The static analyser tool gave the following advice:
./fs/btrfs/ioctl.c:4987:9-16: WARNING opportunity for kmemdup
4986 if (!iov) {
→ 4987 iov = kmalloc(sizeof(struct iovec) * args.iovcnt, GFP_NOFS);
4988 if (!iov) {
4989 unlock_extent(io_tree, start, lockend, &cached_state);
4990 btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
4991 ret = -ENOMEM;
4992 goto out_acct;
4993 }
4994
→ 4995 memcpy(iov, iovstack, sizeof(struct iovec) * args.iovcnt);
4996 }
Replacing kmalloc() + memcpy() with kmemdump() doesn't change semantics.
Original code works without fault, so this is not a bug fix but proposed improvement.
Link: https://lwn.net/Articles/198928/
Fixes: 34310c442e175 ("btrfs: add io_uring command for encoded reads (ENCODED_READ ioctl)")
Cc: Chris Mason <clm@xxxxxx>
Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
Cc: David Sterba <dsterba@xxxxxxxx>
Cc: linux-btrfs@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Mirsad Todorovac <mtodorovac69@xxxxxxxxx>
---
v1:
initial version.
fs/btrfs/ioctl.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 3af8bb0c8d75..c2f769334d3c 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4984,15 +4984,13 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue
* undo this.
*/
if (!iov) {
- iov = kmalloc(sizeof(struct iovec) * args.iovcnt, GFP_NOFS);
+ iov = kmemdup(iovstack, sizeof(struct iovec) * args.iovcnt, GFP_NOFS);
if (!iov) {
unlock_extent(io_tree, start, lockend, &cached_state);
btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
ret = -ENOMEM;
goto out_acct;
}
-
- memcpy(iov, iovstack, sizeof(struct iovec) * args.iovcnt);
}
count = min_t(u64, iov_iter_count(&iter), disk_io_size);
--
2.43.0
