Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755275AbZCEIjs (ORCPT ); Thu, 5 Mar 2009 03:39:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752711AbZCEIjg (ORCPT ); Thu, 5 Mar 2009 03:39:36 -0500 Received: from sh.osrg.net ([192.16.179.4]:43413 "EHLO sh.osrg.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750972AbZCEIjg (ORCPT ); Thu, 5 Mar 2009 03:39:36 -0500 Date: Thu, 5 Mar 2009 17:39:17 +0900 To: tglx@linutronix.de Cc: James.Bottomley@HansenPartnership.com, jengelh@medozas.de, bharrosh@panasas.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org Subject: Re: [BUG] 2.6.29-rc6-2450cf in scsi_lib.c (was: Large amount of scsi-sgpool)objects From: FUJITA Tomonori In-Reply-To: <20090305173649M.fujita.tomonori@lab.ntt.co.jp> References: <1236207389.21486.19.camel@localhost.localdomain> <20090305173649M.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20090305173952U.fujita.tomonori@lab.ntt.co.jp> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-3.0 (sh.osrg.net [192.16.179.4]); Thu, 05 Mar 2009 17:39:18 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2797 Lines: 78 On Thu, 5 Mar 2009 17:36:13 +0900 FUJITA Tomonori wrote: > CC'ed Jens, > > On Wed, 04 Mar 2009 22:56:29 +0000 > James Bottomley wrote: > > > On Wed, 2009-03-04 at 22:45 +0100, Thomas Gleixner wrote: > > > On Wed, 4 Mar 2009, Thomas Gleixner wrote: > > > > > > Instrumented the code and the result of the failing request is > > > below. Looks like the function which sets up the request gets > > > nr_phys_segments wrong by one. > > > > > > If you need further trace data feel free to ask. > > > > OK, the mapping all checks out correctly ... there must be something > > wrong with the way we count before mapping. > > Yeah, looks we miscalculate nr_phys_segments in the merging path. > > blk_recount_segments() needs to set bi_seg_front_size and > bi_seg_back_size for ll_merge_requests_fn()? > > = > diff --git a/block/blk-merge.c b/block/blk-merge.c > index a104593..efb65b6 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -111,12 +111,19 @@ void blk_recalc_rq_segments(struct request *rq) > > void blk_recount_segments(struct request_queue *q, struct bio *bio) > { > + unsigned int seg_size; > struct bio *nxt = bio->bi_next; > > bio->bi_next = NULL; > - bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, NULL); > + bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, &seg_size); > bio->bi_next = nxt; > bio->bi_flags |= (1 << BIO_SEG_VALID); > + > + if (bio->bi_phys_segments == 1 && seg_size > bio->bi_seg_front_size) > + bio->bi_seg_front_size = seg_size; > + if (bio->bi_phys_segments > bio->bi_seg_back_size) > + bio->bi_seg_back_size = seg_size; > + > } > EXPORT_SYMBOL(blk_recount_segments); Duh, here's the proper patch. diff --git a/block/blk-merge.c b/block/blk-merge.c index a104593..06e0db4 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -111,12 +111,19 @@ void blk_recalc_rq_segments(struct request *rq) void blk_recount_segments(struct request_queue *q, struct bio *bio) { + unsigned int seg_size; struct bio *nxt = bio->bi_next; bio->bi_next = NULL; - bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, NULL); + bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, &seg_size); bio->bi_next = nxt; bio->bi_flags |= (1 << BIO_SEG_VALID); + + if (bio->bi_phys_segments == 1 && seg_size > bio->bi_seg_front_size) + bio->bi_seg_front_size = seg_size; + if (seg_size > bio->bi_seg_back_size) + bio->bi_seg_back_size = seg_size; + } EXPORT_SYMBOL(blk_recount_segments); -- 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/