drm/i915: Keep refs on the object over the lifetime of vmas for GTT mmap.

[karo-tx-linux.git] / drivers / gpu / drm / drm_gem.c

diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 5dad6b9d0dec29c7d5fe05cde0984848bfaff2ac..88d3368ffddd946974ba9a42ac273810f9c68c21 100644 (file)
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -463,6 +463,26 @@ 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
@@ -524,6 +544,14 @@ int drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 #endif
        vma->vm_page_prot = __pgprot(prot);
 
+       /* Take a ref for this mapping of the object, so that the fault
+        * handler can dereference the mmap offset's pointer to the object.
+        * This reference is cleaned up by the corresponding vm_close
+        * (which should happen whether the vma was created by this call, or
+        * by a vm_open due to mremap or partial unmap or whatever).
+        */
+       drm_gem_object_reference(obj);
+
        vma->vm_file = filp;    /* Needed for drm_vm_open() */
        drm_vm_open_locked(vma);