Fs: Btrfs - Fix possible ERR_PTR() dereferencing.

[Shailendra Verma]

This is of course wrong to call kfree() if memdup_user() fails,
no memory was allocated and the error in the error-valued pointer
should be returned.

Reviewed-by: Ravikant Sharma <ravikant.s2@xxxxxxxxxxx>
Signed-off-by: Shailendra Verma <shailendra.v@xxxxxxxxxxx>
---
 fs/btrfs/ioctl.c | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index da94138..58a40f8 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4512,11 +4512,8 @@ static long btrfs_ioctl_logical_to_ino(struct btrfs_root *root,
 		return -EPERM;
 
 	loi = memdup_user(arg, sizeof(*loi));
-	if (IS_ERR(loi)) {
-		ret = PTR_ERR(loi);
-		loi = NULL;
-		goto out;
-	}
+	if (IS_ERR(loi))
+		return PTR_ERR(loi);
 
 	path = btrfs_alloc_path();
 	if (!path) {
@@ -5143,11 +5140,8 @@ static long btrfs_ioctl_set_received_subvol_32(struct file *file,
 	int ret = 0;
 
 	args32 = memdup_user(arg, sizeof(*args32));
-	if (IS_ERR(args32)) {
-		ret = PTR_ERR(args32);
-		args32 = NULL;
-		goto out;
-	}
+	if (IS_ERR(args32))
+		return PTR_ERR(args32);
 
 	args64 = kmalloc(sizeof(*args64), GFP_NOFS);
 	if (!args64) {
@@ -5195,11 +5189,8 @@ static long btrfs_ioctl_set_received_subvol(struct file *file,
 	int ret = 0;
 
 	sa = memdup_user(arg, sizeof(*sa));
-	if (IS_ERR(sa)) {
-		ret = PTR_ERR(sa);
-		sa = NULL;
-		goto out;
-	}
+	if (IS_ERR(sa))
+		return PTR_ERR(sa);
 
 	ret = _btrfs_ioctl_set_received_subvol(file, sa);
 
-- 
1.9.1