[PATCH 4/5] memstick/mspro_block: simplify refcounting

Christoph Hellwig
2022-02-15T09:45:40Z

Implement the ->free_disk method to free the msb_data structure only once
the last gendisk reference goes away instead of keeping a local
refcount.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/memstick/core/mspro_block.c | 49 +++++------------------------
1 file changed, 7 insertions(+), 42 deletions(-)

diff --git a/drivers/memstick/core/mspro_block.c b/drivers/memstick/core/mspro_block.c
index 7ea312f0840e0..725ba74ded308 100644
--- a/drivers/memstick/core/mspro_block.c
+++ b/drivers/memstick/core/mspro_block.c
@@ -133,7 +133,6 @@ struct mspro_devinfo {

struct mspro_block_data {
struct memstick_dev *card;
- unsigned int usage_count;
unsigned int caps;
struct gendisk *disk;
struct request_queue *queue;
@@ -178,48 +177,16 @@ static int mspro_block_complete_req(struct memstick_dev *card, int error);

/*** Block device ***/

-static int mspro_block_bd_open(struct block_device *bdev, fmode_t mode)
-{
- struct gendisk *disk = bdev->bd_disk;
- struct mspro_block_data *msb = disk->private_data;
- int rc = -ENXIO;
-
- mutex_lock(&mspro_block_disk_lock);
-
- if (msb && msb->card)
- msb->usage_count++;
-
- mutex_unlock(&mspro_block_disk_lock);
-
- return rc;
-}
-
-
-static void mspro_block_disk_release(struct gendisk *disk)
+static void mspro_block_bd_free_disk(struct gendisk *disk)
{
struct mspro_block_data *msb = disk->private_data;
int disk_id = MINOR(disk_devt(disk)) >> MSPRO_BLOCK_PART_SHIFT;

mutex_lock(&mspro_block_disk_lock);
-
- if (msb) {
- if (msb->usage_count)
- msb->usage_count--;
-
- if (!msb->usage_count) {
- kfree(msb);
- disk->private_data = NULL;
- idr_remove(&mspro_block_disk_idr, disk_id);
- put_disk(disk);
- }
- }
-
+ idr_remove(&mspro_block_disk_idr, disk_id);
mutex_unlock(&mspro_block_disk_lock);
-}

-static void mspro_block_bd_release(struct gendisk *disk, fmode_t mode)
-{
- mspro_block_disk_release(disk);
+ kfree(msb);
}

static int mspro_block_bd_getgeo(struct block_device *bdev,
@@ -235,10 +202,9 @@ static int mspro_block_bd_getgeo(struct block_device *bdev,
}

static const struct block_device_operations ms_block_bdops = {
- .open = mspro_block_bd_open,
- .release = mspro_block_bd_release,
- .getgeo = mspro_block_bd_getgeo,
- .owner = THIS_MODULE
+ .owner = THIS_MODULE,
+ .getgeo = mspro_block_bd_getgeo,
+ .free_disk = mspro_block_bd_free_disk,
};

/*** Information ***/
@@ -1221,7 +1187,6 @@ static int mspro_block_init_disk(struct memstick_dev *card)
msb->disk->first_minor = disk_id << MSPRO_BLOCK_PART_SHIFT;
msb->disk->minors = 1 << MSPRO_BLOCK_PART_SHIFT;
msb->disk->fops = &ms_block_bdops;
- msb->usage_count = 1;
msb->disk->private_data = msb;

sprintf(msb->disk->disk_name, "mspblk%d", disk_id);
@@ -1339,7 +1304,7 @@ static void mspro_block_remove(struct memstick_dev *card)
mspro_block_data_clear(msb);
mutex_unlock(&mspro_block_disk_lock);

- mspro_block_disk_release(msb->disk);
+ put_disk(msb->disk);
memstick_set_drvdata(card, NULL);
}

--
2.30.2