dev->tr->getgeo ? dev->tr->getgeo(dev, geo) : -ENOTTY;
 unlock:
 	mutex_unlock(&dev->lock);
-	blktrans_dev_put(dev);
 	return ret;
 }
 
@@ -315,12 +280,8 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 	struct gendisk *gd;
 	int ret;
 
-	if (mutex_trylock(&mtd_table_mutex)) {
-		mutex_unlock(&mtd_table_mutex);
-		BUG();
-	}
+	lockdep_assert_held(&mtd_table_mutex);
 
-	mutex_lock(&blktrans_ref_mutex);
 	list_for_each_entry(d, &tr->devs, list) {
 		if (new->devnum == -1) {
 			/* Use first free number */
@@ -332,7 +293,6 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 			}
 		} else if (d->devnum == new->devnum) {
 			/* Required number taken */
-			mutex_unlock(&blktrans_ref_mutex);
 			return -EBUSY;
 		} else if (d->devnum > new->devnum) {
 			/* Required number was free */
@@ -350,14 +310,11 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 	 * minor numbers and that the disk naming code below can cope
 	 * with this number. */
 	if (new->devnum > (MINORMASK >> tr->part_bits) ||
-	    (tr->part_bits && new->devnum >= 27 * 26)) {
-		mutex_unlock(&blktrans_ref_mutex);
+	    (tr->part_bits && new->devnum >= 27 * 26))
 		return ret;
-	}
 
 	list_add_tail(&new->list, &tr->devs);
  added:
-	mutex_unlock(&blktrans_ref_mutex);
 
 	mutex_init(&new->lock);
 	kref_init(&new->ref);
@@ -419,6 +376,7 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)
 	if (tr->discard) {
 		blk_queue_flag_set(QUEUE_FLAG_DISCARD, new->rq);
 		blk_queue_max_discard_sectors(new->rq, UINT_MAX);
+		new->rq->limits.discard_granularity = tr->blksize;
 	}
 
 	gd->queue = new->rq;
@@ -448,10 +406,7 @@ int del_mtd_blktrans_dev(struct mtd_blktrans_dev *old)
 {
 	unsigned long flags;
 
-	if (mutex_trylock(&mtd_table_mutex)) {
-		mutex_unlock(&mtd_table_mutex);
-		BUG();
-	}
+	lockdep_assert_held(&mtd_table_mutex);
 
 	if (old->disk_attributes)
 		sysfs_remove_group(&disk_to_dev(old->disk)->kobj,
@@ -525,14 +480,10 @@ int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
 	if (!blktrans_notifier.list.next)
 		register_mtd_user(&blktrans_notifier);
 
-
-	mutex_lock(&mtd_table_mutex);
-
 	ret = register_blkdev(tr->major, tr->name);
 	if (ret < 0) {
 		printk(KERN_WARNING "Unable to register %s block device on major %d: %d\n",
 		       tr->name, tr->major, ret);
-		mutex_unlock(&mtd_table_mutex);
 		return ret;
 	}
 
@@ -542,12 +493,12 @@ int register_mtd_blktrans(struct mtd_blktrans_ops *tr)
 	tr->blkshift = ffs(tr->blksize) - 1;
 
 	INIT_LIST_HEAD(&tr->devs);
-	list_add(&tr->list, &blktrans_majors);
 
+	mutex_lock(&mtd_table_mutex);
+	list_add(&tr->list, &blktrans_majors);
 	mtd_for_each_device(mtd)
 		if (mtd->type != MTD_ABSENT)
 			tr->add_mtd(tr, mtd);
-
 	mutex_unlock(&mtd_table_mutex);
 	return 0;
 }
@@ -564,8 +515,8 @@ int deregister_mtd_blktrans(struct mtd_blktrans_ops *tr)
 	list_for_each_entry_safe(dev, next, &tr->devs, list)
 		tr->remove_dev(dev);
 
-	unregister_blkdev(tr->major, tr->name);
 	mutex_unlock(&mtd_table_mutex);
+	unregister_blkdev(tr->major, tr->name);
 
 	BUG_ON(!list_empty(&tr->devs));
 	return 0;