Commit 7bfe54b5 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

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: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/16a571bb32eb6e8cd44bda484c8d81cd8a25e6d7.1604668827.git.christophe.leroy@csgroup.eu
parent 5f1888a0

arch/powerpc/mm/hugetlbpage.c

+19 −37
Original line number Diff line number Diff line
@@ -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);

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