Commit dbdc1be3 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: add a disk_openers helper 



Add a helper that returns the openers for a given gendisk to avoid having
drivers poke into disk->part0 to get at this information in a somewhat
cumbersome way.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220330052917.2566582-5-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7a86d6dc

drivers/block/nbd.c

+2 −2
Original line number Diff line number Diff line
@@ -1219,7 +1219,7 @@ static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg) 


static void nbd_bdev_reset(struct nbd_device *nbd)

{

	if (nbd->disk->part0->bd_openers > 1)

	if (disk_openers(nbd->disk) > 1)

		return;

	set_capacity(nbd->disk, 0);

}
@@ -1576,7 +1576,7 @@ static void nbd_release(struct gendisk *disk, fmode_t mode) 
	struct nbd_device *nbd = disk->private_data;



	if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&

			disk->part0->bd_openers == 0)

			disk_openers(disk) == 0)

		nbd_disconnect_and_put(nbd);



	nbd_config_put(nbd);

drivers/block/zram/zram_drv.c

+2 −2
Original line number Diff line number Diff line
@@ -1800,7 +1800,7 @@ static ssize_t reset_store(struct device *dev, 


	mutex_lock(&disk->open_mutex);

	/* Do not reset an active device or claimed device */

	if (disk->part0->bd_openers || zram->claim) {

	if (disk_openers(disk) || zram->claim) {

		mutex_unlock(&disk->open_mutex);

		return -EBUSY;

	}
@@ -1989,7 +1989,7 @@ static int zram_remove(struct zram *zram) 
	bool claimed;



	mutex_lock(&zram->disk->open_mutex);

	if (zram->disk->part0->bd_openers) {

	if (disk_openers(zram->disk)) {

		mutex_unlock(&zram->disk->open_mutex);

		return -EBUSY;

	}

include/linux/blkdev.h

+15 −0
Original line number Diff line number Diff line
@@ -176,6 +176,21 @@ static inline bool disk_live(struct gendisk *disk) 
	return !inode_unhashed(disk->part0->bd_inode);

}



/**

 * disk_openers - returns how many openers are there for a disk

 * @disk: disk to check

 *

 * This returns the number of openers for a disk.  Note that this value is only

 * stable if disk->open_mutex is held.

 *

 * Note: Due to a quirk in the block layer open code, each open partition is

 * only counted once even if there are multiple openers.

 */

static inline unsigned int disk_openers(struct gendisk *disk)

{

	return disk->part0->bd_openers;

}



/*

 * The gendisk is refcounted by the part0 block_device, and the bd_device

 * therein is also used for device model presentation in sysfs.