From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423176AbXDXW2u (ORCPT ); Tue, 24 Apr 2007 18:28:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423183AbXDXW1U (ORCPT ); Tue, 24 Apr 2007 18:27:20 -0400 Received: from netops-testserver-4-out.sgi.com ([192.48.171.29]:56820 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1423177AbXDXWXI (ORCPT ); Tue, 24 Apr 2007 18:23:08 -0400 Message-Id: <20070424222307.720364206@sgi.com> References: <20070424222105.883597089@sgi.com> User-Agent: quilt/0.45-1 Date: Tue, 24 Apr 2007 15:21:19 -0700 From: clameter@sgi.com To: linux-kernel@vger.kernel.org Cc: Mel Gorman , William Lee Irwin III , David Chinner , Jens Axboe , Badari Pulavarty , Maxim Levitsky Subject: [14/17] Add VM_BUG_ONs to check for correct page order Content-Disposition: inline; filename=var_pc_guards Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Before we start changing the page order we better get some debugging in there that trips us up whenever a wrong order page shows up in a mapping. This will be helpful for converting new filesystems to utilize higher orders. Signed-off-by: Christoph Lameter --- mm/filemap.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) Index: linux-2.6.21-rc7/mm/filemap.c =================================================================== --- linux-2.6.21-rc7.orig/mm/filemap.c 2007-04-24 11:45:26.000000000 -0700 +++ linux-2.6.21-rc7/mm/filemap.c 2007-04-24 11:46:04.000000000 -0700 @@ -127,6 +127,7 @@ void remove_from_page_cache(struct page struct address_space *mapping = page->mapping; BUG_ON(!PageLocked(page)); + VM_BUG_ON(mapping_order(mapping) != compound_order(page)); write_lock_irq(&mapping->tree_lock); __remove_from_page_cache(page); @@ -268,6 +269,7 @@ int wait_on_page_writeback_range(struct if (page->index > end) continue; + VM_BUG_ON(mapping_order(mapping) != compound_order(page)); wait_on_page_writeback(page); if (PageError(page)) ret = -EIO; @@ -439,6 +441,7 @@ int add_to_page_cache(struct page *page, { int error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); + VM_BUG_ON(mapping_order(mapping) != compound_order(page)); if (error == 0) { write_lock_irq(&mapping->tree_lock); error = radix_tree_insert(&mapping->page_tree, offset, page); @@ -598,8 +601,10 @@ struct page * find_get_page(struct addre read_lock_irq(&mapping->tree_lock); page = radix_tree_lookup(&mapping->page_tree, offset); - if (page) + if (page) { + VM_BUG_ON(mapping_order(mapping) != compound_order(page)); page_cache_get(page); + } read_unlock_irq(&mapping->tree_lock); return page; } @@ -624,6 +629,7 @@ struct page *find_lock_page(struct addre repeat: page = radix_tree_lookup(&mapping->page_tree, offset); if (page) { + VM_BUG_ON(mapping_order(mapping) != compound_order(page)); page_cache_get(page); if (TestSetPageLocked(page)) { read_unlock_irq(&mapping->tree_lock); @@ -685,6 +691,7 @@ repeat: } else if (err == -EEXIST) goto repeat; } + VM_BUG_ON(mapping_order(mapping) != compound_order(page)); if (cached_page) page_cache_release(cached_page); return page; @@ -716,8 +723,10 @@ unsigned find_get_pages(struct address_s read_lock_irq(&mapping->tree_lock); ret = radix_tree_gang_lookup(&mapping->page_tree, (void **)pages, start, nr_pages); - for (i = 0; i < ret; i++) + for (i = 0; i < ret; i++) { + VM_BUG_ON(mapping_order(mapping) != compound_order(pages[i])); page_cache_get(pages[i]); + } read_unlock_irq(&mapping->tree_lock); return ret; } @@ -747,6 +756,7 @@ unsigned find_get_pages_contig(struct ad if (pages[i]->mapping == NULL || pages[i]->index != index) break; + VM_BUG_ON(mapping_order(mapping) != compound_order(pages[i])); page_cache_get(pages[i]); index++; } @@ -774,8 +784,10 @@ unsigned find_get_pages_tag(struct addre read_lock_irq(&mapping->tree_lock); ret = radix_tree_gang_lookup_tag(&mapping->page_tree, (void **)pages, *index, nr_pages, tag); - for (i = 0; i < ret; i++) + for (i = 0; i < ret; i++) { + VM_BUG_ON(mapping_order(mapping) != compound_order(pages[i])); page_cache_get(pages[i]); + } if (ret) *index = pages[ret - 1]->index + 1; read_unlock_irq(&mapping->tree_lock); @@ -2457,6 +2469,7 @@ int try_to_release_page(struct page *pag struct address_space * const mapping = page->mapping; BUG_ON(!PageLocked(page)); + VM_BUG_ON(mapping_order(mapping) != compound_order(page)); if (PageWriteback(page)) return 0; --