Commit fa362045 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

ublk: simplify ublk_ch_open and ublk_ch_release 



fops->open and fops->release are always paired.  Use simple atomic bit
ops ot indicate if the device is opened instead of a count that can
only be 0 and 1 and a useless cmpxchg loop in ublk_ch_release.

Also don't bother clearing file->private_data is the file is about to
be freed anyway.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20220721130916.1869719-5-hch@lst.de


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 49d686cc

drivers/block/ublk_drv.c

+7 −10
Original line number Diff line number Diff line
@@ -125,7 +125,8 @@ struct ublk_device { 
	struct cdev		cdev;

	struct device		cdev_dev;



	atomic_t		ch_open_cnt;

#define UB_STATE_OPEN		(1 << 0)

	unsigned long		state;

	int			ub_number;



	struct mutex		mutex;
@@ -647,21 +648,17 @@ static int ublk_ch_open(struct inode *inode, struct file *filp) 
	struct ublk_device *ub = container_of(inode->i_cdev,

			struct ublk_device, cdev);



	if (atomic_cmpxchg(&ub->ch_open_cnt, 0, 1) == 0) {

	if (test_and_set_bit(UB_STATE_OPEN, &ub->state))

		return -EBUSY;

	filp->private_data = ub;

	return 0;

}

	return -EBUSY;

}



static int ublk_ch_release(struct inode *inode, struct file *filp)

{

	struct ublk_device *ub = filp->private_data;



	while (atomic_cmpxchg(&ub->ch_open_cnt, 1, 0) != 1)

		cpu_relax();



	filp->private_data = NULL;

	clear_bit(UB_STATE_OPEN, &ub->state);

	return 0;

}