[PATCH v7 0/5] Support for creating/using Stolen memory backed objects

[PATCH v7 0/5] Support for creating/using Stolen memory backed objects

[ankitprasad.r.sharma]

From: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>

This patch series adds support for creating/using Stolen memory backed
objects.

Despite being a unified memory architecture (UMA) some bits of memory
are more equal than others. In particular we have the thorny issue of
stolen memory, memory stolen from the system by the BIOS and reserved
for igfx use. Stolen memory is required for some functions of the GPU
and display engine, but in general it goes wasted. Whilst we cannot
return it back to the system, we need to find some other method for
utilising it. As we do not support direct access to the physical address
in the stolen region, it behaves like a different class of memory,
closer in kin to local GPU memory. This strongly suggests that we need a
placement model like TTM if we are to fully utilize these discrete
chunks of differing memory.

To add support for creating Stolen memory backed objects, we extend the
drm_i915_gem_create structure, by adding a new flag through which user
can specify the preference to allocate the object from stolen memory,
which if set, an attempt will be made to allocate the object from stolen
memory subject to the availability of free space in the stolen region.

This patch series adds support for clearing buffer objects via CPU/GTT.
This is particularly useful for clearing out the memory from stolen
region, but can also be used for other shmem allocated objects. Currently
being used for buffers allocated in the stolen region. Also adding support
for stealing purgable stolen pages, if we run out of stolen memory when
trying to allocate an object.

v2: Added support for read/write from/to objects not backed by
shmem using the pread/pwrite interface.
Also extended the current get_aperture ioctl to retrieve the
total and available size of the stolen region

v3: Removed the extended get_aperture ioctl patch 5 (to be submitted as
part of other patch series), addressed comments by Chris about pread/pwrite
for non shmem backed objects

v4: Rebased to the latest drm-intel-nightly

v5: Addressed comments, replaced patch 1/4 "Clearing buffers via blitter
engine" by "Clearing buffers via CPU/GTT"

v6: Rebased to the latest drm-intel-nightly, Addressed comments, updated
stolen memory purging logic by maintaining a list for purgable stolen
memory objects, enabled pread/pwrite for all non-shmem backed objects
without tiling restrictions

v7: Addressed comments, compiler optimization, new patch added for correct
error code propagation to the userspace

This can be verified using IGT tests: igt/gem_stolen, igt/gem_create

Ankitprasad Sharma (4):
  drm/i915: Clearing buffer objects via CPU/GTT
  drm/i915: Support for creating Stolen memory backed objects
  drm/i915: Support for pread/pwrite from/to non shmem backed objects
  drm/i915: Propagating correct error codes to the userspace

Chris Wilson (1):
  drm/i915: Add support for stealing purgable stolen pages

 drivers/gpu/drm/i915/i915_debugfs.c     |   4 +-
 drivers/gpu/drm/i915/i915_dma.c         |   3 +
 drivers/gpu/drm/i915/i915_drv.h         |  20 ++-
 drivers/gpu/drm/i915/i915_gem.c         | 216 ++++++++++++++++++++++++++++----
 drivers/gpu/drm/i915/i915_gem_stolen.c  | 200 +++++++++++++++++++++++------
 drivers/gpu/drm/i915/intel_display.c    |   2 +-
 drivers/gpu/drm/i915/intel_fbdev.c      |   2 +-
 drivers/gpu/drm/i915/intel_overlay.c    |   4 +-
 drivers/gpu/drm/i915/intel_pm.c         |   6 +-
 drivers/gpu/drm/i915/intel_ringbuffer.c |   4 +-
 include/uapi/drm/i915_drm.h             |  16 +++
 11 files changed, 402 insertions(+), 75 deletions(-)

-- 
1.9.1

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[PATCH 1/5] drm/i915: Clearing buffer objects via CPU/GTT

[ankitprasad.r.sharma]

From: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>

This patch adds support for clearing buffer objects via CPU/GTT. This
is particularly useful for clearing out the non shmem backed objects.
Currently intend to use this only for buffers allocated from stolen
region.

v2: Added kernel doc for i915_gem_clear_object(), corrected/removed
variable assignments (Tvrtko)

Testcase: igt/gem_stolen

Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h |  1 +
 drivers/gpu/drm/i915/i915_gem.c | 39 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e0f3f05..8db905a 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2820,6 +2820,7 @@ int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj,
 				    int *needs_clflush);
 
 int __must_check i915_gem_object_get_pages(struct drm_i915_gem_object *obj);
+int i915_gem_clear_object(struct drm_i915_gem_object *obj);
 
 static inline int __sg_page_count(struct scatterlist *sg)
 {
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 1ac57ec..94533bf 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -5139,3 +5139,42 @@ fail:
 	drm_gem_object_unreference(&obj->base);
 	return ERR_PTR(ret);
 }
+
+/**
+ * i915_gem_clear_object() - Clear buffer object via CPU/GTT
+ * @obj: Buffer object to be cleared
+ *
+ * Return: 0 - success, non-zero - failure
+ */
+int i915_gem_clear_object(struct drm_i915_gem_object *obj)
+{
+	int ret;
+	char __iomem *base;
+	size_t size = obj->base.size;
+	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
+
+	WARN_ON(!mutex_is_locked(&obj->base.dev->struct_mutex));
+	ret = i915_gem_obj_ggtt_pin(obj, 0, PIN_MAPPABLE);
+	if (ret)
+		return ret;
+
+	ret = i915_gem_object_put_fence(obj);
+	if (ret)
+		goto unpin;
+
+	/* Get the CPU virtual address of the buffer */
+	base = ioremap_wc(dev_priv->gtt.mappable_base +
+				i915_gem_obj_ggtt_offset(obj), size);
+	if (base == NULL) {
+		DRM_ERROR("Mapping of gem object to CPU failed!\n");
+		ret = -ENOSPC;
+		goto unpin;
+	}
+
+	memset_io(base, 0, size);
+
+	iounmap(base);
+unpin:
+	i915_gem_object_ggtt_unpin(obj);
+	return ret;
+}
-- 
1.9.1

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[PATCH 2/5] drm/i915: Support for creating Stolen memory backed objects

[ankitprasad.r.sharma]

From: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>

Extend the drm_i915_gem_create structure to add support for
creating Stolen memory backed objects. Added a new flag through
which user can specify the preference to allocate the object from
stolen memory, which if set, an attempt will be made to allocate
the object from stolen memory subject to the availability of
free space in the stolen region.

v2: Rebased to the latest drm-intel-nightly (Ankit)

v3: Changed versioning of GEM_CREATE param, added new comments (Tvrtko)

v4: Changed size from 32b to 64b to prevent userspace overflow (Tvrtko)
Corrected function arguments ordering (Chris)

Testcase: igt/gem_stolen

Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/i915_dma.c        |  3 +++
 drivers/gpu/drm/i915/i915_drv.h        |  2 +-
 drivers/gpu/drm/i915/i915_gem.c        | 30 +++++++++++++++++++++++++++---
 drivers/gpu/drm/i915/i915_gem_stolen.c |  4 ++--
 include/uapi/drm/i915_drm.h            | 16 ++++++++++++++++
 5 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 2193cc2..8319e07 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -170,6 +170,9 @@ static int i915_getparam(struct drm_device *dev, void *data,
 	case I915_PARAM_HAS_RESOURCE_STREAMER:
 		value = HAS_RESOURCE_STREAMER(dev);
 		break;
+	case I915_PARAM_CREATE_VERSION:
+		value = 2;
+		break;
 	default:
 		DRM_DEBUG("Unknown parameter %d\n", param->param);
 		return -EINVAL;
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 8db905a..e6ef083 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -3159,7 +3159,7 @@ void i915_gem_stolen_remove_node(struct drm_i915_private *dev_priv,
 int i915_gem_init_stolen(struct drm_device *dev);
 void i915_gem_cleanup_stolen(struct drm_device *dev);
 struct drm_i915_gem_object *
-i915_gem_object_create_stolen(struct drm_device *dev, u32 size);
+i915_gem_object_create_stolen(struct drm_device *dev, u64 size);
 struct drm_i915_gem_object *
 i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 					       u32 stolen_offset,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 94533bf..6568a7f 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -375,6 +375,7 @@ static int
 i915_gem_create(struct drm_file *file,
 		struct drm_device *dev,
 		uint64_t size,
+		uint32_t flags,
 		uint32_t *handle_p)
 {
 	struct drm_i915_gem_object *obj;
@@ -385,8 +386,31 @@ i915_gem_create(struct drm_file *file,
 	if (size == 0)
 		return -EINVAL;
 
+	if (flags & __I915_CREATE_UNKNOWN_FLAGS)
+		return -EINVAL;
+
 	/* Allocate the new object */
-	obj = i915_gem_alloc_object(dev, size);
+	if (flags & I915_CREATE_PLACEMENT_STOLEN) {
+		mutex_lock(&dev->struct_mutex);
+		obj = i915_gem_object_create_stolen(dev, size);
+		if (!obj) {
+			mutex_unlock(&dev->struct_mutex);
+			return -ENOMEM;
+		}
+
+		/* Always clear fresh buffers before handing to userspace */
+		ret = i915_gem_clear_object(obj);
+		if (ret) {
+			drm_gem_object_unreference(&obj->base);
+			mutex_unlock(&dev->struct_mutex);
+			return ret;
+		}
+
+		mutex_unlock(&dev->struct_mutex);
+	} else {
+		obj = i915_gem_alloc_object(dev, size);
+	}
+
 	if (obj == NULL)
 		return -ENOMEM;
 
@@ -409,7 +433,7 @@ i915_gem_dumb_create(struct drm_file *file,
 	args->pitch = ALIGN(args->width * DIV_ROUND_UP(args->bpp, 8), 64);
 	args->size = args->pitch * args->height;
 	return i915_gem_create(file, dev,
-			       args->size, &args->handle);
+			       args->size, 0, &args->handle);
 }
 
 /**
@@ -422,7 +446,7 @@ i915_gem_create_ioctl(struct drm_device *dev, void *data,
 	struct drm_i915_gem_create *args = data;
 
 	return i915_gem_create(file, dev,
-			       args->size, &args->handle);
+			       args->size, args->flags, &args->handle);
 }
 
 static inline int
diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index a36cb95..99f2bce 100644
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -457,7 +457,7 @@ cleanup:
 }
 
 struct drm_i915_gem_object *
-i915_gem_object_create_stolen(struct drm_device *dev, u32 size)
+i915_gem_object_create_stolen(struct drm_device *dev, u64 size)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj;
@@ -467,7 +467,7 @@ i915_gem_object_create_stolen(struct drm_device *dev, u32 size)
 	if (!drm_mm_initialized(&dev_priv->mm.stolen))
 		return NULL;
 
-	DRM_DEBUG_KMS("creating stolen object: size=%x\n", size);
+	DRM_DEBUG_KMS("creating stolen object: size=%llx\n", size);
 	if (size == 0)
 		return NULL;
 
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index dbd16a2..f71f75c 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -356,6 +356,7 @@ typedef struct drm_i915_irq_wait {
 #define I915_PARAM_EU_TOTAL		 34
 #define I915_PARAM_HAS_GPU_RESET	 35
 #define I915_PARAM_HAS_RESOURCE_STREAMER 36
+#define I915_PARAM_CREATE_VERSION	 37
 
 typedef struct drm_i915_getparam {
 	s32 param;
@@ -455,6 +456,21 @@ struct drm_i915_gem_create {
 	 */
 	__u32 handle;
 	__u32 pad;
+	/**
+	 * Requested flags (currently used for placement
+	 * (which memory domain))
+	 *
+	 * You can request that the object be created from special memory
+	 * rather than regular system pages using this parameter. Such
+	 * irregular objects may have certain restrictions (such as CPU
+	 * access to a stolen object is verboten).
+	 *
+	 * This can be used in the future for other purposes too
+	 * e.g. specifying tiling/caching/madvise
+	 */
+	__u32 flags;
+#define I915_CREATE_PLACEMENT_STOLEN 	(1<<0) /* Cannot use CPU mmaps */
+#define __I915_CREATE_UNKNOWN_FLAGS	-(I915_CREATE_PLACEMENT_STOLEN << 1)
 };
 
 struct drm_i915_gem_pread {
-- 
1.9.1

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[PATCH 3/5] drm/i915: Add support for stealing purgable stolen pages

[ankitprasad.r.sharma]

From: Chris Wilson <chris at chris-wilson.co.uk>

If we run out of stolen memory when trying to allocate an object, see if
we can reap enough purgeable objects to free up enough contiguous free
space for the allocation. This is in principle very much like evicting
objects to free up enough contiguous space in the vma when binding
a new object - and you will be forgiven for thinking that the code looks
very similar.

