Use memdup_user_nul() helper instead of open-coding
to simplify the code.

Signed-off-by: Ruan Jinjie <redacted>
---
 drivers/block/ublk_drv.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 85a81ee556d5..fa7e6955eb3b 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c

@@ -2743,14 +2743,9 @@ static int ublk_ctrl_uring_cmd_permission(struct ublk_device *ub,
 	if (header->len < header->dev_path_len)
 		return -EINVAL;
 
-	dev_path = kmalloc(header->dev_path_len + 1, GFP_KERNEL);
-	if (!dev_path)
-		return -ENOMEM;
-
-	ret = -EFAULT;
-	if (copy_from_user(dev_path, argp, header->dev_path_len))
-		goto exit;
-	dev_path[header->dev_path_len] = 0;
+	dev_path = memdup_user_nul(argp, header->dev_path_len);
+	if (IS_ERR(dev_path))
+		return PTR_ERR(dev_path);