diff options
| author | David Lechner <david@lechnology.com> | 2021-10-17 13:55:21 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-10-19 11:36:28 +0200 |
| commit | f5245a5fdf757f50a6c905fc16cceb1a6146ccf5 (patch) | |
| tree | 80a651b5444b70ceff26f93d2e97e37cd64c6f7b /drivers/counter/counter-chrdev.c | |
| parent | c3ed761c9e1e4987406671b326dab48a048614ee (diff) | |
| download | linux-f5245a5fdf757f50a6c905fc16cceb1a6146ccf5.tar.bz2 | |
counter: drop chrdev_lock
This removes the chrdev_lock from the counter subsystem. This was
intended to prevent opening the chrdev more than once. However, this
doesn't work in practice since userspace can duplicate file descriptors
and pass file descriptors to other processes. Since this protection
can't be relied on, it is best to just remove it.
Suggested-by: Greg KH <gregkh@linuxfoundation.org>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: David Lechner <david@lechnology.com>
Link: https://lore.kernel.org/r/20211017185521.3468640-1-david@lechnology.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/counter/counter-chrdev.c')
| -rw-r--r-- | drivers/counter/counter-chrdev.c | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c index 967c94ae95bb..b747dc81cfc6 100644 --- a/drivers/counter/counter-chrdev.c +++ b/drivers/counter/counter-chrdev.c @@ -384,10 +384,6 @@ static int counter_chrdev_open(struct inode *inode, struct file *filp) typeof(*counter), chrdev); - /* Ensure chrdev is not opened more than 1 at a time */ - if (!atomic_add_unless(&counter->chrdev_lock, 1, 1)) - return -EBUSY; - get_device(&counter->dev); filp->private_data = counter; @@ -419,7 +415,6 @@ out_unlock: mutex_unlock(&counter->ops_exist_lock); put_device(&counter->dev); - atomic_dec(&counter->chrdev_lock); return ret; } @@ -445,7 +440,6 @@ int counter_chrdev_add(struct counter_device *const counter) mutex_init(&counter->events_lock); /* Initialize character device */ - atomic_set(&counter->chrdev_lock, 0); cdev_init(&counter->chrdev, &counter_fops); /* Allocate Counter events queue */ |