At the moment, we do not allow userspace to allocate objects in stolen,
so there is neither the memory pressure to trigger stolen eviction nor
any purgeable objects inside the stolen arena. However, this will change
in the near future, and so better management and defragmentation of
stolen memory will become a real issue.

v2: Remember to remove the drm_mm_node.

v3: Rebased to the latest drm-intel-nightly (Ankit)

v4: corrected if-else braces format (Tvrtko/kerneldoc)

v5: Rebased to the latest drm-intel-nightly (Ankit)
Added a seperate list to maintain purgable objects from stolen memory
region (Chris/Daniel)

v6: Compiler optimization (merging 2 single loops into one for() loop),
corrected code for object eviction, retire_requests before starting
object eviction (Chris)

Testcase: igt/gem_stolen

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c    |   4 +-
 drivers/gpu/drm/i915/i915_drv.h        |  17 +++-
 drivers/gpu/drm/i915/i915_gem.c        |  16 ++++
 drivers/gpu/drm/i915/i915_gem_stolen.c | 165 ++++++++++++++++++++++++++++-----
 drivers/gpu/drm/i915/intel_pm.c        |   4 +-
 5 files changed, 178 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 7a28de5..0db8c47 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -179,7 +179,7 @@ describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
 			seq_puts(m, ")");
 	}
 	if (obj->stolen)
-		seq_printf(m, " (stolen: %08llx)", obj->stolen->start);
+		seq_printf(m, " (stolen: %08llx)", obj->stolen->base.start);
 	if (obj->pin_display || obj->fault_mappable) {
 		char s[3], *t = s;
 		if (obj->pin_display)
@@ -258,7 +258,7 @@ static int obj_rank_by_stolen(void *priv,
 	struct drm_i915_gem_object *b =
 		container_of(B, struct drm_i915_gem_object, obj_exec_link);
 
-	return a->stolen->start - b->stolen->start;
+	return a->stolen->base.start - b->stolen->base.start;
 }
 
 static int i915_gem_stolen_list_info(struct seq_file *m, void *data)
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e6ef083..37ee32d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -841,6 +841,12 @@ struct i915_ctx_hang_stats {
 	bool banned;
 };
 
+struct i915_stolen_node {
+	struct drm_mm_node base;
+	struct list_head mm_link;
+	struct drm_i915_gem_object *obj;
+};
+
 /* This must match up with the value previously used for execbuf2.rsvd1. */
 #define DEFAULT_CONTEXT_HANDLE 0
 
@@ -1268,6 +1274,13 @@ struct i915_gem_mm {
 	 */
 	struct list_head unbound_list;
 
+	/**
+	 * List of stolen objects that have been marked as purgeable and
+	 * thus available for reaping if we need more space for a new
+	 * allocation. Ordered by time of marking purgeable.
+	 */
+	struct list_head stolen_list;
+
 	/** Usable portion of the GTT for GEM */
 	unsigned long stolen_base; /* limited to low memory (32-bit) */
 
@@ -2026,7 +2039,7 @@ struct drm_i915_gem_object {
 	struct list_head vma_list;
 
 	/** Stolen memory for this object, instead of being backed by shmem. */
-	struct drm_mm_node *stolen;
+	struct i915_stolen_node *stolen;
 	struct list_head global_list;
 
 	struct list_head ring_list[I915_NUM_RINGS];
@@ -2034,6 +2047,7 @@ struct drm_i915_gem_object {
 	struct list_head obj_exec_link;
 
 	struct list_head batch_pool_link;
+	struct list_head tmp_link;
 
 	/**
 	 * This is set if the object is on the active lists (has pending
@@ -2150,6 +2164,7 @@ struct drm_i915_gem_object {
 	};
 };
 #define to_intel_bo(x) container_of(x, struct drm_i915_gem_object, base)
+#define I915_BO_IS_ACTIVE(__obj) (__obj->active)
 
 void i915_gem_track_fb(struct drm_i915_gem_object *old,
 		       struct drm_i915_gem_object *new,
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6568a7f..85025b1 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4228,6 +4228,20 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
 	if (obj->madv == I915_MADV_DONTNEED && obj->pages == NULL)
 		i915_gem_object_truncate(obj);
 
+	if (obj->stolen) {
+		switch (obj->madv) {
+		case I915_MADV_WILLNEED:
+			list_del_init(&obj->stolen->mm_link);
+			break;
+		case I915_MADV_DONTNEED:
+			list_move(&obj->stolen->mm_link,
+				  &dev_priv->mm.stolen_list);
+			break;
+		default:
+			break;
+		}
+	}
+
 	args->retained = obj->madv != __I915_MADV_PURGED;
 
 out:
@@ -4248,6 +4262,7 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
 	INIT_LIST_HEAD(&obj->obj_exec_link);
 	INIT_LIST_HEAD(&obj->vma_list);
 	INIT_LIST_HEAD(&obj->batch_pool_link);
+	INIT_LIST_HEAD(&obj->tmp_link);
 
 	obj->ops = ops;
 
@@ -4898,6 +4913,7 @@ i915_gem_load(struct drm_device *dev)
 	INIT_LIST_HEAD(&dev_priv->context_list);
 	INIT_LIST_HEAD(&dev_priv->mm.unbound_list);
 	INIT_LIST_HEAD(&dev_priv->mm.bound_list);
+	INIT_LIST_HEAD(&dev_priv->mm.stolen_list);
 	INIT_LIST_HEAD(&dev_priv->mm.fence_list);
 	for (i = 0; i < I915_NUM_RINGS; i++)
 		init_ring_lists(&dev_priv->ring[i]);
diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index 99f2bce..d3c44cb 100644
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -414,7 +414,8 @@ i915_gem_object_release_stolen(struct drm_i915_gem_object *obj)
 	struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
 
 	if (obj->stolen) {
-		i915_gem_stolen_remove_node(dev_priv, obj->stolen);
+		list_del(&obj->stolen->mm_link);
+		i915_gem_stolen_remove_node(dev_priv, &obj->stolen->base);
 		kfree(obj->stolen);
 		obj->stolen = NULL;
 	}
@@ -427,7 +428,7 @@ static const struct drm_i915_gem_object_ops i915_gem_object_stolen_ops = {
 
 static struct drm_i915_gem_object *
 _i915_gem_object_create_stolen(struct drm_device *dev,
-			       struct drm_mm_node *stolen)
+			       struct i915_stolen_node *stolen)
 {
 	struct drm_i915_gem_object *obj;
 
@@ -435,17 +436,21 @@ _i915_gem_object_create_stolen(struct drm_device *dev,
 	if (obj == NULL)
 		return NULL;
 
-	drm_gem_private_object_init(dev, &obj->base, stolen->size);
+	drm_gem_private_object_init(dev, &obj->base, stolen->base.size);
 	i915_gem_object_init(obj, &i915_gem_object_stolen_ops);
 
 	obj->pages = i915_pages_create_for_stolen(dev,
-						  stolen->start, stolen->size);
+						  stolen->base.start,
+						  stolen->base.size);
 	if (obj->pages == NULL)
 		goto cleanup;
 
 	i915_gem_object_pin_pages(obj);
 	obj->stolen = stolen;
 
+	stolen->obj = obj;
+	INIT_LIST_HEAD(&stolen->mm_link);
+
 	obj->base.read_domains = I915_GEM_DOMAIN_CPU | I915_GEM_DOMAIN_GTT;
 	obj->cache_level = HAS_LLC(dev) ? I915_CACHE_LLC : I915_CACHE_NONE;
 
@@ -456,36 +461,150 @@ cleanup:
 	return NULL;
 }
 
-struct drm_i915_gem_object *
-i915_gem_object_create_stolen(struct drm_device *dev, u64 size)
+static bool mark_free(struct drm_i915_gem_object *obj, struct list_head *unwind)
+{
+	BUG_ON(obj->stolen == NULL);
+
+	if (obj->madv != I915_MADV_DONTNEED)
+		return false;
+
+	if (obj->pin_display)
+		return false;
+
+	list_add(&obj->tmp_link, unwind);
+	return drm_mm_scan_add_block(&obj->stolen->base);
+}
+
+static int
+stolen_evict(struct drm_i915_private *dev_priv, u64 size)
 {
-	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj;
-	struct drm_mm_node *stolen;
-	int ret;
+	struct list_head unwind, evict;
+	struct i915_stolen_node *iter;
+	int ret, active;
 
-	if (!drm_mm_initialized(&dev_priv->mm.stolen))
-		return NULL;
+	drm_mm_init_scan(&dev_priv->mm.stolen, size, 0, 0);
+	INIT_LIST_HEAD(&unwind);
+
+	/* Retire all requests before creating the evict list */
+	i915_gem_retire_requests(dev_priv->dev);
+
+	for (active = 0; active <= 1; active++) {
+		list_for_each_entry(iter, &dev_priv->mm.stolen_list, mm_link) {
+			if (I915_BO_IS_ACTIVE(iter->obj) != active)
+				continue;
+
+			if (mark_free(iter->obj, &unwind))
+				goto found;
+		}
+	}
+
+found:
+	INIT_LIST_HEAD(&evict);
+	while (!list_empty(&unwind)) {
+		obj = list_first_entry(&unwind,
+				       struct drm_i915_gem_object,
+				       tmp_link);
+		list_del(&obj->tmp_link);
+
+		if (drm_mm_scan_remove_block(&obj->stolen->base)) {
+			list_add(&obj->tmp_link, &evict);
+			drm_gem_object_reference(&obj->base);
+		}
+	}
+
+	ret = 0;
+	while (!list_empty(&evict)) {
+		obj = list_first_entry(&evict,
+				       struct drm_i915_gem_object,
+				       tmp_link);
+		list_del(&obj->tmp_link);
+
+		if (ret == 0) {
+			struct i915_vma *vma, *vma_next;
+
+			list_for_each_entry_safe(vma, vma_next,
+						 &obj->vma_list,
+						 vma_link)
+				if (i915_vma_unbind(vma))
+					break;
+
+			/* Stolen pins its pages to prevent the
+			 * normal shrinker from processing stolen
+			 * objects.
+			 */
+			i915_gem_object_unpin_pages(obj);
+
+			ret = i915_gem_object_put_pages(obj);
+			if (ret == 0) {
+				i915_gem_object_release_stolen(obj);
+				obj->madv = __I915_MADV_PURGED;
+			} else {
+				i915_gem_object_pin_pages(obj);
+			}
+		}
+
+		drm_gem_object_unreference(&obj->base);
+	}
+
+	return ret;
+}
+
+static struct i915_stolen_node *
+stolen_alloc(struct drm_i915_private *dev_priv, u64 size)
+{
+	struct i915_stolen_node *stolen;
+	int ret;
 
