From 2833ddccbdb4a23d79070603eb271acb680818e2 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 20 Aug 2019 11:05:31 +0100
Subject: drm/i915: Be defensive when starting vma activity
Git-commit: 2833ddccbdb4a23d79070603eb271acb680818e2
Patch-mainline: v5.4-rc1
References: bsc#1152489
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 <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190820100531.8430-1-chris@chris-wilson.co.uk
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
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);
--
2.28.0