drm_gem_get_pages — helper to allocate backing pages for a GEM object from shmem
struct page ** drm_gem_get_pages ( | struct drm_gem_object * obj); |
This reads the page-array of the shmem-backing storage of the given gem object. An array of pages is returned. If a page is not allocated or swapped-out, this will allocate/swap-in the required pages. Note that the whole object is covered by the page-array and pinned in memory.
Use drm_gem_put_pages to release the array and unpin all pages.
This uses the GFP-mask set on the shmem-mapping (see mapping_set_gfp_mask).
If you require other GFP-masks, you have to do those allocations yourself.
Note that you are not allowed to change gfp-zones during runtime. That is,
shmem_read_mapping_page_gfp must be called with the same gfp_zone(gfp) as
set during initialization. If you have special zone constraints, set them
after drm_gem_init_object via mapping_set_gfp_mask. shmem-core takes care
to keep pages in the required zone during swap-in.