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From: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
To: Intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org, Chris Wilson <chris@chris-wilson.co.uk>
Subject: [Intel-gfx] [PATCH 04/12] drm/i915: Wrap cmpxchg64 with try_cmpxchg64() helper
Date: Wed, 26 May 2021 15:14:48 +0100	[thread overview]
Message-ID: <20210526141456.2334192-5-tvrtko.ursulin@linux.intel.com> (raw)
In-Reply-To: <20210526141456.2334192-1-tvrtko.ursulin@linux.intel.com>

From: Chris Wilson <chris@chris-wilson.co.uk>

Wrap cmpxchg64 with a try_cmpxchg()-esque helper. Hiding the old-value
dance in the helper allows for cleaner code.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_utils.h | 32 +++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index c3d234133da7..a42d9ddd0415 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -475,4 +475,36 @@ void __mark_lock_used_irq(struct lockdep_map *lock);
  */
 #define IS_ACTIVE(config) ((config) != 0)
 
+#ifndef try_cmpxchg64
+#if IS_ENABLED(CONFIG_64BIT)
+#define try_cmpxchg64(_ptr, _pold, _new) try_cmpxchg(_ptr, _pold, _new)
+#else
+#define try_cmpxchg64(_ptr, _pold, _new)				\
+({									\
+	__typeof__(_ptr) _old = (__typeof__(_ptr))(_pold);		\
+	__typeof__(*(_ptr)) __old = *_old;				\
+	__typeof__(*(_ptr)) __cur = cmpxchg64(_ptr, __old, _new);	\
+	bool success = __cur == __old;					\
+	if (unlikely(!success))						\
+		*_old = __cur;						\
+	likely(success);						\
+})
+#endif
+#endif
+
+#ifndef xchg64
+#if IS_ENABLED(CONFIG_64BIT)
+#define xchg64(_ptr, _new) xchg(_ptr, _new)
+#else
+#define xchg64(_ptr, _new)						\
+({									\
+	__typeof__(_ptr) __ptr = (_ptr);				\
+	__typeof__(*(_ptr)) __old = *__ptr;				\
+	while (!try_cmpxchg64(__ptr, &__old, (_new)))			\
+		;							\
+	__old;								\
+})
+#endif
+#endif
+
 #endif /* !__I915_UTILS_H */
-- 
2.30.2

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  parent reply	other threads:[~2021-05-26 14:15 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-26 14:14 [Intel-gfx] [PATCH 00/12] Catchup with a few dropped patches Tvrtko Ursulin
2021-05-26 14:14 ` [Intel-gfx] [PATCH 01/12] drm/i915: Take rcu_read_lock for querying fence's driver/timeline names Tvrtko Ursulin
2021-05-27 10:46   ` Daniel Vetter
2021-05-26 14:14 ` [Intel-gfx] [PATCH 02/12] drm/i915: Remove notion of GEM from i915_gem_shrinker_taints_mutex Tvrtko Ursulin
2021-05-26 14:14 ` [Intel-gfx] [PATCH 03/12] drm/i915: Lift marking a lock as used to utils Tvrtko Ursulin
2021-05-26 14:14 ` Tvrtko Ursulin [this message]
2021-05-26 14:14 ` [Intel-gfx] [PATCH 05/12] drm/i915/selftests: Set cache status for huge_gem_object Tvrtko Ursulin
2021-05-26 14:14 ` [Intel-gfx] [PATCH 06/12] drm/i915/selftests: Use a coherent map to setup scratch batch buffers Tvrtko Ursulin
2021-05-26 14:14 ` [Intel-gfx] [PATCH 07/12] drm/i915/selftests: Replace the unbounded set-domain with an explicit wait Tvrtko Ursulin
2021-05-26 14:14 ` [Intel-gfx] [PATCH 08/12] drm/i915/selftests: Remove redundant set-to-gtt-domain Tvrtko Ursulin
2021-05-26 14:14 ` [Intel-gfx] [PATCH 09/12] drm/i915/selftests: Replace unbound set-domain waits with explicit timeouts Tvrtko Ursulin
2021-05-26 14:14 ` [Intel-gfx] [PATCH 10/12] drm/i915/selftests: Replace an unbounded set-domain wait with a timeout Tvrtko Ursulin
2021-05-26 14:14 ` [Intel-gfx] [PATCH 11/12] drm/i915/selftests: Remove redundant set-to-gtt-domain before batch submission Tvrtko Ursulin
2021-05-26 14:14 ` [Intel-gfx] [PATCH 12/12] drm/i915/gem: Manage all set-domain waits explicitly Tvrtko Ursulin
2021-05-26 14:30   ` Matthew Auld
2021-05-26 14:37     ` [Intel-gfx] [PATCH v2 " Tvrtko Ursulin
2021-05-27 10:44     ` [Intel-gfx] [PATCH " Daniel Vetter
2021-05-26 20:19 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for Catchup with a few dropped patches (rev2) Patchwork
2021-05-26 20:21 ` [Intel-gfx] ✗ Fi.CI.SPARSE: " Patchwork
2021-05-26 21:00 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork

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