mm: Fix generic hugetlb pte check return type.

2013-10-03T00:02:35Z

The include/asm-generic/hugetlb.h stubs that just vector huge_pte_*() calls to the pte_*() implementations won't work in certain situations. x86 and sparc, for example, return "unsigned long" from the bit checks, and just go "return pte_val(pte) & PTE_BIT_FOO;" But since huge_pte_*() returns 'int', if any high bits on 64-bit are relevant, they get chopped off. The net effect is that we can loop forever trying to COW a huge page, because the huge_pte_write() check signals false all the time. Reported-by: Gurudas Pai Tested-by: Gurudas Pai Signed-off-by: David S. Miller Acked-by: David Rientjes

mm/hugetlb: add more arch-defined huge_pte functions

2013-04-29T22:54:33Z

Commit abf09bed3cce ("s390/mm: implement software dirty bits") introduced another difference in the pte layout vs. the pmd layout on s390, thoroughly breaking the s390 support for hugetlbfs. This requires replacing some more pte_xxx functions in mm/hugetlbfs.c with a huge_pte_xxx version. This patch introduces those huge_pte_xxx functions and their generic implementation in asm-generic/hugetlb.h, which will now be included on all architectures supporting hugetlbfs apart from s390. This change will be a no-op for those architectures. [akpm@linux-foundation.org: fix warning] Signed-off-by: Gerald Schaefer Cc: Mel Gorman Cc: Hugh Dickins Cc: Hillf Danton Acked-by: Michal Hocko [for !s390 parts] Cc: Tony Luck Cc: Fenghua Yu Cc: Ralf Baechle Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Paul Mundt Cc: "David S. Miller" Cc: Chris Metcalf Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Martin Schwidefsky Cc: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/include/asm-generic/hugetlb.h, branch linux-4.1.y

mm: Fix generic hugetlb pte check return type.

mm/hugetlb: add more arch-defined huge_pte functions