io_uring: simplify io_req_map_rw()

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>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index ddff3ab..3b8465d 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2828,15 +2828,17 @@ 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;
        }
 }