[tip: locking/futex] futex: Correct the kernedoc return value for futex_wait_setup().

["tip-bot2 for Sebastian Andrzej Siewior" <tip-bot2@linutronix.de>]

The following commit has been merged into the locking/futex branch of tip:

Commit-ID:     73c6c02b4febbb2c2761e559f31af8c7b87e81a5
Gitweb:        https://git.kernel.org/tip/73c6c02b4febbb2c2761e559f31af8c7b87e81a5
Author:        Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate:    Sat, 17 May 2025 17:14:55 +02:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 21 May 2025 13:57:41 +02:00

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.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
Link: https://lore.kernel.org/r/20250517151455.1065363-6-bigeasy@linutronix.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 b3738fb..e2bbe55 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,