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.
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Frederic Weisbecker <fweis...@gmail.com>
---
include/linux/atomic.h | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/include/linux/atomic.h b/include/linux/atomic.h
index df4f369..3d64c08 100644
--- a/include/linux/atomic.h
+++ b/include/linux/atomic.h
@@ -559,6 +559,27 @@ 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
* @mask: mask to OR on the value
--
2.7.0
