From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: [md PATCH 2/5] md/raid5: use md_write_start to count stripes, not bios Date: Mon, 21 Nov 2016 12:19:43 +1100 Message-ID: <147969118330.5434.9548726247224162889.stgit@noble> References: <147969099621.5434.12384452255155063186.stgit@noble> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <147969099621.5434.12384452255155063186.stgit@noble> Sender: linux-raid-owner@vger.kernel.org To: Shaohua Li Cc: Konstantin Khlebnikov , Christoph Hellwig , linux-raid@vger.kernel.org List-Id: linux-raid.ids We use md_write_start() to increase the count of pending writes, and md_write_end() to decrement the count. We currently count bios submitted to md/raid5. Change it count stripe_heads that a WRITE bio has been attached to. So raid5_make_request() call md_write_start() and then md_write_end(). add_stripe_bio() calls md_write_start() for each stripe_head, and the completion routines always call md_write_end(), instead of only calling when raid5_dec_bi_active_stripes() returns 0. This reduces our dependence on keeping a per-bio count of active stripes in bi_phys_segments. Signed-off-by: NeilBrown --- drivers/md/raid5.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index df88656d8798..d07d2dce6856 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2998,6 +2998,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, bi->bi_next = *bip; *bip = bi; raid5_inc_bi_active_stripes(bi); + md_write_start(conf->mddev, bi); if (forwrite) { /* check if page is covered */ @@ -3121,10 +3122,9 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh, struct bio *nextbi = r5_next_bio(bi, sh->dev[i].sector); bi->bi_error = -EIO; - if (!raid5_dec_bi_active_stripes(bi)) { - md_write_end(conf->mddev); + md_write_end(conf->mddev); + if (!raid5_dec_bi_active_stripes(bi)) bio_list_add(return_bi, bi); - } bi = nextbi; } if (bitmap_end) @@ -3145,10 +3145,9 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh, struct bio *bi2 = r5_next_bio(bi, sh->dev[i].sector); bi->bi_error = -EIO; - if (!raid5_dec_bi_active_stripes(bi)) { - md_write_end(conf->mddev); + md_write_end(conf->mddev); + if (!raid5_dec_bi_active_stripes(bi)) bio_list_add(return_bi, bi); - } bi = bi2; } @@ -3490,10 +3489,9 @@ static void handle_stripe_clean_event(struct r5conf *conf, while (wbi && wbi->bi_iter.bi_sector < dev->sector + STRIPE_SECTORS) { wbi2 = r5_next_bio(wbi, dev->sector); - if (!raid5_dec_bi_active_stripes(wbi)) { - md_write_end(conf->mddev); + md_write_end(conf->mddev); + if (!raid5_dec_bi_active_stripes(wbi)) bio_list_add(return_bi, wbi); - } wbi = wbi2; } bitmap_endwrite(conf->mddev->bitmap, sh->sector, @@ -5142,9 +5140,9 @@ static void make_discard_request(struct mddev *mddev, struct bio *bi) release_stripe_plug(mddev, sh); } + md_write_end(mddev); remaining = raid5_dec_bi_active_stripes(bi); if (remaining == 0) { - md_write_end(mddev); bio_endio(bi); } } @@ -5173,8 +5171,6 @@ static void raid5_make_request(struct mddev *mddev, struct bio * bi) /* ret == -EAGAIN, fallback */ } - md_write_start(mddev, bi); - /* * If array is degraded, better not do chunk aligned read because * later we might have to read it again in order to reconstruct @@ -5196,6 +5192,7 @@ static void raid5_make_request(struct mddev *mddev, struct bio * bi) last_sector = bio_end_sector(bi); bi->bi_next = NULL; bi->bi_phys_segments = 1; /* over-loaded to count active stripes */ + md_write_start(mddev, bi); prepare_to_wait(&conf->wait_for_overlap, &w, TASK_UNINTERRUPTIBLE); for (;logical_sector < last_sector; logical_sector += STRIPE_SECTORS) { @@ -5324,11 +5321,11 @@ static void raid5_make_request(struct mddev *mddev, struct bio * bi) } finish_wait(&conf->wait_for_overlap, &w); + if (rw == WRITE) + md_write_end(mddev); remaining = raid5_dec_bi_active_stripes(bi); if (remaining == 0) { - if ( rw == WRITE ) - md_write_end(mddev); trace_block_bio_complete(bdev_get_queue(bi->bi_bdev), bi, 0);