drm/i915: Embed the scratch page struct into each VM

As the scratch page is no longer shared between all VM, and each has
their own, forgo the small allocation and simply embed the scratch page
struct into the i915_address_space.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20160822074431.26872-2-chris@chris-wilson.co.ukReviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Mika Kuoppala <mika.kuoppala@intel.com>

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -409,29 +409,16 @@ static void fill_page_dma_32(struct drm_device *dev, struct i915_page_dma *p,
 	fill_page_dma(dev, p, v);
 }
 
-static struct i915_page_scratch *alloc_scratch_page(struct drm_device *dev)
+static int
+setup_scratch_page(struct drm_device *dev, struct i915_page_dma *scratch)
 {
-	struct i915_page_scratch *sp;
-	int ret;
-
-	sp = kzalloc(sizeof(*sp), GFP_KERNEL);
-	if (sp == NULL)
-		return ERR_PTR(-ENOMEM);
-
-	ret = __setup_page_dma(dev, px_base(sp), GFP_DMA32 | __GFP_ZERO);
-	if (ret) {
-		kfree(sp);
-		return ERR_PTR(ret);
-	}
-
-	return sp;
+	return __setup_page_dma(dev, scratch, GFP_DMA32 | __GFP_ZERO);
 }
 
-static void free_scratch_page(struct drm_device *dev,
-			      struct i915_page_scratch *sp)
+static void cleanup_scratch_page(struct drm_device *dev,
+				 struct i915_page_dma *scratch)
 {
-	cleanup_px(dev, sp);
-	kfree(sp);
+	cleanup_page_dma(dev, scratch);
 }
 
 static struct i915_page_table *alloc_pt(struct drm_device *dev)
@@ -477,7 +464,7 @@ static void gen8_initialize_pt(struct i915_address_space *vm,
 {
 	gen8_pte_t scratch_pte;
 
-	scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page),
+	scratch_pte = gen8_pte_encode(vm->scratch_page.daddr,
 				      I915_CACHE_LLC, true);
 
 	fill_px(vm->dev, pt, scratch_pte);
@@ -488,9 +475,9 @@ static void gen6_initialize_pt(struct i915_address_space *vm,
 {
 	gen6_pte_t scratch_pte;
 
-	WARN_ON(px_dma(vm->scratch_page) == 0);
+	WARN_ON(vm->scratch_page.daddr == 0);
 
-	scratch_pte = vm->pte_encode(px_dma(vm->scratch_page),
+	scratch_pte = vm->pte_encode(vm->scratch_page.daddr,
 				     I915_CACHE_LLC, true, 0);
 
 	fill32_px(vm->dev, pt, scratch_pte);
@@ -774,7 +761,7 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
 				   bool use_scratch)
 {
 	struct i915_hw_ppgtt *ppgtt = i915_vm_to_ppgtt(vm);
-	gen8_pte_t scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page),
+	gen8_pte_t scratch_pte = gen8_pte_encode(vm->scratch_page.daddr,
 						 I915_CACHE_LLC, use_scratch);
 
 	if (!USES_FULL_48BIT_PPGTT(vm->dev)) {
@@ -880,9 +867,9 @@ static int gen8_init_scratch(struct i915_address_space *vm)
 	struct drm_device *dev = vm->dev;
 	int ret;
 
-	vm->scratch_page = alloc_scratch_page(dev);
-	if (IS_ERR(vm->scratch_page))
-		return PTR_ERR(vm->scratch_page);
+	ret = setup_scratch_page(dev, &vm->scratch_page);
+	if (ret)
+		return ret;
 
 	vm->scratch_pt = alloc_pt(dev);
 	if (IS_ERR(vm->scratch_pt)) {
@@ -916,7 +903,7 @@ static int gen8_init_scratch(struct i915_address_space *vm)
 free_pt:
 	free_pt(dev, vm->scratch_pt);
 free_scratch_page:
-	free_scratch_page(dev, vm->scratch_page);
+	cleanup_scratch_page(dev, &vm->scratch_page);
 
 	return ret;
 }
@@ -960,7 +947,7 @@ static void gen8_free_scratch(struct i915_address_space *vm)
 		free_pdp(dev, vm->scratch_pdp);
 	free_pd(dev, vm->scratch_pd);
 	free_pt(dev, vm->scratch_pt);
-	free_scratch_page(dev, vm->scratch_page);
+	cleanup_scratch_page(dev, &vm->scratch_page);
 }
 
 static void gen8_ppgtt_cleanup_3lvl(struct drm_device *dev,
@@ -1457,7 +1444,7 @@ static void gen8_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
 	struct i915_address_space *vm = &ppgtt->base;
 	uint64_t start = ppgtt->base.start;
 	uint64_t length = ppgtt->base.total;
-	gen8_pte_t scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page),
+	gen8_pte_t scratch_pte = gen8_pte_encode(vm->scratch_page.daddr,
 						 I915_CACHE_LLC, true);
 
 	if (!USES_FULL_48BIT_PPGTT(vm->dev)) {
@@ -1574,7 +1561,7 @@ static void gen6_dump_ppgtt(struct i915_hw_ppgtt *ppgtt, struct seq_file *m)
 	uint32_t  pte, pde;
 	uint32_t start = ppgtt->base.start, length = ppgtt->base.total;
 
