[Intel-gfx] [CI 2/2] drm/i915: Fix DMA mapped scatterlist lookup

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

As the previous patch fixed the places where we walk the whole scatterlist
for DMA addresses, this patch fixes the random lookup functionality.

To achieve this we have to add a second lookup iterator and add a
i915_gem_object_get_sg_dma helper, to be used analoguous to existing
i915_gem_object_get_sg_dma. Therefore two lookup caches are maintained per
object and they are flushed at the same point for simplicity. (Strictly
speaking the DMA cache should be flushed from i915_gem_gtt_finish_pages,
but today this conincides with unsetting of the pages in general.)

Partial VMA view is then fixed to use the new DMA lookup and properly
query sg length.

v2:
 * Checkpatch.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Cc: Tom Murphy <murphyt7@tcd.ie>
Cc: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gem/i915_gem_object.c    |  2 ++
 drivers/gpu/drm/i915/gem/i915_gem_object.h    | 20 +++++++++++++++++-
 .../gpu/drm/i915/gem/i915_gem_object_types.h  | 17 ++++++++-------
 drivers/gpu/drm/i915/gem/i915_gem_pages.c     | 21 ++++++++++++-------
 drivers/gpu/drm/i915/gt/intel_ggtt.c          |  4 ++--
 drivers/gpu/drm/i915/i915_scatterlist.h       |  5 +++++
 6 files changed, 51 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index 3389ac972d16..00d24000b5e8 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -82,6 +82,8 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
 	obj->mm.madv = I915_MADV_WILLNEED;
 	INIT_RADIX_TREE(&obj->mm.get_page.radix, GFP_KERNEL | __GFP_NOWARN);
 	mutex_init(&obj->mm.get_page.lock);
+	INIT_RADIX_TREE(&obj->mm.get_dma_page.radix, GFP_KERNEL | __GFP_NOWARN);
+	mutex_init(&obj->mm.get_dma_page.lock);
 
 	if (IS_ENABLED(CONFIG_LOCKDEP) && i915_gem_object_is_shrinkable(obj))
 		i915_gem_shrinker_taints_mutex(to_i915(obj->base.dev),
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index eaf3d4147be0..be14486f63a7 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -272,8 +272,26 @@ int i915_gem_object_set_tiling(struct drm_i915_gem_object *obj,
 			       unsigned int tiling, unsigned int stride);
 
 struct scatterlist *
+__i915_gem_object_get_sg(struct drm_i915_gem_object *obj,
+			 struct i915_gem_object_page_iter *iter,
+			 unsigned int n,
+			 unsigned int *offset);
+
+static inline struct scatterlist *
 i915_gem_object_get_sg(struct drm_i915_gem_object *obj,
-		       unsigned int n, unsigned int *offset);
+		       unsigned int n,
+		       unsigned int *offset)
+{
+	return __i915_gem_object_get_sg(obj, &obj->mm.get_page, n, offset);
+}
+
+static inline struct scatterlist *
+i915_gem_object_get_sg_dma(struct drm_i915_gem_object *obj,
+			   unsigned int n,
+			   unsigned int *offset)
+{
+	return __i915_gem_object_get_sg(obj, &obj->mm.get_dma_page, n, offset);
+}
 
 struct page *
 i915_gem_object_get_page(struct drm_i915_gem_object *obj,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index b5c15557cc87..fedfebf13344 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -80,6 +80,14 @@ struct i915_mmap_offset {
 	struct rb_node offset;
 };
 
+struct i915_gem_object_page_iter {
+	struct scatterlist *sg_pos;
+	unsigned int sg_idx; /* in pages, but 32bit eek! */
+
+	struct radix_tree_root radix;
+	struct mutex lock; /* protects this cache */
+};
+
 struct drm_i915_gem_object {
 	struct drm_gem_object base;
 
@@ -246,13 +254,8 @@ struct drm_i915_gem_object {
 
 		I915_SELFTEST_DECLARE(unsigned int page_mask);
 
-		struct i915_gem_object_page_iter {
-			struct scatterlist *sg_pos;
-			unsigned int sg_idx; /* in pages, but 32bit eek! */
-
-			struct radix_tree_root radix;
-			struct mutex lock; /* protects this cache */
-		} get_page;
+		struct i915_gem_object_page_iter get_page;
+		struct i915_gem_object_page_iter get_dma_page;
 
 		/**
 		 * Element within i915->mm.unbound_list or i915->mm.bound_list,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index d6eeefab3d01..256e69f4eb5a 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -33,6 +33,8 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
 
 	obj->mm.get_page.sg_pos = pages->sgl;
 	obj->mm.get_page.sg_idx = 0;
+	obj->mm.get_dma_page.sg_pos = pages->sgl;
+	obj->mm.get_dma_page.sg_idx = 0;
 
 	obj->mm.pages = pages;
 
