[tip: locking/core] kernel/futex: Explicitly document pi_lock for pi_state owner fixup

[tip-bot2 for Davidlohr Bueso]

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

Commit-ID:     c2e4bfe0eef313eeb1c4c9d921be7a9d91d5d71a
Gitweb:        https://git.kernel.org/tip/c2e4bfe0eef313eeb1c4c9d921be7a9d91d5d71a
Author:        Davidlohr Bueso <dave@xxxxxxxxxxxx>
AuthorDate:    Fri, 26 Feb 2021 09:50:29 -08:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Thu, 11 Mar 2021 19:19:17 +01:00

kernel/futex: Explicitly document pi_lock for pi_state owner fixup

This seems to belong in the serialization and lifetime rules section.
pi_state_update_owner() will take the pi_mutex's owner's pi_lock to
do whatever fixup, successful or not.

Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210226175029.50335-4-dave@xxxxxxxxxxxx

---
 kernel/futex.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/futex.c b/kernel/futex.c
index dcd6132..4750557 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -981,6 +981,7 @@ static inline void exit_pi_state_list(struct task_struct *curr) { }
  * p->pi_lock:
  *
  *	p->pi_state_list -> pi_state->list, relation
+ *	pi_mutex->owner -> pi_state->owner, relation
  *
  * pi_state->refcount:
  *