drm/i915: push set_pages down to the callers

Each backend is now responsible for calling __i915_gem_object_set_pages
upon successfully gathering its backing storage. This eliminates the
inconsistency between the async and sync paths, which stands out even
more when we start throwing around an sg_mask in a later patch.

Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171006145041.21673-6-matthew.auld@intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171006221833.32439-5-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -162,8 +162,7 @@ i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,
 	return 0;
 }
 
-static struct sg_table *
-i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
+static int i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
 {
 	struct address_space *mapping = obj->base.filp->f_mapping;
 	drm_dma_handle_t *phys;
@@ -171,9 +170,10 @@ i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
 	struct scatterlist *sg;
 	char *vaddr;
 	int i;
+	int err;
 
 	if (WARN_ON(i915_gem_object_needs_bit17_swizzle(obj)))
-		return ERR_PTR(-EINVAL);
+		return -EINVAL;
 
 	/* Always aligning to the object size, allows a single allocation
 	 * to handle all possible callers, and given typical object sizes,
@@ -183,7 +183,7 @@ i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
 			     roundup_pow_of_two(obj->base.size),
 			     roundup_pow_of_two(obj->base.size));
 	if (!phys)
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 
 	vaddr = phys->vaddr;
 	for (i = 0; i < obj->base.size / PAGE_SIZE; i++) {
@@ -192,7 +192,7 @@ i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
 
 		page = shmem_read_mapping_page(mapping, i);
 		if (IS_ERR(page)) {
-			st = ERR_CAST(page);
+			err = PTR_ERR(page);
 			goto err_phys;
 		}
 
@@ -209,13 +209,13 @@ i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
 
 	st = kmalloc(sizeof(*st), GFP_KERNEL);
 	if (!st) {
-		st = ERR_PTR(-ENOMEM);
+		err = -ENOMEM;
 		goto err_phys;
 	}
 
 	if (sg_alloc_table(st, 1, GFP_KERNEL)) {
 		kfree(st);
-		st = ERR_PTR(-ENOMEM);
+		err = -ENOMEM;
 		goto err_phys;
 	}
 
@@ -227,11 +227,15 @@ i915_gem_object_get_pages_phys(struct drm_i915_gem_object *obj)
 	sg_dma_len(sg) = obj->base.size;
 
 	obj->phys_handle = phys;
-	return st;
+
+	__i915_gem_object_set_pages(obj, st);
+
+	return 0;
 
 err_phys:
 	drm_pci_free(obj->base.dev, phys);
-	return st;
+
+	return err;
 }
 
 static void __start_cpu_write(struct drm_i915_gem_object *obj)
@@ -2292,8 +2296,7 @@ static bool i915_sg_trim(struct sg_table *orig_st)
 	return true;
 }
 
-static struct sg_table *
-i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
+static int i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
 {
 	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
 	const unsigned long page_count = obj->base.size / PAGE_SIZE;
@@ -2317,12 +2320,12 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
 
 	st = kmalloc(sizeof(*st), GFP_KERNEL);
 	if (st == NULL)
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 
 rebuild_st:
 	if (sg_alloc_table(st, page_count, GFP_KERNEL)) {
 		kfree(st);
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 	}
 
 	/* Get the list of pages out of our struct file.  They'll be pinned
@@ -2430,7 +2433,9 @@ rebuild_st:
 	if (i915_gem_object_needs_bit17_swizzle(obj))
 		i915_gem_object_do_bit_17_swizzle(obj, st);
 
-	return st;
+	__i915_gem_object_set_pages(obj, st);
+
+	return 0;
 
 err_sg:
 	sg_mark_end(sg);
@@ -2451,7 +2456,7 @@ err_pages:
 	if (ret == -ENOSPC)
 		ret = -ENOMEM;
 
-	return ERR_PTR(ret);
+	return ret;
 }
 
 void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
@@ -2474,19 +2479,17 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
 
 static int ____i915_gem_object_get_pages(struct drm_i915_gem_object *obj)
 {
-	struct sg_table *pages;
+	int err;
 
 	if (unlikely(obj->mm.madv != I915_MADV_WILLNEED)) {
 		DRM_DEBUG("Attempting to obtain a purgeable object\n");
 		return -EFAULT;
 	}
 
