drm/gem: replace misleading comment (2123000b) · Commits · 戴 / test

drivers/gpu/drm/drm_gem.c

+4 −15

Original line number	Diff line number	Diff line
		@@ -474,21 +474,10 @@ struct page *drm_gem_get_pages(struct drm_gem_object obj, gfp_t gfpmask)
		goto fail;
		pages[i] = p;

		/* There is a hypothetical issue w/ drivers that require
		* buffer memory in the low 4GB.. if the pages are un-
		* pinned, and swapped out, they can end up swapped back
		* in above 4GB. If pages are already in memory, then
		* shmem_read_mapping_page_gfp will ignore the gfpmask,
		* even if the already in-memory page disobeys the mask.
		*
		* It is only a theoretical issue today, because none of
		* the devices with this limitation can be populated with
		* enough memory to trigger the issue. But this BUG_ON()
		* is here as a reminder in case the problem with
		* shmem_read_mapping_page_gfp() isn't solved by the time
		* it does become a real issue.
		*
		* See this thread: http://lkml.org/lkml/2011/7/11/238
		/* Make sure shmem keeps __GFP_DMA32 allocated pages in the
		* correct region during swapin. Note that this requires
		* __GFP_DMA32 to be set in mapping_gfp_mask(inode->i_mapping)
		* so shmem can relocate pages during swapin if required.
		*/
		BUG_ON((gfpmask & __GFP_DMA32) &&
		(page_to_pfn(p) >= 0x00100000UL));