From fb27274a90eac5a687fe73229775ad36df737d8b Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Sat, 23 Oct 2021 12:14:02 +0100
Subject: [PATCH] io_uring: clusterise ki_flags access in rw_prep
Git-commit: fb27274a90eac5a687fe73229775ad36df737d8b
Patch-mainline: v5.16-rc1
References: bsc#1205205
ioprio setup doesn't depend on other fields that are modified in
io_prep_rw() and we can move it down in the function without worrying
about performance. It's useful as it makes iocb->ki_flags
accesses/modifications closer together, so it's more likely the compiler
will cache it in a register and avoid extra reloads.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8ee98779c06f1b59f6039b1e292db4332efd664b.1634987320.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
fs/io_uring.c | 21 +++++++++++----------
1 file changed, 11 insertions(+), 10 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 7042ed870b52..bba2f77ae7e7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2840,16 +2840,6 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req)))
req->flags |= REQ_F_NOWAIT;
- ioprio = READ_ONCE(sqe->ioprio);
- if (ioprio) {
- ret = ioprio_check_cap(ioprio);
- if (ret)
- return ret;
-
- kiocb->ki_ioprio = ioprio;
- } else
- kiocb->ki_ioprio = get_current_ioprio();
-
if (ctx->flags & IORING_SETUP_IOPOLL) {
if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll)
return -EOPNOTSUPP;
@@ -2863,6 +2853,17 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
kiocb->ki_complete = io_complete_rw;
}
+ ioprio = READ_ONCE(sqe->ioprio);
+ if (ioprio) {
+ ret = ioprio_check_cap(ioprio);
+ if (ret)
+ return ret;
+
+ kiocb->ki_ioprio = ioprio;
+ } else {
+ kiocb->ki_ioprio = get_current_ioprio();
+ }
+
req->imu = NULL;
req->rw.addr = READ_ONCE(sqe->addr);
req->rw.len = READ_ONCE(sqe->len);
--
2.35.3