From: Cyrill Gorcunov Subject: mm: Cleanup pte_to_pgoff and pgoff_to_pte helpers Andrew asked if there a way to make pte_to_pgoff and pgoff_to_pte macro helpers somehow more readable. With this patch it should be more understandable what is happening with bits when they come to and from pte entry. Signed-off-by: Cyrill Gorcunov Cc: Andrew Morton Cc: Andy Lutomirski Cc: Pavel Emelyanov Cc: Matt Mackall Cc: Xiao Guangrong Cc: Marcelo Tosatti Cc: KOSAKI Motohiro Cc: Stephen Rothwell Cc: Peter Zijlstra Cc: "Aneesh Kumar K.V" --- Guys, is there a reason for "if _PAGE_BIT_FILE < _PAGE_BIT_PROTNONE" test present in this pgtable-2level.h file at all? I can't imagine where it can be false on x86. arch/x86/include/asm/pgtable-2level.h | 82 +++++++++++++++++----------------- 1 file changed, 41 insertions(+), 41 deletions(-) Index: linux-2.6.git/arch/x86/include/asm/pgtable-2level.h =================================================================== --- linux-2.6.git.orig/arch/x86/include/asm/pgtable-2level.h +++ linux-2.6.git/arch/x86/include/asm/pgtable-2level.h @@ -55,6 +55,9 @@ static inline pmd_t native_pmdp_get_and_ #define native_pmdp_get_and_clear(xp) native_local_pmdp_get_and_clear(xp) #endif +#define _mfrob(v,r,m,l) ((((v) >> (r)) & (m)) << (l)) +#define __frob(v,r,l) (((v) >> (r)) << (l)) + #ifdef CONFIG_MEM_SOFT_DIRTY /* @@ -71,31 +74,27 @@ static inline pmd_t native_pmdp_get_and_ #define PTE_FILE_BITS2 (PTE_FILE_SHIFT3 - PTE_FILE_SHIFT2 - 1) #define PTE_FILE_BITS3 (PTE_FILE_SHIFT4 - PTE_FILE_SHIFT3 - 1) -#define pte_to_pgoff(pte) \ - ((((pte).pte_low >> (PTE_FILE_SHIFT1)) \ - & ((1U << PTE_FILE_BITS1) - 1))) \ - + ((((pte).pte_low >> (PTE_FILE_SHIFT2)) \ - & ((1U << PTE_FILE_BITS2) - 1)) \ - << (PTE_FILE_BITS1)) \ - + ((((pte).pte_low >> (PTE_FILE_SHIFT3)) \ - & ((1U << PTE_FILE_BITS3) - 1)) \ - << (PTE_FILE_BITS1 + PTE_FILE_BITS2)) \ - + ((((pte).pte_low >> (PTE_FILE_SHIFT4))) \ - << (PTE_FILE_BITS1 + PTE_FILE_BITS2 + PTE_FILE_BITS3)) - -#define pgoff_to_pte(off) \ - ((pte_t) { .pte_low = \ - ((((off)) & ((1U << PTE_FILE_BITS1) - 1)) << PTE_FILE_SHIFT1) \ - + ((((off) >> PTE_FILE_BITS1) \ - & ((1U << PTE_FILE_BITS2) - 1)) \ - << PTE_FILE_SHIFT2) \ - + ((((off) >> (PTE_FILE_BITS1 + PTE_FILE_BITS2)) \ - & ((1U << PTE_FILE_BITS3) - 1)) \ - << PTE_FILE_SHIFT3) \ - + ((((off) >> \ - (PTE_FILE_BITS1 + PTE_FILE_BITS2 + PTE_FILE_BITS3))) \ - << PTE_FILE_SHIFT4) \ - + _PAGE_FILE }) +#define PTE_FILE_MASK1 ((1U << PTE_FILE_BITS1) - 