diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 62 |
1 files changed, 28 insertions, 34 deletions
diff --git a/mm/memory.c b/mm/memory.c index 5dfc9fac8b74..0c69908d3eed 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -129,7 +129,7 @@ static int __init init_zero_pfn(void) zero_pfn = page_to_pfn(ZERO_PAGE(0)); return 0; } -core_initcall(init_zero_pfn); +early_initcall(init_zero_pfn); #if defined(SPLIT_RSS_COUNTING) @@ -1686,11 +1686,11 @@ static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, unsigned long addr, unsigned long end, unsigned long pfn, pgprot_t prot) { - pte_t *pte; + pte_t *pte, *mapped_pte; spinlock_t *ptl; int err = 0; - pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); + mapped_pte = pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); if (!pte) return -ENOMEM; arch_enter_lazy_mmu_mode(); @@ -1704,7 +1704,7 @@ static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, pfn++; } while (pte++, addr += PAGE_SIZE, addr != end); arch_leave_lazy_mmu_mode(); - pte_unmap_unlock(pte - 1, ptl); + pte_unmap_unlock(mapped_pte, ptl); return err; } @@ -2399,39 +2399,31 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, * Take out anonymous pages first, anonymous shared vmas are * not dirty accountable. */ - if (PageAnon(old_page) && !PageKsm(old_page)) { - if (!trylock_page(old_page)) { - page_cache_get(old_page); - pte_unmap_unlock(page_table, ptl); - lock_page(old_page); - page_table = pte_offset_map_lock(mm, pmd, address, - &ptl); - if (!pte_same(*page_table, orig_pte)) { - unlock_page(old_page); - pte_unmap_unlock(page_table, ptl); - page_cache_release(old_page); - return 0; - } - page_cache_release(old_page); - } - if (reuse_swap_page(old_page)) { - /* - * The page is all ours. Move it to our anon_vma so - * the rmap code will not search our parent or siblings. - * Protected against the rmap code by the page lock. - */ - page_move_anon_rmap(old_page, vma, address); + if (PageAnon(old_page)) { + /* PageKsm() doesn't necessarily raise the page refcount */ + if (PageKsm(old_page) || page_count(old_page) != 1) + goto copy; + if (!trylock_page(old_page)) + goto copy; + if (PageKsm(old_page) || page_mapcount(old_page) != 1 || page_count(old_page) != 1) { unlock_page(old_page); - return wp_page_reuse(mm, vma, address, page_table, ptl, - orig_pte, old_page, 0, 0); + goto copy; } + /* + * Ok, we've got the only map reference, and the only + * page count reference, and the page is locked, + * it's dark out, and we're wearing sunglasses. Hit it. + */ unlock_page(old_page); + wp_page_reuse(mm, vma, address, page_table, ptl, + orig_pte, old_page, 0, 0); + return VM_FAULT_WRITE; } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == (VM_WRITE|VM_SHARED))) { return wp_page_shared(mm, vma, address, page_table, pmd, ptl, orig_pte, old_page); } - +copy: /* * Ok, we need to copy. Oh, well.. */ @@ -3210,9 +3202,6 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, bool was_writable = pte_write(pte); int flags = 0; - /* A PROT_NONE fault should not end up here */ - BUG_ON(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))); - /* * The "pte" at this point cannot be used safely without * validation through pte_unmap_same(). It's of NUMA type but @@ -3305,6 +3294,11 @@ static int wp_huge_pmd(struct mm_struct *mm, struct vm_area_struct *vma, return VM_FAULT_FALLBACK; } +static inline bool vma_is_accessible(struct vm_area_struct *vma) +{ + return vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE); +} + /* * These routines also need to handle stuff like marking pages dirty * and/or accessed for architectures that don't do it in hardware (most @@ -3351,7 +3345,7 @@ static int handle_pte_fault(struct mm_struct *mm, pte, pmd, flags, entry); } - if (pte_protnone(entry)) + if (pte_protnone(entry) && vma_is_accessible(vma)) return do_numa_page(mm, vma, address, entry, pte, pmd); ptl = pte_lockptr(mm, pmd); @@ -3426,7 +3420,7 @@ static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (pmd_trans_splitting(orig_pmd)) return 0; - if (pmd_protnone(orig_pmd)) + if (pmd_protnone(orig_pmd) && vma_is_accessible(vma)) return do_huge_pmd_numa_page(mm, vma, address, orig_pmd, pmd); |