arch: Cleanup read_barrier_depends() and comments

This patch is meant to cleanup the handling of read_barrier_depends and
smp_read_barrier_depends.  In multiple spots in the kernel headers
read_barrier_depends is defined as "do {} while (0)", however we then go
into the SMP vs non-SMP sections and have the SMP version reference
read_barrier_depends, and the non-SMP define it as yet another empty
do/while.

With this commit I went through and cleaned out the duplicate definitions
and reduced the number of definitions down to 2 per header.  In addition I
moved the 50 line comments for the macro from the x86 and mips headers that
defined it as an empty do/while to those that were actually defining the
macro, alpha and blackfin.

Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/sparc/include/asm/barrier_64.h b/arch/sparc/include/asm/barrier_64.h
index 305dcc3dc721..6c974c0977ad 100644
--- a/arch/sparc/include/asm/barrier_64.h
+++ b/arch/sparc/include/asm/barrier_64.h
@@ -37,7 +37,6 @@ do {	__asm__ __volatile__("ba,pt	%%xcc, 1f\n\t" \
 #define rmb()   __asm__ __volatile__("":::"memory")
 #define wmb()   __asm__ __volatile__("":::"memory")
 
-#define read_barrier_depends()          do { } while(0)
 #define set_mb(__var, __value) \
         do { __var = __value; membar_safe("#StoreLoad"); } while(0)
 
@@ -51,7 +50,8 @@ do {	__asm__ __volatile__("ba,pt	%%xcc, 1f\n\t" \
 #define smp_wmb()       __asm__ __volatile__("":::"memory")
 #endif
 
-#define smp_read_barrier_depends()      do { } while(0)
+#define read_barrier_depends()          do { } while (0)
+#define smp_read_barrier_depends()      do { } while (0)
 
 #define smp_store_release(p, v)                                         \
 do {                                                                    \