[PATCH 22/40] drm/i915: Convert i915_ggtt_view to use an anonymous union

Chris Wilson chris at chris-wilson.co.uk
Thu Jan 5 14:55:04 UTC 2017


Save a lot of characters by making the union anonymous, with the
side-effect of ignoring unset bits when comparing views.

v2: Roll up the memcmps back into one.
v3: And split again as Ville points out we can't trust the compiler.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem.c      | 11 +++++------
 drivers/gpu/drm/i915/i915_gem_gtt.c  |  7 ++++---
 drivers/gpu/drm/i915/i915_gem_gtt.h  | 16 ++++++++--------
 drivers/gpu/drm/i915/i915_vma.c      |  9 ++++-----
 drivers/gpu/drm/i915/i915_vma.h      | 16 ++++++++++------
 drivers/gpu/drm/i915/intel_display.c |  2 +-
 6 files changed, 32 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 2c1631190a60..43233069ccc8 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1841,13 +1841,12 @@ int i915_gem_fault(struct vm_area_struct *area, struct vm_fault *vmf)
 		if (i915_gem_object_is_tiled(obj))
 			chunk = roundup(chunk, tile_row_pages(obj));
 
-		memset(&view, 0, sizeof(view));
 		view.type = I915_GGTT_VIEW_PARTIAL;
-		view.params.partial.offset_size = rounddown(page_offset, chunk);
-		view.params.partial.offset_size =
-			(view.params.partial.offset_size << INTEL_PARTIAL_SIZE_BITS) |
+		view.partial.offset_size = rounddown(page_offset, chunk);
+		view.partial.offset_size =
+			(view.partial.offset_size << INTEL_PARTIAL_SIZE_BITS) |
 			(min_t(unsigned int, chunk,
-			      vma_pages(area) - view.params.partial.offset_size) - 1);
+			      vma_pages(area) - view.partial.offset_size) - 1);
 
 		/* If the partial covers the entire object, just create a
 		 * normal VMA.
@@ -1882,7 +1881,7 @@ int i915_gem_fault(struct vm_area_struct *area, struct vm_fault *vmf)
 
 	/* Finally, remap it using the new GTT offset */
 	ret = remap_io_mapping(area,
-			       area->vm_start + intel_partial_get_offset(&vma->ggtt_view.params.partial),
+			       area->vm_start + intel_partial_get_offset(&vma->ggtt_view.partial),
 			       (ggtt->mappable_base + vma->node.start) >> PAGE_SHIFT,
 			       min_t(u64, vma->size, area->vm_end - area->vm_start),
 			       &ggtt->mappable);
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 4e77baf7d652..f863f2f98c7e 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3492,7 +3492,7 @@ intel_partial_pages(const struct i915_ggtt_view *view,
 {
 	struct sg_table *st;
 	struct scatterlist *sg, *iter;
-	unsigned int count = intel_partial_get_pages(&view->params.partial);
+	unsigned int count = intel_partial_get_pages(&view->partial);
 	unsigned int offset;
 	int ret = -ENOMEM;
 
@@ -3505,7 +3505,7 @@ intel_partial_pages(const struct i915_ggtt_view *view,
 		goto err_sg_alloc;
 
 	iter = i915_gem_object_get_sg(obj,
-				      intel_partial_get_page_offset(&view->params.partial),
+				      intel_partial_get_page_offset(&view->partial),
 				      &offset);
 	GEM_BUG_ON(!iter);
 
@@ -3558,7 +3558,8 @@ i915_get_ggtt_vma_pages(struct i915_vma *vma)
 		vma->pages = vma->obj->mm.pages;
 	else if (vma->ggtt_view.type == I915_GGTT_VIEW_ROTATED)
 		vma->pages =
-			intel_rotate_fb_obj_pages(&vma->ggtt_view.params.rotated, vma->obj);
+			intel_rotate_fb_obj_pages(&vma->ggtt_view.rotated,
+						  vma->obj);
 	else if (vma->ggtt_view.type == I915_GGTT_VIEW_PARTIAL)
 		vma->pages = intel_partial_pages(&vma->ggtt_view, vma->obj);
 	else
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h
index 023bf6ac3dc7..b2daca712df7 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.h
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.h
@@ -142,12 +142,6 @@ typedef uint64_t gen8_ppgtt_pml4e_t;
 
 struct sg_table;
 