-	pages = obj->ops->get_pages(obj);
-	if (unlikely(IS_ERR(pages)))
-		return PTR_ERR(pages);
+	err = obj->ops->get_pages(obj);
+	GEM_BUG_ON(!err && IS_ERR_OR_NULL(obj->mm.pages));
 
-	__i915_gem_object_set_pages(obj, pages);
-	return 0;
+	return err;
 }
 
 /* Ensure that the associated pages are gathered from the backing storage

drivers/gpu/drm/i915/i915_gem_dmabuf.c

@@ -256,11 +256,18 @@ struct dma_buf *i915_gem_prime_export(struct drm_device *dev,
 	return drm_gem_dmabuf_export(dev, &exp_info);
 }
 
-static struct sg_table *
-i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
+static int i915_gem_object_get_pages_dmabuf(struct drm_i915_gem_object *obj)
 {
-	return dma_buf_map_attachment(obj->base.import_attach,
-				      DMA_BIDIRECTIONAL);
+	struct sg_table *pages;
+
+	pages = dma_buf_map_attachment(obj->base.import_attach,
+				       DMA_BIDIRECTIONAL);
+	if (IS_ERR(pages))
+		return PTR_ERR(pages);
+
+	__i915_gem_object_set_pages(obj, pages);
+
+	return 0;
 }
 
 static void i915_gem_object_put_pages_dmabuf(struct drm_i915_gem_object *obj,

drivers/gpu/drm/i915/i915_gem_internal.c

@@ -44,8 +44,7 @@ static void internal_free_pages(struct sg_table *st)
 	kfree(st);
 }
 
-static struct sg_table *
-i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
+static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
 {
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	struct sg_table *st;
@@ -78,12 +77,12 @@ i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
 create_st:
 	st = kmalloc(sizeof(*st), GFP_KERNEL);
 	if (!st)
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 
 	npages = obj->base.size / PAGE_SIZE;
 	if (sg_alloc_table(st, npages, GFP_KERNEL)) {
 		kfree(st);
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 	}
 
 	sg = st->sgl;
@@ -132,13 +131,17 @@ create_st:
 	 * object are only valid whilst active and pinned.
 	 */
 	obj->mm.madv = I915_MADV_DONTNEED;
-	return st;
+
+	__i915_gem_object_set_pages(obj, st);
+
+	return 0;
 
 err:
 	sg_set_page(sg, NULL, 0, 0);
 	sg_mark_end(sg);
 	internal_free_pages(st);
-	return ERR_PTR(-ENOMEM);
+
+	return -ENOMEM;
 }
 
 static void i915_gem_object_put_pages_internal(struct drm_i915_gem_object *obj,

drivers/gpu/drm/i915/i915_gem_object.h

@@ -69,7 +69,7 @@ struct drm_i915_gem_object_ops {
 	 * being released or under memory pressure (where we attempt to
 	 * reap pages for the shrinker).
 	 */
-	struct sg_table *(*get_pages)(struct drm_i915_gem_object *);
+	int (*get_pages)(struct drm_i915_gem_object *);
 	void (*put_pages)(struct drm_i915_gem_object *, struct sg_table *);
 
 	int (*pwrite)(struct drm_i915_gem_object *,

drivers/gpu/drm/i915/i915_gem_stolen.c

@@ -539,12 +539,18 @@ i915_pages_create_for_stolen(struct drm_device *dev,
 	return st;
 }
 
-static struct sg_table *
-i915_gem_object_get_pages_stolen(struct drm_i915_gem_object *obj)
+static int i915_gem_object_get_pages_stolen(struct drm_i915_gem_object *obj)
 {
-	return i915_pages_create_for_stolen(obj->base.dev,
-					    obj->stolen->start,
-					    obj->stolen->size);
+	struct sg_table *pages =
+		i915_pages_create_for_stolen(obj->base.dev,
+					     obj->stolen->start,
+					     obj->stolen->size);
+	if (IS_ERR(pages))
+		return PTR_ERR(pages);
+
+	__i915_gem_object_set_pages(obj, pages);
+
+	return 0;
 }
 
