From e126391c092014af7ea6786648c9f1d3fce512a3 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Tue, 12 Apr 2022 15:09:45 +0100
Subject: [PATCH] io_uring: shrink final link flush
Git-commit: e126391c092014af7ea6786648c9f1d3fce512a3
Patch-mainline: v5.19-rc1
References: bsc#1205205
All good users should not set IOSQE_IO_*LINK flags for the last request
of a link. io_uring flushes collected links at the end of submission,
but it's not the optimal way and so we don't care too much about it.
Replace io_queue_sqe() call with io_queue_sqe_fallback() as the former
one is inlined and will generate a bunch of extra code. This will also
help compilers with the submission path inlining.
> size ./fs/io_uring.o
text data bss dec hex filename
87265 13734 8 101007 18a8f ./fs/io_uring.o
> size ./fs/io_uring.o
text data bss dec hex filename
87073 13734 8 100815 189cf ./fs/io_uring.o
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/01fb5e417ef49925d544a0b0bae30409845ed2b4.1649771823.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 | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 188923c38bfc..a3a3c80e2faa 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7785,8 +7785,8 @@ static void io_submit_state_end(struct io_ring_ctx *ctx)
{
struct io_submit_state *state = &ctx->submit_state;
- if (state->link.head)
- io_queue_sqe(state->link.head);
+ if (unlikely(state->link.head))
+ io_queue_sqe_fallback(state->link.head);
/* flush only after queuing links as they can generate completions */
io_submit_flush_completions(ctx);
if (state->plug_started)
--
2.35.3