diff options
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | mm/memory.c | 73 |
2 files changed, 0 insertions, 75 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 62bd89414897..d750be768121 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2368,8 +2368,6 @@ void free_pgd_range(struct mmu_gather *tlb, unsigned long addr, unsigned long end, unsigned long floor, unsigned long ceiling); int copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma); -int follow_pte(struct vm_area_struct *vma, unsigned long address, - pte_t **ptepp, spinlock_t **ptlp); int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, void *buf, int len, int write); diff --git a/mm/memory.c b/mm/memory.c index cfc278691466..42674c0748cb 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -6099,79 +6099,6 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) } #endif /* __PAGETABLE_PMD_FOLDED */ -/** - * follow_pte - look up PTE at a user virtual address - * @vma: the memory mapping - * @address: user virtual address - * @ptepp: location to store found PTE - * @ptlp: location to store the lock for the PTE - * - * On a successful return, the pointer to the PTE is stored in @ptepp; - * the corresponding lock is taken and its location is stored in @ptlp. - * - * The contents of the PTE are only stable until @ptlp is released using - * pte_unmap_unlock(). This function will fail if the PTE is non-present. - * Present PTEs may include PTEs that map refcounted pages, such as - * anonymous folios in COW mappings. - * - * Callers must be careful when relying on PTE content after - * pte_unmap_unlock(). Especially if the PTE maps a refcounted page, - * callers must protect against invalidation with MMU notifiers; otherwise - * access to the PFN at a later point in time can trigger use-after-free. - * - * Only IO mappings and raw PFN mappings are allowed. The mmap semaphore - * should be taken for read. - * - * This function must not be used to modify PTE content. - * - * Return: zero on success, -ve otherwise. - */ -int follow_pte(struct vm_area_struct *vma, unsigned long address, - pte_t **ptepp, spinlock_t **ptlp) -{ - struct mm_struct *mm = vma->vm_mm; - pgd_t *pgd; - p4d_t *p4d; - pud_t *pud; - pmd_t *pmd; - pte_t *ptep; - - mmap_assert_locked(mm); - if (unlikely(address < vma->vm_start || address >= vma->vm_end)) - goto out; - - if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) - goto out; - - pgd = pgd_offset(mm, address); - if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) - goto out; - - p4d = p4d_offset(pgd, address); - if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d))) - goto out; - - pud = pud_offset(p4d, address); - if (pud_none(*pud) || unlikely(pud_bad(*pud))) - goto out; - - pmd = pmd_offset(pud, address); - VM_BUG_ON(pmd_trans_huge(*pmd)); - - ptep = pte_offset_map_lock(mm, pmd, address, ptlp); - if (!ptep) - goto out; - if (!pte_present(ptep_get(ptep))) - goto unlock; - *ptepp = ptep; - return 0; -unlock: - pte_unmap_unlock(ptep, *ptlp); -out: - return -EINVAL; -} -EXPORT_SYMBOL_GPL(follow_pte); - static inline void pfnmap_args_setup(struct follow_pfnmap_args *args, spinlock_t *lock, pte_t *ptep, pgprot_t pgprot, unsigned long pfn_base, |