[PATCH 1/3] io_uring: simplify io_req_map_rw()

[Pavel Begunkov <asml.silence@gmail.com>]

Don't deref req->io->rw every time, but put it in a local variable. This
looks prettier, generates less instructions and doesn't break alias
analysis.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 fs/io_uring.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6eae2fb469f9..d9c10070dcba 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2827,15 +2827,17 @@ static void io_req_map_rw(struct io_kiocb *req, ssize_t io_size,
 			  struct iovec *iovec, struct iovec *fast_iov,
 			  struct iov_iter *iter)
 {
-	req->io->rw.nr_segs = iter->nr_segs;
-	req->io->rw.size = io_size;
-	req->io->rw.iov = iovec;
-	if (!req->io->rw.iov) {
-		req->io->rw.iov = req->io->rw.fast_iov;
-		if (req->io->rw.iov != fast_iov)
-			memcpy(req->io->rw.iov, fast_iov,
+	struct io_async_rw *rw = &req->io->rw;
+
+	rw->nr_segs = iter->nr_segs;
+	rw->size = io_size;
+	if (!iovec) {
+		rw->iov = rw->fast_iov;
+		if (rw->iov != fast_iov)
+			memcpy(rw->iov, fast_iov,
 			       sizeof(struct iovec) * iter->nr_segs);
 	} else {
+		rw->iov = iovec;
 		req->flags |= REQ_F_NEED_CLEANUP;
 	}
 }
-- 
2.24.0