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drm/i915/gem: Limit lmem scatterlist elements to UINT_MAX

Browse source 
Adhere to the i915_sg_max_segment() limit on the lengths of individual
scatterlist elements, and in doing so split up very large chunks of lmem
into manageable pieces for the dma-mapping backend.

Reported-by: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@intel.com>
Suggested-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201202173444.14903-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson 2020-12-02 17:34:43 +00:00
parent 840291a7b9
commit a2843b3bd1
2 changed files with 41 additions and 22 deletions
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36
drivers/gpu/drm/i915/gem/i915_gem_region.c
View file

@ -22,6 +22,7 @@ i915_gem_object_put_pages_buddy(struct drm_i915_gem_object *obj,
int
i915_gem_object_get_pages_buddy(struct drm_i915_gem_object *obj)
{
const u64 max_segment = i915_sg_segment_size();
struct intel_memory_region *mem = obj->mm.region;
struct list_head *blocks = &obj->mm.blocks;
resource_size_t size = obj->base.size;
@ -37,7 +38,7 @@ i915_gem_object_get_pages_buddy(struct drm_i915_gem_object *obj)
if (!st)
return -ENOMEM;
if (sg_alloc_table(st, size >> ilog2(mem->mm.chunk_size), GFP_KERNEL)) {
if (sg_alloc_table(st, size >> PAGE_SHIFT, GFP_KERNEL)) {
kfree(st);
return -ENOMEM;
}
@ -64,27 +65,30 @@ i915_gem_object_get_pages_buddy(struct drm_i915_gem_object *obj)
i915_buddy_block_size(&mem->mm, block));
offset = i915_buddy_block_offset(block);
GEM_BUG_ON(overflows_type(block_size, sg->length));
while (block_size) {
u64 len;
if (offset != prev_end ||
add_overflows_t(typeof(sg->length), sg->length, block_size)) {
if (st->nents) {
sg_page_sizes |= sg->length;
sg = __sg_next(sg);
if (offset != prev_end || sg->length >= max_segment) {
if (st->nents) {
sg_page_sizes |= sg->length;
sg = __sg_next(sg);
}
sg_dma_address(sg) = mem->region.start + offset;
sg_dma_len(sg) = 0;
sg->length = 0;
st->nents++;
}
sg_dma_address(sg) = mem->region.start + offset;
sg_dma_len(sg) = block_size;
len = min(block_size, max_segment - sg->length);
sg->length += len;
sg_dma_len(sg) += len;
sg->length = block_size;
offset += len;
block_size -= len;
st->nents++;
} else {
sg->length += block_size;
sg_dma_len(sg) += block_size;
prev_end = offset;
}
prev_end = offset + block_size;
}
sg_page_sizes |= sg->length;

27
drivers/gpu/drm/i915/selftests/intel_memory_region.c
View file

@ -129,6 +129,21 @@ static void igt_object_release(struct drm_i915_gem_object *obj)
i915_gem_object_put(obj);
}
static bool is_contiguous(struct drm_i915_gem_object *obj)
{
struct scatterlist *sg;
dma_addr_t addr = -1;
for (sg = obj->mm.pages->sgl; sg; sg = sg_next(sg)) {
if (addr != -1 && sg_dma_address(sg) != addr)
return false;
addr = sg_dma_address(sg) + sg_dma_len(sg);
}
return true;
}
static int igt_mock_contiguous(void *arg)
{
struct intel_memory_region *mem = arg;
@ -150,8 +165,8 @@ static int igt_mock_contiguous(void *arg)
if (IS_ERR(obj))
return PTR_ERR(obj);
if (obj->mm.pages->nents != 1) {
pr_err("%s min object spans multiple sg entries\n", __func__);
if (!is_contiguous(obj)) {
pr_err("%s min object spans disjoint sg entries\n", __func__);
err = -EINVAL;
goto err_close_objects;
}
@ -163,8 +178,8 @@ static int igt_mock_contiguous(void *arg)
if (IS_ERR(obj))
return PTR_ERR(obj);
if (obj->mm.pages->nents != 1) {
pr_err("%s max object spans multiple sg entries\n", __func__);
if (!is_contiguous(obj)) {
pr_err("%s max object spans disjoint sg entries\n", __func__);
err = -EINVAL;
goto err_close_objects;
}
@ -189,8 +204,8 @@ static int igt_mock_contiguous(void *arg)
goto err_close_objects;
}
if (obj->mm.pages->nents != 1) {
pr_err("%s object spans multiple sg entries\n", __func__);
if (!is_contiguous(obj)) {
pr_err("%s object spans disjoint sg entries\n", __func__);
err = -EINVAL;
goto err_close_objects;
}