diff options
| -rw-r--r-- | mm/memory.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c index af76397c2c54..56784e9a7151 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3317,6 +3317,43 @@ static int __do_fault(struct vm_area_struct *vma, unsigned long address, return ret; } +static int do_read_fault(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long address, pmd_t *pmd, + pgoff_t pgoff, unsigned int flags, pte_t orig_pte) +{ + struct page *fault_page; + spinlock_t *ptl; + pte_t entry, *pte; + int ret; + + ret = __do_fault(vma, address, pgoff, flags, &fault_page); + if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) + return ret; + + pte = pte_offset_map_lock(mm, pmd, address, &ptl); + if (unlikely(!pte_same(*pte, orig_pte))) { + pte_unmap_unlock(pte, ptl); + unlock_page(fault_page); + page_cache_release(fault_page); + return ret; + } + + flush_icache_page(vma, fault_page); + entry = mk_pte(fault_page, vma->vm_page_prot); + if (pte_file(orig_pte) && pte_file_soft_dirty(orig_pte)) + pte_mksoft_dirty(entry); + inc_mm_counter_fast(mm, MM_FILEPAGES); + page_add_file_rmap(fault_page); + set_pte_at(mm, address, pte, entry); + + /* no need to invalidate: a not-present page won't be cached */ + update_mmu_cache(vma, address, pte); + pte_unmap_unlock(pte, ptl); + unlock_page(fault_page); + + return ret; +} + /* * do_fault() tries to create a new page mapping. It aggressively * tries to share with existing pages, but makes a separate copy if @@ -3510,6 +3547,9 @@ static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; pte_unmap(page_table); + if (!(flags & FAULT_FLAG_WRITE)) + return do_read_fault(mm, vma, address, pmd, pgoff, flags, + orig_pte); return do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); } @@ -3542,6 +3582,9 @@ static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, } pgoff = pte_to_pgoff(orig_pte); + if (!(flags & FAULT_FLAG_WRITE)) + return do_read_fault(mm, vma, address, pmd, pgoff, flags, + orig_pte); return do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); } |