diff options
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | mm/memory.c | 37 |
2 files changed, 32 insertions, 7 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index fe6b4036664a..02793ac64ac6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1212,6 +1212,8 @@ void unmap_mapping_range(struct address_space *mapping, loff_t const holebegin, loff_t const holelen, int even_cows); int follow_pte(struct mm_struct *mm, unsigned long address, pte_t **ptepp, spinlock_t **ptlp); +int follow_pte_pmd(struct mm_struct *mm, unsigned long address, + pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp); int follow_pfn(struct vm_area_struct *vma, unsigned long address, unsigned long *pfn); int follow_phys(struct vm_area_struct *vma, unsigned long address, diff --git a/mm/memory.c b/mm/memory.c index 9f2c15cdb32c..b62f3bc63481 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3772,8 +3772,8 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) } #endif /* __PAGETABLE_PMD_FOLDED */ -static int __follow_pte(struct mm_struct *mm, unsigned long address, - pte_t **ptepp, spinlock_t **ptlp) +static int __follow_pte_pmd(struct mm_struct *mm, unsigned long address, + pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp) { pgd_t *pgd; pud_t *pud; @@ -3790,11 +3790,20 @@ static int __follow_pte(struct mm_struct *mm, unsigned long address, pmd = pmd_offset(pud, address); VM_BUG_ON(pmd_trans_huge(*pmd)); - if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) - goto out; - /* We cannot handle huge page PFN maps. Luckily they don't exist. */ - if (pmd_huge(*pmd)) + if (pmd_huge(*pmd)) { + if (!pmdpp) + goto out; + + *ptlp = pmd_lock(mm, pmd); + if (pmd_huge(*pmd)) { + *pmdpp = pmd; + return 0; + } + spin_unlock(*ptlp); + } + + if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) goto out; ptep = pte_offset_map_lock(mm, pmd, address, ptlp); @@ -3817,9 +3826,23 @@ int follow_pte(struct mm_struct *mm, unsigned long address, pte_t **ptepp, /* (void) is needed to make gcc happy */ (void) __cond_lock(*ptlp, - !(res = __follow_pte(mm, address, ptepp, ptlp))); + !(res = __follow_pte_pmd(mm, address, ptepp, NULL, + ptlp))); + return res; +} + +int follow_pte_pmd(struct mm_struct *mm, unsigned long address, + pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp) +{ + int res; + + /* (void) is needed to make gcc happy */ + (void) __cond_lock(*ptlp, + !(res = __follow_pte_pmd(mm, address, ptepp, pmdpp, + ptlp))); return res; } +EXPORT_SYMBOL(follow_pte_pmd); /** * follow_pfn - look up PFN at a user virtual address |