drm: pre allocate node for create_block

For an upcoming patch where we introduce the i915 VMA, it's ideal to
have the drm_mm_node as part of the VMA struct (ie. it's pre-allocated).
Part of the conversion to VMAs is to kill off obj->gtt_space. Doing this
will break a bunch of code, but amongst them are 2 callers of
drm_mm_create_block(), both related to stolen memory.

It also allows us to embed the drm_mm_node into the object currently
which provides a nice transition over to the new code.

v2: Reordered to do before ripping out obj->gtt_offset.
Some minor cleanups made available because of reordering.

v3: s/continue/break on failed stolen node allocation (David)
Set obj->gtt_space on failed node allocation (David)
Only unref stolen (fix double free) on failed create_stolen (David)
Free node, and NULL it in failed create_stolen (David)
Add back accidentally removed newline (David)

CC: <dri-devel@lists.freedesktop.org>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Acked-by: David Airlie <airlied@linux.ie>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

4 files changed, 53 insertions, 29 deletions

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 07cf99cc8862..9e8dfbc1955e 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -147,12 +147,10 @@ static void drm_mm_insert_helper(struct drm_mm_node *hole_node,
         }
 }
 
-struct drm_mm_node *drm_mm_create_block(struct drm_mm *mm,
-                                        unsigned long start,
-                                        unsigned long size,
-                                        bool atomic)
+int drm_mm_create_block(struct drm_mm *mm, struct drm_mm_node *node,
+                        unsigned long start, unsigned long size)
 {
-        struct drm_mm_node *hole, *node;
+        struct drm_mm_node *hole;
         unsigned long end = start + size;
         unsigned long hole_start;
         unsigned long hole_end;
@@ -161,10 +159,6 @@ struct drm_mm_node *drm_mm_create_block(struct drm_mm *mm,
                 if (hole_start > start || hole_end < end)
                         continue;
 
-                node = drm_mm_kmalloc(mm, atomic);
-                if (unlikely(node == NULL))
-                        return NULL;
-
                 node->start = start;
                 node->size = size;
                 node->mm = mm;
@@ -184,11 +178,11 @@ struct drm_mm_node *drm_mm_create_block(struct drm_mm *mm,
                         node->hole_follows = 1;
                 }
 
-                return node;
+                return 0;
         }
 
         WARN(1, "no hole found for block 0x%lx + 0x%lx\n", start, size);
-        return NULL;
+        return -ENOSPC;
 }
 EXPORT_SYMBOL(drm_mm_create_block);
 
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 66929eac6367..88180a597c0a 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -629,14 +629,26 @@ void i915_gem_setup_global_gtt(struct drm_device *dev,
 
         /* Mark any preallocated objects as occupied */
         list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
+                int ret;
                 DRM_DEBUG_KMS("reserving preallocated space: %x + %zx\n",
                               obj->gtt_offset, obj->base.size);
 
                 BUG_ON(obj->gtt_space != I915_GTT_RESERVED);
-                obj->gtt_space = drm_mm_create_block(&dev_priv->mm.gtt_space,
-                                                     obj->gtt_offset,
-                                                     obj->base.size,
-                                                     false);
+                obj->gtt_space = kzalloc(sizeof(*obj->gtt_space), GFP_KERNEL);
+                if (!obj->gtt_space) {
+                        DRM_ERROR("Failed to preserve object at offset %x\n",
+                                  obj->gtt_offset);
+                        continue;
+                }
+                ret = drm_mm_create_block(&dev_priv->mm.gtt_space,
+                                          obj->gtt_space,
+                                          obj->gtt_offset,
+                                          obj->base.size);
+                if (ret) {
+                        DRM_DEBUG_KMS("Reservation failed\n");
+                        kfree(obj->gtt_space);
+                        obj->gtt_space = NULL;
+                }
                 obj->has_global_gtt_mapping = 1;
         }
 
diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index 0f18d75fa9f8..2746ff2d846a 100644
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -330,6 +330,7 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
         struct drm_i915_private *dev_priv = dev->dev_private;
         struct drm_i915_gem_object *obj;
         struct drm_mm_node *stolen;
+        int ret;
 
         if (dev_priv->mm.stolen_base == 0)
                 return NULL;
@@ -344,11 +345,15 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
         if (WARN_ON(size == 0))
                 return NULL;
 
-        stolen = drm_mm_create_block(&dev_priv->mm.stolen,
-                                     stolen_offset, size,
-                                     false);
-        if (stolen == NULL) {
+        stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
+        if (!stolen)
+                return NULL;
+
+        ret = drm_mm_create_block(&dev_priv->mm.stolen, stolen, stolen_offset,
+                                  size);
+        if (ret) {
                 DRM_DEBUG_KMS("failed to allocate stolen space\n");
+                kfree(stolen);
                 return NULL;
         }
 
@@ -369,13 +374,18 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
          * later.
          */
         if (drm_mm_initialized(&dev_priv->mm.gtt_space)) {
-                obj->gtt_space = drm_mm_create_block(&dev_priv->mm.gtt_space,
-                                                     gtt_offset, size,
-                                                     false);
-                if (obj->gtt_space == NULL) {
+                obj->gtt_space = kzalloc(sizeof(*obj->gtt_space), GFP_KERNEL);
+                if (!obj->gtt_space) {
+                        DRM_DEBUG_KMS("-ENOMEM stolen GTT space\n");
+                        goto unref_out;
+                }
+
+                ret = drm_mm_create_block(&dev_priv->mm.gtt_space,
+                                          obj->gtt_space,
+                                          gtt_offset, size);
+                if (ret) {
                         DRM_DEBUG_KMS("failed to allocate stolen GTT space\n");
-                        drm_gem_object_unreference(&obj->base);
-                        return NULL;
+                        goto free_out;
                 }
         } else
                 obj->gtt_space = I915_GTT_RESERVED;
@@ -387,6 +397,13 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
         list_add_tail(&obj->mm_list, &dev_priv->mm.inactive_list);
 
         return obj;
+
+free_out:
+        kfree(obj->gtt_space);
+        obj->gtt_space = NULL;
+unref_out:
+        drm_gem_object_unreference(&obj->base);
+        return NULL;
 }
 
 void
diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index 88591ef8fa24..d8b56b7d1839 100644
--- a/include/drm/drm_mm.h
+++ b/include/drm/drm_mm.h
@@ -138,10 +138,10 @@ static inline unsigned long drm_mm_hole_node_end(struct drm_mm_node *hole_node)
 /*
  * Basic range manager support (drm_mm.c)
  */
-extern struct drm_mm_node *drm_mm_create_block(struct drm_mm *mm,
-                                               unsigned long start,
-                                               unsigned long size,
-                                               bool atomic);
+extern int drm_mm_create_block(struct drm_mm *mm,
+                               struct drm_mm_node *node,
+                               unsigned long start,
+                               unsigned long size);
 extern struct drm_mm_node *drm_mm_get_block_generic(struct drm_mm_node *node,
                                                     unsigned long size,
                                                     unsigned alignment,
@@ -155,6 +155,7 @@ extern struct drm_mm_node *drm_mm_get_block_range_generic(
                                                 unsigned long start,
                                                 unsigned long end,
                                                 int atomic);
+
 static inline struct drm_mm_node *drm_mm_get_block(struct drm_mm_node *parent,
                                                    unsigned long size,
                                                    unsigned alignment)