From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753505AbdJaCRG (ORCPT ); Mon, 30 Oct 2017 22:17:06 -0400 Received: from LGEAMRELO12.lge.com ([156.147.23.52]:45449 "EHLO lgeamrelo12.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751956AbdJaCRE (ORCPT ); Mon, 30 Oct 2017 22:17:04 -0400 X-Original-SENDERIP: 156.147.1.121 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.220.163 X-Original-MAILFROM: minchan@kernel.org Date: Tue, 31 Oct 2017 11:17:02 +0900 From: Minchan Kim To: Michal Hocko Cc: "Huang, Ying" , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Tim Chen , stable@vger.kernel.org, Christian Kujau Subject: Re: [PATCH -mm -V2] mm, swap: Fix false error message in __swp_swapcount() Message-ID: <20171031021702.GA942@bbox> References: <20171027055327.5428-1-ying.huang@intel.com> <20171029235713.GA4332@bbox> <20171030080230.apijacsx7fd3qeox@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171030080230.apijacsx7fd3qeox@dhcp22.suse.cz> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 30, 2017 at 09:02:30AM +0100, Michal Hocko wrote: > On Mon 30-10-17 08:57:13, Minchan Kim wrote: > [...] > > Although it's better than old, we can make it simple, still. > > > > diff --git a/include/linux/swapops.h b/include/linux/swapops.h > > index 291c4b534658..f50d5a48f03a 100644 > > --- a/include/linux/swapops.h > > +++ b/include/linux/swapops.h > > @@ -41,6 +41,13 @@ static inline unsigned swp_type(swp_entry_t entry) > > return (entry.val >> SWP_TYPE_SHIFT(entry)); > > } > > > > +extern struct swap_info_struct *swap_info[]; > > + > > +static inline struct swap_info_struct *swp_si(swp_entry_t entry) > > +{ > > + return swap_info[swp_type(entry)]; > > +} > > + > > /* > > * Extract the `offset' field from a swp_entry_t. The swp_entry_t is in > > * arch-independent format > > diff --git a/mm/swap_state.c b/mm/swap_state.c > > index 378262d3a197..a0fe2d54ad09 100644 > > --- a/mm/swap_state.c > > +++ b/mm/swap_state.c > > @@ -554,6 +554,7 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, > > struct vm_area_struct *vma, unsigned long addr) > > { > > struct page *page; > > + struct swap_info_struct *si = swp_si(entry); > > Aren't you accessing beyond the array here? I couldn't understand what you intend. Could you explain what case does it accesses beyond the arrary? Thanks. > > > unsigned long entry_offset = swp_offset(entry); > > unsigned long offset = entry_offset; > > unsigned long start_offset, end_offset; > > @@ -572,6 +573,9 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, > > if (!start_offset) /* First page is swap header. */ > > start_offset++; > > > > + if (end_offset >= si->max) > > + end_offset = si->max - 1; > > + > > blk_start_plug(&plug); > > for (offset = start_offset; offset <= end_offset ; offset++) { > > /* Ok, do the async read-ahead now */ > > -- > Michal Hocko > SUSE Labs > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org