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Commit 25591b07 authored by Martin Schwidefsky's avatar Martin Schwidefsky Committed by Martin Schwidefsky
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[S390] fix get_user_pages_fast 



The check for the _PAGE_RO bit in get_user_pages_fast for write==1 is
the wrong way around. It must not be set for the fast path.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent f6614b7b

arch/s390/mm/gup.c

+3 −4
Original line number Original line Diff line number Diff line
@@ -20,18 +20,17 @@ 
static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr,

static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr,

		unsigned long end, int write, struct page **pages, int *nr)

		unsigned long end, int write, struct page **pages, int *nr)

{

{

	unsigned long mask, result;

	unsigned long mask;

	pte_t *ptep, pte;

	pte_t *ptep, pte;

	struct page *page;

	struct page *page;





	result = write ? 0 : _PAGE_RO;

	mask = (write ? _PAGE_RO : 0) | _PAGE_INVALID | _PAGE_SPECIAL;

	mask = result | _PAGE_INVALID | _PAGE_SPECIAL;





	ptep = ((pte_t *) pmd_deref(pmd)) + pte_index(addr);

	ptep = ((pte_t *) pmd_deref(pmd)) + pte_index(addr);

	do {

	do {

		pte = *ptep;

		pte = *ptep;

		barrier();

		barrier();

		if ((pte_val(pte) & mask) != result)

		if ((pte_val(pte) & mask) != 0)

			return 0;

			return 0;

		VM_BUG_ON(!pfn_valid(pte_pfn(pte)));

		VM_BUG_ON(!pfn_valid(pte_pfn(pte)));

		page = pte_page(pte);

		page = pte_page(pte);