Commit e2efa079 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

memstick/ms_block: simplify refcounting 



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: default avatarChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220215094514.3828912-3-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 76792055

drivers/memstick/core/ms_block.c

+15 −49
Original line number Diff line number Diff line
@@ -1943,22 +1943,6 @@ static void msb_io_work(struct work_struct *work) 
static DEFINE_IDR(msb_disk_idr); /*set of used disk numbers */

static DEFINE_MUTEX(msb_disk_lock); /* protects against races in open/release */



static int msb_bd_open(struct block_device *bdev, fmode_t mode)

{

	struct gendisk *disk = bdev->bd_disk;

	struct msb_data *msb = disk->private_data;



	dbg_verbose("block device open");



	mutex_lock(&msb_disk_lock);



	if (msb && msb->card)

		msb->usage_count++;



	mutex_unlock(&msb_disk_lock);

	return 0;

}



static void msb_data_clear(struct msb_data *msb)

{

	kfree(msb->boot_page);
@@ -1968,39 +1952,23 @@ static void msb_data_clear(struct msb_data *msb) 
	msb->card = NULL;

}



static int msb_disk_release(struct gendisk *disk)

static int msb_bd_getgeo(struct block_device *bdev,

				 struct hd_geometry *geo)

{

	struct msb_data *msb = bdev->bd_disk->private_data;

	*geo = msb->geometry;

	return 0;

}



static void msb_bd_free_disk(struct gendisk *disk)

{

	struct msb_data *msb = disk->private_data;



	dbg_verbose("block device release");

	mutex_lock(&msb_disk_lock);



	if (msb) {

		if (msb->usage_count)

			msb->usage_count--;



		if (!msb->usage_count) {

			disk->private_data = NULL;

	idr_remove(&msb_disk_idr, msb->disk_id);

			put_disk(disk);

			kfree(msb);

		}

	}

	mutex_unlock(&msb_disk_lock);

	return 0;

}



static void msb_bd_release(struct gendisk *disk, fmode_t mode)

{

	msb_disk_release(disk);

}



static int msb_bd_getgeo(struct block_device *bdev,

				 struct hd_geometry *geo)

{

	struct msb_data *msb = bdev->bd_disk->private_data;

	*geo = msb->geometry;

	return 0;

	kfree(msb);

}



static blk_status_t msb_queue_rq(struct blk_mq_hw_ctx *hctx,
@@ -2096,10 +2064,9 @@ static void msb_start(struct memstick_dev *card) 
}



static const struct block_device_operations msb_bdops = {

	.open    = msb_bd_open,

	.release = msb_bd_release,

	.owner		= THIS_MODULE,

	.getgeo		= msb_bd_getgeo,

	.owner   = THIS_MODULE

	.free_disk	= msb_bd_free_disk, 

};



static const struct blk_mq_ops msb_mq_ops = {
@@ -2147,7 +2114,6 @@ static int msb_init_disk(struct memstick_dev *card) 
	set_capacity(msb->disk, capacity);

	dbg("Set total disk size to %lu sectors", capacity);



	msb->usage_count = 1;

	msb->io_queue = alloc_ordered_workqueue("ms_block", WQ_MEM_RECLAIM);

	INIT_WORK(&msb->io_work, msb_io_work);

	sg_init_table(msb->prealloc_sg, MS_BLOCK_MAX_SEGS+1);
@@ -2229,7 +2195,7 @@ static void msb_remove(struct memstick_dev *card) 
	msb_data_clear(msb);

	mutex_unlock(&msb_disk_lock);



	msb_disk_release(msb->disk);

	put_disk(msb->disk);

	memstick_set_drvdata(card, NULL);

}

drivers/memstick/core/ms_block.h

+0 −1
Original line number Diff line number Diff line
@@ -143,7 +143,6 @@ struct ms_boot_page { 
} __packed;



struct msb_data {

	unsigned int			usage_count;

	struct memstick_dev		*card;

	struct gendisk			*disk;

	struct request_queue		*queue;