-	DRM_DEBUG_KMS("creating stolen object: size=%llx\n", size);
 	if (size == 0)
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
 	if (!stolen)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
-	ret = i915_gem_stolen_insert_node(dev_priv, stolen, size, 4096);
+	ret = i915_gem_stolen_insert_node(dev_priv, &stolen->base, size, 4096);
+	if (ret == 0)
+		goto out;
+
+	/* No more stolen memory available, or too fragmented.
+	 * Try evicting purgeable objects and search again.
+	 */
+	ret = stolen_evict(dev_priv, size);
+
+	if (ret == 0)
+		ret = i915_gem_stolen_insert_node(dev_priv, &stolen->base,
+						  size, 0);
+out:
 	if (ret) {
 		kfree(stolen);
-		return NULL;
+		stolen = ERR_PTR(ret);
 	}
 
+	return stolen;
+}
+
+struct drm_i915_gem_object *
+i915_gem_object_create_stolen(struct drm_device *dev, u64 size)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_i915_gem_object *obj;
+	struct i915_stolen_node *stolen;
+
+	if (!drm_mm_initialized(&dev_priv->mm.stolen))
+		return NULL;
+
+	DRM_DEBUG_KMS("creating stolen object: size=%llx\n", size);
+
+	stolen = stolen_alloc(dev_priv, size);
+	if (IS_ERR(stolen))
+		return NULL;
+
 	obj = _i915_gem_object_create_stolen(dev, stolen);
 	if (obj)
 		return obj;
 
-	i915_gem_stolen_remove_node(dev_priv, stolen);
+	i915_gem_stolen_remove_node(dev_priv, &stolen->base);
 	kfree(stolen);
 	return NULL;
 }
@@ -499,7 +618,7 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct i915_address_space *ggtt = &dev_priv->gtt.base;
 	struct drm_i915_gem_object *obj;
-	struct drm_mm_node *stolen;
+	struct i915_stolen_node *stolen;
 	struct i915_vma *vma;
 	int ret;
 
@@ -518,10 +637,10 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 	if (!stolen)
 		return NULL;
 
-	stolen->start = stolen_offset;
-	stolen->size = size;
+	stolen->base.start = stolen_offset;
+	stolen->base.size = size;
 	mutex_lock(&dev_priv->mm.stolen_lock);
-	ret = drm_mm_reserve_node(&dev_priv->mm.stolen, stolen);
+	ret = drm_mm_reserve_node(&dev_priv->mm.stolen, &stolen->base);
 	mutex_unlock(&dev_priv->mm.stolen_lock);
 	if (ret) {
 		DRM_DEBUG_KMS("failed to allocate stolen space\n");
@@ -532,7 +651,7 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 	obj = _i915_gem_object_create_stolen(dev, stolen);
 	if (obj == NULL) {
 		DRM_DEBUG_KMS("failed to allocate stolen object\n");
-		i915_gem_stolen_remove_node(dev_priv, stolen);
+		i915_gem_stolen_remove_node(dev_priv, &stolen->base);
 		kfree(stolen);
 		return NULL;
 	}
@@ -573,7 +692,7 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 err_vma:
 	i915_gem_vma_destroy(vma);
 err_out:
-	i915_gem_stolen_remove_node(dev_priv, stolen);
+	i915_gem_stolen_remove_node(dev_priv, &stolen->base);
 	kfree(stolen);
 	drm_gem_object_unreference(&obj->base);
 	return NULL;
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index fff0c22..51f2f91 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5235,7 +5235,7 @@ static void valleyview_check_pctx(struct drm_i915_private *dev_priv)
 	unsigned long pctx_addr = I915_READ(VLV_PCBR) & ~4095;
 
 	WARN_ON(pctx_addr != dev_priv->mm.stolen_base +
-			     dev_priv->vlv_pctx->stolen->start);
+			     dev_priv->vlv_pctx->stolen->base.start);
 }
 
 
@@ -5309,7 +5309,7 @@ static void valleyview_setup_pctx(struct drm_device *dev)
 		return;
 	}
 
-	pctx_paddr = dev_priv->mm.stolen_base + pctx->stolen->start;
+	pctx_paddr = dev_priv->mm.stolen_base + pctx->stolen->base.start;
 	I915_WRITE(VLV_PCBR, pctx_paddr);
 
 out:
-- 
1.9.1

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[PATCH 4/5] drm/i915: Support for pread/pwrite from/to non shmem backed objects

[ankitprasad.r.sharma]

From: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>

This patch adds support for extending the pread/pwrite functionality
for objects not backed by shmem. The access will be made through
gtt interface.
This will cover prime objects as well as stolen memory backed objects
but for userptr objects it is still forbidden.

v2: Drop locks around slow_user_access, prefault the pages before
access (Chris)

v3: Rebased to the latest drm-intel-nightly (Ankit)

v4: Moved page base & offset calculations outside the copy loop,
corrected data types for size and offset variables, corrected if-else
braces format (Tvrtko/kerneldocs)

v5: Enabled pread/pwrite for all non-shmem backed objects including
without tiling restrictions (Ankit)

v6: Using pwrite_fast for non-shmem backed objects as well (Chris)

Testcase: igt/gem_stolen

Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 131 +++++++++++++++++++++++++++++++++-------
 1 file changed, 110 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 85025b1..b4c64d6 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -614,6 +614,99 @@ shmem_pread_slow(struct page *page, int shmem_page_offset, int page_length,
 	return ret ? - EFAULT : 0;
 }
 
+static inline uint64_t
+slow_user_access(struct io_mapping *mapping,
+		 uint64_t page_base, int page_offset,
+		 char __user *user_data,
+		 int length, bool pwrite)
+{
+	void __iomem *vaddr_inatomic;
+	void *vaddr;
+	uint64_t unwritten;
+
+	vaddr_inatomic = io_mapping_map_wc(mapping, page_base);
+	/* We can use the cpu mem copy function because this is X86. */
+	vaddr = (void __force *)vaddr_inatomic + page_offset;
+	if (pwrite)
+		unwritten = __copy_from_user(vaddr, user_data, length);
+	else
+		unwritten = __copy_to_user(user_data, vaddr, length);
+
+	io_mapping_unmap(vaddr_inatomic);
+	return unwritten;
+}
+
+static int
+i915_gem_gtt_pread(struct drm_device *dev,
+		   struct drm_i915_gem_object *obj, uint64_t size,
+		   uint64_t data_offset, uint64_t data_ptr)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	char __user *user_data;
+	uint64_t remain;
+	uint64_t offset, page_base;
+	int page_offset, page_length, ret = 0;
+
+	ret = i915_gem_obj_ggtt_pin(obj, 0, PIN_MAPPABLE);
+	if (ret)
+		goto out;
+
+	ret = i915_gem_object_set_to_gtt_domain(obj, false);
+	if (ret)
+		goto out_unpin;
+
+	ret = i915_gem_object_put_fence(obj);
+	if (ret)
+		goto out_unpin;
+
+	user_data = to_user_ptr(data_ptr);
+	remain = size;
+	offset = i915_gem_obj_ggtt_offset(obj) + data_offset;
+
+	mutex_unlock(&dev->struct_mutex);
+	if (likely(!i915.prefault_disable))
+		ret = fault_in_multipages_writeable(user_data, remain);
+
+	/*
+	 * page_offset = offset within page
+	 * page_base = page offset within aperture
+	 */
+	page_offset = offset_in_page(offset);
+	page_base = offset & PAGE_MASK;
+
+	while (remain > 0) {
+		/* page_length = bytes to copy for this page */
+		page_length = remain;
+		if ((page_offset + remain) > PAGE_SIZE)
+			page_length = PAGE_SIZE - page_offset;
+
+		/* This is a slow read/write as it tries to read from
+		 * and write to user memory which may result into page
+		 * faults
+		 */
+		ret = slow_user_access(dev_priv->gtt.mappable, page_base,
+				       page_offset, user_data,
+				       page_length, false);
+
+		if (ret) {
+			ret = -EFAULT;
+			break;
+		}
+
+		remain -= page_length;
+		user_data += page_length;
+		page_base += page_length;
+		page_offset = 0;
+	}
+
+	mutex_lock(&dev->struct_mutex);
+
+out_unpin:
+	i915_gem_object_ggtt_unpin(obj);
+out:
+	return ret;
+}
+
 static int
 i915_gem_shmem_pread(struct drm_device *dev,
 		     struct drm_i915_gem_object *obj,
@@ -737,17 +830,14 @@ i915_gem_pread_ioctl(struct drm_device *dev, void *data,
 		goto out;
 	}
 
-	/* prime objects have no backing filp to GEM pread/pwrite
-	 * pages from.
-	 */
-	if (!obj->base.filp) {
-		ret = -EINVAL;
-		goto out;
-	}
-
 	trace_i915_gem_object_pread(obj, args->offset, args->size);
 
-	ret = i915_gem_shmem_pread(dev, obj, args, file);
+	/* pread for non shmem backed objects */
+	if (!obj->base.filp && obj->tiling_mode == I915_TILING_NONE)
+		ret = i915_gem_gtt_pread(dev, obj, args->size,
+					 args->offset, args->data_ptr);
+	else
+		ret = i915_gem_shmem_pread(dev, obj, args, file);
 
 out:
 	drm_gem_object_unreference(&obj->base);
@@ -831,10 +921,16 @@ i915_gem_gtt_pwrite_fast(struct drm_device *dev,
 		 * source page isn't available.  Return the error and we'll
 		 * retry in the slow path.
 		 */
-		if (fast_user_write(dev_priv->gtt.mappable, page_base,
+		if (obj->base.filp &&
+		    fast_user_write(dev_priv->gtt.mappable, page_base,
 				    page_offset, user_data, page_length)) {
 			ret = -EFAULT;
 			goto out_flush;
+		} else if (slow_user_access(dev_priv->gtt.mappable,
+					    page_base, page_offset,
+					    user_data, page_length, true)) {
+			ret = -EFAULT;
+			goto out_flush;
 		}
 
 		remain -= page_length;
@@ -1090,14 +1186,6 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
 		goto out;
 	}
 
-	/* prime objects have no backing filp to GEM pread/pwrite
-	 * pages from.
-	 */
-	if (!obj->base.filp) {
-		ret = -EINVAL;
-		goto out;
-	}
-
 	trace_i915_gem_object_pwrite(obj, args->offset, args->size);
 
 	ret = -EFAULT;
@@ -1108,8 +1196,9 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
 	 * perspective, requiring manual detiling by the client.
 	 */
 	if (obj->tiling_mode == I915_TILING_NONE &&
-	    obj->base.write_domain != I915_GEM_DOMAIN_CPU &&
-	    cpu_write_needs_clflush(obj)) {
+	    (!obj->base.filp ||
+	    (obj->base.write_domain != I915_GEM_DOMAIN_CPU &&
+	    cpu_write_needs_clflush(obj)))) {
 		ret = i915_gem_gtt_pwrite_fast(dev, obj, args, file);
 		/* Note that the gtt paths might fail with non-page-backed user
 		 * pointers (e.g. gtt mappings when moving data between
@@ -1119,7 +1208,7 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
 	if (ret == -EFAULT || ret == -ENOSPC) {
 		if (obj->phys_handle)
 			ret = i915_gem_phys_pwrite(obj, args, file);
-		else
+		else if (obj->base.filp)
 			ret = i915_gem_shmem_pwrite(dev, obj, args, file);
 	}
 
-- 
1.9.1

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[PATCH 5/5] drm/i915: Propagating correct error codes to the userspace

[ankitprasad.r.sharma]

From: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>

Propagating correct error codes to userspace by using ERR_PTR and
PTR_ERR macros for stolen memory based object allocation. We generally
return -ENOMEM to the user whenever there is a failure in object
allocation. This patch helps user to identify the correct reason for the
failure and not just -ENOMEM each time.

Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c         |  4 ++--
 drivers/gpu/drm/i915/i915_gem_stolen.c  | 39 +++++++++++++++++++--------------
 drivers/gpu/drm/i915/intel_display.c    |  2 +-
 drivers/gpu/drm/i915/intel_fbdev.c      |  2 +-
 drivers/gpu/drm/i915/intel_overlay.c    |  4 ++--
 drivers/gpu/drm/i915/intel_pm.c         |  2 +-
 drivers/gpu/drm/i915/intel_ringbuffer.c |  4 ++--
 7 files changed, 31 insertions(+), 26 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index b4c64d6..586610e 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -393,9 +393,9 @@ i915_gem_create(struct drm_file *file,
 	if (flags & I915_CREATE_PLACEMENT_STOLEN) {
 		mutex_lock(&dev->struct_mutex);
 		obj = i915_gem_object_create_stolen(dev, size);
-		if (!obj) {
+		if (IS_ERR(obj)) {
 			mutex_unlock(&dev->struct_mutex);
-			return -ENOMEM;
+			return PTR_ERR(obj);
 		}
 
 		/* Always clear fresh buffers before handing to userspace */
diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index d3c44cb..84ca15a 100644
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -366,6 +366,7 @@ i915_pages_create_for_stolen(struct drm_device *dev,
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct sg_table *st;
 	struct scatterlist *sg;
+	int ret;
 
 	DRM_DEBUG_DRIVER("offset=0x%x, size=%d\n", offset, size);
 	BUG_ON(offset > dev_priv->gtt.stolen_size - size);
@@ -377,11 +378,12 @@ i915_pages_create_for_stolen(struct drm_device *dev,
 
 	st = kmalloc(sizeof(*st), GFP_KERNEL);
 	if (st == NULL)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
-	if (sg_alloc_table(st, 1, GFP_KERNEL)) {
+	ret = sg_alloc_table(st, 1, GFP_KERNEL);
+	if (ret) {
 		kfree(st);
-		return NULL;
+		return ERR_PTR(ret);
 	}
 
 	sg = st->sgl;
@@ -431,10 +433,11 @@ _i915_gem_object_create_stolen(struct drm_device *dev,
 			       struct i915_stolen_node *stolen)
 {
 	struct drm_i915_gem_object *obj;
+	int ret;
 
 	obj = i915_gem_object_alloc(dev);
 	if (obj == NULL)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	drm_gem_private_object_init(dev, &obj->base, stolen->base.size);
 	i915_gem_object_init(obj, &i915_gem_object_stolen_ops);
@@ -442,8 +445,10 @@ _i915_gem_object_create_stolen(struct drm_device *dev,
 	obj->pages = i915_pages_create_for_stolen(dev,
 						  stolen->base.start,
 						  stolen->base.size);
-	if (obj->pages == NULL)
+	if (IS_ERR(obj->pages)) {
+		ret = PTR_ERR(obj->pages);
 		goto cleanup;
+	}
 
 	i915_gem_object_pin_pages(obj);
 	obj->stolen = stolen;
@@ -458,7 +463,7 @@ _i915_gem_object_create_stolen(struct drm_device *dev,
 
 cleanup:
 	i915_gem_object_free(obj);
-	return NULL;
+	return ERR_PTR(ret);
 }
 
 static bool mark_free(struct drm_i915_gem_object *obj, struct list_head *unwind)
@@ -592,21 +597,21 @@ i915_gem_object_create_stolen(struct drm_device *dev, u64 size)
 	struct i915_stolen_node *stolen;
 
 	if (!drm_mm_initialized(&dev_priv->mm.stolen))
-		return NULL;
+		return ERR_PTR(-ENODEV);
 
 	DRM_DEBUG_KMS("creating stolen object: size=%llx\n", size);
 
 	stolen = stolen_alloc(dev_priv, size);
 	if (IS_ERR(stolen))
-		return NULL;
+		return (void *) stolen;
 
 	obj = _i915_gem_object_create_stolen(dev, stolen);
-	if (obj)
+	if (!IS_ERR(obj))
 		return obj;
 
 	i915_gem_stolen_remove_node(dev_priv, &stolen->base);
 	kfree(stolen);
-	return NULL;
+	return obj;
 }
 
 struct drm_i915_gem_object *
@@ -623,7 +628,7 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 	int ret;
 
 	if (!drm_mm_initialized(&dev_priv->mm.stolen))
-		return NULL;
+		return ERR_PTR(-ENODEV);
 
 	DRM_DEBUG_KMS("creating preallocated stolen object: stolen_offset=%x, gtt_offset=%x, size=%x\n",
 			stolen_offset, gtt_offset, size);
@@ -631,11 +636,11 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 	/* KISS and expect everything to be page-aligned */
 	if (WARN_ON(size == 0) || WARN_ON(size & 4095) ||
 	    WARN_ON(stolen_offset & 4095))
-		return NULL;
+		return ERR_PTR(-EINVAL);
 
 	stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
 	if (!stolen)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
 	stolen->base.start = stolen_offset;
 	stolen->base.size = size;
@@ -645,15 +650,15 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 	if (ret) {
 		DRM_DEBUG_KMS("failed to allocate stolen space\n");
 		kfree(stolen);
-		return NULL;
+		return ERR_PTR(ret);
 	}
 
 	obj = _i915_gem_object_create_stolen(dev, stolen);
-	if (obj == NULL) {
+	if (IS_ERR(obj)) {
 		DRM_DEBUG_KMS("failed to allocate stolen object\n");
 		i915_gem_stolen_remove_node(dev_priv, &stolen->base);
 		kfree(stolen);
-		return NULL;
+		return obj;
 	}
 
 	/* Some objects just need physical mem from stolen space */
@@ -695,5 +700,5 @@ err_out:
 	i915_gem_stolen_remove_node(dev_priv, &stolen->base);
 	kfree(stolen);
 	drm_gem_object_unreference(&obj->base);
-	return NULL;
+	return ERR_PTR(ret);
 }
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index f604ce1..9719f86 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2538,7 +2538,7 @@ intel_alloc_initial_plane_obj(struct intel_crtc *crtc,
 							     base_aligned,
 							     base_aligned,
 							     size_aligned);
-	if (!obj)
+	if (IS_ERR(obj))
 		return false;
 
 	obj->tiling_mode = plane_config->tiling;
diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index 96476d7..6f5be31 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -140,7 +140,7 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
 	size = mode_cmd.pitches[0] * mode_cmd.height;
 	size = PAGE_ALIGN(size);
 	obj = i915_gem_object_create_stolen(dev, size);
-	if (obj == NULL)
+	if (IS_ERR(obj))
 		obj = i915_gem_alloc_object(dev, size);
 	if (!obj) {
 		DRM_ERROR("failed to allocate framebuffer\n");
diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
index 4445426..d36a650 100644
--- a/drivers/gpu/drm/i915/intel_overlay.c
+++ b/drivers/gpu/drm/i915/intel_overlay.c
@@ -1389,10 +1389,10 @@ void intel_setup_overlay(struct drm_device *dev)
 
 	overlay->dev = dev;
 
-	reg_bo = NULL;
+	reg_bo = ERR_PTR(-ENOMEM);
 	if (!OVERLAY_NEEDS_PHYSICAL(dev))
 		reg_bo = i915_gem_object_create_stolen(dev, PAGE_SIZE);
-	if (reg_bo == NULL)
+	if (IS_ERR(reg_bo))
 		reg_bo = i915_gem_alloc_object(dev, PAGE_SIZE);
 	if (reg_bo == NULL)
 		goto out_free;
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 51f2f91..ba1657f 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5304,7 +5304,7 @@ static void valleyview_setup_pctx(struct drm_device *dev)
 	 * memory, or any other relevant ranges.
 	 */
 	pctx = i915_gem_object_create_stolen(dev, pctx_size);
-	if (!pctx) {
+	if (IS_ERR(pctx)) {
 		DRM_DEBUG("not enough stolen space for PCTX, disabling\n");
 		return;
 	}
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 6e6b8db..74c0b7d 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -2007,10 +2007,10 @@ int intel_alloc_ringbuffer_obj(struct drm_device *dev,
 {
 	struct drm_i915_gem_object *obj;
 
-	obj = NULL;
+	obj = ERR_PTR(-ENOMEM);
 	if (!HAS_LLC(dev))
 		obj = i915_gem_object_create_stolen(dev, ringbuf->size);
-	if (obj == NULL)
+	if (IS_ERR(obj))
 		obj = i915_gem_alloc_object(dev, ringbuf->size);
 	if (obj == NULL)
 		return -ENOMEM;
-- 
1.9.1

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Re: [PATCH 5/5] drm/i915: Propagating correct error codes to the userspace

[Chris Wilson]

On Wed, Sep 23, 2015 at 04:21:23PM +0530, ankitprasad.r.sharma@intel.com wrote:
> From: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
> 
> Propagating correct error codes to userspace by using ERR_PTR and
> PTR_ERR macros for stolen memory based object allocation. We generally
> return -ENOMEM to the user whenever there is a failure in object
> allocation. This patch helps user to identify the correct reason for the
> failure and not just -ENOMEM each time.

This should be done before patch 3, so that the error progation is in
place before adding the possible EINTR.

Also note that the current i915_gem_object_alloc() itself can return
more than just ENOMEM and is worth expanding the possible error returns
as well.

Otherwise, lgtm.
-Chris

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Re: [PATCH 3/5] drm/i915: Add support for stealing purgable stolen pages

[Chris Wilson]

On Wed, Sep 23, 2015 at 04:21:21PM +0530, ankitprasad.r.sharma@intel.com wrote:
> From: Chris Wilson <chris at chris-wilson.co.uk>
> 
> If we run out of stolen memory when trying to allocate an object, see if
> we can reap enough purgeable objects to free up enough contiguous free
> space for the allocation. This is in principle very much like evicting
> objects to free up enough contiguous space in the vma when binding
> a new object - and you will be forgiven for thinking that the code looks
> very similar.
> 
> At the moment, we do not allow userspace to allocate objects in stolen,
> so there is neither the memory pressure to trigger stolen eviction nor
> any purgeable objects inside the stolen arena. However, this will change
> in the near future, and so better management and defragmentation of
> stolen memory will become a real issue.
> 
> v2: Remember to remove the drm_mm_node.
> 
> v3: Rebased to the latest drm-intel-nightly (Ankit)
> 
> v4: corrected if-else braces format (Tvrtko/kerneldoc)
> 
> v5: Rebased to the latest drm-intel-nightly (Ankit)
> Added a seperate list to maintain purgable objects from stolen memory
> region (Chris/Daniel)
> 
> v6: Compiler optimization (merging 2 single loops into one for() loop),
> corrected code for object eviction, retire_requests before starting
> object eviction (Chris)
> 
> Testcase: igt/gem_stolen
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>

I could not find anything to complain about.
-Chris

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Re: [PATCH 4/5] drm/i915: Support for pread/pwrite from/to non shmem backed objects

[Chris Wilson]

