From 863a8eb3f27098b42772f668e3977ff4cae10b04 Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: Tue, 19 Sep 2023 20:48:55 +0100
Subject: [PATCH] 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) <willy@infradead.org>
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 <oleksandr@natalenko.name>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230919194855.347582-1-willy@infradead.org
(cherry picked from commit 26a8e32e6d77900819c0c730fbfb393692dbbeea)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
index 8f1633c3fb935..73a4a4eb29e08 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);
--
2.30.2