block: Convert bio_for_each_segment() to bvec_iter

More prep work for immutable biovecs - with immutable bvecs drivers
won't be able to use the biovec directly, they'll need to use helpers
that take into account bio->bi_iter.bi_bvec_done.

This updates callers for the new usage without changing the
implementation yet.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Paul Clements <Paul.Clements@steeleye.com>
Cc: Jim Paris <jim@jtan.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@inktank.com>
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris <josh.h.morris@us.ibm.com>
Cc: Philip Kelleher <pjk1939@linux.vnet.ibm.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Neil Brown <neilb@suse.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: linux390@de.ibm.com
Cc: Nagalakshmi Nandigama <Nagalakshmi.Nandigama@lsi.com>
Cc: Sreekanth Reddy <Sreekanth.Reddy@lsi.com>
Cc: support@lsi.com
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Quoc-Son Anh <quoc-sonx.anh@intel.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Seth Jennings <sjenning@linux.vnet.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Jan Kara <jack@suse.cz>
Cc: linux-m68k@lists.linux-m68k.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: drbd-user@lists.linbit.com
Cc: nbd-general@lists.sourceforge.net
Cc: cbe-oss-dev@lists.ozlabs.org
Cc: xen-devel@lists.xensource.com
Cc: virtualization@lists.linux-foundation.org
Cc: linux-raid@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: DL-MPTFusionLinux@lsi.com
Cc: linux-scsi@vger.kernel.org
Cc: devel@driverdev.osuosl.org
Cc: linux-fsdevel@vger.kernel.org
Cc: cluster-devel@redhat.com
Cc: linux-mm@kvack.org
Acked-by: Geoff Levand <geoff@infradead.org>

39 files changed, 401 insertions, 397 deletions

diff --git a/arch/m68k/emu/nfblock.c b/arch/m68k/emu/nfblock.c
index 0a9d0b3c794b..2d75ae246167 100644
--- a/arch/m68k/emu/nfblock.c
+++ b/arch/m68k/emu/nfblock.c
@@ -62,17 +62,18 @@ struct nfhd_device {
 static void nfhd_make_request(struct request_queue *queue, struct bio *bio)
 {
 	struct nfhd_device *dev = queue->queuedata;
-	struct bio_vec *bvec;
-	int i, dir, len, shift;
+	struct bio_vec bvec;
+	struct bvec_iter iter;
+	int dir, len, shift;
 	sector_t sec = bio->bi_iter.bi_sector;
 
 	dir = bio_data_dir(bio);
 	shift = dev->bshift;
-	bio_for_each_segment(bvec, bio, i) {
-		len = bvec->bv_len;
+	bio_for_each_segment(bvec, bio, iter) {
+		len = bvec.bv_len;
 		len >>= 9;
 		nfhd_read_write(dev->id, 0, dir, sec >> shift, len >> shift,
-				bvec_to_phys(bvec));
+				bvec_to_phys(&bvec));
 		sec += len;
 	}
 	bio_endio(bio, 0);
diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c
index f33bcbaa6a07..47b6b9f81d43 100644
--- a/arch/powerpc/sysdev/axonram.c
+++ b/arch/powerpc/sysdev/axonram.c
@@ -109,28 +109,28 @@ axon_ram_make_request(struct request_queue *queue, struct bio *bio)
 	struct axon_ram_bank *bank = bio->bi_bdev->bd_disk->private_data;
 	unsigned long phys_mem, phys_end;
 	void *user_mem;
-	struct bio_vec *vec;
+	struct bio_vec vec;
 	unsigned int transfered;
-	unsigned short idx;
+	struct bvec_iter iter;
 
 	phys_mem = bank->io_addr + (bio->bi_iter.bi_sector <<
 				    AXON_RAM_SECTOR_SHIFT);
 	phys_end = bank->io_addr + bank->size;
 	transfered = 0;
-	bio_for_each_segment(vec, bio, idx) {
-		if (unlikely(phys_mem + vec->bv_len > phys_end)) {
+	bio_for_each_segment(vec, bio, iter) {
+		if (unlikely(phys_mem + vec.bv_len > phys_end)) {
 			bio_io_error(bio);
 			return;
 		}
 
