From: Matthew Wilcox (Oracle) Date: Tue, 19 Sep 2023 19:48:55 +0000 (+0100) Subject: i915: Limit the length of an sg list to the requested length X-Git-Tag: microblaze-v6.8~383^2^2~2 X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=863a8eb3f27098b42772f668e3977ff4cae10b04;p=linux-2.6-microblaze.git i915: Limit the length of an sg list to the requested length The folio conversion changed the behaviour of shmem_sg_alloc_table() to put the entire length of the last folio into the sg list, even if the sg list should have been shorter. gen8_ggtt_insert_entries() relied on the list being the right length and would overrun the end of the page tables. Other functions may also have been affected. Clamp the length of the last entry in the sg list to be the expected length. Signed-off-by: Matthew Wilcox (Oracle) Fixes: 0b62af28f249 ("i915: convert shmem_sg_free_table() to use a folio_batch") Cc: stable@vger.kernel.org # 6.5.x Link: https://gitlab.freedesktop.org/drm/intel/-/issues/9256 Link: https://lore.kernel.org/lkml/6287208.lOV4Wx5bFT@natalenko.name/ Reported-by: Oleksandr Natalenko Tested-by: Oleksandr Natalenko Reviewed-by: Andrzej Hajda Signed-off-by: Andrzej Hajda Link: https://patchwork.freedesktop.org/patch/msgid/20230919194855.347582-1-willy@infradead.org (cherry picked from commit 26a8e32e6d77900819c0c730fbfb393692dbbeea) Signed-off-by: Rodrigo Vivi --- diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c index 8f1633c3fb93..73a4a4eb29e0 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c @@ -100,6 +100,7 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st, st->nents = 0; for (i = 0; i < page_count; i++) { struct folio *folio; + unsigned long nr_pages; const unsigned int shrink[] = { I915_SHRINK_BOUND | I915_SHRINK_UNBOUND, 0, @@ -150,6 +151,8 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st, } } while (1); + nr_pages = min_t(unsigned long, + folio_nr_pages(folio), page_count - i); if (!i || sg->length >= max_segment || folio_pfn(folio) != next_pfn) { @@ -157,13 +160,13 @@ int shmem_sg_alloc_table(struct drm_i915_private *i915, struct sg_table *st, sg = sg_next(sg); st->nents++; - sg_set_folio(sg, folio, folio_size(folio), 0); + sg_set_folio(sg, folio, nr_pages * PAGE_SIZE, 0); } else { /* XXX: could overflow? */ - sg->length += folio_size(folio); + sg->length += nr_pages * PAGE_SIZE; } - next_pfn = folio_pfn(folio) + folio_nr_pages(folio); - i += folio_nr_pages(folio) - 1; + next_pfn = folio_pfn(folio) + nr_pages; + i += nr_pages - 1; /* Check that the i965g/gm workaround works. */ GEM_BUG_ON(gfp & __GFP_DMA32 && next_pfn >= 0x00100000UL);