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Message-ID: <20110412210045.GA19901@p183>
Date: Wed, 13 Apr 2011 00:00:45 +0300
From: Alexey Dobriyan <adobriyan@...il.com>
To: akpm@...ux-foundation.org
Cc: linux-kernel@...r.kernel.org, behlendorf1@...l.gov, oleg@...hat.com
Subject: [PATCH] remove abs64()
We don't need no stinking abs64() given some GCC extensions
(especially __builtin_choose_expr()).
One abs() implementation is better than two abs() implementations.
New abs() doesn't expand type needlessly.
Signed-off-by: Alexey Dobriyan <adobriyan@...il.com>
---
drivers/gpu/drm/drm_irq.c | 4 ++--
include/linux/kernel.h | 43 +++++++++++++++++++++----------------------
lib/div64.c | 2 +-
3 files changed, 24 insertions(+), 25 deletions(-)
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -154,7 +154,7 @@ static void vblank_disable_and_save(struct drm_device *dev, int crtc)
* available. In that case we can't account for this and just
* hope for the best.
*/
- if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
+ if ((vblrc > 0) && (abs(diff_ns) > 1000000)) {
atomic_inc(&dev->_vblank_count[crtc]);
smp_mb__after_atomic_inc();
}
@@ -1290,7 +1290,7 @@ bool drm_handle_vblank(struct drm_device *dev, int crtc)
* e.g., due to spurious vblank interrupts. We need to
* ignore those for accounting.
*/
- if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
+ if (abs(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
/* Store new timestamp in ringbuffer. */
vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -143,28 +143,27 @@ extern int _cond_resched(void);
#define might_sleep_if(cond) do { if (cond) might_sleep(); } while (0)
-/*
- * abs() handles unsigned and signed longs, ints, shorts and chars. For all
- * input types abs() returns a signed long.
- * abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()
- * for those.
- */
-#define abs(x) ({ \
- long ret; \
- if (sizeof(x) == sizeof(long)) { \
- long __x = (x); \
- ret = (__x < 0) ? -__x : __x; \
- } else { \
- int __x = (x); \
- ret = (__x < 0) ? -__x : __x; \
- } \
- ret; \
- })
-
-#define abs64(x) ({ \
- s64 __x = (x); \
- (__x < 0) ? -__x : __x; \
- })
+#define abs(x) \
+({ \
+ typeof(x) _x = (x); \
+ \
+ __builtin_choose_expr( \
+ __builtin_types_compatible_p(typeof(_x), signed char), \
+ (unsigned char)({ _x < 0 ? -_x : _x; }), \
+ __builtin_choose_expr( \
+ __builtin_types_compatible_p(typeof(_x), short), \
+ (unsigned short)({ _x < 0 ? -_x : _x; }), \
+ __builtin_choose_expr( \
+ __builtin_types_compatible_p(typeof(_x), int), \
+ (unsigned int)({ _x < 0 ? -_x : _x; }), \
+ __builtin_choose_expr( \
+ __builtin_types_compatible_p(typeof(_x), long), \
+ (unsigned long)({ _x < 0 ? -_x : _x; }), \
+ __builtin_choose_expr( \
+ __builtin_types_compatible_p(typeof(_x), long long), \
+ (unsigned long long)({ _x < 0 ? -_x : _x; }), \
+ _x))))); \
+})
#ifdef CONFIG_PROVE_LOCKING
void might_fault(void);
--- a/lib/div64.c
+++ b/lib/div64.c
@@ -121,7 +121,7 @@ s64 div64_s64(s64 dividend, s64 divisor)
{
s64 quot, t;
- quot = div64_u64(abs64(dividend), abs64(divisor));
+ quot = div64_u64(abs(dividend), abs(divisor));
t = (dividend ^ divisor) >> 63;
return (quot ^ t) - t;
--
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