From 4ad1d9849ffa8738b5e9b3f8bda5f17d3b31dfcd Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Thu, 16 Jun 2022 13:19:41 -0600 Subject: [PATCH] md/raid5: Refactor add_stripe_bio() Factor out two helper functions from add_stripe_bio(): one to check for overlap (stripe_bio_overlaps()), and one to actually add the bio to the stripe (__add_stripe_bio()). The latter function will always succeed. This will be useful in the next patch so that overlap can be checked for multiple disks before adding any Signed-off-by: Logan Gunthorpe Reviewed-by: Christoph Hellwig Signed-off-by: Song Liu Signed-off-by: Jens Axboe --- drivers/md/raid5.c | 86 +++++++++++++++++++++++++++++++++++------------------- 1 file changed, 56 insertions(+), 30 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 200dc64..f243043 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3416,39 +3416,32 @@ schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s, s->locked, s->ops_request); } -/* - * Each stripe/dev can have one or more bion attached. - * toread/towrite point to the first in a chain. - * The bi_next chain must be in order. - */ -static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, - int forwrite, int previous) +static bool stripe_bio_overlaps(struct stripe_head *sh, struct bio *bi, + int dd_idx, int forwrite) { - struct bio **bip; struct r5conf *conf = sh->raid_conf; - int firstwrite=0; + struct bio **bip; - pr_debug("adding bi b#%llu to stripe s#%llu\n", - (unsigned long long)bi->bi_iter.bi_sector, - (unsigned long long)sh->sector); + pr_debug("checking bi b#%llu to stripe s#%llu\n", + bi->bi_iter.bi_sector, sh->sector); - spin_lock_irq(&sh->stripe_lock); /* Don't allow new IO added to stripes in batch list */ if (sh->batch_head) - goto overlap; - if (forwrite) { + return true; + + if (forwrite) bip = &sh->dev[dd_idx].towrite; - if (*bip == NULL) - firstwrite = 1; - } else + else bip = &sh->dev[dd_idx].toread; + while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) { if (bio_end_sector(*bip) > bi->bi_iter.bi_sector) - goto overlap; - bip = & (*bip)->bi_next; + return true; + bip = &(*bip)->bi_next; } + if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi)) - goto overlap; + return true; if (forwrite && raid5_has_ppl(conf)) { /* @@ -3477,9 +3470,30 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, } if (first + conf->chunk_sectors * (count - 1) != last) - goto overlap; + return true; } + return false; +} + +static void __add_stripe_bio(struct stripe_head *sh, struct bio *bi, + int dd_idx, int forwrite, int previous) +{ + struct r5conf *conf = sh->raid_conf; + struct bio **bip; + int firstwrite = 0; + + if (forwrite) { + bip = &sh->dev[dd_idx].towrite; + if (!*bip) + firstwrite = 1; + } else { + bip = &sh->dev[dd_idx].toread; + } + + while (*bip && (*bip)->bi_iter.bi_sector < bi->bi_iter.bi_sector) + bip = &(*bip)->bi_next; + if (!forwrite || previous) clear_bit(STRIPE_BATCH_READY, &sh->state); @@ -3506,8 +3520,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, } pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n", - (unsigned long long)(*bip)->bi_iter.bi_sector, - (unsigned long long)sh->sector, dd_idx); + (*bip)->bi_iter.bi_sector, sh->sector, dd_idx); if (conf->mddev->bitmap && firstwrite) { /* Cannot hold spinlock over bitmap_startwrite, @@ -3515,7 +3528,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, * we have added to the bitmap and set bm_seq. * So set STRIPE_BITMAP_PENDING to prevent * batching. - * If multiple add_stripe_bio() calls race here they + * If multiple __add_stripe_bio() calls race here they * much all set STRIPE_BITMAP_PENDING. So only the first one * to complete "bitmap_startwrite" gets to set * STRIPE_BIT_DELAY. This is important as once a stripe @@ -3533,14 +3546,27 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, set_bit(STRIPE_BIT_DELAY, &sh->state); } } - spin_unlock_irq(&sh->stripe_lock); +} - return 1; +/* + * Each stripe/dev can have one or more bios attached. + * toread/towrite point to the first in a chain. + * The bi_next chain must be in order. + */ +static bool add_stripe_bio(struct stripe_head *sh, struct bio *bi, + int dd_idx, int forwrite, int previous) +{ + spin_lock_irq(&sh->stripe_lock); - overlap: - set_bit(R5_Overlap, &sh->dev[dd_idx].flags); + if (stripe_bio_overlaps(sh, bi, dd_idx, forwrite)) { + set_bit(R5_Overlap, &sh->dev[dd_idx].flags); + spin_unlock_irq(&sh->stripe_lock); + return false; + } + + __add_stripe_bio(sh, bi, dd_idx, forwrite, previous); spin_unlock_irq(&sh->stripe_lock); - return 0; + return true; } static void end_reshape(struct r5conf *conf); -- 2.7.4