From 7bfe54b5f16561bb703de6482f880614ada8dbf2 Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Fri, 6 Nov 2020 13:20:54 +0000 Subject: [PATCH] powerpc/mm: Refactor the floor/ceiling check in hugetlb range freeing functions 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[ Signed-off-by: Christophe Leroy Reviewed-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/16a571bb32eb6e8cd44bda484c8d81cd8a25e6d7.1604668827.git.christophe.leroy@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);