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 managable pieces for the dma-mapping backend.
Reported-by: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@xxxxxxxxx>
Suggested-by: Matthew Auld <matthew.auld@xxxxxxxxx>
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@xxxxxxxxx>
Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
---
drivers/gpu/drm/i915/gem/i915_gem_region.c | 42 ++++++++++++----------
1 file changed, 24 insertions(+), 18 deletions(-)
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_region.c b/drivers/gpu/drm/i915/gem/i915_gem_region.c
index e72d78074c9e..edb84072f979 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_region.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_region.c
@@ -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;
}
@@ -58,33 +59,38 @@ i915_gem_object_get_pages_buddy(struct drm_i915_gem_object *obj)
prev_end = (resource_size_t)-1;
list_for_each_entry(block, blocks, link) {
- u64 block_size, offset;
+ u64 block_size, offset, len;
block_size = min_t(u64, size,
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) {
+ if (offset != prev_end || sg->length >= max_segment) {
+ if (st->nents) {
+ sg_page_sizes |= sg->length;
+ sg = __sg_next(sg);
+ }
- 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);
- }
+ len = min(block_size, max_segment);
- sg_dma_address(sg) = mem->region.start + offset;
- sg_dma_len(sg) = block_size;
+ sg_dma_address(sg) = mem->region.start + offset;
+ sg_dma_len(sg) = len;
- sg->length = block_size;
+ sg->length = len;
- st->nents++;
- } else {
- sg->length += block_size;
- sg_dma_len(sg) += block_size;
- }
+ st->nents++;
+ } else {
+ len = min(block_size, max_segment - sg->length);
+ sg->length += len;
+ sg_dma_len(sg) += len;
+ }
- prev_end = offset + block_size;
+ offset += len;
+ block_size -= len;
+
+ prev_end = offset;
+ }
}
sg_page_sizes |= sg->length;
--
2.20.1
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