[PATCH v4 2/7] x86: use s64* for old arg of atomic64_try_cmpxchg()

[Dmitry Vyukov]

atomic64_try_cmpxchg() declares old argument as long*,
this makes it impossible to use it in portable code.
If caller passes long*, it becomes 32-bits on 32-bit arches.
If caller passes s64*, it does not compile on x86_64.

Change type of old arg to s64*.

Signed-off-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: kasan-dev@xxxxxxxxxxxxxxxx
Cc: linux-mm@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: x86@xxxxxxxxxx
---
 arch/x86/include/asm/atomic64_64.h | 12 ++++++------
 arch/x86/include/asm/cmpxchg.h     |  2 +-
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index 8db8879a6d8c..5d9de36a2f04 100644
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -177,7 +177,7 @@ static inline long atomic64_cmpxchg(atomic64_t *v, long old, long new)
 }
 
 #define atomic64_try_cmpxchg atomic64_try_cmpxchg
-static __always_inline bool atomic64_try_cmpxchg(atomic64_t *v, long *old, long new)
+static __always_inline bool atomic64_try_cmpxchg(atomic64_t *v, s64 *old, long new)
 {
 	return try_cmpxchg(&v->counter, old, new);
 }
@@ -198,7 +198,7 @@ static inline long atomic64_xchg(atomic64_t *v, long new)
  */
 static inline bool atomic64_add_unless(atomic64_t *v, long a, long u)
 {
-	long c = atomic64_read(v);
+	s64 c = atomic64_read(v);
 	do {
 		if (unlikely(c == u))
 			return false;
@@ -217,7 +217,7 @@ static inline bool atomic64_add_unless(atomic64_t *v, long a, long u)
  */
 static inline long atomic64_dec_if_positive(atomic64_t *v)
 {
-	long dec, c = atomic64_read(v);
+	s64 dec, c = atomic64_read(v);
 	do {
 		dec = c - 1;
 		if (unlikely(dec < 0))
@@ -236,7 +236,7 @@ static inline void atomic64_and(long i, atomic64_t *v)
 
 static inline long atomic64_fetch_and(long i, atomic64_t *v)
 {
-	long val = atomic64_read(v);
+	s64 val = atomic64_read(v);
 
 	do {
 	} while (!atomic64_try_cmpxchg(v, &val, val & i));
@@ -253,7 +253,7 @@ static inline void atomic64_or(long i, atomic64_t *v)
 
 static inline long atomic64_fetch_or(long i, atomic64_t *v)
 {
-	long val = atomic64_read(v);
+	s64 val = atomic64_read(v);
 
 	do {
 	} while (!atomic64_try_cmpxchg(v, &val, val | i));
@@ -270,7 +270,7 @@ static inline void atomic64_xor(long i, atomic64_t *v)
 
 static inline long atomic64_fetch_xor(long i, atomic64_t *v)
 {
-	long val = atomic64_read(v);
+	s64 val = atomic64_read(v);
 
 	do {
 	} while (!atomic64_try_cmpxchg(v, &val, val ^ i));
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h
index d90296d061e8..b5069e802d5c 100644
--- a/arch/x86/include/asm/cmpxchg.h
+++ b/arch/x86/include/asm/cmpxchg.h
@@ -157,7 +157,7 @@ extern void __add_wrong_size(void)
 #define __raw_try_cmpxchg(_ptr, _pold, _new, size, lock)		\
 ({									\
 	bool success;							\
-	__typeof__(_ptr) _old = (_pold);				\
+	__typeof__(_ptr) _old = (__typeof__(_ptr))(_pold);		\
 	__typeof__(*(_ptr)) __old = *_old;				\
 	__typeof__(*(_ptr)) __new = (_new);				\
 	switch (size) {							\
-- 
2.13.1.518.g3df882009-goog