linux-kernel - [PATCH v2 01/12] locking/atomic: Introduce inc/dec calls for FETCH-OP flavors

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Date:	Tue, 21 Jun 2016 06:33:10 -0700
From:	Davidlohr Bueso <dave@...olabs.net>
To:	peterz@...radead.org, mingo@...nel.org
Cc:	davem@...emloft.net, cw00.choi@...sung.com,
	dougthompson@...ssion.com, bp@...en8.de, mchehab@....samsung.com,
	gregkh@...uxfoundation.org, pfg@....com, jikos@...nel.org,
	hans.verkuil@...co.com, awalls@...metrocast.net,
	dledford@...hat.com, sean.hefty@...el.com, kys@...rosoft.com,
	heiko.carstens@...ibm.com, James.Bottomley@...senPartnership.com,
	sumit.semwal@...aro.org, schwidefsky@...ibm.com,
	linux-kernel@...r.kernel.org, Davidlohr Bueso <dbueso@...e.de>
Subject: [PATCH v2 01/12] locking/atomic: Introduce inc/dec calls for
 FETCH-OP flavors

With the inclusion of atomic FETCH-OP variants, many places in the
kernel can make use of atomic_fetch_$op() to avoid the hacky callers
that need to compute the value/state _before_ the operation. Peter
laid out the machinery but we are still missing the simpler dec,inc
calls (which future patches will make use of).

This patch only deals with the generic code, as at least right now
no arch actually implement them -- which is similar to what the
OP-RETURN primitives currently do.

Signed-off-by: Davidlohr Bueso <dbueso@...e.de>
---

Changes from v1: added atomic64 flavors, only define atomic_fetch_inc/dec once,
                 the fence logic will come through the add/sub calls instead.

 include/linux/atomic.h | 96 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)

diff --git a/include/linux/atomic.h b/include/linux/atomic.h
index 12d910d61b83..c848d89bc9a0 100644
--- a/include/linux/atomic.h
+++ b/include/linux/atomic.h
@@ -188,6 +188,29 @@
 #endif
 #endif /* atomic_fetch_add_relaxed */
 
+#ifndef atomic_fetch_inc
+#define atomic_fetch_inc(v)  (atomic_fetch_add(1, v))
+#endif
+
+/* atomic_fetch_inc_relaxed */
+#ifndef atomic_fetch_inc_relaxed
+#define atomic_fetch_inc_relaxed	atomic_fetch_inc
+#define atomic_fetch_inc_acquire	atomic_fetch_inc
+#define atomic_fetch_inc_release	atomic_fetch_inc
+
+#else /* atomic_fetch_inc_relaxed */
+
+#ifndef atomic_fetch_inc_acquire
+#define atomic_fetch_inc_acquire(...)					\
+	__atomic_op_acquire(atomic_fetch_inc, __VA_ARGS__)
+#endif
+
+#ifndef atomic_fetch_inc_release
+#define atomic_fetch_inc_release(...)					\
+	__atomic_op_release(atomic_fetch_inc, __VA_ARGS__)
+#endif
+#endif /* atomic_fetch_inc_relaxed */
+
 /* atomic_fetch_sub_relaxed */
 #ifndef atomic_fetch_sub_relaxed
 #define atomic_fetch_sub_relaxed	atomic_fetch_sub
@@ -212,6 +235,33 @@
 #endif
 #endif /* atomic_fetch_sub_relaxed */
 
+#ifndef atomic_fetch_dec
+#define atomic_fetch_dec(v)  (atomic_fetch_sub(1, v))
+#endif
+
+/* atomic_fetch_dec_relaxed */
+#ifndef atomic_fetch_dec_relaxed
+#define atomic_fetch_dec_relaxed	atomic_fetch_dec
+#define atomic_fetch_dec_acquire	atomic_fetch_dec
+#define atomic_fetch_dec_release	atomic_fetch_dec
+
+#else /* atomic_fetch_dec_relaxed */
+
+#ifndef atomic_fetch_dec_acquire
+#define atomic_fetch_dec_acquire(...)					\
+	__atomic_op_acquire(atomic_fetch_dec, __VA_ARGS__)
+#endif
+
+#ifndef atomic_fetch_dec_release
+#define atomic_fetch_dec_release(...)					\
+	__atomic_op_release(atomic_fetch_dec, __VA_ARGS__)
+#endif
+#endif /* atomic_fetch_dec_relaxed */
+
+#ifndef atomic_fetch_dec
+#define atomic_fetch_dec(v)  (atomic_fetch_sub(1, v))
+#endif
+
 /* atomic_fetch_or_relaxed */
 #ifndef atomic_fetch_or_relaxed
 #define atomic_fetch_or_relaxed	atomic_fetch_or
@@ -697,6 +747,29 @@ static inline int atomic_dec_if_positive(atomic_t *v)
 #endif
 #endif /* atomic64_fetch_add_relaxed */
 
+#ifndef atomic64_fetch_inc
+#define atomic64_fetch_inc(v)  (atomic64_fetch_add(1, v))
+#endif
+
+/* atomic64_fetch_inc_relaxed */
+#ifndef atomic64_fetch_inc_relaxed
+#define atomic64_fetch_inc_relaxed	atomic64_fetch_inc
+#define atomic64_fetch_inc_acquire	atomic64_fetch_inc
+#define atomic64_fetch_inc_release	atomic64_fetch_inc
+
+#else /* atomic64_fetch_inc_relaxed */
+
+#ifndef atomic64_fetch_inc_acquire
+#define atomic64_fetch_inc_acquire(...)					\
+	__atomic_op_acquire(atomic64_fetch_inc, __VA_ARGS__)
+#endif
+
+#ifndef atomic64_fetch_inc_release
+#define atomic64_fetch_inc_release(...)					\
+	__atomic_op_release(atomic64_fetch_inc, __VA_ARGS__)
+#endif
+#endif /* atomic64_fetch_inc_relaxed */
+
 /* atomic64_fetch_sub_relaxed */
 #ifndef atomic64_fetch_sub_relaxed
 #define atomic64_fetch_sub_relaxed	atomic64_fetch_sub
@@ -721,6 +794,29 @@ static inline int atomic_dec_if_positive(atomic_t *v)
 #endif
 #endif /* atomic64_fetch_sub_relaxed */
 
+#ifndef atomic64_fetch_dec
+#define atomic64_fetch_dec(v)  (atomic64_fetch_sub(1, v))
+#endif
+
+/* atomic64_fetch_dec_relaxed */
+#ifndef atomic64_fetch_dec_relaxed
+#define atomic64_fetch_dec_relaxed	atomic64_fetch_dec
+#define atomic64_fetch_dec_acquire	atomic64_fetch_dec
+#define atomic64_fetch_dec_release	atomic64_fetch_dec
+
+#else /* atomic64_fetch_dec_relaxed */
+
+#ifndef atomic64_fetch_dec_acquire
+#define atomic64_fetch_dec_acquire(...)					\
+	__atomic_op_acquire(atomic64_fetch_dec, __VA_ARGS__)
+#endif
+
+#ifndef atomic64_fetch_dec_release
+#define atomic64_fetch_dec_release(...)					\
+	__atomic_op_release(atomic64_fetch_dec, __VA_ARGS__)
+#endif
+#endif /* atomic64_fetch_dec_relaxed */
+
 /* atomic64_fetch_or_relaxed */
 #ifndef atomic64_fetch_or_relaxed
 #define atomic64_fetch_or_relaxed	atomic64_fetch_or
-- 
2.6.6