On Friday, February 6, 2009 1:35 pm Thomas Hellström wrote: > Jesse Barnes wrote: > > On Thursday, February 5, 2009 10:37 am Jesse Barnes wrote: > >> So if we leave the lookup reference around from the GTT mapping ioctl, > >> that would take care of new mappings. And if we added/removed > >> references at VM open/close time, we should be covered for fork. But is > >> it ok to add a new unref in the finish ioctl for GTT mapped objects? I > >> don't think so, because we don't know for sure if the caller was the one > >> that created the new fake offset (which would be one way of detecting > >> whether it was GTT mapped). Seems like we need a new unmap ioctl? Or we > >> could put the mapping ref/unref in libdrm, where it would be tracked on > >> a per-process basis... > > > > Ah but maybe we should just tear down the fake offset at unmap time; then > > we'd be able to use it as an existence test for the mapping and get the > > refcounting right. The last thing I thought of was whether we'd be ok in > > a map_gtt -> crash case. I *think* the vm_close code will deal with > > that, if we do a deref there? > > Yes, an mmap() is always paired with a vm_close(), and the vm_close() > also happens in a crash situation.
This one should cover the cases you found. - ref at map time will keep the object around so fault shouldn't fail - additional threads will take their refs in vm_open/close - unmap will unref and remove mmap_offset allowing object to be freed -- Jesse Barnes, Intel Open Source Technology Center diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c index 6915fb8..2752114 100644 --- a/drivers/gpu/drm/drm_gem.c +++ b/drivers/gpu/drm/drm_gem.c @@ -460,6 +460,23 @@ drm_gem_object_handle_free(struct kref *kref) } EXPORT_SYMBOL(drm_gem_object_handle_free); +void drm_gem_vm_open(struct vm_area_struct *vma) +{ + struct drm_gem_object *obj = vma->vm_private_data; + + drm_gem_object_reference(obj); +} +EXPORT_SYMBOL(drm_gem_vm_open); + +void drm_gem_vm_close(struct vm_area_struct *vma) +{ + struct drm_gem_object *obj = vma->vm_private_data; + + drm_gem_object_unreference(obj); +} +EXPORT_SYMBOL(drm_gem_vm_close); + + /** * drm_gem_mmap - memory map routine for GEM objects * @filp: DRM file pointer diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index aac12ee..a31cbdb 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -94,6 +94,8 @@ static int i915_resume(struct drm_device *dev) static struct vm_operations_struct i915_gem_vm_ops = { .fault = i915_gem_fault, + .open = drm_gem_vm_open, + .close = drm_gem_vm_close, }; static struct drm_driver driver = { diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 1441831..a476de0 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -52,6 +52,7 @@ static void i915_gem_object_free_page_list(struct drm_gem_object *obj); static int i915_gem_object_wait_rendering(struct drm_gem_object *obj); static int i915_gem_object_bind_to_gtt(struct drm_gem_object *obj, unsigned alignment); +static void i915_gem_free_mmap_offset(struct drm_gem_object *obj); static int i915_gem_object_get_fence_reg(struct drm_gem_object *obj, bool write); static void i915_gem_clear_fence_reg(struct drm_gem_object *obj); static int i915_gem_evict_something(struct drm_device *dev); @@ -497,6 +498,13 @@ i915_gem_sw_finish_ioctl(struct drm_device *dev, void *data, i915_gem_object_flush_cpu_write_domain(obj); drm_gem_object_unreference(obj); + + /* If it's been GTT mapped, unref it again... */ + if (obj_priv->mmap_offset) { + i915_gem_free_mmap_offset(obj); + drm_gem_object_unreference(obj); + } + mutex_unlock(&dev->struct_mutex); return ret; } @@ -607,8 +615,6 @@ int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) case -EAGAIN: return VM_FAULT_OOM; case -EFAULT: - case -EBUSY: - DRM_ERROR("can't insert pfn?? fault or busy...\n"); return VM_FAULT_SIGBUS; default: return VM_FAULT_NOPAGE; @@ -684,6 +690,32 @@ out_free_list: return ret; } +static void +i915_gem_free_mmap_offset(struct drm_gem_object *obj) +{ + struct drm_device *dev = obj->dev; + struct drm_i915_gem_object *obj_priv = obj->driver_private; + struct drm_gem_mm *mm = dev->mm_private; + struct drm_map_list *list; + struct drm_map *map; + + list = &obj->map_list; + drm_ht_remove_item(&mm->offset_hash, &list->hash); + + if (list->file_offset_node) { + drm_mm_put_block(list->file_offset_node); + list->file_offset_node = NULL; + } + + map = list->map; + if (map) { + drm_free(map, sizeof(*map), DRM_MEM_DRIVER); + list->map = NULL; + } + + obj_priv->mmap_offset = 0; +} + /** * i915_gem_get_gtt_alignment - return required GTT alignment for an object * @obj: object to check @@ -788,7 +820,7 @@ i915_gem_mmap_gtt_ioctl(struct drm_device *dev, void *data, list_add(&obj_priv->list, &dev_priv->mm.inactive_list); } - drm_gem_object_unreference(obj); + /* Leave lookup reference around until unmap time */ mutex_unlock(&dev->struct_mutex); return 0; @@ -2885,9 +2917,6 @@ int i915_gem_init_object(struct drm_gem_object *obj) void i915_gem_free_object(struct drm_gem_object *obj) { struct drm_device *dev = obj->dev; - struct drm_gem_mm *mm = dev->mm_private; - struct drm_map_list *list; - struct drm_map *map; struct drm_i915_gem_object *obj_priv = obj->driver_private; while (obj_priv->pin_count > 0) @@ -2898,20 +2927,6 @@ void i915_gem_free_object(struct drm_gem_object *obj) i915_gem_object_unbind(obj); - list = &obj->map_list; - drm_ht_remove_item(&mm->offset_hash, &list->hash); - - if (list->file_offset_node) { - drm_mm_put_block(list->file_offset_node); - list->file_offset_node = NULL; - } - - map = list->map; - if (map) { - drm_free(map, sizeof(*map), DRM_MEM_DRIVER); - list->map = NULL; - } - drm_free(obj_priv->page_cpu_valid, 1, DRM_MEM_DRIVER); drm_free(obj->driver_private, 1, DRM_MEM_DRIVER); } diff --git a/include/drm/drmP.h b/include/drm/drmP.h index 8190b9b..e5f4ae9 100644 --- a/include/drm/drmP.h +++ b/include/drm/drmP.h @@ -1321,6 +1321,8 @@ void drm_gem_object_free(struct kref *kref); struct drm_gem_object *drm_gem_object_alloc(struct drm_device *dev, size_t size); void drm_gem_object_handle_free(struct kref *kref); +void drm_gem_vm_open(struct vm_area_struct *vma); +void drm_gem_vm_close(struct vm_area_struct *vma); int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma); static inline void ------------------------------------------------------------------------------ Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) software. 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