Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264145AbTEHAOZ (ORCPT ); Wed, 7 May 2003 20:14:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264436AbTEHAOZ (ORCPT ); Wed, 7 May 2003 20:14:25 -0400 Received: from mion.elka.pw.edu.pl ([194.29.160.35]:30381 "EHLO mion.elka.pw.edu.pl") by vger.kernel.org with ESMTP id S264145AbTEHAOX (ORCPT ); Wed, 7 May 2003 20:14:23 -0400 Date: Thu, 8 May 2003 02:26:37 +0200 (MET DST) From: Bartlomiej Zolnierkiewicz To: Dave Peterson cc: , , Subject: Re: [PATCH] fixes for linked list bugs in block I/O code In-Reply-To: <200305071709.57757.dsp@llnl.gov> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1961 Lines: 56 On Wed, 7 May 2003, Dave Peterson wrote: > On Wednesday 07 May 2003 04:42 pm, Bartlomiej Zolnierkiewicz wrote: > > > ========== START OF 2.5.69 PATCH FOR drivers/block/ll_rw_blk.c > > > =========== --- ll_rw_blk.c.old Wed May 7 15:55:18 2003 > > > +++ ll_rw_blk.c.new Wed May 7 16:01:56 2003 > > > @@ -1721,6 +1721,7 @@ > > > break; > > > } > > > > > > + bio->bi_next = req->biotail->bi_next; > > > > This is simply wrong, look at the line below. > > > > > req->biotail->bi_next = bio; > > > > req->bio - first bio > > req->bio->bi_next - next bio > > ... > > req->biotail - last bio > > > > so req->biotail->bi_next should be NULL > > I believe it is correct. Assuming that the list is initially in a > sane state, req->biotail->bi_next will be NULL immediately before > executing the statement that I added. Therefore, my fix will set > bio->bi_next to NULL, which is what we want because bio becomes the > new end of the list. Yes, but bio->bi_next is a NULL already. > > > req->biotail = bio; > > > req->nr_sectors = req->hard_nr_sectors += > > > nr_sectors; @@ -1811,6 +1812,7 @@ > > > req->buffer = bio_data(bio); /* see ->buffer comment above */ > > > req->waiting = NULL; > > > req->bio = req->biotail = bio; > > > + bio->bi_next = NULL; > > > > No need for that, look at bio_init() in fs/bio.c. > > Yes, it looks like bio_init has been added in the 2.5 kernels, solving > the problem. However, this is still a bug in 2.4.20. Maybe. If so only second part of the patch is important. Regards, -- Bartlomiej - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/