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, 3 insertions, 3 deletions

diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h
index bab79a110c7b..cb6d66c6e3e1 100644
--- a/arch/powerpc/include/asm/barrier.h
+++ b/arch/powerpc/include/asm/barrier.h
@@ -33,7 +33,6 @@
 #define mb()   __asm__ __volatile__ ("sync" : : : "memory")
 #define rmb()  __asm__ __volatile__ ("sync" : : : "memory")
 #define wmb()  __asm__ __volatile__ ("sync" : : : "memory")
-#define read_barrier_depends()  do { } while(0)
 
 #define set_mb(var, value)      do { var = value; mb(); } while (0)
 
@@ -50,16 +49,17 @@
 #define smp_mb()        mb()
 #define smp_rmb()       __lwsync()
 #define smp_wmb()       __asm__ __volatile__ (stringify_in_c(SMPWMB) : : :"memory")
-#define smp_read_barrier_depends()      read_barrier_depends()
 #else
 #define __lwsync()      barrier()
 
 #define smp_mb()        barrier()
 #define smp_rmb()       barrier()
 #define smp_wmb()       barrier()
-#define smp_read_barrier_depends()      do { } while(0)
 #endif /* CONFIG_SMP */
 
+#define read_barrier_depends()          do { } while (0)
+#define smp_read_barrier_depends()      do { } while (0)
+
 /*
  * This is a barrier which prevents following instructions from being
  * started until the value of the argument x is known.  For example, if