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>
Reviewed-by: Matthew Auld <matthew.auld@xxxxxxxxx>
---
drivers/gpu/drm/i915/gem/i915_gem_region.c | 36 ++++++++++---------
.../drm/i915/selftests/intel_memory_region.c | 27 ++++++++++----
2 files changed, 41 insertions(+), 22 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..7d05b5f346c1 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;
}
@@ -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;
diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
index 55ccd957a009..7c02a0c16fc1 100644
--- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
@@ -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;
}
--
2.20.1
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