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Commit 458b76ed authored by Kent Overstreet's avatar Kent Overstreet
Browse files

block: Kill bio_segments()/bi_vcnt usage 



When we start sharing biovecs, keeping bi_vcnt accurate for splits is
going to be error prone - and unnecessary, if we refactor some code.

So bio_segments() has to go - but most of the existing users just needed
to know if the bio had multiple segments, which is easier - add a
bio_multiple_segments() for them.

(Two of the current uses of bio_segments() are going to go away in a
couple patches, but the current implementation of bio_segments() is
unsafe as soon as we start doing driver conversions for immutable
biovecs - so implement a dumb version for bisectability, it'll go away
in a couple patches)

Signed-off-by: default avatarKent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Neil Brown <neilb@suse.de>
Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com>
Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
parent d57a5f7c

drivers/block/ps3disk.c

+3 −4
Original line number Diff line number Diff line
@@ -101,10 +101,9 @@ static void ps3disk_scatter_gather(struct ps3_storage_device *dev, 


	rq_for_each_segment(bvec, req, iter) {

		unsigned long flags;

		dev_dbg(&dev->sbd.core,

			"%s:%u: bio %u: %u segs %u sectors from %lu\n",

			__func__, __LINE__, i, bio_segments(iter.bio),

			bio_sectors(iter.bio), iter.bio->bi_iter.bi_sector);

		dev_dbg(&dev->sbd.core, "%s:%u: bio %u: %u sectors from %lu\n",

			__func__, __LINE__, i, bio_sectors(iter.bio),

			iter.bio->bi_iter.bi_sector);



		size = bvec.bv_len;

		buf = bvec_kmap_irq(&bvec, &flags);

drivers/md/bcache/io.c

+23 −30
Original line number Diff line number Diff line
@@ -24,7 +24,8 @@ static void bch_generic_make_request_hack(struct bio *bio) 
	if (bio->bi_iter.bi_idx) {

		struct bio_vec bv;

		struct bvec_iter iter;

		struct bio *clone = bio_alloc(GFP_NOIO, bio_segments(bio));

		unsigned segs = bio_segments(bio);

		struct bio *clone = bio_alloc(GFP_NOIO, segs);



		bio_for_each_segment(bv, bio, iter)

			clone->bi_io_vec[clone->bi_vcnt++] = bv;
@@ -32,7 +33,7 @@ static void bch_generic_make_request_hack(struct bio *bio) 
		clone->bi_iter.bi_sector = bio->bi_iter.bi_sector;

		clone->bi_bdev		= bio->bi_bdev;

		clone->bi_rw		= bio->bi_rw;

		clone->bi_vcnt		= bio_segments(bio);

		clone->bi_vcnt		= segs;

		clone->bi_iter.bi_size	= bio->bi_iter.bi_size;



		clone->bi_private	= bio;
@@ -133,21 +134,13 @@ struct bio *bch_bio_split(struct bio *bio, int sectors, 


static unsigned bch_bio_max_sectors(struct bio *bio)

{

	unsigned ret = bio_sectors(bio);

	struct request_queue *q = bdev_get_queue(bio->bi_bdev);

	unsigned max_segments = min_t(unsigned, BIO_MAX_PAGES,

				      queue_max_segments(q));



	if (bio->bi_rw & REQ_DISCARD)

		return min(ret, q->limits.max_discard_sectors);



	if (bio_segments(bio) > max_segments ||

	    q->merge_bvec_fn) {

	struct bio_vec bv;

	struct bvec_iter iter;

		unsigned seg = 0;

	unsigned ret = 0, seg = 0;



		ret = 0;

	if (bio->bi_rw & REQ_DISCARD)

		return min(bio_sectors(bio), q->limits.max_discard_sectors);



	bio_for_each_segment(bv, bio, iter) {

		struct bvec_merge_data bvm = {
@@ -157,7 +150,8 @@ static unsigned bch_bio_max_sectors(struct bio *bio) 
			.bi_rw		= bio->bi_rw,

		};



			if (seg == max_segments)

		if (seg == min_t(unsigned, BIO_MAX_PAGES,

				 queue_max_segments(q)))

			break;



		if (q->merge_bvec_fn &&
@@ -167,7 +161,6 @@ static unsigned bch_bio_max_sectors(struct bio *bio) 
		seg++;

		ret += bv.bv_len >> 9;

	}

	}



	ret = min(ret, queue_max_sectors(q));

drivers/md/raid0.c

+1 −1
Original line number Diff line number Diff line
@@ -528,7 +528,7 @@ static void raid0_make_request(struct mddev *mddev, struct bio *bio) 
		sector_t sector = bio->bi_iter.bi_sector;

		struct bio_pair *bp;

		/* Sanity check -- queue functions should prevent this happening */

		if (bio_segments(bio) > 1)

		if (bio_multiple_segments(bio))

			goto bad_map;

		/* This is a one page bio that upper layers

		 * refuse to split for us, so we need to split it.

drivers/md/raid10.c

+1 −1
Original line number Diff line number Diff line
@@ -1188,7 +1188,7 @@ static void make_request(struct mddev *mddev, struct bio * bio) 
			 || conf->prev.near_copies < conf->prev.raid_disks))) {

		struct bio_pair *bp;

		/* Sanity check -- queue functions should prevent this happening */

		if (bio_segments(bio) > 1)

		if (bio_multiple_segments(bio))

			goto bad_map;

		/* This is a one page bio that upper layers

		 * refuse to split for us, so we need to split it.

drivers/message/fusion/mptsas.c

+4 −4
Original line number Diff line number Diff line
@@ -2235,10 +2235,10 @@ static int mptsas_smp_handler(struct Scsi_Host *shost, struct sas_rphy *rphy, 
	}



	/* do we need to support multiple segments? */

	if (bio_segments(req->bio) > 1 || bio_segments(rsp->bio) > 1) {

		printk(MYIOC_s_ERR_FMT "%s: multiple segments req %u %u, rsp %u %u\n",

		    ioc->name, __func__, bio_segments(req->bio), blk_rq_bytes(req),

		    bio_segments(rsp->bio), blk_rq_bytes(rsp));

	if (bio_multiple_segments(req->bio) ||

	    bio_multiple_segments(rsp->bio)) {

		printk(MYIOC_s_ERR_FMT "%s: multiple segments req %u, rsp %u\n",

		    ioc->name, __func__, blk_rq_bytes(req), blk_rq_bytes(rsp));

		return -EINVAL;

	}