Merge tag 'iwlwifi-next-for-kalle-2014-12-30' of https://git.kernel.org/pub/scm/linux...

[cascardo/linux.git] / arch / x86 / include / asm / barrier.h

diff --git a/arch/x86/include/asm/barrier.h b/arch/x86/include/asm/barrier.h
index 0f4460b..2ab1eb3 100644 (file)
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -24,78 +24,28 @@
 #define wmb()  asm volatile("sfence" ::: "memory")
 #endif
 
-/**
- * read_barrier_depends - Flush all pending reads that subsequents reads
- * depend on.
- *
- * No data-dependent reads from memory-like regions are ever reordered
- * over this barrier.  All reads preceding this primitive are guaranteed
- * to access memory (but not necessarily other CPUs' caches) before any
- * reads following this primitive that depend on the data return by
- * any of the preceding reads.  This primitive is much lighter weight than
- * rmb() on most CPUs, and is never heavier weight than is
- * rmb().
- *
- * These ordering constraints are respected by both the local CPU
- * and the compiler.
- *
- * Ordering is not guaranteed by anything other than these primitives,
- * not even by data dependencies.  See the documentation for
- * memory_barrier() for examples and URLs to more information.
- *
- * For example, the following code would force ordering (the initial
- * value of "a" is zero, "b" is one, and "p" is "&a"):
- *
- * <programlisting>
- *     CPU 0                           CPU 1
- *
- *     b = 2;
- *     memory_barrier();
- *     p = &b;                         q = p;
- *                                     read_barrier_depends();
- *                                     d = *q;
- * </programlisting>
- *
- * because the read of "*q" depends on the read of "p" and these
- * two reads are separated by a read_barrier_depends().  However,
- * the following code, with the same initial values for "a" and "b":
- *
- * <programlisting>
- *     CPU 0                           CPU 1
- *
- *     a = 2;
- *     memory_barrier();
- *     b = 3;                          y = b;
- *                                     read_barrier_depends();
- *                                     x = a;
- * </programlisting>
- *
- * does not enforce ordering, since there is no data dependency between
- * the read of "a" and the read of "b".  Therefore, on some CPUs, such
- * as Alpha, "y" could be set to 3 and "x" to 0.  Use rmb()
- * in cases like this where there are no data dependencies.
- **/
-
-#define read_barrier_depends() do { } while (0)
-
-#ifdef CONFIG_SMP
-#define smp_mb()       mb()
 #ifdef CONFIG_X86_PPRO_FENCE
-# define smp_rmb()     rmb()
+#define dma_rmb()      rmb()
 #else
-# define smp_rmb()     barrier()
+#define dma_rmb()      barrier()
 #endif
+#define dma_wmb()      barrier()
+
+#ifdef CONFIG_SMP
+#define smp_mb()       mb()
+#define smp_rmb()      dma_rmb()
 #define smp_wmb()      barrier()
-#define smp_read_barrier_depends()     read_barrier_depends()
 #define set_mb(var, value) do { (void)xchg(&var, value); } while (0)
 #else /* !SMP */
 #define smp_mb()       barrier()
 #define smp_rmb()      barrier()
 #define smp_wmb()      barrier()
-#define smp_read_barrier_depends()     do { } while (0)
 #define set_mb(var, value) do { var = value; barrier(); } while (0)
 #endif /* SMP */
 
+#define read_barrier_depends()         do { } while (0)
+#define smp_read_barrier_depends()     do { } while (0)
+
 #if defined(CONFIG_X86_PPRO_FENCE)
 
 /*