From c0718806cf955d5eb51ea77bffb5b21d9bba4972 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Sat, 29 Oct 2005 18:16:31 -0700 Subject: [PATCH] mm: rmap with inner ptlock rmap's page_check_address descend without page_table_lock. First just pte_offset_map in case there's no pte present worth locking for, then take page_table_lock for the full check, and pass ptl back to caller in the same style as pte_offset_map_lock. __xip_unmap, page_referenced_one and try_to_unmap_one use pte_unmap_unlock. try_to_unmap_cluster also. page_check_address reformatted to avoid progressive indentation. No use is made of its one error code, return NULL when it fails. Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap_xip.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) (limited to 'mm/filemap_xip.c') diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c index 4e74ad60339a..9cf687e4a29a 100644 --- a/mm/filemap_xip.c +++ b/mm/filemap_xip.c @@ -174,6 +174,7 @@ __xip_unmap (struct address_space * mapping, unsigned long address; pte_t *pte; pte_t pteval; + spinlock_t *ptl; struct page *page; spin_lock(&mapping->i_mmap_lock); @@ -183,20 +184,15 @@ __xip_unmap (struct address_space * mapping, ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); BUG_ON(address < vma->vm_start || address >= vma->vm_end); page = ZERO_PAGE(address); - /* - * We need the page_table_lock to protect us from page faults, - * munmap, fork, etc... - */ - pte = page_check_address(page, mm, address); - if (!IS_ERR(pte)) { + pte = page_check_address(page, mm, address, &ptl); + if (pte) { /* Nuke the page table entry. */ flush_cache_page(vma, address, pte_pfn(*pte)); pteval = ptep_clear_flush(vma, address, pte); page_remove_rmap(page); dec_mm_counter(mm, file_rss); BUG_ON(pte_dirty(pteval)); - pte_unmap(pte); - spin_unlock(&mm->page_table_lock); + pte_unmap_unlock(pte, ptl); page_cache_release(page); } } -- cgit v1.2.3-59-g8ed1b