On Wed, Sep 23, 2015 at 04:21:22PM +0530, ankitprasad.r.sharma@intel.com wrote:
> From: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
> 
> This patch adds support for extending the pread/pwrite functionality
> for objects not backed by shmem. The access will be made through
> gtt interface.
> This will cover prime objects as well as stolen memory backed objects
> but for userptr objects it is still forbidden.
> 
> v2: Drop locks around slow_user_access, prefault the pages before
> access (Chris)
> 
> v3: Rebased to the latest drm-intel-nightly (Ankit)
> 
> v4: Moved page base & offset calculations outside the copy loop,
> corrected data types for size and offset variables, corrected if-else
> braces format (Tvrtko/kerneldocs)
> 
> v5: Enabled pread/pwrite for all non-shmem backed objects including
> without tiling restrictions (Ankit)
> 
> v6: Using pwrite_fast for non-shmem backed objects as well (Chris)
> 
> Testcase: igt/gem_stolen
> 
> Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem.c | 131 +++++++++++++++++++++++++++++++++-------
>  1 file changed, 110 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 85025b1..b4c64d6 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -614,6 +614,99 @@ shmem_pread_slow(struct page *page, int shmem_page_offset, int page_length,
>  	return ret ? - EFAULT : 0;
>  }
>  
> +static inline uint64_t
> +slow_user_access(struct io_mapping *mapping,
> +		 uint64_t page_base, int page_offset,
> +		 char __user *user_data,
> +		 int length, bool pwrite)
> +{
> +	void __iomem *vaddr_inatomic;
> +	void *vaddr;
> +	uint64_t unwritten;
> +
> +	vaddr_inatomic = io_mapping_map_wc(mapping, page_base);
> +	/* We can use the cpu mem copy function because this is X86. */
> +	vaddr = (void __force *)vaddr_inatomic + page_offset;
> +	if (pwrite)
> +		unwritten = __copy_from_user(vaddr, user_data, length);
> +	else
> +		unwritten = __copy_to_user(user_data, vaddr, length);
> +
> +	io_mapping_unmap(vaddr_inatomic);
> +	return unwritten;
> +}
> +

> @@ -831,10 +921,16 @@ i915_gem_gtt_pwrite_fast(struct drm_device *dev,
>  		 * source page isn't available.  Return the error and we'll
>  		 * retry in the slow path.
>  		 */
> -		if (fast_user_write(dev_priv->gtt.mappable, page_base,
> +		if (obj->base.filp &&
> +		    fast_user_write(dev_priv->gtt.mappable, page_base,
>  				    page_offset, user_data, page_length)) {
>  			ret = -EFAULT;
>  			goto out_flush;
> +		} else if (slow_user_access(dev_priv->gtt.mappable,
> +					    page_base, page_offset,
> +					    user_data, page_length, true)) {
> +			ret = -EFAULT;
> +			goto out_flush;
>  		}

You cannot use slow_user_access() here as it may generate a pagefault and
trigger lock inversion as we are holding struct_mutex.

Just use fast_user_write(), it works correctly with !obj->base.filp.
-Chris

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[PATCH] drm/i915: Propagate error from drm_gem_object_init()

[Chris Wilson]

Propagate the real error from drm_gem_object_init(). Note this also
fixes some confusion in the error return from i915_gem_alloc_object...

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c         | 12 +++++++-----
 drivers/gpu/drm/i915/i915_gem_context.c |  4 ++--
 drivers/gpu/drm/i915/intel_display.c    |  4 ++--
 drivers/gpu/drm/i915/intel_fbdev.c      |  2 +-
 drivers/gpu/drm/i915/intel_overlay.c    |  2 +-
 5 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 1455bb0ab668..6eabab5c96c4 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -379,8 +379,8 @@ i915_gem_create(struct drm_file *file,
 
 	/* Allocate the new object */
 	obj = i915_gem_alloc_object(dev, size);
-	if (obj == NULL)
-		return -ENOMEM;
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
 
 	ret = drm_gem_handle_create(file, &obj->base, &handle);
 	/* drop reference from allocate - handle holds it now */
@@ -4303,14 +4303,16 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
 	struct drm_i915_gem_object *obj;
 	struct address_space *mapping;
 	gfp_t mask;
+	int ret;
 
 	obj = i915_gem_object_alloc(dev);
 	if (obj == NULL)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
-	if (drm_gem_object_init(dev, &obj->base, size) != 0) {
+	ret = drm_gem_object_init(dev, &obj->base, size);
+	if (ret) {
 		i915_gem_object_free(obj);
-		return NULL;
+		return ERR_PTR(ret);
 	}
 
 	mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index b01137a445ff..e3aae52752c5 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -235,8 +235,8 @@ i915_gem_alloc_context_obj(struct drm_device *dev, size_t size)
 	int ret;
 
 	obj = i915_gem_alloc_object(dev, size);
-	if (obj == NULL)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(obj))
+		return obj;
 
 	/*
 	 * Try to make the context utilize L3 as well as LLC.
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3ad3c10a8a03..0a8e83eb91a6 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -10121,8 +10121,8 @@ intel_framebuffer_create_for_mode(struct drm_device *dev,
 
 	obj = i915_gem_alloc_object(dev,
 				    intel_framebuffer_size_for_mode(mode, bpp));
-	if (obj == NULL)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(obj))
+		return ERR_CAST(obj);
 
 	mode_cmd.width = mode->hdisplay;
 	mode_cmd.height = mode->vdisplay;
diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index d3e2201e0734..e3892f71467d 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -143,7 +143,7 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
 	obj = i915_gem_object_create_stolen(dev, size);
 	if (obj == NULL)
 		obj = i915_gem_alloc_object(dev, size);
-	if (!obj) {
+	if (IS_ERR_OR_NULL(obj)) {
 		DRM_ERROR("failed to allocate framebuffer\n");
 		ret = -ENOMEM;
 		goto out;
diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
index 3b7ea47f963b..b443a0bd889a 100644
--- a/drivers/gpu/drm/i915/intel_overlay.c
+++ b/drivers/gpu/drm/i915/intel_overlay.c
@@ -1397,7 +1397,7 @@ void intel_setup_overlay(struct drm_device *dev)
 		reg_bo = i915_gem_object_create_stolen(dev, PAGE_SIZE);
 	if (reg_bo == NULL)
 		reg_bo = i915_gem_alloc_object(dev, PAGE_SIZE);
-	if (reg_bo == NULL)
+	if (IS_ERR_OR_NULL(reg_bo))
 		goto out_free;
 	overlay->reg_bo = reg_bo;
 
-- 
2.5.3

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Re: [PATCH v7 0/5] Support for creating/using Stolen memory backed objects

[Daniel Vetter]

On Wed, Sep 23, 2015 at 04:21:18PM +0530, ankitprasad.r.sharma@intel.com wrote:
> From: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
> 
> This patch series adds support for creating/using Stolen memory backed
> objects.
> 
> Despite being a unified memory architecture (UMA) some bits of memory
> are more equal than others. In particular we have the thorny issue of
> stolen memory, memory stolen from the system by the BIOS and reserved
> for igfx use. Stolen memory is required for some functions of the GPU
> and display engine, but in general it goes wasted. Whilst we cannot
> return it back to the system, we need to find some other method for
> utilising it. As we do not support direct access to the physical address
> in the stolen region, it behaves like a different class of memory,
> closer in kin to local GPU memory. This strongly suggests that we need a
> placement model like TTM if we are to fully utilize these discrete
> chunks of differing memory.
> 
> To add support for creating Stolen memory backed objects, we extend the
> drm_i915_gem_create structure, by adding a new flag through which user
> can specify the preference to allocate the object from stolen memory,
> which if set, an attempt will be made to allocate the object from stolen
> memory subject to the availability of free space in the stolen region.
> 
> This patch series adds support for clearing buffer objects via CPU/GTT.
> This is particularly useful for clearing out the memory from stolen
> region, but can also be used for other shmem allocated objects. Currently
> being used for buffers allocated in the stolen region. Also adding support
> for stealing purgable stolen pages, if we run out of stolen memory when
> trying to allocate an object.
> 
> v2: Added support for read/write from/to objects not backed by
> shmem using the pread/pwrite interface.
> Also extended the current get_aperture ioctl to retrieve the
> total and available size of the stolen region
> 
> v3: Removed the extended get_aperture ioctl patch 5 (to be submitted as
> part of other patch series), addressed comments by Chris about pread/pwrite
> for non shmem backed objects
> 
> v4: Rebased to the latest drm-intel-nightly
> 
> v5: Addressed comments, replaced patch 1/4 "Clearing buffers via blitter
> engine" by "Clearing buffers via CPU/GTT"
> 
> v6: Rebased to the latest drm-intel-nightly, Addressed comments, updated
> stolen memory purging logic by maintaining a list for purgable stolen
> memory objects, enabled pread/pwrite for all non-shmem backed objects
> without tiling restrictions
> 
> v7: Addressed comments, compiler optimization, new patch added for correct
> error code propagation to the userspace
> 
> This can be verified using IGT tests: igt/gem_stolen, igt/gem_create
> 
> Ankitprasad Sharma (4):
>   drm/i915: Clearing buffer objects via CPU/GTT
>   drm/i915: Support for creating Stolen memory backed objects
>   drm/i915: Support for pread/pwrite from/to non shmem backed objects
>   drm/i915: Propagating correct error codes to the userspace
> 
> Chris Wilson (1):
>   drm/i915: Add support for stealing purgable stolen pages

Hm, where's the patch to evict stolen objects to sysmem over
hibernate-to-disk that Chris raised? I guess we need this to avoid
breaking generic linux distros (and atm that's the only open-source user
afaics).
-Daniel

> 
>  drivers/gpu/drm/i915/i915_debugfs.c     |   4 +-
>  drivers/gpu/drm/i915/i915_dma.c         |   3 +
>  drivers/gpu/drm/i915/i915_drv.h         |  20 ++-
>  drivers/gpu/drm/i915/i915_gem.c         | 216 ++++++++++++++++++++++++++++----
>  drivers/gpu/drm/i915/i915_gem_stolen.c  | 200 +++++++++++++++++++++++------
>  drivers/gpu/drm/i915/intel_display.c    |   2 +-
>  drivers/gpu/drm/i915/intel_fbdev.c      |   2 +-
>  drivers/gpu/drm/i915/intel_overlay.c    |   4 +-
>  drivers/gpu/drm/i915/intel_pm.c         |   6 +-
>  drivers/gpu/drm/i915/intel_ringbuffer.c |   4 +-
>  include/uapi/drm/i915_drm.h             |  16 +++
>  11 files changed, 402 insertions(+), 75 deletions(-)
> 
> -- 
> 1.9.1
> 
> _______________________________________________
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> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

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Re: [PATCH v7 0/5] Support for creating/using Stolen memory backed objects

[Chris Wilson]