-enum i915_ggtt_view_type {
-	I915_GGTT_VIEW_NORMAL = 0,
-	I915_GGTT_VIEW_ROTATED,
-	I915_GGTT_VIEW_PARTIAL,
-};
-
 struct intel_rotation_info {
 	struct intel_rotation_plane_info {
 		/* tiles */
@@ -181,13 +175,19 @@ static inline u64 intel_partial_get_page_offset(const struct intel_partial_info
 	return pi->offset_size >> INTEL_PARTIAL_SIZE_BITS;
 }
 
+enum i915_ggtt_view_type {
+	I915_GGTT_VIEW_NORMAL = 0,
+	I915_GGTT_VIEW_ROTATED = sizeof(struct intel_rotation_info),
+	I915_GGTT_VIEW_PARTIAL = sizeof(struct intel_partial_info),
+};
+
 struct i915_ggtt_view {
 	enum i915_ggtt_view_type type;
-
 	union {
+		/* Members need to contain no holes/padding */
 		struct intel_partial_info partial;
 		struct intel_rotation_info rotated;
-	} params;
+	};
 };
 
 extern const struct i915_ggtt_view i915_ggtt_view_normal;
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index 65770b7109c0..284273056ea2 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -96,14 +96,13 @@ __i915_vma_create(struct drm_i915_gem_object *obj,
 		vma->ggtt_view = *view;
 		if (view->type == I915_GGTT_VIEW_PARTIAL) {
 			GEM_BUG_ON(range_overflows_t(u64,
-						     intel_partial_get_offset(&view->params.partial),
-						     intel_partial_get_size(&view->params.partial),
+						     intel_partial_get_offset(&view->partial),
+						     intel_partial_get_size(&view->partial),
 						     obj->base.size));
-			vma->size = intel_partial_get_size(&view->params.partial);
+			vma->size = intel_partial_get_size(&view->partial);
 			GEM_BUG_ON(vma->size >= obj->base.size);
 		} else if (view->type == I915_GGTT_VIEW_ROTATED) {
-			vma->size =
-				intel_rotation_info_size(&view->params.rotated);
+			vma->size = intel_rotation_info_size(&view->rotated);
 			vma->size <<= PAGE_SHIFT;
 		}
 	}
diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
index e3b2b3b1e056..6d936009f919 100644
--- a/drivers/gpu/drm/i915/i915_vma.h
+++ b/drivers/gpu/drm/i915/i915_vma.h
@@ -196,15 +196,19 @@ i915_vma_compare(struct i915_vma *vma,
 	if (cmp)
 		return cmp;
 
+	cmp = vma->ggtt_view.type;
 	if (!view)
-		return vma->ggtt_view.type;
+		return cmp;
+
+	cmp -= view->type;
+	if (cmp)
+		return cmp;
 
-	if (vma->ggtt_view.type != view->type)
-		return vma->ggtt_view.type - view->type;
+	BUILD_BUG_ON(I915_GGTT_VIEW_PARTIAL == I915_GGTT_VIEW_ROTATED);
+	BUILD_BUG_ON(offsetof(typeof(*view), rotated) !=
+		     offsetof(typeof(*view), partial));
 
-	return memcmp(&vma->ggtt_view.params,
-		      &view->params,
-		      sizeof(view->params));
+	return memcmp(&vma->ggtt_view.partial, &view->partial, view->type);
 }
 
 int i915_vma_bind(struct i915_vma *vma, enum i915_cache_level cache_level,
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index e2150a64860c..f5718f99d0d4 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2139,7 +2139,7 @@ intel_fill_fb_ggtt_view(struct i915_ggtt_view *view,
 {
 	if (drm_rotation_90_or_270(rotation)) {
 		*view = i915_ggtt_view_rotated;
-		view->params.rotated = to_intel_framebuffer(fb)->rot_info;
+		view->rotated = to_intel_framebuffer(fb)->rot_info;
 	} else {
 		*view = i915_ggtt_view_normal;
 	}
-- 
2.11.0



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