Commit 4ad1d984 authored by Logan Gunthorpe's avatar Logan Gunthorpe Committed by Jens Axboe
Browse files

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: default avatarLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarSong Liu <song@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3312e6c8

drivers/md/raid5.c

+56 −30
Original line number Diff line number Diff line
@@ -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;

			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:

	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 0;

		return false;

	}



	__add_stripe_bio(sh, bi, dd_idx, forwrite, previous);

	spin_unlock_irq(&sh->stripe_lock);

	return true;

}



static void end_reshape(struct r5conf *conf);