diff options
Diffstat (limited to 'mm/pgtable-generic.c')
| -rw-r--r-- | mm/pgtable-generic.c | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c index d2fc52bffafc..c7ab18a5fb77 100644 --- a/mm/pgtable-generic.c +++ b/mm/pgtable-generic.c @@ -10,6 +10,8 @@ #include <linux/pagemap.h> #include <linux/hugetlb.h> #include <linux/pgtable.h> +#include <linux/swap.h> +#include <linux/swapops.h> #include <linux/mm_inline.h> #include <asm/tlb.h> @@ -229,3 +231,57 @@ pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address, } #endif #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ + +pte_t *__pte_offset_map(pmd_t *pmd, unsigned long addr, pmd_t *pmdvalp) +{ + pmd_t pmdval; + + /* rcu_read_lock() to be added later */ + pmdval = pmdp_get_lockless(pmd); + if (pmdvalp) + *pmdvalp = pmdval; + if (unlikely(pmd_none(pmdval) || is_pmd_migration_entry(pmdval))) + goto nomap; + if (unlikely(pmd_trans_huge(pmdval) || pmd_devmap(pmdval))) + goto nomap; + if (unlikely(pmd_bad(pmdval))) { + pmd_clear_bad(pmd); + goto nomap; + } + return __pte_map(&pmdval, addr); +nomap: + /* rcu_read_unlock() to be added later */ + return NULL; +} + +pte_t *pte_offset_map_nolock(struct mm_struct *mm, pmd_t *pmd, + unsigned long addr, spinlock_t **ptlp) +{ + pmd_t pmdval; + pte_t *pte; + + pte = __pte_offset_map(pmd, addr, &pmdval); + if (likely(pte)) + *ptlp = pte_lockptr(mm, &pmdval); + return pte; +} + +pte_t *__pte_offset_map_lock(struct mm_struct *mm, pmd_t *pmd, + unsigned long addr, spinlock_t **ptlp) +{ + spinlock_t *ptl; + pmd_t pmdval; + pte_t *pte; +again: + pte = __pte_offset_map(pmd, addr, &pmdval); + if (unlikely(!pte)) + return pte; + ptl = pte_lockptr(mm, &pmdval); + spin_lock(ptl); + if (likely(pmd_same(pmdval, pmdp_get_lockless(pmd)))) { + *ptlp = ptl; + return pte; + } + pte_unmap_unlock(pte, ptl); + goto again; +} |