@@ -155,6 +157,8 @@ static void __i915_gem_object_reset_page_iter(struct drm_i915_gem_object *obj)
 	rcu_read_lock();
 	radix_tree_for_each_slot(slot, &obj->mm.get_page.radix, &iter, 0)
 		radix_tree_delete(&obj->mm.get_page.radix, iter.index);
+	radix_tree_for_each_slot(slot, &obj->mm.get_dma_page.radix, &iter, 0)
+		radix_tree_delete(&obj->mm.get_dma_page.radix, iter.index);
 	rcu_read_unlock();
 }
 
@@ -450,11 +454,12 @@ void __i915_gem_object_release_map(struct drm_i915_gem_object *obj)
 }
 
 struct scatterlist *
-i915_gem_object_get_sg(struct drm_i915_gem_object *obj,
-		       unsigned int n,
-		       unsigned int *offset)
+__i915_gem_object_get_sg(struct drm_i915_gem_object *obj,
+			 struct i915_gem_object_page_iter *iter,
+			 unsigned int n,
+			 unsigned int *offset)
 {
-	struct i915_gem_object_page_iter *iter = &obj->mm.get_page;
+	const bool dma = iter == &obj->mm.get_dma_page;
 	struct scatterlist *sg;
 	unsigned int idx, count;
 
@@ -483,7 +488,7 @@ i915_gem_object_get_sg(struct drm_i915_gem_object *obj,
 
 	sg = iter->sg_pos;
 	idx = iter->sg_idx;
-	count = __sg_page_count(sg);
+	count = dma ? __sg_dma_page_count(sg) : __sg_page_count(sg);
 
 	while (idx + count <= n) {
 		void *entry;
@@ -511,7 +516,7 @@ i915_gem_object_get_sg(struct drm_i915_gem_object *obj,
 
 		idx += count;
 		sg = ____sg_next(sg);
-		count = __sg_page_count(sg);
+		count = dma ? __sg_dma_page_count(sg) : __sg_page_count(sg);
 	}
 
 scan:
@@ -529,7 +534,7 @@ i915_gem_object_get_sg(struct drm_i915_gem_object *obj,
 	while (idx + count <= n) {
 		idx += count;
 		sg = ____sg_next(sg);
-		count = __sg_page_count(sg);
+		count = dma ? __sg_dma_page_count(sg) : __sg_page_count(sg);
 	}
 
 	*offset = n - idx;
@@ -596,7 +601,7 @@ i915_gem_object_get_dma_address_len(struct drm_i915_gem_object *obj,
 	struct scatterlist *sg;
 	unsigned int offset;
 
-	sg = i915_gem_object_get_sg(obj, n, &offset);
+	sg = i915_gem_object_get_sg_dma(obj, n, &offset);
 
 	if (len)
 		*len = sg_dma_len(sg) - (offset << PAGE_SHIFT);
diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c b/drivers/gpu/drm/i915/gt/intel_ggtt.c
index 188a5f70177d..cf94525be2c1 100644
--- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
+++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
@@ -1383,7 +1383,7 @@ intel_partial_pages(const struct i915_ggtt_view *view,
 	if (ret)
 		goto err_sg_alloc;
 
-	iter = i915_gem_object_get_sg(obj, view->partial.offset, &offset);
+	iter = i915_gem_object_get_sg_dma(obj, view->partial.offset, &offset);
 	GEM_BUG_ON(!iter);
 
 	sg = st->sgl;
@@ -1391,7 +1391,7 @@ intel_partial_pages(const struct i915_ggtt_view *view,
 	do {
 		unsigned int len;
 
-		len = min(iter->length - (offset << PAGE_SHIFT),
+		len = min(sg_dma_len(iter) - (offset << PAGE_SHIFT),
 			  count << PAGE_SHIFT);
 		sg_set_page(sg, NULL, len, 0);
 		sg_dma_address(sg) =
diff --git a/drivers/gpu/drm/i915/i915_scatterlist.h b/drivers/gpu/drm/i915/i915_scatterlist.h
index 510856887628..102d8d7007b6 100644
--- a/drivers/gpu/drm/i915/i915_scatterlist.h
+++ b/drivers/gpu/drm/i915/i915_scatterlist.h
@@ -48,6 +48,11 @@ static inline int __sg_page_count(const struct scatterlist *sg)
 	return sg->length >> PAGE_SHIFT;
 }
 
+static inline int __sg_dma_page_count(const struct scatterlist *sg)
+{
+	return sg_dma_len(sg) >> PAGE_SHIFT;
+}
+
 static inline struct scatterlist *____sg_next(struct scatterlist *sg)
 {
 	++sg;
-- 
2.25.1

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