linux-kernel - [PATCH-tip] locking/qspinlock: Remove unnecessary BUG

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Message-Id: <1551057253-3231-1-git-send-email-longman@redhat.com>
Date:   Sun, 24 Feb 2019 20:14:13 -0500
From:   Waiman Long <longman@...hat.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Will Deacon <will.deacon@....com>
Cc:     linux-kernel@...r.kernel.org, Waiman Long <longman@...hat.com>
Subject: [PATCH-tip] locking/qspinlock: Remove unnecessary BUG_ON() call

With the > 4 nesting levels case handled by the commit d682b596d993
("locking/qspinlock: Handle > 4 slowpath nesting levels"), the BUG_ON()
call in encode_tail() will never be triggered. Remove it.

Signed-off-by: Waiman Long <longman@...hat.com>
---
 kernel/locking/qspinlock.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c
index 21ee51b..5e9247d 100644
--- a/kernel/locking/qspinlock.c
+++ b/kernel/locking/qspinlock.c
@@ -124,9 +124,6 @@ static inline __pure u32 encode_tail(int cpu, int idx)
 {
 	u32 tail;
 
-#ifdef CONFIG_DEBUG_SPINLOCK
-	BUG_ON(idx > 3);
-#endif
 	tail  = (cpu + 1) << _Q_TAIL_CPU_OFFSET;
 	tail |= idx << _Q_TAIL_IDX_OFFSET; /* assume < 4 */
 
-- 
1.8.3.1