Christophe Leroy <christophe.le...@csgroup.eu> writes:

> All hugetlb range freeing functions have a verification like the following,
> which only differs by the mask used, depending on the page table level.
>
>       start &= MASK;
>       if (start < floor)
>               return;
>       if (ceiling) {
>               ceiling &= MASK;
>               if (! ceiling)
>                       return;
>               }
>       if (end - 1 > ceiling - 1)
>               return;
>
> Refactor that into a helper function which takes the mask as
> an argument, returning true when [start;end[ is not fully
> contained inside [floor;ceiling[
>

Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>

> Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu>
> ---
>  arch/powerpc/mm/hugetlbpage.c | 56 ++++++++++++-----------------------
>  1 file changed, 19 insertions(+), 37 deletions(-)
>
> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
> index 36c3800769fb..f8d8a4988e15 100644
> --- a/arch/powerpc/mm/hugetlbpage.c
> +++ b/arch/powerpc/mm/hugetlbpage.c
> @@ -294,6 +294,21 @@ static void hugepd_free(struct mmu_gather *tlb, void 
> *hugepte)
>  static inline void hugepd_free(struct mmu_gather *tlb, void *hugepte) {}
>  #endif
>  
> +/* Return true when the entry to be freed maps more than the area being 
> freed */
> +static bool range_is_outside_limits(unsigned long start, unsigned long end,
> +                                 unsigned long floor, unsigned long ceiling,
> +                                 unsigned long mask)
> +{
> +     if ((start & mask) < floor)
> +             return true;
> +     if (ceiling) {
> +             ceiling &= mask;
> +             if (!ceiling)
> +                     return true;
> +     }
> +     return end - 1 > ceiling - 1;
> +}
> +
>  static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int 
> pdshift,
>                             unsigned long start, unsigned long end,
>                             unsigned long floor, unsigned long ceiling)
> @@ -309,15 +324,7 @@ static void free_hugepd_range(struct mmu_gather *tlb, 
> hugepd_t *hpdp, int pdshif
>       if (shift > pdshift)
>               num_hugepd = 1 << (shift - pdshift);
>  
> -     start &= pdmask;
> -     if (start < floor)
> -             return;
> -     if (ceiling) {
> -             ceiling &= pdmask;
> -             if (! ceiling)
> -                     return;
> -     }
> -     if (end - 1 > ceiling - 1)
> +     if (range_is_outside_limits(start, end, floor, ceiling, pdmask))
>               return;
>  
>       for (i = 0; i < num_hugepd; i++, hpdp++)
> @@ -334,18 +341,9 @@ static void hugetlb_free_pte_range(struct mmu_gather 
> *tlb, pmd_t *pmd,
>                                  unsigned long addr, unsigned long end,
>                                  unsigned long floor, unsigned long ceiling)
>  {
> -     unsigned long start = addr;
>       pgtable_t token = pmd_pgtable(*pmd);
>  
> -     start &= PMD_MASK;
> -     if (start < floor)
> -             return;
> -     if (ceiling) {
> -             ceiling &= PMD_MASK;
> -             if (!ceiling)
> -                     return;
> -     }
> -     if (end - 1 > ceiling - 1)
> +     if (range_is_outside_limits(addr, end, floor, ceiling, PMD_MASK))
>               return;
>  
>       pmd_clear(pmd);
> @@ -395,15 +393,7 @@ static void hugetlb_free_pmd_range(struct mmu_gather 
> *tlb, pud_t *pud,
>                                 addr, next, floor, ceiling);
>       } while (addr = next, addr != end);
>  
> -     start &= PUD_MASK;
> -     if (start < floor)
> -             return;
> -     if (ceiling) {
> -             ceiling &= PUD_MASK;
> -             if (!ceiling)
> -                     return;
> -     }
> -     if (end - 1 > ceiling - 1)
> +     if (range_is_outside_limits(start, end, floor, ceiling, PUD_MASK))
>               return;
>  
>       pmd = pmd_offset(pud, start);
> @@ -446,15 +436,7 @@ static void hugetlb_free_pud_range(struct mmu_gather 
> *tlb, p4d_t *p4d,
>               }
>       } while (addr = next, addr != end);
>  
> -     start &= PGDIR_MASK;
> -     if (start < floor)
> -             return;
> -     if (ceiling) {
> -             ceiling &= PGDIR_MASK;
> -             if (!ceiling)
> -                     return;
> -     }
> -     if (end - 1 > ceiling - 1)
> +     if (range_is_outside_limits(start, end, floor, ceiling, PGDIR_MASK))
>               return;
>  
>       pud = pud_offset(p4d, start);
> -- 
> 2.25.0

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