From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757244AbaGABIA (ORCPT ); Mon, 30 Jun 2014 21:08:00 -0400 Received: from mail-pa0-f48.google.com ([209.85.220.48]:63574 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757193AbaGABH4 (ORCPT ); Mon, 30 Jun 2014 21:07:56 -0400 Date: Mon, 30 Jun 2014 18:06:27 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Andrew Morton cc: Hugh Dickins , Johannes Weiner , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH mmotm/next] mm: memcontrol: rewrite charge API: fix shmem_unuse In-Reply-To: <20140630173428.5ebeed18.akpm@linux-foundation.org> Message-ID: References: <20140630160212.46caf9c3d41445b61fece666@linux-foundation.org> <20140630173428.5ebeed18.akpm@linux-foundation.org> User-Agent: Alpine 2.11 (LSU 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 30 Jun 2014, Andrew Morton wrote: > On Mon, 30 Jun 2014 17:10:54 -0700 (PDT) Hugh Dickins wrote: > > On Mon, 30 Jun 2014, Andrew Morton wrote: > > > On Mon, 30 Jun 2014 15:48:39 -0700 (PDT) Hugh Dickins wrote: > > > > - return 0; > > > > + return -EAGAIN; > > > > > > Maybe it's time to document the shmem_unuse_inode() return values. > > > > Oh dear. I had hoped they would look after themselves. This one is a > > private matter between shmem_unuse_inode and its one caller, just below. > > Well, readers of shmem_unuse_inode() won't know that unless we tell them. Add comments on the private use of -EAGAIN. Signed-off-by: Hugh Dickins --- mm/shmem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- 3.16-rc2-mm1+/mm/shmem.c 2014-06-30 15:05:50.736335600 -0700 +++ linux/mm/shmem.c 2014-06-30 18:00:02.820584009 -0700 @@ -611,7 +611,7 @@ static int shmem_unuse_inode(struct shme radswap = swp_to_radix_entry(swap); index = radix_tree_locate_item(&mapping->page_tree, radswap); if (index == -1) - return -EAGAIN; + return -EAGAIN; /* tell shmem_unuse we found nothing */ /* * Move _head_ to start search for next from here. @@ -712,6 +712,7 @@ int shmem_unuse(swp_entry_t swap, struct cond_resched(); if (error != -EAGAIN) break; + /* found nothing in this: move on to search the next */ } mutex_unlock(&shmem_swaplist_mutex);