[PATCH 3/8] x86: use long long for 64-bit atomic ops

Dmitry Vyukov
2017-03-28T16:16:23Z

Some 64-bit atomic operations use 'long long' as operand/return type
(e.g. asm-generic/atomic64.h, arch/x86/include/asm/atomic64_32.h);
while others use 'long' (e.g. arch/x86/include/asm/atomic64_64.h).
This makes it impossible to write portable code.
For example, there is no format specifier that prints result of
atomic64_read() without warnings. atomic64_try_cmpxchg() is almost
impossible to use in portable fashion because it requires either
'long *' or 'long long *' as argument depending on arch.

Switch arch/x86/include/asm/atomic64_64.h to 'long long'.

Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: kasan-dev@googlegroups.com
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Cc: x86@kernel.org
---
arch/x86/include/asm/atomic64_64.h | 54 +++++++++++++++++++-------------------
include/linux/types.h | 2 +-
2 files changed, 28 insertions(+), 28 deletions(-)

diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index 8db8879a6d8c..a62982a2b534 100644
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -16,7 +16,7 @@
* Atomically reads the value of @v.
* Doesn't imply a read memory barrier.
*/
-static inline long atomic64_read(const atomic64_t *v)
+static inline long long atomic64_read(const atomic64_t *v)
{
return READ_ONCE((v)->counter);
}
@@ -28,7 +28,7 @@ static inline long atomic64_read(const atomic64_t *v)
*
* Atomically sets the value of @v to @i.
*/
-static inline void atomic64_set(atomic64_t *v, long i)
+static inline void atomic64_set(atomic64_t *v, long long i)
{
WRITE_ONCE(v->counter, i);
}
@@ -40,7 +40,7 @@ static inline void atomic64_set(atomic64_t *v, long i)
*
* Atomically adds @i to @v.
*/
-static __always_inline void atomic64_add(long i, atomic64_t *v)
+static __always_inline void atomic64_add(long long i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "addq %1,%0"
: "=m" (v->counter)
@@ -54,7 +54,7 @@ static __always_inline void atomic64_add(long i, atomic64_t *v)
*
* Atomically subtracts @i from @v.
*/
-static inline void atomic64_sub(long i, atomic64_t *v)
+static inline void atomic64_sub(long long i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "subq %1,%0"
: "=m" (v->counter)
@@ -70,7 +70,7 @@ static inline void atomic64_sub(long i, atomic64_t *v)
* true if the result is zero, or false for all
* other cases.
*/
-static inline bool atomic64_sub_and_test(long i, atomic64_t *v)
+static inline bool atomic64_sub_and_test(long long i, atomic64_t *v)
{
GEN_BINARY_RMWcc(LOCK_PREFIX "subq", v->counter, "er", i, "%0", e);
}
@@ -136,7 +136,7 @@ static inline bool atomic64_inc_and_test(atomic64_t *v)
* if the result is negative, or false when
* result is greater than or equal to zero.
*/
-static inline bool atomic64_add_negative(long i, atomic64_t *v)
+static inline bool atomic64_add_negative(long long i, atomic64_t *v)
{
GEN_BINARY_RMWcc(LOCK_PREFIX "addq", v->counter, "er", i, "%0", s);
}
@@ -148,22 +148,22 @@ static inline bool atomic64_add_negative(long i, atomic64_t *v)
*
* Atomically adds @i to @v and returns @i + @v
*/
-static __always_inline long atomic64_add_return(long i, atomic64_t *v)
+static __always_inline long long atomic64_add_return(long long i, atomic64_t *v)
{
return i + xadd(&v->counter, i);
}

-static inline long atomic64_sub_return(long i, atomic64_t *v)
+static inline long long atomic64_sub_return(long long i, atomic64_t *v)
{
return atomic64_add_return(-i, v);
}

-static inline long atomic64_fetch_add(long i, atomic64_t *v)
+static inline long long atomic64_fetch_add(long long i, atomic64_t *v)
{
return xadd(&v->counter, i);
}

-static inline long atomic64_fetch_sub(long i, atomic64_t *v)
+static inline long long atomic64_fetch_sub(long long i, atomic64_t *v)
{
return xadd(&v->counter, -i);
}
@@ -171,18 +171,18 @@ static inline long atomic64_fetch_sub(long i, atomic64_t *v)
#define atomic64_inc_return(v) (atomic64_add_return(1, (v)))
#define atomic64_dec_return(v) (atomic64_sub_return(1, (v)))

