On Thu, Jul 04, 2013 at 11:19:58AM +0200, David Herrmann wrote: > Hi > > On Wed, Jul 3, 2013 at 11:45 PM, Ben Widawsky <ben@xxxxxxxxxxxx> wrote: > > 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. > > > > CC: <dri-devel@xxxxxxxxxxxxxxxxxxxxx> > > Signed-off-by: Ben Widawsky <ben@xxxxxxxxxxxx> > > --- > > drivers/gpu/drm/drm_mm.c | 16 +++++---------- > > drivers/gpu/drm/i915/i915_gem_gtt.c | 18 +++++++++++++---- > > drivers/gpu/drm/i915/i915_gem_stolen.c | 36 +++++++++++++++++++++++----------- > > include/drm/drm_mm.h | 9 +++++---- > > 4 files changed, 49 insertions(+), 30 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c > > index 07cf99c..9e8dfbc 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 66929ea..5c6fc0e 100644 > > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c > > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c > > @@ -629,14 +629,24 @@ 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 all objects\n"); > > + break; > > + } > > + 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); > > Are you sure you don't need: > obj->gtt_space = NULL; > here? > I am no expert in i915 gem handling, but looking at i915_gem.c I think > you might run into bugs if not. I'm too lazy to actually check, but I believe you're probably right. It's fixed in a later patch where I added the getters and use node_allocated so I don't check obj->gtt_space != NULL anymore; but it would potentially be a painful bisect point. Thanks for catching it (and the following ones). > > Also, why did you add the "break;" above, but not here? I am confused. The thought at the time was if kzalloc fails at this point, subsequent kzallocs are really likely to fail also. drm_mm_create_block OTOH is something I won't pretend to inquire about failure recurrence. I agree it looks funny though, so I'll change the break to continue. > > > + } > > 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 8e02344..f9db84a 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 unref_out; > > Again: > kfree(obj->gtt_space); > obj->gtt_space = NULL; > Otherwise, if gem-cleanup calls drm_mm_put_block() on an already > removed node, you end up with NULL-derefs in drm_mm.c > > > } > > } else > > obj->gtt_space = I915_GTT_RESERVED; > > @@ -385,8 +395,12 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev, > > > > list_add_tail(&obj->global_list, &dev_priv->mm.bound_list); > > list_add_tail(&obj->mm_list, &dev_priv->mm.inactive_list); > > - > > return obj; > > + > > +unref_out: > > + drm_gem_object_unreference(&obj->base); > > + drm_mm_put_block(stolen); > > "stolen" is already cleared by drm_gem_object_unreference(). So that's > a double-free here. > > The drm_mm_create_block() change looks good. > Cheers > David > Thanks for reviewing the i915 parts so thoroughly :D > > > + return NULL; > > } > > > > void > > diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h > > index 88591ef..d8b56b7 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) > > -- > > 1.8.3.2 > > > > _______________________________________________ > > dri-devel mailing list > > dri-devel@xxxxxxxxxxxxxxxxxxxxx > > http://lists.freedesktop.org/mailman/listinfo/dri-devel -- Ben Widawsky, Intel Open Source Technology Center _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel