From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:54634 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750821AbdGMBls (ORCPT ); Wed, 12 Jul 2017 21:41:48 -0400 Date: Thu, 13 Jul 2017 09:41:33 +0800 From: Ming Lei To: NeilBrown Cc: Shaohua Li , linux-raid@vger.kernel.org, linux-block@vger.kernel.org, Jens Axboe , Christoph Hellwig Subject: Re: [PATCH 1/2] md: remove 'idx' from 'struct resync_pages' Message-ID: <20170713014132.GE670@ming.t460p> References: <20170712082845.436-1-ming.lei@redhat.com> <8737a1437y.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <8737a1437y.fsf@notabene.neil.brown.name> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Thu, Jul 13, 2017 at 09:58:41AM +1000, NeilBrown wrote: > On Wed, Jul 12 2017, Ming Lei wrote: > > > bio_add_page() won't fail for resync bio, and the page index for each > > bio is same, so remove it. > > > > More importantly the 'idx' of 'struct resync_pages' is initialized in > > mempool allocator function, this way is wrong since mempool is only > > responsible for allocation, we can't use that for initialization. > > > > Suggested-by: NeilBrown > > Reported-by: NeilBrown > > Fixes: f0250618361d(md: raid10: don't use bio's vec table to manage resync pages) > > Fixes: 98d30c5812c3(md: raid1: don't use bio's vec table to manage resync pages) > > Signed-off-by: Ming Lei > > --- > > drivers/md/md.h | 1 - > > drivers/md/raid1.c | 6 +++--- > > drivers/md/raid10.c | 6 +++--- > > 3 files changed, 6 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/md/md.h b/drivers/md/md.h > > index 991f0fe2dcc6..2c780aa8d07f 100644 > > --- a/drivers/md/md.h > > +++ b/drivers/md/md.h > > @@ -736,7 +736,6 @@ static inline void mddev_check_write_zeroes(struct mddev *mddev, struct bio *bio > > > > /* for managing resync I/O pages */ > > struct resync_pages { > > - unsigned idx; /* for get/put page from the pool */ > > void *raid_bio; > > struct page *pages[RESYNC_PAGES]; > > }; > > diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c > > index 3febfc8391fb..7901ddc3362f 100644 > > --- a/drivers/md/raid1.c > > +++ b/drivers/md/raid1.c > > @@ -170,7 +170,6 @@ static void * r1buf_pool_alloc(gfp_t gfp_flags, void *data) > > resync_get_all_pages(rp); > > } > > > > - rp->idx = 0; > > rp->raid_bio = r1_bio; > > bio->bi_private = rp; > > } > > @@ -2619,6 +2618,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr, > > int good_sectors = RESYNC_SECTORS; > > int min_bad = 0; /* number of sectors that are bad in all devices */ > > int idx = sector_to_idx(sector_nr); > > + int page_idx = 0; > > > > if (!conf->r1buf_pool) > > if (init_resync(conf)) > > @@ -2846,7 +2846,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr, > > bio = r1_bio->bios[i]; > > rp = get_resync_pages(bio); > > if (bio->bi_end_io) { > > - page = resync_fetch_page(rp, rp->idx++); > > + page = resync_fetch_page(rp, page_idx); > > > > /* > > * won't fail because the vec table is big > > @@ -2858,7 +2858,7 @@ static sector_t raid1_sync_request(struct mddev *mddev, sector_t sector_nr, > > nr_sectors += len>>9; > > sector_nr += len>>9; > > sync_blocks -= (len>>9); > > - } while (get_resync_pages(r1_bio->bios[disk]->bi_private)->idx < RESYNC_PAGES); > > + } while (page_idx++ < RESYNC_PAGES); > > I think you want ++page_idx < RESYNC_PAGES, otherwise there will be > one pass through the loop where page_idx == RESYNC_PAGES Good catch, thanks! thanks, Ming