[PATCH] atomics,cmpxchg: Privatize the inclusion of asm/cmpxchg.h

* [PATCH] atomics,cmpxchg: Privatize the inclusion of asm/cmpxchg.h
@ 2015-08-26 11:52 Boqun Feng
  2015-09-13 11:07 ` [tip:locking/core] locking/atomics, cmpxchg: " tip-bot for Boqun Feng
  0 siblings, 1 reply; 2+ messages in thread
From: Boqun Feng @ 2015-08-26 11:52 UTC (permalink / raw)
  To: linux-kernel
  Cc: Peter Zijlstra, Ingo Molnar, Will Deacon, Jonathan Corbet,
	Shradha Shah, Kishon Vijay Abraham I, William Hubbs,
	Chris Brannon, Kirk Reiser, Samuel Thibault, Greg Kroah-Hartman,
	Aybuke Ozdemir, Davidlohr Bueso, linux-net-drivers, linux-doc,
	netdev, speakup, devel, Boqun Feng

After commit:

atomics: add acquire/release/relaxed variants of some atomic operations

Architectures may only provide {cmp,}xchg_relaxed definitions in
asm/cmpxchg.h. Other variants, such as {cmp,}xchg, may be built in
linux/atomic.h, which means simply including asm/cmpxchg.h may not get
the definitions of all the{cmp,}xchg variants. Therefore, we should
privatize the inclusions of asm/cmpxchg.h to keep it only included in
arch/* and replace the inclusions outside with linux/atomic.h

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 Documentation/atomic_ops.txt        | 4 ++++
 drivers/net/ethernet/sfc/mcdi.c     | 2 +-
 drivers/phy/phy-rcar-gen2.c         | 3 +--
 drivers/staging/speakup/selection.c | 2 +-
 4 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/Documentation/atomic_ops.txt b/Documentation/atomic_ops.txt
index b19fc34..c9d1cac 100644
--- a/Documentation/atomic_ops.txt
+++ b/Documentation/atomic_ops.txt
@@ -542,6 +542,10 @@ The routines xchg() and cmpxchg() must provide the same exact
 memory-barrier semantics as the atomic and bit operations returning
 values.
 
+Note: If someone wants to use xchg(), cmpxchg() and their variants,
+linux/atomic.h should be included rather than asm/cmpxchg.h, unless
+the code is in arch/* and can take care of itself.
+
 Spinlocks and rwlocks have memory barrier expectations as well.
 The rule to follow is simple:
 
diff --git a/drivers/net/ethernet/sfc/mcdi.c b/drivers/net/ethernet/sfc/mcdi.c
index 81640f8..968383e 100644
--- a/drivers/net/ethernet/sfc/mcdi.c
+++ b/drivers/net/ethernet/sfc/mcdi.c
@@ -9,7 +9,7 @@
 
 #include <linux/delay.h>
 #include <linux/moduleparam.h>
-#include <asm/cmpxchg.h>
+#include <linux/atomic.h>
 #include "net_driver.h"
 #include "nic.h"
 #include "io.h"
diff --git a/drivers/phy/phy-rcar-gen2.c b/drivers/phy/phy-rcar-gen2.c
index 39d9b29..117b495 100644
--- a/drivers/phy/phy-rcar-gen2.c
+++ b/drivers/phy/phy-rcar-gen2.c
@@ -17,8 +17,7 @@
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
-
-#include <asm/cmpxchg.h>
+#include <linux/atomic.h>
 
 #define USBHS_LPSTS			0x02
 #define USBHS_UGCTRL			0x80
diff --git a/drivers/staging/speakup/selection.c b/drivers/staging/speakup/selection.c
index a031570..81c0888 100644
--- a/drivers/staging/speakup/selection.c
+++ b/drivers/staging/speakup/selection.c
@@ -7,7 +7,7 @@
 #include <linux/workqueue.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
-#include <asm/cmpxchg.h>
+#include <linux/atomic.h>
 
 #include "speakup.h"
 
-- 
2.5.0


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