From 2833ddccbdb4a23d79070603eb271acb680818e2 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 20 Aug 2019 11:05:31 +0100 Subject: [PATCH] drm/i915: Be defensive when starting vma activity Before we acquire the vma for GPU activity, ensure that the underlying object is not already in the process of being freed. Signed-off-by: Chris Wilson Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20190820100531.8430-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_vma.c | 3 +-- drivers/gpu/drm/i915/i915_vma.h | 8 ++++++++ 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c index 68260b40982b..252edef6c59e 100644 --- a/drivers/gpu/drm/i915/i915_vma.c +++ b/drivers/gpu/drm/i915/i915_vma.c @@ -87,8 +87,7 @@ static inline struct i915_vma *active_to_vma(struct i915_active *ref) static int __i915_vma_active(struct i915_active *ref) { - i915_vma_get(active_to_vma(ref)); - return 0; + return i915_vma_tryget(active_to_vma(ref)) ? 0 : -ENOENT; } static void __i915_vma_retire(struct i915_active *ref) diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h index b3d2121be947..59dfe5246001 100644 --- a/drivers/gpu/drm/i915/i915_vma.h +++ b/drivers/gpu/drm/i915/i915_vma.h @@ -231,6 +231,14 @@ static inline struct i915_vma *i915_vma_get(struct i915_vma *vma) return vma; } +static inline struct i915_vma *i915_vma_tryget(struct i915_vma *vma) +{ + if (likely(kref_get_unless_zero(&vma->obj->base.refcount))) + return vma; + + return NULL; +} + static inline void i915_vma_put(struct i915_vma *vma) { i915_gem_object_put(vma->obj);