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Date:   Tue, 01 Mar 2022 08:47:24 -0500
Message-Id: <84513f7cc1b1fb31d8f4cb910aee033391d036b4.1646142288.git.olivier@trillion01.com>
In-Reply-To: <cover.1646142288.git.olivier@trillion01.com>
References: <cover.1646142288.git.olivier@trillion01.com>
From:   Olivier Langlois <olivier@trillion01.com>
To:     Jens Axboe <axboe@kernel.dk>,
        Pavel Begunkov <asml.silence@gmail.com>
Cc:     Hao Xu <haoxu@linux.alibaba.com>,
        io-uring <io-uring@vger.kernel.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: [PATCH v4 1/2] io_uring: minor io_cqring_wait() optimization
Precedence: bulk

Move up the block manipulating the sig variable to execute code
that may encounter an error and exit first before continuing
exectuing the rest of the function and avoid useless computations

Signed-off-by: Olivier Langlois <olivier@trillion01.com>
---
 fs/io_uring.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4715980e9015..f7b8df79a02b 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7732,14 +7732,6 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 			break;
 	} while (1);
 
-	if (uts) {
-		struct timespec64 ts;
-
-		if (get_timespec64(&ts, uts))
-			return -EFAULT;
-		timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
-	}
-
 	if (sig) {
 #ifdef CONFIG_COMPAT
 		if (in_compat_syscall())
@@ -7753,6 +7745,14 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 			return ret;
 	}
 
+	if (uts) {
+		struct timespec64 ts;
+
+		if (get_timespec64(&ts, uts))
+			return -EFAULT;
+		timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
+	}
+
 	init_waitqueue_func_entry(&iowq.wq, io_wake_function);
 	iowq.wq.private = current;
 	INIT_LIST_HEAD(&iowq.wq.entry);
-- 
2.35.1