linux-kernel - [PATCH v2 1/4] io_uring: remove duplicated calls to io_kiocb

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Message-ID: <20220221141649.624233-2-dylany@fb.com>
Date:   Mon, 21 Feb 2022 06:16:46 -0800
From:   Dylan Yudaken <dylany@...com>
To:     Jens Axboe <axboe@...nel.dk>,
        Pavel Begunkov <asml.silence@...il.com>,
        <io-uring@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>, <kernel-team@...com>,
        Dylan Yudaken <dylany@...com>
Subject: [PATCH v2 1/4] io_uring: remove duplicated calls to io_kiocb_ppos

io_kiocb_ppos is called in both branches, and it seems that the compiler
does not fuse this. Fusing removes a few bytes from loop_rw_iter.

Before:
$ nm -S fs/io_uring.o | grep loop_rw_iter
0000000000002430 0000000000000124 t loop_rw_iter

After:
$ nm -S fs/io_uring.o | grep loop_rw_iter
0000000000002430 000000000000010d t loop_rw_iter

Signed-off-by: Dylan Yudaken <dylany@...com>
---
 fs/io_uring.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 77b9c7e4793b..1f9b4466c269 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3400,6 +3400,7 @@ static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter)
 	struct kiocb *kiocb = &req->rw.kiocb;
 	struct file *file = req->file;
 	ssize_t ret = 0;
+	loff_t *ppos;
 
 	/*
 	 * Don't support polled IO through this interface, and we can't
@@ -3412,6 +3413,8 @@ static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter)
 	    !(kiocb->ki_filp->f_flags & O_NONBLOCK))
 		return -EAGAIN;
 
+	ppos = io_kiocb_ppos(kiocb);
+
 	while (iov_iter_count(iter)) {
 		struct iovec iovec;
 		ssize_t nr;
@@ -3425,10 +3428,10 @@ static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter)
 
 		if (rw == READ) {
 			nr = file->f_op->read(file, iovec.iov_base,
-					      iovec.iov_len, io_kiocb_ppos(kiocb));
+					      iovec.iov_len, ppos);
 		} else {
 			nr = file->f_op->write(file, iovec.iov_base,
-					       iovec.iov_len, io_kiocb_ppos(kiocb));
+					       iovec.iov_len, ppos);
 		}
 
 		if (nr < 0) {
-- 
2.30.2