From 556b748710586afa24a696ba81fe89dc7f41cebd Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 14 Nov 2016 20:40:56 +0000 Subject: [PATCH] drm/i915: Give each sw_fence its own lockclass Localise the static struct lock_class_key to the caller of i915_sw_fence_init() so that we create a lock_class instance for each unique sw_fence rather than all sw_fences sharing the same lock_class. This eliminate some lockdep false positive when using fences from within fence callbacks. For the relatively small number of fences currently in use [2], this adds 160 bytes of unused text/code when lockdep is disabled. This seems quite high, but fully reducing it via ifdeffery is also quite ugly. Removing the #fence strings saves 72 bytes with just a single #ifdef. Signed-off-by: Chris Wilson Reviewed-by: Tvrtko Ursulin Reviewed-by: Joonas Lahtinen Link: http://patchwork.freedesktop.org/patch/msgid/20161114204105.29171-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_sw_fence.c | 7 +++++-- drivers/gpu/drm/i915/i915_sw_fence.h | 17 ++++++++++++++++- 2 files changed, 21 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c b/drivers/gpu/drm/i915/i915_sw_fence.c index 95f2f12e0917..147420ccf49c 100644 --- a/drivers/gpu/drm/i915/i915_sw_fence.c +++ b/drivers/gpu/drm/i915/i915_sw_fence.c @@ -116,11 +116,14 @@ static void i915_sw_fence_await(struct i915_sw_fence *fence) WARN_ON(atomic_inc_return(&fence->pending) <= 1); } -void i915_sw_fence_init(struct i915_sw_fence *fence, i915_sw_fence_notify_t fn) +void __i915_sw_fence_init(struct i915_sw_fence *fence, + i915_sw_fence_notify_t fn, + const char *name, + struct lock_class_key *key) { BUG_ON((unsigned long)fn & ~I915_SW_FENCE_MASK); - init_waitqueue_head(&fence->wait); + __init_waitqueue_head(&fence->wait, name, key); kref_init(&fence->kref); atomic_set(&fence->pending, 1); fence->flags = (unsigned long)fn; diff --git a/drivers/gpu/drm/i915/i915_sw_fence.h b/drivers/gpu/drm/i915/i915_sw_fence.h index 707dfc4f0da5..7508d23f823b 100644 --- a/drivers/gpu/drm/i915/i915_sw_fence.h +++ b/drivers/gpu/drm/i915/i915_sw_fence.h @@ -40,7 +40,22 @@ typedef int (*i915_sw_fence_notify_t)(struct i915_sw_fence *, enum i915_sw_fence_notify state); #define __i915_sw_fence_call __aligned(4) -void i915_sw_fence_init(struct i915_sw_fence *fence, i915_sw_fence_notify_t fn); +void __i915_sw_fence_init(struct i915_sw_fence *fence, + i915_sw_fence_notify_t fn, + const char *name, + struct lock_class_key *key); +#ifdef CONFIG_LOCKDEP +#define i915_sw_fence_init(fence, fn) \ +do { \ + static struct lock_class_key __key; \ + \ + __i915_sw_fence_init((fence), (fn), #fence, &__key); \ +} while (0) +#else +#define i915_sw_fence_init(fence, fn) \ + __i915_sw_fence_init((fence), (fn), NULL, NULL) +#endif + void i915_sw_fence_commit(struct i915_sw_fence *fence); int i915_sw_fence_await_sw_fence(struct i915_sw_fence *fence, -- 2.20.1