block: Convert some code to bio_for_each_segment_all()

More prep work for immutable bvecs:

A few places in the code were either open coding or using the wrong
version - fix.

After we introduce the bvec iter, it'll no longer be possible to modify
the biovec through bio_for_each_segment_all() - it doesn't increment a
pointer to the current bvec, you pass in a struct bio_vec (not a
pointer) which is updated with what the current biovec would be (taking
into account bi_bvec_done and bi_size).

So because of that it's more worthwhile to be consistent about
bio_for_each_segment()/bio_for_each_segment_all() usage.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: NeilBrown <neilb@suse.de>
CC: Alasdair Kergon <agk@redhat.com>
CC: dm-devel@redhat.com
CC: Alexander Viro <viro@zeniv.linux.org.uk>

mm/bounce.c

@@ -231,7 +231,7 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
 bounce:
 	bio = bio_clone_bioset(*bio_orig, GFP_NOIO, fs_bio_set);
 
-	bio_for_each_segment(to, bio, i) {
+	bio_for_each_segment_all(to, bio, i) {
 		struct page *page = to->bv_page;
 
 		if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force)