Greg Kroah-Hartman wrote:
> On Mon, Aug 05, 2019 at 11:11:01PM +0300, Jari Ruusu wrote:
> > Peter Zijlstra's "x86/atomic: Fix smp_mb__{before,after}_atomic()"
> > upstream commit 69d927bba39517d0980462efc051875b7f4db185 seems to
> > be missing/lost from 4.9 and older stable kernels.
>
> Can you send properly backported and tested patches?
linux-4.9 backport of "x86/atomic: Fix smp_mb__{before,after}_atomic()".
Tested.
Signed-off-by: Jari Ruusu <jari.ruusu@xxxxxxxxx>
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -49,7 +49,7 @@
{
asm volatile(LOCK_PREFIX "addl %1,%0"
: "+m" (v->counter)
- : "ir" (i));
+ : "ir" (i) : "memory");
}
/**
@@ -63,7 +63,7 @@
{
asm volatile(LOCK_PREFIX "subl %1,%0"
: "+m" (v->counter)
- : "ir" (i));
+ : "ir" (i) : "memory");
}
/**
@@ -89,7 +89,7 @@
static __always_inline void atomic_inc(atomic_t *v)
{
asm volatile(LOCK_PREFIX "incl %0"
- : "+m" (v->counter));
+ : "+m" (v->counter) :: "memory");
}
/**
@@ -101,7 +101,7 @@
static __always_inline void atomic_dec(atomic_t *v)
{
asm volatile(LOCK_PREFIX "decl %0"
- : "+m" (v->counter));
+ : "+m" (v->counter) :: "memory");
}
/**
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -44,7 +44,7 @@
{
asm volatile(LOCK_PREFIX "addq %1,%0"
: "=m" (v->counter)
- : "er" (i), "m" (v->counter));
+ : "er" (i), "m" (v->counter) : "memory");
}
/**
@@ -58,7 +58,7 @@
{
asm volatile(LOCK_PREFIX "subq %1,%0"
: "=m" (v->counter)
- : "er" (i), "m" (v->counter));
+ : "er" (i), "m" (v->counter) : "memory");
}
/**
@@ -85,7 +85,7 @@
{
asm volatile(LOCK_PREFIX "incq %0"
: "=m" (v->counter)
- : "m" (v->counter));
+ : "m" (v->counter) : "memory");
}
/**
@@ -98,7 +98,7 @@
{
asm volatile(LOCK_PREFIX "decq %0"
: "=m" (v->counter)
- : "m" (v->counter));
+ : "m" (v->counter) : "memory");
}
/**
--- a/arch/x86/include/asm/barrier.h
+++ b/arch/x86/include/asm/barrier.h
@@ -105,8 +105,8 @@
#endif
/* Atomic operations are already serializing on x86 */
-#define __smp_mb__before_atomic() barrier()
-#define __smp_mb__after_atomic() barrier()
+#define __smp_mb__before_atomic() do { } while (0)
+#define __smp_mb__after_atomic() do { } while (0)
#include <asm-generic/barrier.h>
--
Jari Ruusu 4096R/8132F189 12D6 4C3A DCDA 0AA4 27BD ACDF F073 3C80 8132 F189