1) +#define PTE_FILE_MASK2 ((1U << PTE_FILE_BITS2) - 1) +#define PTE_FILE_MASK3 ((1U << PTE_FILE_BITS3) - 1) + +#define PTE_FILE_LSHIFT2 (PTE_FILE_BITS1) +#define PTE_FILE_LSHIFT3 (PTE_FILE_BITS1 + PTE_FILE_BITS2) +#define PTE_FILE_LSHIFT4 (PTE_FILE_BITS1 + PTE_FILE_BITS2 + PTE_FILE_BITS3) + +#define pte_to_pgoff(pte) \ + (_mfrob((pte).pte_low, PTE_FILE_SHIFT1, PTE_FILE_MASK1, 0) + \ + _mfrob((pte).pte_low, PTE_FILE_SHIFT2, PTE_FILE_MASK2, PTE_FILE_LSHIFT2) + \ + _mfrob((pte).pte_low, PTE_FILE_SHIFT3, PTE_FILE_MASK3, PTE_FILE_LSHIFT3) + \ + __frob((pte).pte_low, PTE_FILE_SHIFT4, PTE_FILE_LSHIFT4)) + +#define pgoff_to_pte(off) \ + ((pte_t) { .pte_low = \ + _mfrob(off, 0, PTE_FILE_MASK1, PTE_FILE_SHIFT1) + \ + _mfrob(off, PTE_FILE_LSHIFT2, PTE_FILE_MASK2, PTE_FILE_SHIFT2) + \ + _mfrob(off, PTE_FILE_LSHIFT3, PTE_FILE_MASK3, PTE_FILE_SHIFT3) + \ + __frob(off, PTE_FILE_LSHIFT4, PTE_FILE_SHIFT4) + \ + _PAGE_FILE }) #else /* CONFIG_MEM_SOFT_DIRTY */ @@ -115,22 +114,23 @@ static inline pmd_t native_pmdp_get_and_ #define PTE_FILE_BITS1 (PTE_FILE_SHIFT2 - PTE_FILE_SHIFT1 - 1) #define PTE_FILE_BITS2 (PTE_FILE_SHIFT3 - PTE_FILE_SHIFT2 - 1) -#define pte_to_pgoff(pte) \ - ((((pte).pte_low >> PTE_FILE_SHIFT1) \ - & ((1U << PTE_FILE_BITS1) - 1)) \ - + ((((pte).pte_low >> PTE_FILE_SHIFT2) \ - & ((1U << PTE_FILE_BITS2) - 1)) << PTE_FILE_BITS1) \ - + (((pte).pte_low >> PTE_FILE_SHIFT3) \ - << (PTE_FILE_BITS1 + PTE_FILE_BITS2))) - -#define pgoff_to_pte(off) \ - ((pte_t) { .pte_low = \ - (((off) & ((1U << PTE_FILE_BITS1) - 1)) << PTE_FILE_SHIFT1) \ - + ((((off) >> PTE_FILE_BITS1) & ((1U << PTE_FILE_BITS2) - 1)) \ - << PTE_FILE_SHIFT2) \ - + (((off) >> (PTE_FILE_BITS1 + PTE_FILE_BITS2)) \ - << PTE_FILE_SHIFT3) \ - + _PAGE_FILE }) +#define PTE_FILE_MASK1 ((1U << PTE_FILE_BITS1) - 1) +#define PTE_FILE_MASK2 ((1U << PTE_FILE_BITS2) - 1) + +#define PTE_FILE_LSHIFT2 (PTE_FILE_BITS1) +#define PTE_FILE_LSHIFT3 (PTE_FILE_BITS1 + PTE_FILE_BITS2) + +#define pte_to_pgoff(pte) \ + (_mfrob((pte).pte_low, PTE_FILE_SHIFT1, PTE_FILE_MASK1, 0) + \ + _mfrob((pte).pte_low, PTE_FILE_SHIFT2, PTE_FILE_MASK2, PTE_FILE_LSHIFT2) + \ + __frob((pte).pte_low, PTE_FILE_SHIFT3, PTE_FILE_LSHIFT3)) + +#define pgoff_to_pte(off) \ + ((pte_t) { .pte_low = \ + _mfrob(off, 0, PTE_FILE_MASK1, PTE_FILE_SHIFT1) + \ + _mfrob(off, PTE_FILE_LSHIFT2, PTE_FILE_MASK2, PTE_FILE_SHIFT2) + \ + __frob(off, PTE_FILE_LSHIFT3, PTE_FILE_SHIFT3) + \ + _PAGE_FILE }) #endif /* CONFIG_MEM_SOFT_DIRTY */