-		user_mem = page_address(vec->bv_page) + vec->bv_offset;
+		user_mem = page_address(vec.bv_page) + vec.bv_offset;
 		if (bio_data_dir(bio) == READ)
-			memcpy(user_mem, (void *) phys_mem, vec->bv_len);
+			memcpy(user_mem, (void *) phys_mem, vec.bv_len);
 		else
-			memcpy((void *) phys_mem, user_mem, vec->bv_len);
+			memcpy((void *) phys_mem, user_mem, vec.bv_len);
 
-		phys_mem += vec->bv_len;
-		transfered += vec->bv_len;
+		phys_mem += vec.bv_len;
+		transfered += vec.bv_len;
 	}
 	bio_endio(bio, 0);
 }
diff --git a/block/blk-core.c b/block/blk-core.c
index 5c2ab2c74066..5da8e900d3b1 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2746,10 +2746,10 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
 void rq_flush_dcache_pages(struct request *rq)
 {
 	struct req_iterator iter;
-	struct bio_vec *bvec;
+	struct bio_vec bvec;
 
 	rq_for_each_segment(bvec, rq, iter)
-		flush_dcache_page(bvec->bv_page);
+		flush_dcache_page(bvec.bv_page);
 }
 EXPORT_SYMBOL_GPL(rq_flush_dcache_pages);
 #endif
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 03bc083c28cf..a1ead9049ed6 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -12,10 +12,11 @@
 static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
 					     struct bio *bio)
 {
-	struct bio_vec *bv, *bvprv = NULL;
-	int cluster, i, high, highprv = 1;
+	struct bio_vec bv, bvprv = { NULL };
+	int cluster, high, highprv = 1;
 	unsigned int seg_size, nr_phys_segs;
 	struct bio *fbio, *bbio;
+	struct bvec_iter iter;
 
 	if (!bio)
 		return 0;
@@ -25,25 +26,23 @@ static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
 	seg_size = 0;
 	nr_phys_segs = 0;
 	for_each_bio(bio) {
-		bio_for_each_segment(bv, bio, i) {
+		bio_for_each_segment(bv, bio, iter) {
 			/*
 			 * the trick here is making sure that a high page is
 			 * never considered part of another segment, since that
 			 * might change with the bounce page.
 			 */
-			high = page_to_pfn(bv->bv_page) > queue_bounce_pfn(q);
-			if (high || highprv)
-				goto new_segment;
-			if (cluster) {
-				if (seg_size + bv->bv_len
+			high = page_to_pfn(bv.bv_page) > queue_bounce_pfn(q);
+			if (!high && !highprv && cluster) {
+				if (seg_size + bv.bv_len
 				    > queue_max_segment_size(q))
 					goto new_segment;
-				if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv))
+				if (!BIOVEC_PHYS_MERGEABLE(&bvprv, &bv))
 					goto new_segment;
-				if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv))
+				if (!BIOVEC_SEG_BOUNDARY(q, &bvprv, &bv))
 					goto new_segment;
 
-				seg_size += bv->bv_len;
+				seg_size += bv.bv_len;
 				bvprv = bv;
 				continue;
 			}
@@ -54,7 +53,7 @@ new_segment:
 
 			nr_phys_segs++;
 			bvprv = bv;
-			seg_size = bv->bv_len;
+			seg_size = bv.bv_len;
 			highprv = high;
 		}
 		bbio = bio;
@@ -110,21 +109,21 @@ static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
 	return 0;
 }
 
-static void
+static inline void
 __blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec,
-		     struct scatterlist *sglist, struct bio_vec **bvprv,
+		     struct scatterlist *sglist, struct bio_vec *bvprv,
 		     struct scatterlist **sg, int *nsegs, int *cluster)
 {
 
 	int nbytes = bvec->bv_len;
 
-	if (*bvprv && *cluster) {
+	if (*sg && *cluster) {
 		if ((*sg)->length + nbytes > queue_max_segment_size(q))
 			goto new_segment;
 
-		if (!BIOVEC_PHYS_MERGEABLE(*bvprv, bvec))
+		if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
 			goto new_segment;
-		if (!BIOVEC_SEG_BOUNDARY(q, *bvprv, bvec))
+		if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
 			goto new_segment;
 
 		(*sg)->length += nbytes;
@@ -150,7 +149,7 @@ new_segment:
 		sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset);
 		(*nsegs)++;
 	}
-	*bvprv = bvec;
+	*bvprv = *bvec;
 }
 
