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From:   Dylan Yudaken <dylany@fb.com>
To:     Jens Axboe <axboe@kernel.dk>,
        Pavel Begunkov <asml.silence@gmail.com>,
        <io-uring@vger.kernel.org>
CC:     <Kernel-team@fb.com>, <linux-kernel@vger.kernel.org>,
        Dylan Yudaken <dylany@fb.com>
Subject: [PATCH v2 for-next 05/12] io_uring: clean up io_poll_check_events return values
Date:   Thu, 30 Jun 2022 02:12:24 -0700
Message-ID: <20220630091231.1456789-6-dylany@fb.com>
In-Reply-To: <20220630091231.1456789-1-dylany@fb.com>
References: <20220630091231.1456789-1-dylany@fb.com>
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The values returned are a bit confusing, where 0 and 1 have implied
meaning, so add some definitions for them.

Signed-off-by: Dylan Yudaken <dylany@fb.com>
---
 io_uring/poll.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/io_uring/poll.c b/io_uring/poll.c
index fa25b88a7b93..922a3d1b2e31 100644
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -192,13 +192,18 @@ static void io_poll_remove_entries(struct io_kiocb =
*req)
 	rcu_read_unlock();
 }
=20
+enum {
+	IOU_POLL_DONE =3D 0,
+	IOU_POLL_NO_ACTION =3D 1,
+};
+
 /*
  * All poll tw should go through this. Checks for poll events, manages
  * references, does rewait, etc.
  *
- * Returns a negative error on failure. >0 when no action require, which=
 is
- * either spurious wakeup or multishot CQE is served. 0 when it's done w=
ith
- * the request, then the mask is stored in req->cqe.res.
+ * Returns a negative error on failure. IOU_POLL_NO_ACTION when no actio=
n require,
+ * which is either spurious wakeup or multishot CQE is served.
+ * IOU_POLL_DONE when it's done with the request, then the mask is store=
d in req->cqe.res.
  */
 static int io_poll_check_events(struct io_kiocb *req, bool *locked)
 {
@@ -214,10 +219,11 @@ static int io_poll_check_events(struct io_kiocb *re=
q, bool *locked)
=20
 		/* tw handler should be the owner, and so have some references */
 		if (WARN_ON_ONCE(!(v & IO_POLL_REF_MASK)))
-			return 0;
+			return IOU_POLL_DONE;
 		if (v & IO_POLL_CANCEL_FLAG)
 			return -ECANCELED;
=20
+		/* the mask was stashed in __io_poll_execute */
 		if (!req->cqe.res) {
 			struct poll_table_struct pt =3D { ._key =3D req->apoll_events };
 			req->cqe.res =3D vfs_poll(req->file, &pt) & req->apoll_events;
@@ -226,7 +232,7 @@ static int io_poll_check_events(struct io_kiocb *req,=
 bool *locked)
 		if ((unlikely(!req->cqe.res)))
 			continue;
 		if (req->apoll_events & EPOLLONESHOT)
-			return 0;
+			return IOU_POLL_DONE;
=20
 		/* multishot, just fill a CQE and proceed */
 		if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
@@ -238,7 +244,7 @@ static int io_poll_check_events(struct io_kiocb *req,=
 bool *locked)
 				return -ECANCELED;
 		} else {
 			ret =3D io_poll_issue(req, locked);
-			if (ret)
+			if (ret < 0)
 				return ret;
 		}
=20
@@ -248,7 +254,7 @@ static int io_poll_check_events(struct io_kiocb *req,=
 bool *locked)
 		 */
 	} while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs));
=20
-	return 1;
+	return IOU_POLL_NO_ACTION;
 }
=20
 static void io_poll_task_func(struct io_kiocb *req, bool *locked)
@@ -256,12 +262,11 @@ static void io_poll_task_func(struct io_kiocb *req,=
 bool *locked)
 	int ret;
=20
 	ret =3D io_poll_check_events(req, locked);
-	if (ret > 0)
+	if (ret =3D=3D IOU_POLL_NO_ACTION)
 		return;
=20
-	if (!ret) {
+	if (ret =3D=3D IOU_POLL_DONE) {
 		struct io_poll *poll =3D io_kiocb_to_cmd(req);
-
 		req->cqe.res =3D mangle_poll(req->cqe.res & poll->events);
 	} else {
 		req->cqe.res =3D ret;
@@ -280,7 +285,7 @@ static void io_apoll_task_func(struct io_kiocb *req, =
bool *locked)
 	int ret;
=20
 	ret =3D io_poll_check_events(req, locked);
-	if (ret > 0)
+	if (ret =3D=3D IOU_POLL_NO_ACTION)
 		return;
=20
 	io_poll_remove_entries(req);
--=20
2.30.2