Hi, Yes, I see you have the prior work and I have duplicated your work. Apology for the inconvenience. Best regards, Mirsad Todorovac On 12/18/24 11:32, Mark Harmstone wrote: > There's a fix for this already in the for-next branch: > https://github.com/btrfs/linux/commit/1a287050962c6847fa4918d6b2a0f4cee35c6943 > > On 17/12/24 22:58, Mirsad Todorovac wrote: >>> >> 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://urldefense.com/v3/__https://lwn.net/Articles/198928/__;!!Bt8RZUm9aw!4OVzQmIUbyH-UGdUwMAL582hR4Q-7HN2fn9IpyxeA1T8qrcC8RdBVz4xuL4m35_kksUllAi6OmdbRehcFpwfHw$ >> 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); >
