From: Michal Hocko Date: Fri, 17 Aug 2018 22:46:01 +0000 (-0700) Subject: mm: drop VM_BUG_ON from __get_free_pages X-Git-Tag: v5.15~8195^2~66 X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=9ea9a68064035dee70f465f605a3e63990e33bd9;p=mirror_ubuntu-kernels.git mm: drop VM_BUG_ON from __get_free_pages There is no real reason to blow up just because the caller doesn't know that __get_free_pages cannot return highmem pages. Simply fix that up silently. Even if we have some confused users such a fixup will not be harmful. [akpm@linux-foundation.org: mask off __GFP_HIGHMEM] Link: http://lkml.kernel.org/r/20180622162841.25114-1-mhocko@kernel.org Signed-off-by: Michal Hocko Reviewed-by: Andrew Morton Cc: Jiankang Chen Cc: Mel Gorman Cc: Johannes Weiner Cc: Yisheng Xie Cc: Hanjun Guo Cc: Kefeng Wang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 0303a3b24610..e1517bb143dc 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4404,19 +4404,15 @@ out: EXPORT_SYMBOL(__alloc_pages_nodemask); /* - * Common helper functions. + * Common helper functions. Never use with __GFP_HIGHMEM because the returned + * address cannot represent highmem pages. Use alloc_pages and then kmap if + * you need to access high mem. */ unsigned long __get_free_pages(gfp_t gfp_mask, unsigned int order) { struct page *page; - /* - * __get_free_pages() returns a virtual address, which cannot represent - * a highmem page - */ - VM_BUG_ON((gfp_mask & __GFP_HIGHMEM) != 0); - - page = alloc_pages(gfp_mask, order); + page = alloc_pages(gfp_mask & ~__GFP_HIGHMEM, order); if (!page) return 0; return (unsigned long) page_address(page);