int drm_mmap (struct file * filp, struct vm_area_struct * vma);
\param filp file pointer. \param vma virtual memory area. \return zero on success or a negative number on failure.
If the virtual memory area has no offset associated with it then it's a DMA area, so calls mmap_dma. Otherwise searches the map in drm_device::maplist, checks that the restricted flag is not set, sets the virtual memory operations according to the mapping type and remaps the pages. Finally sets the file pointer and calls vm_open.