s390/zcrypt: fix memleak at release

If a process is interrupted while accessing the crypto device and the
global ap_perms_mutex is contented, release() could return early and
fail to free related resources.

Fixes: 00fab23 ("s390/zcrypt: multiple zcrypt device nodes support")
Cc: <[email protected]> # 4.19
Cc: Harald Freudenberger <[email protected]>
Signed-off-by: Johan Hovold <[email protected]>
Signed-off-by: Heiko Carstens <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>

Author: jhovold

drivers/s390/crypto/zcrypt_api.c

@@ -522,8 +522,7 @@ static int zcrypt_release(struct inode *inode, struct file *filp)
 	if (filp->f_inode->i_cdev == &zcrypt_cdev) {
 		struct zcdn_device *zcdndev;
 
-		if (mutex_lock_interruptible(&ap_perms_mutex))
-			return -ERESTARTSYS;
+		mutex_lock(&ap_perms_mutex);
 		zcdndev = find_zcdndev_by_devt(filp->f_inode->i_rdev);
 		mutex_unlock(&ap_perms_mutex);
 		if (zcdndev) {