From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 15 Aug 2021 21:29:09 +0000 (+0200)
Subject: futex: Remove bogus condition for requeue PI
X-Git-Tag: accepted/tizen/unified/20230118.172025~6489^2~15
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8e74633dcefb280f2cefb49b7201d99650243d96;p=platform%2Fkernel%2Flinux-rpi.git

futex: Remove bogus condition for requeue PI

For requeue PI it's required to establish PI state for the PI futex to
which waiters are requeued. This either acquires the user space futex on
behalf of the top most waiter on the inner 'waitqueue' futex, or attaches to
the PI state of an existing waiter, or creates on attached to the owner of
the futex.

This code can retry in case of failure, but retry can never happen when the
pi state was successfully created. The condition to run this code is:

  (task_count - nr_wake) < nr_requeue

which is always true because:

   task_count = 0
   nr_wake = 1
   nr_requeue >= 0

Remove it completely.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211305.362730187@linutronix.de
---

diff --git a/kernel/futex.c b/kernel/futex.c
index c39d5f1..8ddc87c 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -2000,7 +2000,7 @@ retry_private:
 		}
 	}
 
-	if (requeue_pi && (task_count - nr_wake < nr_requeue)) {
+	if (requeue_pi) {
 		struct task_struct *exiting = NULL;
 
 		/*