diff options
| -rw-r--r-- | mm/memory.c | 72 |
1 files changed, 38 insertions, 34 deletions
diff --git a/mm/memory.c b/mm/memory.c index d0cc1c134a64..9144fae9a68b 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2229,8 +2229,45 @@ reuse: entry = maybe_mkwrite(pte_mkdirty(entry), vma); if (ptep_set_access_flags(vma, address, page_table, entry,1)) update_mmu_cache(vma, address, page_table); + pte_unmap_unlock(page_table, ptl); ret |= VM_FAULT_WRITE; - goto unlock; + + if (!dirty_page) + return ret; + + /* + * Yes, Virginia, this is actually required to prevent a race + * with clear_page_dirty_for_io() from clearing the page dirty + * bit after it clear all dirty ptes, but before a racing + * do_wp_page installs a dirty pte. + * + * do_no_page is protected similarly. + */ + if (!page_mkwrite) { + wait_on_page_locked(dirty_page); + set_page_dirty_balance(dirty_page, page_mkwrite); + } + put_page(dirty_page); + if (page_mkwrite) { + struct address_space *mapping = dirty_page->mapping; + + set_page_dirty(dirty_page); + unlock_page(dirty_page); + page_cache_release(dirty_page); + if (mapping) { + /* + * Some device drivers do not set page.mapping + * but still dirty their pages + */ + balance_dirty_pages_ratelimited(mapping); + } + } + + /* file_update_time outside page_lock */ + if (vma->vm_file) + file_update_time(vma->vm_file); + + return ret; } /* @@ -2336,39 +2373,6 @@ gotten: page_cache_release(old_page); unlock: pte_unmap_unlock(page_table, ptl); - if (dirty_page) { - /* - * Yes, Virginia, this is actually required to prevent a race - * with clear_page_dirty_for_io() from clearing the page dirty - * bit after it clear all dirty ptes, but before a racing - * do_wp_page installs a dirty pte. - * - * do_no_page is protected similarly. - */ - if (!page_mkwrite) { - wait_on_page_locked(dirty_page); - set_page_dirty_balance(dirty_page, page_mkwrite); - } - put_page(dirty_page); - if (page_mkwrite) { - struct address_space *mapping = dirty_page->mapping; - - set_page_dirty(dirty_page); - unlock_page(dirty_page); - page_cache_release(dirty_page); - if (mapping) { - /* - * Some device drivers do not set page.mapping - * but still dirty their pages - */ - balance_dirty_pages_ratelimited(mapping); - } - } - - /* file_update_time outside page_lock */ - if (vma->vm_file) - file_update_time(vma->vm_file); - } return ret; oom_free_new: page_cache_release(new_page); |