[PATCH] drm/i915: Add a few more sanity checks for stolen handling

[PATCH] drm/i915: Add a few more sanity checks for stolen handling

[Chris Wilson]

We should never be called via obj->ops->release() on anything other than
a fully formed stolen object, so raise that to an assert. In the process
tidy up a comment and variable no longer used outside of a conditional
BUG.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_stolen.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index 9b182ed93f3e..5bc9f699fdd2 100644
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -513,11 +513,10 @@ i915_pages_create_for_stolen(struct drm_device *dev,
 			     u32 offset, u32 size)
 {
 	struct drm_i915_private *dev_priv = to_i915(dev);
-	struct i915_ggtt *ggtt = &dev_priv->ggtt;
 	struct sg_table *st;
 	struct scatterlist *sg;
 
-	GEM_BUG_ON(offset > ggtt->stolen_size - size);
+	GEM_BUG_ON(offset > dev_priv->ggtt.stolen_size - size);
 
 	/* We hide that we have no struct page backing our stolen object
 	 * by wrapping the contiguous physical allocation with a fake
@@ -554,7 +553,7 @@ i915_gem_object_get_pages_stolen(struct drm_i915_gem_object *obj)
 static void i915_gem_object_put_pages_stolen(struct drm_i915_gem_object *obj,
 					     struct sg_table *pages)
 {
-	/* Should only be called during free */
+	/* Should only be called from i915_gem_object_release_stolen() */
 	sg_free_table(pages);
 	kfree(pages);
 }
@@ -563,15 +562,16 @@ static void
 i915_gem_object_release_stolen(struct drm_i915_gem_object *obj)
 {
 	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
+	struct drm_mm_node *stolen = fetch_and_zero(&obj->stolen);
+
+	GEM_BUG_ON(!stolen);
 
 	__i915_gem_object_unpin_pages(obj);
 
-	if (obj->stolen) {
-		i915_gem_stolen_remove_node(dev_priv, obj->stolen);
-		kfree(obj->stolen);
-		obj->stolen = NULL;
-	}
+	i915_gem_stolen_remove_node(dev_priv, stolen);
+	kfree(stolen);
 }
+
 static const struct drm_i915_gem_object_ops i915_gem_object_stolen_ops = {
 	.get_pages = i915_gem_object_get_pages_stolen,
 	.put_pages = i915_gem_object_put_pages_stolen,
-- 
2.10.2

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✓ Fi.CI.BAT: success for drm/i915: Add a few more sanity checks for stolen handling

[Patchwork]

== Series Details ==

Series: drm/i915: Add a few more sanity checks for stolen handling
URL   : https://patchwork.freedesktop.org/series/15507/
State : success

== Summary ==

Series 15507v1 drm/i915: Add a few more sanity checks for stolen handling
https://patchwork.freedesktop.org/api/1.0/series/15507/revisions/1/mbox/

Test drv_module_reload_basic:
                dmesg-warn -> PASS       (fi-skl-6770hq)

fi-bdw-5557u     total:244  pass:229  dwarn:0   dfail:0   fail:0   skip:15 
fi-bsw-n3050     total:244  pass:204  dwarn:0   dfail:0   fail:0   skip:40 
fi-bxt-t5700     total:244  pass:216  dwarn:0   dfail:0   fail:0   skip:28 
fi-byt-j1900     total:244  pass:216  dwarn:0   dfail:0   fail:0   skip:28 
fi-byt-n2820     total:244  pass:212  dwarn:0   dfail:0   fail:0   skip:32 
fi-hsw-4770      total:244  pass:224  dwarn:0   dfail:0   fail:0   skip:20 
fi-hsw-4770r     total:244  pass:224  dwarn:0   dfail:0   fail:0   skip:20 
fi-ilk-650       total:244  pass:191  dwarn:0   dfail:0   fail:0   skip:53 
fi-ivb-3520m     total:244  pass:222  dwarn:0   dfail:0   fail:0   skip:22 
fi-ivb-3770      total:244  pass:222  dwarn:0   dfail:0   fail:0   skip:22 
fi-kbl-7200u     total:244  pass:222  dwarn:0   dfail:0   fail:0   skip:22 
fi-skl-6260u     total:244  pass:230  dwarn:0   dfail:0   fail:0   skip:14 
fi-skl-6700hq    total:244  pass:223  dwarn:0   dfail:0   fail:0   skip:21 
fi-skl-6700k     total:244  pass:222  dwarn:1   dfail:0   fail:0   skip:21 
fi-skl-6770hq    total:244  pass:230  dwarn:0   dfail:0   fail:0   skip:14 
fi-snb-2520m     total:244  pass:212  dwarn:0   dfail:0   fail:0   skip:32 
fi-snb-2600      total:244  pass:211  dwarn:0   dfail:0   fail:0   skip:33 

4f5493e90cc50f1c6391c4f389f7a79c8fe52355 drm-intel-nightly: 2016y-11m-17d-15h-37m-59s UTC integration manifest
18c4faf drm/i915: Add a few more sanity checks for stolen handling

== Logs ==

For more details see: https://intel-gfx-ci.01.org/CI/Patchwork_3040/
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Re: [PATCH] drm/i915: Add a few more sanity checks for stolen handling

[Matthew Auld]

On 17 November 2016 at 15:58, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> We should never be called via obj->ops->release() on anything other than
> a fully formed stolen object, so raise that to an assert. In the process
> tidy up a comment and variable no longer used outside of a conditional
> BUG.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
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