Note that just because we have n == MAX elements left, does not imply
that there are only MAX elements left in the scatterlist and so we may
not be on the last chain, and the nth element may in fact be a chain ptr.
This is exercised by the improved hangman tests and the gem_exec_big
test in i-g-t.
This regression has been introduced in
commit 9da3da660d8c19a54f6e93361d147509be3fff84
Author: Chris Wilson <ch...@chris-wilson.co.uk>
Date: Fri Jun 1 15:20:22 2012 +0100
drm/i915: Replace the array of pages with a scatterlist
v2: KISS, replace the direct lookup with a for_each_sg() [danvet]
v3: Try to be clever again.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_drv.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d2dda78..babe43d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1383,9 +1383,14 @@ int __must_check i915_gem_object_get_pages(struct
drm_i915_gem_object *obj);
static inline struct page *i915_gem_object_get_page(struct drm_i915_gem_object
*obj, int n)
{
struct scatterlist *sg = obj->pages->sgl;
- while (n >= SG_MAX_SINGLE_ALLOC) {
+ int nents = obj->pages->nents;
+ while (nents > SG_MAX_SINGLE_ALLOC) {
+ if (n < SG_MAX_SINGLE_ALLOC - 1)
+ break;
+
sg = sg_chain_ptr(sg + SG_MAX_SINGLE_ALLOC - 1);
n -= SG_MAX_SINGLE_ALLOC - 1;
+ nents -= SG_MAX_SINGLE_ALLOC - 1;
}
return sg_page(sg+n);
}
--
1.7.10.4
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