 /*
@@ -160,7 +159,7 @@ new_segment:
 int blk_rq_map_sg(struct request_queue *q, struct request *rq,
 		  struct scatterlist *sglist)
 {
-	struct bio_vec *bvec, *bvprv;
+	struct bio_vec bvec, bvprv;
 	struct req_iterator iter;
 	struct scatterlist *sg;
 	int nsegs, cluster;
@@ -171,10 +170,9 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
 	/*
 	 * for each bio in rq
 	 */
-	bvprv = NULL;
 	sg = NULL;
 	rq_for_each_segment(bvec, rq, iter) {
-		__blk_segment_map_sg(q, bvec, sglist, &bvprv, &sg,
+		__blk_segment_map_sg(q, &bvec, sglist, &bvprv, &sg,
 				     &nsegs, &cluster);
 	} /* segments in rq */
 
@@ -223,18 +221,17 @@ EXPORT_SYMBOL(blk_rq_map_sg);
 int blk_bio_map_sg(struct request_queue *q, struct bio *bio,
 		   struct scatterlist *sglist)
 {
-	struct bio_vec *bvec, *bvprv;
+	struct bio_vec bvec, bvprv;
 	struct scatterlist *sg;
 	int nsegs, cluster;
-	unsigned long i;
+	struct bvec_iter iter;
 
 	nsegs = 0;
 	cluster = blk_queue_cluster(q);
 
-	bvprv = NULL;
 	sg = NULL;
-	bio_for_each_segment(bvec, bio, i) {
-		__blk_segment_map_sg(q, bvec, sglist, &bvprv, &sg,
+	bio_for_each_segment(bvec, bio, iter) {
+		__blk_segment_map_sg(q, &bvec, sglist, &bvprv, &sg,
 				     &nsegs, &cluster);
 	} /* segments in bio */
 
diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index 77c24ab1898a..7a06aec1dedc 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -897,15 +897,15 @@ rqbiocnt(struct request *r)
 static void
 bio_pageinc(struct bio *bio)
 {
-	struct bio_vec *bv;
+	struct bio_vec bv;
 	struct page *page;
-	int i;
+	struct bvec_iter iter;
 
-	bio_for_each_segment(bv, bio, i) {
+	bio_for_each_segment(bv, bio, iter) {
 		/* Non-zero page count for non-head members of
 		 * compound pages is no longer allowed by the kernel.
 		 */
-		page = compound_trans_head(bv->bv_page);
+		page = compound_trans_head(bv.bv_page);
 		atomic_inc(&page->_count);
 	}
 }
@@ -913,12 +913,12 @@ bio_pageinc(struct bio *bio)
 static void
 bio_pagedec(struct bio *bio)
 {
-	struct bio_vec *bv;
 	struct page *page;
-	int i;
+	struct bio_vec bv;
+	struct bvec_iter iter;
 
-	bio_for_each_segment(bv, bio, i) {
-		page = compound_trans_head(bv->bv_page);
+	bio_for_each_segment(bv, bio, iter) {
+		page = compound_trans_head(bv.bv_page);
 		atomic_dec(&page->_count);
 	}
 }
diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 66f5aaae15a2..e73b85cf0756 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -328,9 +328,9 @@ static void brd_make_request(struct request_queue *q, struct bio *bio)
 	struct block_device *bdev = bio->bi_bdev;
 	struct brd_device *brd = bdev->bd_disk->private_data;
 	int rw;
-	struct bio_vec *bvec;
+	struct bio_vec bvec;
 	sector_t sector;
-	int i;
+	struct bvec_iter iter;
 	int err = -EIO;
 
 	sector = bio->bi_iter.bi_sector;
@@ -347,10 +347,10 @@ static void brd_make_request(struct request_queue *q, struct bio *bio)
 	if (rw == READA)
 		rw = READ;
 
-	bio_for_each_segment(bvec, bio, i) {
-		unsigned int len = bvec->bv_len;
-		err = brd_do_bvec(brd, bvec->bv_page, len,
-					bvec->bv_offset, rw, sector);
+	bio_for_each_segment(bvec, bio, iter) {
+		unsigned int len = bvec.bv_len;
+		err = brd_do_bvec(brd, bvec.bv_page, len,
+					bvec.bv_offset, rw, sector);
 		if (err)
 			break;
 		sector += len >> SECTOR_SHIFT;
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 9e3818b1bc83..f4e5440aba05 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1537,15 +1537,17 @@ static int _drbd_send_page(struct drbd_conf *mdev, struct page *page,
 
 static int _drbd_send_bio(struct drbd_conf *mdev, struct bio *bio)
 {
-	struct bio_vec *bvec;
-	int i;
+	struct bio_vec bvec;
+	struct bvec_iter iter;
+
 	/* hint all but last page with MSG_MORE */
-	bio_for_each_segment(bvec, bio, i) {
+	bio_for_each_segment(bvec, bio, iter) {
 		int err;
 