On Wed, Sep 23, 2015 at 06:03:55PM +0200, Daniel Vetter wrote:
> On Wed, Sep 23, 2015 at 04:21:18PM +0530, ankitprasad.r.sharma@intel.com wrote:
> > From: Ankitprasad Sharma <ankitprasad.r.sharma@intel.com>
> > 
> > This patch series adds support for creating/using Stolen memory backed
> > objects.
> > 
> > Despite being a unified memory architecture (UMA) some bits of memory
> > are more equal than others. In particular we have the thorny issue of
> > stolen memory, memory stolen from the system by the BIOS and reserved
> > for igfx use. Stolen memory is required for some functions of the GPU
> > and display engine, but in general it goes wasted. Whilst we cannot
> > return it back to the system, we need to find some other method for
> > utilising it. As we do not support direct access to the physical address
> > in the stolen region, it behaves like a different class of memory,
> > closer in kin to local GPU memory. This strongly suggests that we need a
> > placement model like TTM if we are to fully utilize these discrete
> > chunks of differing memory.
> > 
> > To add support for creating Stolen memory backed objects, we extend the
> > drm_i915_gem_create structure, by adding a new flag through which user
> > can specify the preference to allocate the object from stolen memory,
> > which if set, an attempt will be made to allocate the object from stolen
> > memory subject to the availability of free space in the stolen region.
> > 
> > This patch series adds support for clearing buffer objects via CPU/GTT.
> > This is particularly useful for clearing out the memory from stolen
> > region, but can also be used for other shmem allocated objects. Currently
> > being used for buffers allocated in the stolen region. Also adding support
> > for stealing purgable stolen pages, if we run out of stolen memory when
> > trying to allocate an object.
> > 
> > v2: Added support for read/write from/to objects not backed by
> > shmem using the pread/pwrite interface.
> > Also extended the current get_aperture ioctl to retrieve the
> > total and available size of the stolen region
> > 
> > v3: Removed the extended get_aperture ioctl patch 5 (to be submitted as
> > part of other patch series), addressed comments by Chris about pread/pwrite
> > for non shmem backed objects
> > 
> > v4: Rebased to the latest drm-intel-nightly
> > 
> > v5: Addressed comments, replaced patch 1/4 "Clearing buffers via blitter
> > engine" by "Clearing buffers via CPU/GTT"
> > 
> > v6: Rebased to the latest drm-intel-nightly, Addressed comments, updated
> > stolen memory purging logic by maintaining a list for purgable stolen
> > memory objects, enabled pread/pwrite for all non-shmem backed objects
> > without tiling restrictions
> > 
> > v7: Addressed comments, compiler optimization, new patch added for correct
> > error code propagation to the userspace
> > 
> > This can be verified using IGT tests: igt/gem_stolen, igt/gem_create
> > 
> > Ankitprasad Sharma (4):
> >   drm/i915: Clearing buffer objects via CPU/GTT
> >   drm/i915: Support for creating Stolen memory backed objects
> >   drm/i915: Support for pread/pwrite from/to non shmem backed objects
> >   drm/i915: Propagating correct error codes to the userspace
> > 
> > Chris Wilson (1):
> >   drm/i915: Add support for stealing purgable stolen pages
> 
> Hm, where's the patch to evict stolen objects to sysmem over
> hibernate-to-disk that Chris raised? I guess we need this to avoid
> breaking generic linux distros (and atm that's the only open-source user
> afaics).

As far as users go, I'm dubious as to the merits of using stolen (and so
have not written patches for the ddx/mesa) simply because we do not have
CPU access to them and so that excludes using all of the fast paths and
general flexibility. And I have complications like if I allocate a buffer
from stolen I need to migrate it if it is exported to a client over
DRI2/DRI3 (because I can't communicate that it is not first class). For
internal auxiliary buffers (which aren't that many as they get recycled
quickly like vertex/batch/instruction/temporary buffers), the quandary is
to save a few hundred KiB of memory or stick to fast access along generic
paths.

The no-CPU access also ends up severely limiting what we can use stolen
for inside the kernel as well (or at least makes it much more
complicated than need be). Totally snafu.
-Chris

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Re: [PATCH v7 0/5] Support for creating/using Stolen memory backed objects

[Chris Wilson]

On Wed, Sep 23, 2015 at 05:14:25PM +0100, Chris Wilson wrote:
> As far as users go, I'm dubious as to the merits of using stolen (and so
> have not written patches for the ddx/mesa) simply because we do not have
> CPU access to them and so that excludes using all of the fast paths and
> general flexibility. And I have complications like if I allocate a buffer
> from stolen I need to migrate it if it is exported to a client over
> DRI2/DRI3 (because I can't communicate that it is not first class). For
> internal auxiliary buffers (which aren't that many as they get recycled
> quickly like vertex/batch/instruction/temporary buffers), the quandary is
> to save a few hundred KiB of memory or stick to fast access along generic
> paths.

Typical, hit send and think of a use. Scratch for EU kernels - can be a
few megabytes in size and do not need user access.
-Chris

-- 
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Re: [PATCH v7 0/5] Support for creating/using Stolen memory backed objects

[Daniel Vetter]

On Wed, Sep 23, 2015 at 05:19:04PM +0100, Chris Wilson wrote:
> On Wed, Sep 23, 2015 at 05:14:25PM +0100, Chris Wilson wrote:
> > As far as users go, I'm dubious as to the merits of using stolen (and so
> > have not written patches for the ddx/mesa) simply because we do not have
> > CPU access to them and so that excludes using all of the fast paths and
> > general flexibility. And I have complications like if I allocate a buffer
> > from stolen I need to migrate it if it is exported to a client over
> > DRI2/DRI3 (because I can't communicate that it is not first class). For
> > internal auxiliary buffers (which aren't that many as they get recycled
> > quickly like vertex/batch/instruction/temporary buffers), the quandary is
> > to save a few hundred KiB of memory or stick to fast access along generic
> > paths.
> 
> Typical, hit send and think of a use. Scratch for EU kernels - can be a
> few megabytes in size and do not need user access.

Well whatever it is, it better exists before I'm pulling this series in
... And scratch would be good since then it doesn't matter if we totally
nuke the contents on hibernate when the gpu is idled.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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[PATCH] drm/i915: Propagate error from drm_gem_object_init()

[Matthew Auld]

From: Chris Wilson <chris@chris-wilson.co.uk>

Propagate the real error from drm_gem_object_init(). Note this also
fixes some confusion in the error return from i915_gem_alloc_object...

v2:
(Matthew Auld)
  - updated new users of gem_alloc_object from latest drm-nightly
  - replaced occurrences of IS_ERR_OR_NULL() with IS_ERR()
v3:
(Joonas Lahtinen)
  - fix double "From:" in commit message
  - add goto teardown path
v4:
(Matthew Auld)
  - rebase with i915_gem_alloc_object name change

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c              | 21 +++++++++++++--------
 drivers/gpu/drm/i915/i915_gem_batch_pool.c   |  4 ++--
 drivers/gpu/drm/i915/i915_gem_context.c      |  4 ++--
 drivers/gpu/drm/i915/i915_gem_render_state.c |  7 +++++--
 drivers/gpu/drm/i915/i915_guc_submission.c   |  2 +-
 drivers/gpu/drm/i915/intel_display.c         |  4 ++--
 drivers/gpu/drm/i915/intel_fbdev.c           |  4 ++--
 drivers/gpu/drm/i915/intel_lrc.c             | 10 ++++++----
 drivers/gpu/drm/i915/intel_overlay.c         |  2 +-
 drivers/gpu/drm/i915/intel_ringbuffer.c      | 19 ++++++++++---------
 10 files changed, 44 insertions(+), 33 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index d493e79..f749065 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -382,8 +382,8 @@ i915_gem_create(struct drm_file *file,
 
 	/* Allocate the new object */
 	obj = i915_gem_object_create(dev, size);
-	if (obj == NULL)
-		return -ENOMEM;
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
 
 	ret = drm_gem_handle_create(file, &obj->base, &handle);
 	/* drop reference from allocate - handle holds it now */
@@ -4498,15 +4498,15 @@ struct drm_i915_gem_object *i915_gem_object_create(struct drm_device *dev,
 	struct drm_i915_gem_object *obj;
 	struct address_space *mapping;
 	gfp_t mask;
+	int ret;
 
 	obj = i915_gem_object_alloc(dev);
 	if (obj == NULL)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
-	if (drm_gem_object_init(dev, &obj->base, size) != 0) {
-		i915_gem_object_free(obj);
-		return NULL;
-	}
+	ret = drm_gem_object_init(dev, &obj->base, size);
+	if (ret)
+		goto fail;
 
 	mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
 	if (IS_CRESTLINE(dev) || IS_BROADWATER(dev)) {
@@ -4543,6 +4543,11 @@ struct drm_i915_gem_object *i915_gem_object_create(struct drm_device *dev,
 	trace_i915_gem_object_create(obj);
 
 	return obj;
+
+fail:
+	i915_gem_object_free(obj);
+
+	return ERR_PTR(ret);
 }
 
 static bool discard_backing_storage(struct drm_i915_gem_object *obj)
@@ -5348,7 +5353,7 @@ i915_gem_object_create_from_data(struct drm_device *dev,
 	int ret;
 
 	obj = i915_gem_object_create(dev, round_up(size, PAGE_SIZE));
-	if (IS_ERR_OR_NULL(obj))
+	if (IS_ERR(obj))
 		return obj;
 
 	ret = i915_gem_object_set_to_cpu_domain(obj, true);
diff --git a/drivers/gpu/drm/i915/i915_gem_batch_pool.c b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
index 1bc46ba..3752d5d 100644
--- a/drivers/gpu/drm/i915/i915_gem_batch_pool.c
+++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
@@ -135,8 +135,8 @@ i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
 		int ret;
 
 		obj = i915_gem_object_create(pool->dev, size);
-		if (obj == NULL)
-			return ERR_PTR(-ENOMEM);
+		if (IS_ERR(obj))
+			return obj;
 
 		ret = i915_gem_object_get_pages(obj);
 		if (ret)
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index 4e12bae..e78e2f6 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -179,8 +179,8 @@ i915_gem_alloc_context_obj(struct drm_device *dev, size_t size)
 	int ret;
 
 	obj = i915_gem_object_create(dev, size);
-	if (obj == NULL)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(obj))
+		return obj;
 
 	/*
 	 * Try to make the context utilize L3 as well as LLC.
diff --git a/drivers/gpu/drm/i915/i915_gem_render_state.c b/drivers/gpu/drm/i915/i915_gem_render_state.c
index 65c9dad..841081e 100644
--- a/drivers/gpu/drm/i915/i915_gem_render_state.c
+++ b/drivers/gpu/drm/i915/i915_gem_render_state.c
@@ -58,8 +58,11 @@ static int render_state_init(struct render_state *so, struct drm_device *dev)
 		return -EINVAL;
 
 	so->obj = i915_gem_object_create(dev, 4096);
-	if (so->obj == NULL)
-		return -ENOMEM;
+	if (IS_ERR(so->obj)) {
+		ret = PTR_ERR(so->obj);
+		so->obj = NULL;
+		return ret;
+	}
 
 	ret = i915_gem_obj_ggtt_pin(so->obj, 4096, 0);
 	if (ret)
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index 72d6665..a304b0e 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -588,7 +588,7 @@ static struct drm_i915_gem_object *gem_allocate_guc_obj(struct drm_device *dev,
 	struct drm_i915_gem_object *obj;
 
 	obj = i915_gem_object_create(dev, size);
-	if (!obj)
+	if (IS_ERR(obj))
 		return NULL;
 
 	if (i915_gem_object_get_pages(obj)) {
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index b7cb632..739c12f 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -10320,8 +10320,8 @@ intel_framebuffer_create_for_mode(struct drm_device *dev,
 
 	obj = i915_gem_object_create(dev,
 				    intel_framebuffer_size_for_mode(mode, bpp));
-	if (obj == NULL)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(obj))
+		return ERR_CAST(obj);
 
 	mode_cmd.width = mode->hdisplay;
 	mode_cmd.height = mode->vdisplay;
diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index af56154..37fc68e 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -151,9 +151,9 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
 		obj = i915_gem_object_create_stolen(dev, size);
 	if (obj == NULL)
 		obj = i915_gem_object_create(dev, size);
-	if (!obj) {
+	if (IS_ERR(obj)) {
 		DRM_ERROR("failed to allocate framebuffer\n");
-		ret = -ENOMEM;
+		ret = PTR_ERR(obj);
 		goto out;
 	}
 
