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Date: Wed, 11 Feb 2009 14:01:46 -0800
From: Jesse Barnes <jbarnes@...tuousgeek.org>
To: dri-devel@...ts.sourceforge.net, Eric Anholt <eric@...olt.net>
Cc: Chris Wilson <chris@...is-wilson.co.uk>,
Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: Gem GTT mmaps..
On Friday, February 6, 2009 4:52 pm Chris Wilson wrote:
> I tried it, it's not too happy. My only concern is that this now relies
> on userspace to correctly call SW_FINISH (and not unmap after mmapping
> the GTT_MMAP) or otherwise the object is leaked? Patch comments inline.
This one relies on munmap or exit (as it should be). I think we're leaking a
refcount somewhere, but afaict it's not caused by this patch (failing to take
a ref at mmap time leads to a panic in unpin). That leak may have been fixed
by one of your other patches, haven't updated & tested yet.
- 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
Tested with modetest while looking at /proc/dri/...
--
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..393d2db 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -460,6 +460,26 @@ 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;
+ struct drm_device *dev = obj->dev;
+
+ mutex_lock(&dev->struct_mutex);
+ drm_gem_object_unreference(obj);
+ mutex_unlock(&dev->struct_mutex);
+}
+EXPORT_SYMBOL(drm_gem_vm_close);
+
+
/**
* drm_gem_mmap - memory map routine for GEM objects
* @filp: DRM file pointer
@@ -521,6 +541,12 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
#endif
vma->vm_page_prot = __pgprot(prot);
+ /* Take a ref here so our fault handler always has an object
+ * to work with. This ref will be dropped when the last
+ * process does a vm_close (at munmap or exit time).
+ */
+ drm_gem_object_reference(obj);
+
vma->vm_file = filp; /* Needed for drm_vm_open() */
drm_vm_open_locked(vma);
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..d1a031b 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -607,8 +607,6 @@ 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 +682,30 @@ 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;
+
+ 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;
+ }
+
+ if (list->map) {
+ drm_free(list->map, sizeof(struct drm_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
@@ -2885,9 +2907,6 @@ 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)
@@ -2898,19 +2917,7 @@ 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;
- }
+ i915_gem_free_mmap_offset(obj);
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
--
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