-		err = _drbd_no_send_page(mdev, bvec->bv_page,
-					 bvec->bv_offset, bvec->bv_len,
-					 i == bio->bi_vcnt - 1 ? 0 : MSG_MORE);
+		err = _drbd_no_send_page(mdev, bvec.bv_page,
+					 bvec.bv_offset, bvec.bv_len,
+					 bio_iter_last(bio, iter)
+					 ? 0 : MSG_MORE);
 		if (err)
 			return err;
 	}
@@ -1554,15 +1556,16 @@ static int _drbd_send_bio(struct drbd_conf *mdev, struct bio *bio)
 
 static int _drbd_send_zc_bio(struct drbd_conf *mdev, struct bio *bio)
 {
-	struct bio_vec *bvec;
-	int i;
+	struct bio_vec bvec;
+	struct bvec_iter iter;
+
 	/* hint all but last page with MSG_MORE */
-	bio_for_each_segment(bvec, bio, i) {
+	bio_for_each_segment(bvec, bio, iter) {
 		int err;
 
-		err = _drbd_send_page(mdev, bvec->bv_page,
-				      bvec->bv_offset, bvec->bv_len,
-				      i == bio->bi_vcnt - 1 ? 0 : MSG_MORE);
+		err = _drbd_send_page(mdev, bvec.bv_page,
+				      bvec.bv_offset, bvec.bv_len,
+				      bio_iter_last(bio, iter) ? 0 : MSG_MORE);
 		if (err)
 			return err;
 	}
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 5326c22cdb9d..d073305ffd5e 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1595,9 +1595,10 @@ static int drbd_drain_block(struct drbd_conf *mdev, int data_size)
 static int recv_dless_read(struct drbd_conf *mdev, struct drbd_request *req,
 			   sector_t sector, int data_size)
 {
-	struct bio_vec *bvec;
+	struct bio_vec bvec;
+	struct bvec_iter iter;
 	struct bio *bio;
-	int dgs, err, i, expect;
+	int dgs, err, expect;
 	void *dig_in = mdev->tconn->int_dig_in;
 	void *dig_vv = mdev->tconn->int_dig_vv;
 
@@ -1617,11 +1618,11 @@ static int recv_dless_read(struct drbd_conf *mdev, struct drbd_request *req,
 	bio = req->master_bio;
 	D_ASSERT(sector == bio->bi_iter.bi_sector);
 
-	bio_for_each_segment(bvec, bio, i) {
-		void *mapped = kmap(bvec->bv_page) + bvec->bv_offset;
-		expect = min_t(int, data_size, bvec->bv_len);
+	bio_for_each_segment(bvec, bio, iter) {
+		void *mapped = kmap(bvec.bv_page) + bvec.bv_offset;
+		expect = min_t(int, data_size, bvec.bv_len);
 		err = drbd_recv_all_warn(mdev->tconn, mapped, expect);
-		kunmap(bvec->bv_page);
+		kunmap(bvec.bv_page);
 		if (err)
 			return err;
 		data_size -= expect;
diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 891c0ecaa292..84d3175d493a 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -313,8 +313,8 @@ void drbd_csum_bio(struct drbd_conf *mdev, struct crypto_hash *tfm, struct bio *
 {
 	struct hash_desc desc;
 	struct scatterlist sg;
-	struct bio_vec *bvec;
-	int i;
+	struct bio_vec bvec;
+	struct bvec_iter iter;
 
 	desc.tfm = tfm;
 	desc.flags = 0;
@@ -322,8 +322,8 @@ void drbd_csum_bio(struct drbd_conf *mdev, struct crypto_hash *tfm, struct bio *
 	sg_init_table(&sg, 1);
 	crypto_hash_init(&desc);
 
