[PATCH 6/8] mtd_blkdevs: remove blktrans_ref_mutex

Christoph Hellwig
2021-08-23T07:39:43Z

blktrans_ref_mutex is not actually needed. The kref is serialized
internally, and devnum assignment in add_mtd_blktrans_dev happens before
the disk is added and thus any of the block_device_operations methods
otherwise using it are called. It is also already serialized by the
global mtd_table_mutex.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/mtd/mtd_blkdevs.c | 13 +------------
1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
index f5e13b919614..6f226b7cbb5c 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)
{
@@ -41,18 +40,13 @@ static struct mtd_blktrans_dev *blktrans_dev_get(struct gendisk *disk)
{
struct mtd_blktrans_dev *dev = disk->private_data;

- mutex_lock(&blktrans_ref_mutex);
kref_get(&dev->ref);
- 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);
}

@@ -299,7 +293,6 @@ int add_mtd_blktrans_dev(struct mtd_blktrans_dev *new)

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 */
@@ -311,7 +304,6 @@ 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 */
@@ -329,14 +321,11 @@ 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);
--
2.30.2