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 2b7e6bb..1b065e7 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1474,9 +1474,11 @@ static int lrc_setup_wa_ctx_obj(struct intel_engine_cs *engine, u32 size)
 
 	engine->wa_ctx.obj = i915_gem_object_create(engine->dev,
 						   PAGE_ALIGN(size));
-	if (!engine->wa_ctx.obj) {
+	if (IS_ERR(engine->wa_ctx.obj)) {
 		DRM_DEBUG_DRIVER("alloc LRC WA ctx backing obj failed.\n");
-		return -ENOMEM;
+		ret = PTR_ERR(engine->wa_ctx.obj);
+		engine->wa_ctx.obj = NULL;
+		return ret;
 	}
 
 	ret = i915_gem_obj_ggtt_pin(engine->wa_ctx.obj, PAGE_SIZE, 0);
@@ -2666,9 +2668,9 @@ int intel_lr_context_deferred_alloc(struct intel_context *ctx,
 	context_size += PAGE_SIZE * LRC_PPHWSP_PN;
 
 	ctx_obj = i915_gem_object_create(dev, context_size);
-	if (!ctx_obj) {
+	if (IS_ERR(ctx_obj)) {
 		DRM_DEBUG_DRIVER("Alloc LRC backing obj failed.\n");
-		return -ENOMEM;
+		return PTR_ERR(ctx_obj);
 	}
 
 	ringbuf = intel_engine_create_ringbuffer(engine, 4 * PAGE_SIZE);
diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
index 597fbcd..6b016c9 100644
--- a/drivers/gpu/drm/i915/intel_overlay.c
+++ b/drivers/gpu/drm/i915/intel_overlay.c
@@ -1397,7 +1397,7 @@ void intel_setup_overlay(struct drm_device *dev)
 		reg_bo = i915_gem_object_create_stolen(dev, PAGE_SIZE);
 	if (reg_bo == NULL)
 		reg_bo = i915_gem_object_create(dev, PAGE_SIZE);
-	if (reg_bo == NULL)
+	if (IS_ERR(reg_bo))
 		goto out_free;
 	overlay->reg_bo = reg_bo;
 
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 66f69cd..aff26be 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -672,9 +672,10 @@ intel_init_pipe_control(struct intel_engine_cs *engine)
 	WARN_ON(engine->scratch.obj);
 
 	engine->scratch.obj = i915_gem_object_create(engine->dev, 4096);
-	if (engine->scratch.obj == NULL) {
+	if (IS_ERR(engine->scratch.obj)) {
 		DRM_ERROR("Failed to allocate seqno page\n");
-		ret = -ENOMEM;
+		ret = PTR_ERR(engine->scratch.obj);
+		engine->scratch.obj = NULL;
 		goto err;
 	}
 
@@ -2027,9 +2028,9 @@ static int init_status_page(struct intel_engine_cs *engine)
 		int ret;
 
 		obj = i915_gem_object_create(engine->dev, 4096);
-		if (obj == NULL) {
+		if (IS_ERR(obj)) {
 			DRM_ERROR("Failed to allocate status page\n");
-			return -ENOMEM;
+			return PTR_ERR(obj);
 		}
 
 		ret = i915_gem_object_set_cache_level(obj, I915_CACHE_LLC);
@@ -2168,8 +2169,8 @@ static int intel_alloc_ringbuffer_obj(struct drm_device *dev,
 		obj = i915_gem_object_create_stolen(dev, ringbuf->size);
 	if (obj == NULL)
 		obj = i915_gem_object_create(dev, ringbuf->size);
-	if (obj == NULL)
-		return -ENOMEM;
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
 
 	/* mark ring buffers as read-only from GPU side by default */
 	obj->gt_ro = 1;
@@ -2781,7 +2782,7 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
 	if (INTEL_INFO(dev)->gen >= 8) {
 		if (i915_semaphore_is_enabled(dev)) {
 			obj = i915_gem_object_create(dev, 4096);
-			if (obj == NULL) {
+			if (IS_ERR(obj)) {
 				DRM_ERROR("Failed to allocate semaphore bo. Disabling semaphores\n");
 				i915.semaphores = 0;
 			} else {
@@ -2890,9 +2891,9 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
 	/* Workaround batchbuffer to combat CS tlb bug. */
 	if (HAS_BROKEN_CS_TLB(dev)) {
 		obj = i915_gem_object_create(dev, I830_WA_SIZE);
-		if (obj == NULL) {
+		if (IS_ERR(obj)) {
 			DRM_ERROR("Failed to allocate batch bo\n");
-			return -ENOMEM;
+			return PTR_ERR(obj);
 		}
 
 		ret = i915_gem_obj_ggtt_pin(obj, 0, 0);
-- 
2.4.11

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Re: [PATCH] drm/i915: Propagate error from drm_gem_object_init()

[Joonas Lahtinen]

On pe, 2016-04-22 at 12:59 +0100, Dave Gordon wrote:
> On 22/04/16 11:57, Matthew Auld wrote:
> > 
> > From: Chris Wilson <chris@chris-wilson.co.uk>
> > 
> > Propagate the real error from drm_gem_object_init(). Note this also
> > fixes some confusion in the error return from i915_gem_alloc_object...
> > 
> > v2:
> > (Matthew Auld)
> >    - updated new users of gem_alloc_object from latest drm-nightly
> >    - replaced occurrences of IS_ERR_OR_NULL() with IS_ERR()
> > v3:
> > (Joonas Lahtinen)
> >    - fix double "From:" in commit message
> >    - add goto teardown path
> > 
> > Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> > Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> > Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> > ---
> >   drivers/gpu/drm/i915/i915_gem.c              | 21 +++++++++++++--------
> >   drivers/gpu/drm/i915/i915_gem_batch_pool.c   |  4 ++--
> >   drivers/gpu/drm/i915/i915_gem_context.c      |  4 ++--
> >   drivers/gpu/drm/i915/i915_gem_render_state.c |  7 +++++--
> >   drivers/gpu/drm/i915/i915_guc_submission.c   |  2 +-
> >   drivers/gpu/drm/i915/intel_display.c         |  4 ++--
> >   drivers/gpu/drm/i915/intel_fbdev.c           |  4 ++--
> >   drivers/gpu/drm/i915/intel_lrc.c             | 10 ++++++----
> >   drivers/gpu/drm/i915/intel_overlay.c         |  2 +-
> >   drivers/gpu/drm/i915/intel_ringbuffer.c      | 19 ++++++++++---------
> >   10 files changed, 44 insertions(+), 33 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> > index 261a3ef..c6c17dd 100644
> > --- a/drivers/gpu/drm/i915/i915_gem.c
> > +++ b/drivers/gpu/drm/i915/i915_gem.c
> > @@ -382,8 +382,8 @@ i915_gem_create(struct drm_file *file,
> > 
> >   	/* Allocate the new object */
> >   	obj = i915_gem_alloc_object(dev, size);
> > -	if (obj == NULL)
> > -		return -ENOMEM;
> > +	if (IS_ERR(obj))
> > +		return PTR_ERR(obj);
> > 
> >   	ret = drm_gem_handle_create(file, &obj->base, &handle);
> >   	/* drop reference from allocate - handle holds it now */
> > @@ -4498,15 +4498,15 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
> >   	struct drm_i915_gem_object *obj;
> >   	struct address_space *mapping;
> >   	gfp_t mask;
> > +	int ret;
> > 
> >   	obj = i915_gem_object_alloc(dev);
> >   	if (obj == NULL)
> > -		return NULL;
> > +		return ERR_PTR(-ENOMEM);
> The two changes above looked really really confusing, where one tests 
> the returned pointer and returns it if it's an ERR_PTR, and the other 
> tests for NULL and returns ERR_PTR(-ENOMEM).
> 
> Then I realised one was i915_gem_alloc_object() and the other was 
> i915_gem_object_alloc()!

Yep, noticed that a few days ago too, +1 on correcting it.

Regards, Joonas

> 
> Can we please get rid of one or the other? Since we generally use 
> subsystem_class_action naming, I'd suggest keeping (the low-level 
> memory-allocator) i915_gem_object_alloc(), and renaming the high-level 
> i915_gem_alloc_object() to i915_gem_object_create() or similar.
> 
> > 
> > -	if (drm_gem_object_init(dev, &obj->base, size) != 0) {
> > -		i915_gem_object_free(obj);
> > -		return NULL;
> > -	}
> > +	ret = drm_gem_object_init(dev, &obj->base, size);
> > +	if (ret)
> > +		goto fail;
> > 
> >   	mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
> >   	if (IS_CRESTLINE(dev) || IS_BROADWATER(dev)) {
> > @@ -4543,6 +4543,11 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
> >   	trace_i915_gem_object_create(obj);
> Oh and BTW i915_gem_alloc_object() already calls itself 
> i915_gem_object_create() in trace messages!
> 
> .Dave.
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
-- 
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Open Source Technology Center
Intel Corporation
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Re: [PATCH] drm/i915: Propagate error from drm_gem_object_init()

[Dave Gordon]

On 22/04/16 11:57, Matthew Auld wrote:
> From: Chris Wilson <chris@chris-wilson.co.uk>
>
> Propagate the real error from drm_gem_object_init(). Note this also
> fixes some confusion in the error return from i915_gem_alloc_object...
>
> v2:
> (Matthew Auld)
>    - updated new users of gem_alloc_object from latest drm-nightly
>    - replaced occurrences of IS_ERR_OR_NULL() with IS_ERR()
> v3:
> (Joonas Lahtinen)
>    - fix double "From:" in commit message
>    - add goto teardown path
>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> ---
>   drivers/gpu/drm/i915/i915_gem.c              | 21 +++++++++++++--------
>   drivers/gpu/drm/i915/i915_gem_batch_pool.c   |  4 ++--
>   drivers/gpu/drm/i915/i915_gem_context.c      |  4 ++--
>   drivers/gpu/drm/i915/i915_gem_render_state.c |  7 +++++--
>   drivers/gpu/drm/i915/i915_guc_submission.c   |  2 +-
>   drivers/gpu/drm/i915/intel_display.c         |  4 ++--
>   drivers/gpu/drm/i915/intel_fbdev.c           |  4 ++--
>   drivers/gpu/drm/i915/intel_lrc.c             | 10 ++++++----
>   drivers/gpu/drm/i915/intel_overlay.c         |  2 +-
>   drivers/gpu/drm/i915/intel_ringbuffer.c      | 19 ++++++++++---------
>   10 files changed, 44 insertions(+), 33 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index 261a3ef..c6c17dd 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -382,8 +382,8 @@ i915_gem_create(struct drm_file *file,
>
>   	/* Allocate the new object */
>   	obj = i915_gem_alloc_object(dev, size);
> -	if (obj == NULL)
> -		return -ENOMEM;
> +	if (IS_ERR(obj))
> +		return PTR_ERR(obj);
>
>   	ret = drm_gem_handle_create(file, &obj->base, &handle);
>   	/* drop reference from allocate - handle holds it now */
> @@ -4498,15 +4498,15 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
>   	struct drm_i915_gem_object *obj;
>   	struct address_space *mapping;
>   	gfp_t mask;
> +	int ret;
>
>   	obj = i915_gem_object_alloc(dev);
>   	if (obj == NULL)
> -		return NULL;
> +		return ERR_PTR(-ENOMEM);

The two changes above looked really really confusing, where one tests 
the returned pointer and returns it if it's an ERR_PTR, and the other 
tests for NULL and returns ERR_PTR(-ENOMEM).

Then I realised one was i915_gem_alloc_object() and the other was 
i915_gem_object_alloc()!

Can we please get rid of one or the other? Since we generally use 
subsystem_class_action naming, I'd suggest keeping (the low-level 
memory-allocator) i915_gem_object_alloc(), and renaming the high-level 
i915_gem_alloc_object() to i915_gem_object_create() or similar.

> -	if (drm_gem_object_init(dev, &obj->base, size) != 0) {
> -		i915_gem_object_free(obj);
> -		return NULL;
> -	}
> +	ret = drm_gem_object_init(dev, &obj->base, size);
> +	if (ret)
> +		goto fail;
>
>   	mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
>   	if (IS_CRESTLINE(dev) || IS_BROADWATER(dev)) {
> @@ -4543,6 +4543,11 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
>   	trace_i915_gem_object_create(obj);

Oh and BTW i915_gem_alloc_object() already calls itself 
i915_gem_object_create() in trace messages!

