aoe: use bio->bi_idx

Instead of starting with bio->bi_io_vec, use the offset in bio->bi_idx.
Signed-off-by: "Ed L. Cashin" <ecashin@coraid.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/block/aoe/aoeblk.c

@@ -142,7 +142,8 @@ aoeblk_make_request(request_queue_t *q, struct bio *bio)
 	buf->bio = bio;
 	buf->resid = bio->bi_size;
 	buf->sector = bio->bi_sector;
-	buf->bv = buf->bio->bi_io_vec;
+	buf->bv = &bio->bi_io_vec[bio->bi_idx];
+	WARN_ON(buf->bv->bv_len == 0);
 	buf->bv_resid = buf->bv->bv_len;
 	buf->bufaddr = page_address(buf->bv->bv_page) + buf->bv->bv_offset;
 

drivers/block/aoe/aoecmd.c

@@ -166,6 +166,7 @@ aoecmd_ata_rw(struct aoedev *d, struct frame *f)
 		d->inprocess = NULL;
 	} else if (buf->bv_resid == 0) {
 		buf->bv++;
+		WARN_ON(buf->bv->bv_len == 0);
 		buf->bv_resid = buf->bv->bv_len;
 		buf->bufaddr = page_address(buf->bv->bv_page) + buf->bv->bv_offset;
 	}