-static inline long atomic64_cmpxchg(atomic64_t *v, long old, long new)
+static inline long long atomic64_cmpxchg(atomic64_t *v, long long old, long long new)
{
return cmpxchg(&v->counter, old, 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, long long *old, long long new)
{
return try_cmpxchg(&v->counter, old, new);
}

-static inline long atomic64_xchg(atomic64_t *v, long new)
+static inline long long atomic64_xchg(atomic64_t *v, long long new)
{
return xchg(&v->counter, new);
}
@@ -193,12 +193,12 @@ static inline long atomic64_xchg(atomic64_t *v, long new)
* @a: the amount to add to v...
* @u: ...unless v is equal to u.
*
- * Atomically adds @a to @v, so long as it was not @u.
+ * Atomically adds @a to @v, so long long as it was not @u.
* Returns the old value of @v.
*/
-static inline bool atomic64_add_unless(atomic64_t *v, long a, long u)
+static inline bool atomic64_add_unless(atomic64_t *v, long long a, long long u)
{
- long c = atomic64_read(v);
+ long long c = atomic64_read(v);
do {
if (unlikely(c == u))
return false;
@@ -215,9 +215,9 @@ static inline bool atomic64_add_unless(atomic64_t *v, long a, long u)
* The function returns the old value of *v minus 1, even if
* the atomic variable, v, was not decremented.
*/
-static inline long atomic64_dec_if_positive(atomic64_t *v)
+static inline long long atomic64_dec_if_positive(atomic64_t *v)
{
- long dec, c = atomic64_read(v);
+ long long dec, c = atomic64_read(v);
do {
dec = c - 1;
if (unlikely(dec < 0))
@@ -226,7 +226,7 @@ static inline long atomic64_dec_if_positive(atomic64_t *v)
return dec;
}

-static inline void atomic64_and(long i, atomic64_t *v)
+static inline void atomic64_and(long long i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "andq %1,%0"
: "+m" (v->counter)
@@ -234,16 +234,16 @@ static inline void atomic64_and(long i, atomic64_t *v)
: "memory");
}

-static inline long atomic64_fetch_and(long i, atomic64_t *v)
+static inline long long atomic64_fetch_and(long long i, atomic64_t *v)
{
- long val = atomic64_read(v);
+ long long val = atomic64_read(v);

do {
} while (!atomic64_try_cmpxchg(v, &val, val & i));
return val;
}

-static inline void atomic64_or(long i, atomic64_t *v)
+static inline void atomic64_or(long long i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "orq %1,%0"
: "+m" (v->counter)
@@ -251,16 +251,16 @@ static inline void atomic64_or(long i, atomic64_t *v)
: "memory");
}

-static inline long atomic64_fetch_or(long i, atomic64_t *v)
+static inline long long atomic64_fetch_or(long long i, atomic64_t *v)
{
- long val = atomic64_read(v);
+ long long val = atomic64_read(v);

do {
} while (!atomic64_try_cmpxchg(v, &val, val | i));
return val;
}

-static inline void atomic64_xor(long i, atomic64_t *v)
+static inline void atomic64_xor(long long i, atomic64_t *v)
{
asm volatile(LOCK_PREFIX "xorq %1,%0"
: "+m" (v->counter)
@@ -268,9 +268,9 @@ static inline void atomic64_xor(long i, atomic64_t *v)
: "memory");
}

-static inline long atomic64_fetch_xor(long i, atomic64_t *v)
+static inline long long atomic64_fetch_xor(long long i, atomic64_t *v)
{
- long val = atomic64_read(v);
+ long long val = atomic64_read(v);

do {
} while (!atomic64_try_cmpxchg(v, &val, val ^ i));
diff --git a/include/linux/types.h b/include/linux/types.h
index 1e7bd24848fc..569fc6db1bd5 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -177,7 +177,7 @@ typedef struct {

#ifdef CONFIG_64BIT
typedef struct {
- long counter;
+ long long counter;
} atomic64_t;
#endif

--
2.12.2.564.g063fe858b8-goog