-	scratch_pte = vm->pte_encode(px_dma(vm->scratch_page),
+	scratch_pte = vm->pte_encode(vm->scratch_page.daddr,
 				     I915_CACHE_LLC, true, 0);
 
 	gen6_for_each_pde(unused, &ppgtt->pd, start, length, pde) {
@@ -1799,7 +1786,7 @@ static void gen6_ppgtt_clear_range(struct i915_address_space *vm,
 	unsigned first_pte = first_entry % GEN6_PTES;
 	unsigned last_pte, i;
 
-	scratch_pte = vm->pte_encode(px_dma(vm->scratch_page),
+	scratch_pte = vm->pte_encode(vm->scratch_page.daddr,
 				     I915_CACHE_LLC, true, 0);
 
 	while (num_entries) {
@@ -1945,14 +1932,15 @@ static int gen6_alloc_va_range(struct i915_address_space *vm,
 static int gen6_init_scratch(struct i915_address_space *vm)
 {
 	struct drm_device *dev = vm->dev;
+	int ret;
 
-	vm->scratch_page = alloc_scratch_page(dev);
-	if (IS_ERR(vm->scratch_page))
-		return PTR_ERR(vm->scratch_page);
+	ret = setup_scratch_page(dev, &vm->scratch_page);
+	if (ret)
+		return ret;
 
 	vm->scratch_pt = alloc_pt(dev);
 	if (IS_ERR(vm->scratch_pt)) {
-		free_scratch_page(dev, vm->scratch_page);
+		cleanup_scratch_page(dev, &vm->scratch_page);
 		return PTR_ERR(vm->scratch_pt);
 	}
 
@@ -1966,7 +1954,7 @@ static void gen6_free_scratch(struct i915_address_space *vm)
 	struct drm_device *dev = vm->dev;
 
 	free_pt(dev, vm->scratch_pt);
-	free_scratch_page(dev, vm->scratch_page);
+	cleanup_scratch_page(dev, &vm->scratch_page);
 }
 
 static void gen6_ppgtt_cleanup(struct i915_address_space *vm)
@@ -2507,7 +2495,7 @@ static void gen8_ggtt_clear_range(struct i915_address_space *vm,
 		 first_entry, num_entries, max_entries))
 		num_entries = max_entries;
 
-	scratch_pte = gen8_pte_encode(px_dma(vm->scratch_page),
+	scratch_pte = gen8_pte_encode(vm->scratch_page.daddr,
 				      I915_CACHE_LLC,
 				      use_scratch);
 	for (i = 0; i < num_entries; i++)
@@ -2539,7 +2527,7 @@ static void gen6_ggtt_clear_range(struct i915_address_space *vm,
 		 first_entry, num_entries, max_entries))
 		num_entries = max_entries;
 
-	scratch_pte = vm->pte_encode(px_dma(vm->scratch_page),
+	scratch_pte = vm->pte_encode(vm->scratch_page.daddr,
 				     I915_CACHE_LLC, use_scratch, 0);
 
 	for (i = 0; i < num_entries; i++)
@@ -2892,8 +2880,8 @@ static size_t gen9_get_stolen_size(u16 gen9_gmch_ctl)
 static int ggtt_probe_common(struct i915_ggtt *ggtt, u64 size)
 {
 	struct pci_dev *pdev = ggtt->base.dev->pdev;
-	struct i915_page_scratch *scratch_page;
 	phys_addr_t phys_addr;
+	int ret;
 
 	/* For Modern GENs the PTEs and register space are split in the BAR */
 	phys_addr = pci_resource_start(pdev, 0) + pci_resource_len(pdev, 0) / 2;
@@ -2914,16 +2902,14 @@ static int ggtt_probe_common(struct i915_ggtt *ggtt, u64 size)
 		return -ENOMEM;
 	}
 
-	scratch_page = alloc_scratch_page(ggtt->base.dev);
-	if (IS_ERR(scratch_page)) {
+	ret = setup_scratch_page(ggtt->base.dev, &ggtt->base.scratch_page);
+	if (ret) {
 		DRM_ERROR("Scratch setup failed\n");
 		/* iounmap will also get called at remove, but meh */
 		iounmap(ggtt->gsm);
-		return PTR_ERR(scratch_page);
+		return ret;
 	}
 
-	ggtt->base.scratch_page = scratch_page;
-
 	return 0;
 }
 
@@ -3005,7 +2991,7 @@ static void gen6_gmch_remove(struct i915_address_space *vm)
 	struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm);
 
 	iounmap(ggtt->gsm);
-	free_scratch_page(vm->dev, vm->scratch_page);
+	cleanup_scratch_page(vm->dev, &vm->scratch_page);
 }
 
 static int gen8_gmch_probe(struct i915_ggtt *ggtt)

drivers/gpu/drm/i915/i915_gem_gtt.h

@@ -312,10 +312,6 @@ struct i915_page_dma {
 #define px_page(px) (px_base(px)->page)
 #define px_dma(px) (px_base(px)->daddr)
 
-struct i915_page_scratch {
-	struct i915_page_dma base;
-};
-
 struct i915_page_table {
 	struct i915_page_dma base;
 
@@ -361,7 +357,7 @@ struct i915_address_space {
 
 	bool closed;
 
-	struct i915_page_scratch *scratch_page;
+	struct i915_page_dma scratch_page;
 	struct i915_page_table *scratch_pt;
 	struct i915_page_directory *scratch_pd;
 	struct i915_page_directory_pointer *scratch_pdp; /* GEN8+ & 48b PPGTT */