locking/atomics, cmpxchg: Privatize the inclusion of asm/cmpxchg.h

After commit:

654672d4ba1a ("locking/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

Signed-off-by: Boqun Feng <[e-mail]>
Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Acked-by: Greg Kroah-Hartman <[e-mail]>
Acked-by: Will Deacon <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: Aybuke Ozdemir <[e-mail]>
Cc: Chris Brannon <[e-mail]>
Cc: Davidlohr Bueso <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: Kirk Reiser <[e-mail]>
Cc: Kishon Vijay Abraham I <[e-mail]>
Cc: Linus Torvalds <[e-mail]>
Cc: Paul E. McKenney <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Samuel Thibault <[e-mail]>
Cc: Shradha Shah <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Cc: William Hubbs <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: [e-mail]
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Ingo Molnar <[e-mail]>

Documentation/atomic_ops.txt

···
 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:
 

drivers/net/ethernet/sfc/mcdi.c

···
 
 #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"

drivers/phy/phy-rcar-gen2.c

···
 #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

drivers/staging/speakup/selection.c

···
 #include <linux/workqueue.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
-#include <asm/cmpxchg.h>
+#include <linux/atomic.h>
 
 #include "speakup.h"