netfs: Remove redundant use of smp_rmb()

The function netfs_unbuffered_write_iter_locked() in
fs/netfs/direct_write.c contains an unnecessary smp_rmb() call after
wait_on_bit(). Since wait_on_bit() already incorporates a memory barrier
that ensures the flag update is visible before the function returns, the
smp_rmb() provides no additional benefit and incurs unnecessary overhead.

This patch removes the redundant barrier to simplify and optimize the code.

Signed-off-by: Zilin Guan <[email protected]>
Signed-off-by: David Howells <[email protected]>
Link: https://lore.kernel.org/r/[email protected]/
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Akira Yokosawa <[email protected]>
cc: Akira Yokosawa <[email protected]>
cc: Jeff Layton <[email protected]>
cc: [email protected]
cc: [email protected]
Signed-off-by: Christian Brauner <[email protected]>

Author: GoodLuck612

fs/netfs/direct_write.c

@@ -104,7 +104,6 @@ ssize_t netfs_unbuffered_write_iter_locked(struct kiocb *iocb, struct iov_iter *
 		trace_netfs_rreq(wreq, netfs_rreq_trace_wait_ip);
 		wait_on_bit(&wreq->flags, NETFS_RREQ_IN_PROGRESS,
 			    TASK_UNINTERRUPTIBLE);
-		smp_rmb(); /* Read error/transferred after RIP flag */
 		ret = wreq->error;
 		if (ret == 0) {
 			ret = wreq->transferred;