From 1a2cc0ce8d18c9e5592733cb6381e9ff5c23d916 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Thu, 4 Feb 2021 13:52:00 +0000
Subject: [PATCH] io_uring: further simplify do_read error parsing
First, instead of checking iov_iter_count(iter) for 0 to find out that
all needed bytes were read, just compare returned code against io_size.
It's more reliable and arguably cleaner.
Also, place the half-read case into an else branch and delete an extra
label.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
fs/io_uring.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 866e0ea83dbec..1d1fa1f773322 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3552,19 +3552,18 @@ static int io_read(struct io_kiocb *req, bool force_nonblock,
/* some cases will consume bytes even on error returns */
iov_iter_revert(iter, io_size - iov_iter_count(iter));
ret = 0;
- goto copy_iov;
- } else if (ret <= 0) {
+ } else if (ret <= 0 || ret == io_size) {
/* make sure -ERESTARTSYS -> -EINTR is done */
goto done;
- }
+ } else {
+ /* we did blocking attempt. no retry. */
+ if (!force_nonblock || (req->file->f_flags & O_NONBLOCK) ||
+ !(req->flags & REQ_F_ISREG))
+ goto done;
- /* read it all, or we did blocking attempt. no retry. */
- if (!iov_iter_count(iter) || !force_nonblock ||
- (req->file->f_flags & O_NONBLOCK) || !(req->flags & REQ_F_ISREG))
- goto done;
+ io_size -= ret;
+ }
- io_size -= ret;
-copy_iov:
ret2 = io_setup_async_rw(req, iovec, inline_vecs, iter, true);
if (ret2) {
ret = ret2;
--
2.30.2