.Dave.
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[PATCH] drm/i915: Propagate error from drm_gem_object_init()

[Matthew Auld]

From: Chris Wilson <chris@chris-wilson.co.uk>

Propagate the real error from drm_gem_object_init(). Note this also
fixes some confusion in the error return from i915_gem_alloc_object...

v2:
(Matthew Auld)
  - updated new users of gem_alloc_object from latest drm-nightly
  - replaced occurrences of IS_ERR_OR_NULL() with IS_ERR()
v3:
(Joonas Lahtinen)
  - fix double "From:" in commit message
  - add goto teardown path

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c              | 21 +++++++++++++--------
 drivers/gpu/drm/i915/i915_gem_batch_pool.c   |  4 ++--
 drivers/gpu/drm/i915/i915_gem_context.c      |  4 ++--
 drivers/gpu/drm/i915/i915_gem_render_state.c |  7 +++++--
 drivers/gpu/drm/i915/i915_guc_submission.c   |  2 +-
 drivers/gpu/drm/i915/intel_display.c         |  4 ++--
 drivers/gpu/drm/i915/intel_fbdev.c           |  4 ++--
 drivers/gpu/drm/i915/intel_lrc.c             | 10 ++++++----
 drivers/gpu/drm/i915/intel_overlay.c         |  2 +-
 drivers/gpu/drm/i915/intel_ringbuffer.c      | 19 ++++++++++---------
 10 files changed, 44 insertions(+), 33 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 261a3ef..c6c17dd 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -382,8 +382,8 @@ i915_gem_create(struct drm_file *file,
 
 	/* Allocate the new object */
 	obj = i915_gem_alloc_object(dev, size);
-	if (obj == NULL)
-		return -ENOMEM;
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
 
 	ret = drm_gem_handle_create(file, &obj->base, &handle);
 	/* drop reference from allocate - handle holds it now */
@@ -4498,15 +4498,15 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
 	struct drm_i915_gem_object *obj;
 	struct address_space *mapping;
 	gfp_t mask;
+	int ret;
 
 	obj = i915_gem_object_alloc(dev);
 	if (obj == NULL)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 
-	if (drm_gem_object_init(dev, &obj->base, size) != 0) {
-		i915_gem_object_free(obj);
-		return NULL;
-	}
+	ret = drm_gem_object_init(dev, &obj->base, size);
+	if (ret)
+		goto fail;
 
 	mask = GFP_HIGHUSER | __GFP_RECLAIMABLE;
 	if (IS_CRESTLINE(dev) || IS_BROADWATER(dev)) {
@@ -4543,6 +4543,11 @@ struct drm_i915_gem_object *i915_gem_alloc_object(struct drm_device *dev,
 	trace_i915_gem_object_create(obj);
 
 	return obj;
+
+fail:
+	i915_gem_object_free(obj);
+
+	return ERR_PTR(ret);
 }
 
 static bool discard_backing_storage(struct drm_i915_gem_object *obj)
@@ -5362,7 +5367,7 @@ i915_gem_object_create_from_data(struct drm_device *dev,
 	int ret;
 
 	obj = i915_gem_alloc_object(dev, round_up(size, PAGE_SIZE));
-	if (IS_ERR_OR_NULL(obj))
+	if (IS_ERR(obj))
 		return obj;
 
 	ret = i915_gem_object_set_to_cpu_domain(obj, true);
diff --git a/drivers/gpu/drm/i915/i915_gem_batch_pool.c b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
index 7bf2f3f..d79caa2 100644
--- a/drivers/gpu/drm/i915/i915_gem_batch_pool.c
+++ b/drivers/gpu/drm/i915/i915_gem_batch_pool.c
@@ -135,8 +135,8 @@ i915_gem_batch_pool_get(struct i915_gem_batch_pool *pool,
 		int ret;
 
 		obj = i915_gem_alloc_object(pool->dev, size);
-		if (obj == NULL)
-			return ERR_PTR(-ENOMEM);
+		if (IS_ERR(obj))
+			return obj;
 
 		ret = i915_gem_object_get_pages(obj);
 		if (ret)
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index e5acc39..34f4930 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -179,8 +179,8 @@ i915_gem_alloc_context_obj(struct drm_device *dev, size_t size)
 	int ret;
 
 	obj = i915_gem_alloc_object(dev, size);
-	if (obj == NULL)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(obj))
+		return obj;
 
 	/*
 	 * Try to make the context utilize L3 as well as LLC.
diff --git a/drivers/gpu/drm/i915/i915_gem_render_state.c b/drivers/gpu/drm/i915/i915_gem_render_state.c
index 71611bf..071c11e 100644
--- a/drivers/gpu/drm/i915/i915_gem_render_state.c
+++ b/drivers/gpu/drm/i915/i915_gem_render_state.c
@@ -58,8 +58,11 @@ static int render_state_init(struct render_state *so, struct drm_device *dev)
 		return -EINVAL;
 
 	so->obj = i915_gem_alloc_object(dev, 4096);
-	if (so->obj == NULL)
-		return -ENOMEM;
+	if (IS_ERR(so->obj)) {
+		ret = PTR_ERR(so->obj);
+		so->obj = NULL;
+		return ret;
+	}
 
 	ret = i915_gem_obj_ggtt_pin(so->obj, 4096, 0);
 	if (ret)
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index d40c13f..85122d9 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -588,7 +588,7 @@ static struct drm_i915_gem_object *gem_allocate_guc_obj(struct drm_device *dev,
 	struct drm_i915_gem_object *obj;
 
 	obj = i915_gem_alloc_object(dev, size);
-	if (!obj)
+	if (IS_ERR(obj))
 		return NULL;
 
 	if (i915_gem_object_get_pages(obj)) {
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index ff60241..5aff4ca 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -10320,8 +10320,8 @@ intel_framebuffer_create_for_mode(struct drm_device *dev,
 
 	obj = i915_gem_alloc_object(dev,
 				    intel_framebuffer_size_for_mode(mode, bpp));
-	if (obj == NULL)
-		return ERR_PTR(-ENOMEM);
+	if (IS_ERR(obj))
+		return ERR_CAST(obj);
 
 	mode_cmd.width = mode->hdisplay;
 	mode_cmd.height = mode->vdisplay;
diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index 79ac202..7047b38 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -151,9 +151,9 @@ static int intelfb_alloc(struct drm_fb_helper *helper,
 		obj = i915_gem_object_create_stolen(dev, size);
 	if (obj == NULL)
 		obj = i915_gem_alloc_object(dev, size);
-	if (!obj) {
+	if (IS_ERR(obj)) {
 		DRM_ERROR("failed to allocate framebuffer\n");
-		ret = -ENOMEM;
+		ret = PTR_ERR(obj);
 		goto out;
 	}
 
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 6179b59..1983198 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1474,9 +1474,11 @@ static int lrc_setup_wa_ctx_obj(struct intel_engine_cs *engine, u32 size)
 
 	engine->wa_ctx.obj = i915_gem_alloc_object(engine->dev,
 						   PAGE_ALIGN(size));
-	if (!engine->wa_ctx.obj) {
+	if (IS_ERR(engine->wa_ctx.obj)) {
 		DRM_DEBUG_DRIVER("alloc LRC WA ctx backing obj failed.\n");
-		return -ENOMEM;
+		ret = PTR_ERR(engine->wa_ctx.obj);
+		engine->wa_ctx.obj = NULL;
+		return ret;
 	}
 
 	ret = i915_gem_obj_ggtt_pin(engine->wa_ctx.obj, PAGE_SIZE, 0);
@@ -2666,9 +2668,9 @@ int intel_lr_context_deferred_alloc(struct intel_context *ctx,
 	context_size += PAGE_SIZE * LRC_PPHWSP_PN;
 
 	ctx_obj = i915_gem_alloc_object(dev, context_size);
-	if (!ctx_obj) {
+	if (IS_ERR(ctx_obj)) {
 		DRM_DEBUG_DRIVER("Alloc LRC backing obj failed.\n");
-		return -ENOMEM;
+		return PTR_ERR(ctx_obj);
 	}
 
 	ringbuf = intel_engine_create_ringbuffer(engine, 4 * PAGE_SIZE);
diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
index bcc3b6a..0d4bcbe 100644
--- a/drivers/gpu/drm/i915/intel_overlay.c
+++ b/drivers/gpu/drm/i915/intel_overlay.c
@@ -1397,7 +1397,7 @@ void intel_setup_overlay(struct drm_device *dev)
 		reg_bo = i915_gem_object_create_stolen(dev, PAGE_SIZE);
 	if (reg_bo == NULL)
 		reg_bo = i915_gem_alloc_object(dev, PAGE_SIZE);
-	if (reg_bo == NULL)
+	if (IS_ERR(reg_bo))
 		goto out_free;
 	overlay->reg_bo = reg_bo;
 
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 245386e..29094ef 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -672,9 +672,10 @@ intel_init_pipe_control(struct intel_engine_cs *engine)
 	WARN_ON(engine->scratch.obj);
 
 	engine->scratch.obj = i915_gem_alloc_object(engine->dev, 4096);
-	if (engine->scratch.obj == NULL) {
+	if (IS_ERR(engine->scratch.obj)) {
 		DRM_ERROR("Failed to allocate seqno page\n");
-		ret = -ENOMEM;
+		ret = PTR_ERR(engine->scratch.obj);
+		engine->scratch.obj = NULL;
 		goto err;
 	}
 
@@ -2023,9 +2024,9 @@ static int init_status_page(struct intel_engine_cs *engine)
 		int ret;
 
 		obj = i915_gem_alloc_object(engine->dev, 4096);
-		if (obj == NULL) {
+		if (IS_ERR(obj)) {
 			DRM_ERROR("Failed to allocate status page\n");
-			return -ENOMEM;
+			return PTR_ERR(obj);
 		}
 
 		ret = i915_gem_object_set_cache_level(obj, I915_CACHE_LLC);
@@ -2164,8 +2165,8 @@ static int intel_alloc_ringbuffer_obj(struct drm_device *dev,
 		obj = i915_gem_object_create_stolen(dev, ringbuf->size);
 	if (obj == NULL)
 		obj = i915_gem_alloc_object(dev, ringbuf->size);
-	if (obj == NULL)
-		return -ENOMEM;
+	if (IS_ERR(obj))
+		return PTR_ERR(obj);
 
 	/* mark ring buffers as read-only from GPU side by default */
 	obj->gt_ro = 1;
@@ -2777,7 +2778,7 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
 	if (INTEL_INFO(dev)->gen >= 8) {
 		if (i915_semaphore_is_enabled(dev)) {
 			obj = i915_gem_alloc_object(dev, 4096);
-			if (obj == NULL) {
+			if (IS_ERR(obj)) {
 				DRM_ERROR("Failed to allocate semaphore bo. Disabling semaphores\n");
 				i915.semaphores = 0;
 			} else {
@@ -2886,9 +2887,9 @@ int intel_init_render_ring_buffer(struct drm_device *dev)
 	/* Workaround batchbuffer to combat CS tlb bug. */
 	if (HAS_BROKEN_CS_TLB(dev)) {
 		obj = i915_gem_alloc_object(dev, I830_WA_SIZE);
-		if (obj == NULL) {
+		if (IS_ERR(obj)) {
 			DRM_ERROR("Failed to allocate batch bo\n");
-			return -ENOMEM;
+			return PTR_ERR(obj);
 		}
 
 		ret = i915_gem_obj_ggtt_pin(obj, 0, 0);
-- 
2.5.5

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