diff options
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | mm/memory.c | 45 |
2 files changed, 47 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 77a76101dcd9..903f3b71f4a7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1124,6 +1124,8 @@ unsigned long vmalloc_to_pfn(void *addr); int remap_pfn_range(struct vm_area_struct *, unsigned long addr, unsigned long pfn, unsigned long size, pgprot_t); int vm_insert_page(struct vm_area_struct *, unsigned long addr, struct page *); +int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, + unsigned long pfn); struct page *follow_page(struct vm_area_struct *, unsigned long address, unsigned int foll_flags); diff --git a/mm/memory.c b/mm/memory.c index 072c1135ad37..8b8f0d2b453d 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1277,6 +1277,51 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page * } EXPORT_SYMBOL(vm_insert_page); +/** + * vm_insert_pfn - insert single pfn into user vma + * @vma: user vma to map to + * @addr: target user address of this page + * @pfn: source kernel pfn + * + * Similar to vm_inert_page, this allows drivers to insert individual pages + * they've allocated into a user vma. Same comments apply. + * + * This function should only be called from a vm_ops->fault handler, and + * in that case the handler should return NULL. + */ +int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, + unsigned long pfn) +{ + struct mm_struct *mm = vma->vm_mm; + int retval; + pte_t *pte, entry; + spinlock_t *ptl; + + BUG_ON(!(vma->vm_flags & VM_PFNMAP)); + BUG_ON(is_cow_mapping(vma->vm_flags)); + + retval = -ENOMEM; + pte = get_locked_pte(mm, addr, &ptl); + if (!pte) + goto out; + retval = -EBUSY; + if (!pte_none(*pte)) + goto out_unlock; + + /* Ok, finally just insert the thing.. */ + entry = pfn_pte(pfn, vma->vm_page_prot); + set_pte_at(mm, addr, pte, entry); + update_mmu_cache(vma, addr, entry); + + retval = 0; +out_unlock: + pte_unmap_unlock(pte, ptl); + +out: + return retval; +} +EXPORT_SYMBOL(vm_insert_pfn); + /* * maps a range of physical memory into the requested pages. the old * mappings are removed. any references to nonexistent pages results |