Introduce rq_for_each_segment replacing rq_for_each_bio

Every usage of rq_for_each_bio wraps a usage of
bio_for_each_segment, so these can be combined into
rq_for_each_segment.

We define "struct req_iterator" to hold the 'bio' and 'index' that
are needed for the double iteration.

Signed-off-by: Neil Brown <neilb@suse.de>

Various compile fixes by me...

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 9 insertions, 13 deletions

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index be92c658f06e..228b2ff577aa 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -180,7 +180,7 @@ static inline int sock_send_bvec(struct socket *sock, struct bio_vec *bvec,
 
 static int nbd_send_req(struct nbd_device *lo, struct request *req)
 {
-        int result, i, flags;
+        int result, flags;
         struct nbd_request request;
         unsigned long size = req->nr_sectors << 9;
         struct socket *sock = lo->sock;
@@ -205,16 +205,15 @@ static int nbd_send_req(struct nbd_device *lo, struct request *req)
         }
 
         if (nbd_cmd(req) == NBD_CMD_WRITE) {
-                struct bio *bio;
+                struct req_iterator iter;
+                struct bio_vec *bvec;
                 /*
                  * we are really probing at internals to determine
                  * whether to set MSG_MORE or not...
                  */
-                rq_for_each_bio(bio, req) {
-                        struct bio_vec *bvec;
-                        bio_for_each_segment(bvec, bio, i) {
+                rq_for_each_segment(bvec, req, iter) {
                                 flags = 0;
-                                if ((i < (bio->bi_vcnt - 1)) || bio->bi_next)
+                                if (!rq_iter_last(req, iter))
                                         flags = MSG_MORE;
                                 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
                                                 lo->disk->disk_name, req,
@@ -226,7 +225,6 @@ static int nbd_send_req(struct nbd_device *lo, struct request *req)
                                                         result);
                                         goto error_out;
                                 }
-                        }
                 }
         }
         return 0;
@@ -321,11 +319,10 @@ static struct request *nbd_read_stat(struct nbd_device *lo)
         dprintk(DBG_RX, "%s: request %p: got reply\n",
                         lo->disk->disk_name, req);
         if (nbd_cmd(req) == NBD_CMD_READ) {
-                int i;
-                struct bio *bio;
-                rq_for_each_bio(bio, req) {
-                        struct bio_vec *bvec;
-                        bio_for_each_segment(bvec, bio, i) {
+                struct req_iterator iter;
+                struct bio_vec *bvec;
+
+                rq_for_each_segment(bvec, req, iter) {
                                 result = sock_recv_bvec(sock, bvec);
                                 if (result <= 0) {
                                         printk(KERN_ERR "%s: Receive data failed (result %d)\n",
@@ -336,7 +333,6 @@ static struct request *nbd_read_stat(struct nbd_device *lo)
                                 }
                                 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
                                         lo->disk->disk_name, req, bvec->bv_len);
-                        }
                 }
         }
         return req;