 static void i915_gem_object_put_pages_stolen(struct drm_i915_gem_object *obj,

drivers/gpu/drm/i915/i915_gem_userptr.c

@@ -434,6 +434,8 @@ alloc_table:
 		return ERR_PTR(ret);
 	}
 
+	__i915_gem_object_set_pages(obj, st);
+
 	return st;
 }
 
@@ -521,7 +523,6 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
 			pages = __i915_gem_userptr_alloc_pages(obj, pvec,
 							       npages);
 			if (!IS_ERR(pages)) {
-				__i915_gem_object_set_pages(obj, pages);
 				pinned = 0;
 				pages = NULL;
 			}
@@ -582,8 +583,7 @@ __i915_gem_userptr_get_pages_schedule(struct drm_i915_gem_object *obj)
 	return ERR_PTR(-EAGAIN);
 }
 
-static struct sg_table *
-i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
+static int i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 {
 	const int num_pages = obj->base.size >> PAGE_SHIFT;
 	struct mm_struct *mm = obj->userptr.mm->mm;
@@ -612,9 +612,9 @@ i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 	if (obj->userptr.work) {
 		/* active flag should still be held for the pending work */
 		if (IS_ERR(obj->userptr.work))
-			return ERR_CAST(obj->userptr.work);
+			return PTR_ERR(obj->userptr.work);
 		else
-			return ERR_PTR(-EAGAIN);
+			return -EAGAIN;
 	}
 
 	pvec = NULL;
@@ -650,7 +650,7 @@ i915_gem_userptr_get_pages(struct drm_i915_gem_object *obj)
 		release_pages(pvec, pinned, 0);
 	kvfree(pvec);
 
-	return pages;
+	return PTR_ERR_OR_ZERO(pages);
 }
 
 static void

drivers/gpu/drm/i915/selftests/huge_gem_object.c

@@ -37,8 +37,7 @@ static void huge_free_pages(struct drm_i915_gem_object *obj,
 	kfree(pages);
 }
 
-static struct sg_table *
-huge_get_pages(struct drm_i915_gem_object *obj)
+static int huge_get_pages(struct drm_i915_gem_object *obj)
 {
 #define GFP (GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY)
 	const unsigned long nreal = obj->scratch / PAGE_SIZE;
@@ -49,11 +48,11 @@ huge_get_pages(struct drm_i915_gem_object *obj)
 
 	pages = kmalloc(sizeof(*pages), GFP);
 	if (!pages)
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 
 	if (sg_alloc_table(pages, npages, GFP)) {
 		kfree(pages);
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 	}
 
 	sg = pages->sgl;
@@ -81,11 +80,14 @@ huge_get_pages(struct drm_i915_gem_object *obj)
 	if (i915_gem_gtt_prepare_pages(obj, pages))
 		goto err;
 
-	return pages;
+	__i915_gem_object_set_pages(obj, pages);
+
+	return 0;
 
 err:
 	huge_free_pages(obj, pages);
-	return ERR_PTR(-ENOMEM);
+
+	return -ENOMEM;
 #undef GFP
 }
 

drivers/gpu/drm/i915/selftests/i915_gem_gtt.c

@@ -39,8 +39,7 @@ static void fake_free_pages(struct drm_i915_gem_object *obj,
 	kfree(pages);
 }
 
-static struct sg_table *
-fake_get_pages(struct drm_i915_gem_object *obj)
+static int fake_get_pages(struct drm_i915_gem_object *obj)
 {
 #define GFP (GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY)
 #define PFN_BIAS 0x1000
@@ -50,12 +49,12 @@ fake_get_pages(struct drm_i915_gem_object *obj)
 
 	pages = kmalloc(sizeof(*pages), GFP);
 	if (!pages)
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 
 	rem = round_up(obj->base.size, BIT(31)) >> 31;
 	if (sg_alloc_table(pages, rem, GFP)) {
 		kfree(pages);
-		return ERR_PTR(-ENOMEM);
+		return -ENOMEM;
 	}
 
 	rem = obj->base.size;
@@ -72,7 +71,10 @@ fake_get_pages(struct drm_i915_gem_object *obj)
 	GEM_BUG_ON(rem);
 
 	obj->mm.madv = I915_MADV_DONTNEED;
-	return pages;
+
+	__i915_gem_object_set_pages(obj, pages);
+
+	return 0;
 #undef GFP
 }