Commit 5acba71e authored Mar 24, 2016 by Frederic Weisbecker Committed by Ingo Molnar Mar 29, 2016

locking/atomic: Introduce atomic_fetch_or()



This is deemed to replace the type generic fetch_or() which brings a lot
of issues such as macro induced block variable aliasing and sloppy types.
Not to mention fetch_or() doesn't refer to any namespace, adding even
more confusion.

So lets provide an atomic_t version. Current and next users of fetch_or()
are thus encouraged to use atomic_t.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1458830281-4255-2-git-send-email-fweisbec@gmail.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 1993b176

include/linux/atomic.h

+21 −0

Original line number	Diff line number	Diff line
		@@ -558,6 +558,27 @@ static inline int atomic_dec_if_positive(atomic_t *v)
		}
		#endif

		/**
		* atomic_fetch_or - perform p \|= mask and return old value of p
		* @p: pointer to atomic_t
		* @mask: mask to OR on the atomic_t
		*/
		#ifndef atomic_fetch_or
		static inline int atomic_fetch_or(atomic_t *p, int mask)
		{
		int old, val = atomic_read(p);

		for (;;) {
		old = atomic_cmpxchg(p, val, val \| mask);
		if (old == val)
		break;
		val = old;
		}

		return old;
		}
		#endif

		/**
		* fetch_or - perform ptr \|= mask and return old value of ptr
		* @ptr: pointer to value