-	bio_for_each_segment(bvec, bio, i) {
-		sg_set_page(&sg, bvec->bv_page, bvec->bv_len, bvec->bv_offset);
+	bio_for_each_segment(bvec, bio, iter) {
+		sg_set_page(&sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset);
 		crypto_hash_update(&desc, &sg, sg.length);
 	}
 	crypto_hash_final(&desc, digest);
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 6a86fe7b730f..6b29c4422828 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -2351,7 +2351,7 @@ static void rw_interrupt(void)
 /* Compute maximal contiguous buffer size. */
 static int buffer_chain_size(void)
 {
-	struct bio_vec *bv;
+	struct bio_vec bv;
 	int size;
 	struct req_iterator iter;
 	char *base;
@@ -2360,10 +2360,10 @@ static int buffer_chain_size(void)
 	size = 0;
 
 	rq_for_each_segment(bv, current_req, iter) {
-		if (page_address(bv->bv_page) + bv->bv_offset != base + size)
+		if (page_address(bv.bv_page) + bv.bv_offset != base + size)
 			break;
 
-		size += bv->bv_len;
+		size += bv.bv_len;
 	}
 
 	return size >> 9;
@@ -2389,7 +2389,7 @@ static int transfer_size(int ssize, int max_sector, int max_size)
 static void copy_buffer(int ssize, int max_sector, int max_sector_2)
 {
 	int remaining;		/* number of transferred 512-byte sectors */
-	struct bio_vec *bv;
+	struct bio_vec bv;
 	char *buffer;
 	char *dma_buffer;
 	int size;
@@ -2427,10 +2427,10 @@ static void copy_buffer(int ssize, int max_sector, int max_sector_2)
 		if (!remaining)
 			break;
 
-		size = bv->bv_len;
+		size = bv.bv_len;
 		SUPBOUND(size, remaining);
 
-		buffer = page_address(bv->bv_page) + bv->bv_offset;
+		buffer = page_address(bv.bv_page) + bv.bv_offset;
 		if (dma_buffer + size >
 		    floppy_track_buffer + (max_buffer_sectors << 10) ||
 		    dma_buffer < floppy_track_buffer) {
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index f5e39989adde..33fde3a39759 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -288,9 +288,10 @@ static int lo_send(struct loop_device *lo, struct bio *bio, loff_t pos)
 {
 	int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t,
 			struct page *page);
-	struct bio_vec *bvec;
+	struct bio_vec bvec;
+	struct bvec_iter iter;
 	struct page *page = NULL;
-	int i, ret = 0;
+	int ret = 0;
 
 	if (lo->transfer != transfer_none) {
 		page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);
@@ -302,11 +303,11 @@ static int lo_send(struct loop_device *lo, struct bio *bio, loff_t pos)
 		do_lo_send = do_lo_send_direct_write;
 	}
 
-	bio_for_each_segment(bvec, bio, i) {
-		ret = do_lo_send(lo, bvec, pos, page);
+	bio_for_each_segment(bvec, bio, iter) {
+		ret = do_lo_send(lo, &bvec, pos, page);
 		if (ret < 0)
 			break;
-		pos += bvec->bv_len;
+		pos += bvec.bv_len;
 	}
 	if (page) {
 		kunmap(page);
@@ -392,20 +393,20 @@ do_lo_receive(struct loop_device *lo,
 static int
 lo_receive(struct loop_device *lo, struct bio *bio, int bsize, loff_t pos)
 {
-	struct bio_vec *bvec;
+	struct bio_vec bvec;
+	struct bvec_iter iter;
 	ssize_t s;
-	int i;
 
-	bio_for_each_segment(bvec, bio, i) {
-		s = do_lo_receive(lo, bvec, bsize, pos);
+	bio_for_each_segment(bvec, bio, iter) {
+		s = do_lo_receive(lo, &bvec, bsize, pos);
 		if (s < 0)
 			return s;
 
-		if (s != bvec->bv_len) {
+		if (s != bvec.bv_len) {
 			zero_fill_bio(bio);
 			break;
 		}
-		pos += bvec->bv_len;
+		pos += bvec.bv_len;
 	}
 	return 0;
 }
diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 69e9eb5a6b34..52b2f2a71470 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -3962,8 +3962,9 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio)
 {
 	struct driver_data *dd = queue->queuedata;
 	struct scatterlist *sg;
-	struct bio_vec *bvec;
-	int i, nents = 0;
+	struct bio_vec bvec;
+	struct bvec_iter iter;
+	int nents = 0;
 	int tag = 0, unaligned = 0;
 
 	if (unlikely(dd->dd_flag & MTIP_DDF_STOP_IO)) {
@@ -4026,11 +4027,11 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio)
 		}
 
