From 88e77dc6a354095ddaaae715bc0d3b55702fa3db Mon Sep 17 00:00:00 2001 From: Peter Zijlstra <peterz@infradead.org> Date: Tue, 20 Feb 2018 16:01:36 +0100 Subject: [PATCH] locking/mutex: Add comment to __mutex_owner() to deter usage Attempt to deter usage, this is not a public interface. It is entirely possible to implement a conformant mutex without having this owner field (in fact, we used to have that). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> --- include/linux/mutex.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/linux/mutex.h b/include/linux/mutex.h index f25c13423bd4..cb3bbed4e633 100644 --- a/include/linux/mutex.h +++ b/include/linux/mutex.h @@ -66,6 +66,11 @@ struct mutex { #endif }; +/* + * Internal helper function; C doesn't allow us to hide it :/ + * + * DO NOT USE (outside of mutex code). + */ static inline struct task_struct *__mutex_owner(struct mutex *lock) { return (struct task_struct *)(atomic_long_read(&lock->owner) & ~0x07); -- GitLab