linux-kernel - [PATCH 1/5] io_uring: remove REQ_F_MUST

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Message-Id: <ea87b4425681664d82ea3454003038abc33376cb.1581450491.git.asml.silence@gmail.com>
Date:   Tue, 11 Feb 2020 23:01:54 +0300
From:   Pavel Begunkov <asml.silence@...il.com>
To:     Jens Axboe <axboe@...nel.dk>, io-uring@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/5] io_uring: remove REQ_F_MUST_PUNT

REQ_F_MUST_PUNT is needed to ignore REQ_F_NOWAIT and thus always punt
async if have got -EAGAIN. It's enough to clear REQ_F_NOWAIT instead of
having yet another flag.

Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
---
 fs/io_uring.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 63beda9bafc5..98da478ae56c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -477,7 +477,6 @@ enum {
 	REQ_F_LINK_TIMEOUT_BIT,
 	REQ_F_TIMEOUT_BIT,
 	REQ_F_ISREG_BIT,
-	REQ_F_MUST_PUNT_BIT,
 	REQ_F_TIMEOUT_NOSEQ_BIT,
 	REQ_F_COMP_LOCKED_BIT,
 	REQ_F_NEED_CLEANUP_BIT,
@@ -513,8 +512,6 @@ enum {
 	REQ_F_TIMEOUT		= BIT(REQ_F_TIMEOUT_BIT),
 	/* regular file */
 	REQ_F_ISREG		= BIT(REQ_F_ISREG_BIT),
-	/* must be punted even for NONBLOCK */
-	REQ_F_MUST_PUNT		= BIT(REQ_F_MUST_PUNT_BIT),
 	/* no timeout sequence */
 	REQ_F_TIMEOUT_NOSEQ	= BIT(REQ_F_TIMEOUT_NOSEQ_BIT),
 	/* completion under lock */
@@ -2246,11 +2243,11 @@ static int io_read(struct io_kiocb *req, struct io_kiocb **nxt,
 		req->result = io_size;
 
 	/*
-	 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
-	 * we know to async punt it even if it was opened O_NONBLOCK
+	 * If the file doesn't support async, async punt it even if it
+	 * was opened O_NONBLOCK
 	 */
 	if (force_nonblock && !io_file_supports_async(req->file)) {
-		req->flags |= REQ_F_MUST_PUNT;
+		req->flags &= ~REQ_F_NOWAIT;
 		goto copy_iov;
 	}
 
@@ -2335,11 +2332,11 @@ static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
 		req->result = io_size;
 
 	/*
-	 * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
-	 * we know to async punt it even if it was opened O_NONBLOCK
+	 * If the file doesn't support async, async punt it even if it
+	 * was opened O_NONBLOCK
 	 */
 	if (force_nonblock && !io_file_supports_async(req->file)) {
-		req->flags |= REQ_F_MUST_PUNT;
+		req->flags &= ~REQ_F_NOWAIT;
 		goto copy_iov;
 	}
 
@@ -4715,8 +4712,7 @@ static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	 * We async punt it if the file wasn't marked NOWAIT, or if the file
 	 * doesn't support non-blocking read/write attempts
 	 */
-	if (ret == -EAGAIN && (!(req->flags & REQ_F_NOWAIT) ||
-	    (req->flags & REQ_F_MUST_PUNT))) {
+	if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
 punt:
 		if (io_op_defs[req->opcode].file_table) {
 			ret = io_grab_files(req);
-- 
2.24.0