 		/* Create the scatter list for this bio. */
-		bio_for_each_segment(bvec, bio, i) {
+		bio_for_each_segment(bvec, bio, iter) {
 			sg_set_page(&sg[nents],
-					bvec->bv_page,
-					bvec->bv_len,
-					bvec->bv_offset);
+					bvec.bv_page,
+					bvec.bv_len,
+					bvec.bv_offset);
 			nents++;
 		}
 
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 2dc3b5153f0d..aa362f493216 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -271,7 +271,7 @@ static int nbd_send_req(struct nbd_device *nbd, struct request *req)
 
 	if (nbd_cmd(req) == NBD_CMD_WRITE) {
 		struct req_iterator iter;
-		struct bio_vec *bvec;
+		struct bio_vec bvec;
 		/*
 		 * we are really probing at internals to determine
 		 * whether to set MSG_MORE or not...
@@ -281,8 +281,8 @@ static int nbd_send_req(struct nbd_device *nbd, struct request *req)
 			if (!rq_iter_last(req, iter))
 				flags = MSG_MORE;
 			dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
-					nbd->disk->disk_name, req, bvec->bv_len);
-			result = sock_send_bvec(nbd, bvec, flags);
+					nbd->disk->disk_name, req, bvec.bv_len);
+			result = sock_send_bvec(nbd, &bvec, flags);
 			if (result <= 0) {
 				dev_err(disk_to_dev(nbd->disk),
 					"Send data failed (result %d)\n",
@@ -378,10 +378,10 @@ static struct request *nbd_read_stat(struct nbd_device *nbd)
 			nbd->disk->disk_name, req);
 	if (nbd_cmd(req) == NBD_CMD_READ) {
 		struct req_iterator iter;
-		struct bio_vec *bvec;
+		struct bio_vec bvec;
 
 		rq_for_each_segment(bvec, req, iter) {
-			result = sock_recv_bvec(nbd, bvec);
+			result = sock_recv_bvec(nbd, &bvec);
 			if (result <= 0) {
 				dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
 					result);
@@ -389,7 +389,7 @@ static struct request *nbd_read_stat(struct nbd_device *nbd)
 				return req;
 			}
 			dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
-				nbd->disk->disk_name, req, bvec->bv_len);
+				nbd->disk->disk_name, req, bvec.bv_len);
 		}
 	}
 	return req;
diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index 53d217381873..5539d2920872 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -550,9 +550,11 @@ static int nvme_split_and_submit(struct bio *bio, struct nvme_queue *nvmeq,
 static int nvme_map_bio(struct nvme_queue *nvmeq, struct nvme_iod *iod,
 		struct bio *bio, enum dma_data_direction dma_dir, int psegs)
 {
-	struct bio_vec *bvec, *bvprv = NULL;
+	struct bio_vec bvec, bvprv;
+	struct bvec_iter iter;
 	struct scatterlist *sg = NULL;
-	int i, length = 0, nsegs = 0, split_len = bio->bi_iter.bi_size;
+	int length = 0, nsegs = 0, split_len = bio->bi_iter.bi_size;
+	int first = 1;
 
 	if (nvmeq->dev->stripe_size)
 		split_len = nvmeq->dev->stripe_size -
@@ -560,25 +562,28 @@ static int nvme_map_bio(struct nvme_queue *nvmeq, struct nvme_iod *iod,
 			 (nvmeq->dev->stripe_size - 1));
 
 	sg_init_table(iod->sg, psegs);
-	bio_for_each_segment(bvec, bio, i) {
-		if (bvprv && BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) {
-			sg->length += bvec->bv_len;
+	bio_for_each_segment(bvec, bio, iter) {
+		if (!first && BIOVEC_PHYS_MERGEABLE(&bvprv, &bvec)) {
+			sg->length += bvec.bv_len;
 		} else {
-			if (bvprv && BIOVEC_NOT_VIRT_MERGEABLE(bvprv, bvec))
-				return nvme_split_and_submit(bio, nvmeq, i,
-								length, 0);
+			if (!first && BIOVEC_NOT_VIRT_MERGEABLE(&bvprv, &bvec))
+				return nvme_split_and_submit(bio, nvmeq,
+							     iter.bi_idx,
+							     length, 0);
 
 			sg = sg ? sg + 1 : iod->sg;
-			sg_set_page(sg, bvec->bv_page, bvec->bv_len,
-							bvec->bv_offset);
+			sg_set_page(sg, bvec.bv_page,
+				    bvec.bv_len, bvec.bv_offset);
 			nsegs++;
 		}
 
-		if (split_len - length < bvec->bv_