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: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
drivers/block/ublk_drv.c | 17 +++++++----------
1 file changed, 7 insertions(+), 10 deletions(-)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index deabcb23ae2af..1f7bbbc3276a2 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -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) {
- filp->private_data = ub;
- return 0;
- }
- return -EBUSY;
+ if (test_and_set_bit(UB_STATE_OPEN, &ub->state))
+ return -EBUSY;
+ filp->private_data = ub;
+ return 0;
}
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;
}
--
2.30.2
