linux-kernel - [PATCH v2 5/5] futex: Correct the kernedoc return value for futex_wait

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Message-ID: <20250517151455.1065363-6-bigeasy@linutronix.de>
Date: Sat, 17 May 2025 17:14:55 +0200
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: linux-kernel@...r.kernel.org
Cc: André Almeida <andrealmeid@...lia.com>,
	Darren Hart <dvhart@...radead.org>,
	Davidlohr Bueso <dave@...olabs.net>,
	Ingo Molnar <mingo@...hat.com>,
	Juri Lelli <juri.lelli@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Valentin Schneider <vschneid@...hat.com>,
	Waiman Long <longman@...hat.com>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH v2 5/5] futex: Correct the kernedoc return value for futex_wait_setup().

The kerneldoc for futex_wait_setup() states it can return "0" or "<1".
This isn't true because the error case is "<0" not less than 1.

Document that <0 is returned on error. Drop the possible return values
and state possible reasons.

Reviewed-by: André Almeida <andrealmeid@...lia.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
 kernel/futex/waitwake.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c
index b3738fbe83c62..e2bbe5509ec27 100644
--- a/kernel/futex/waitwake.c
+++ b/kernel/futex/waitwake.c
@@ -585,7 +585,8 @@ int futex_wait_multiple(struct futex_vector *vs, unsigned int count,
  *
  * Return:
  *  -  0 - uaddr contains val and hb has been locked;
- *  - <1 - -EFAULT or -EWOULDBLOCK (uaddr does not contain val) and hb is unlocked
+ *  - <0 - On error and the hb is unlocked. A possible reason: the uaddr can not
+ *	   be read, does not contain the expected value or is not properly aligned.
  */
 int futex_wait_setup(u32 __user *uaddr, u32 val, unsigned int flags,
 		     struct futex_q *q, union futex_key *key2,
-- 
2.49.0