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>

3 files changed, 15 insertions, 26 deletions

diff --git a/drivers/s390/block/dasd_diag.c b/drivers/s390/block/dasd_diag.c
index d32c60dbdd82..6bb9676f203e 100644
--- a/drivers/s390/block/dasd_diag.c
+++ b/drivers/s390/block/dasd_diag.c
@@ -472,14 +472,13 @@ dasd_diag_build_cp(struct dasd_device * device, struct request *req)
         struct dasd_ccw_req *cqr;
         struct dasd_diag_req *dreq;
         struct dasd_diag_bio *dbio;
-        struct bio *bio;
+        struct req_iterator iter;
         struct bio_vec *bv;
         char *dst;
         unsigned int count, datasize;
         sector_t recid, first_rec, last_rec;
         unsigned int blksize, off;
         unsigned char rw_cmd;
-        int i;
 
         if (rq_data_dir(req) == READ)
                 rw_cmd = MDSK_READ_REQ;
@@ -493,13 +492,11 @@ dasd_diag_build_cp(struct dasd_device * device, struct request *req)
         last_rec = (req->sector + req->nr_sectors - 1) >> device->s2b_shift;
         /* Check struct bio and count the number of blocks for the request. */
         count = 0;
-        rq_for_each_bio(bio, req) {
-                bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, req, iter) {
                         if (bv->bv_len & (blksize - 1))
                                 /* Fba can only do full blocks. */
                                 return ERR_PTR(-EINVAL);
                         count += bv->bv_len >> (device->s2b_shift + 9);
-                }
         }
         /* Paranoia. */
         if (count != last_rec - first_rec + 1)
@@ -516,8 +513,7 @@ dasd_diag_build_cp(struct dasd_device * device, struct request *req)
         dreq->block_count = count;
         dbio = dreq->bio;
         recid = first_rec;
-        rq_for_each_bio(bio, req) {
-                bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, req, iter) {
                         dst = page_address(bv->bv_page) + bv->bv_offset;
                         for (off = 0; off < bv->bv_len; off += blksize) {
                                 memset(dbio, 0, sizeof (struct dasd_diag_bio));
@@ -528,7 +524,6 @@ dasd_diag_build_cp(struct dasd_device * device, struct request *req)
                                 dst += blksize;
                                 recid++;
                         }
-                }
         }
         cqr->retries = DIAG_MAX_RETRIES;
         cqr->buildclk = get_clock();
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index ea63ba7828f9..36ba45849874 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1176,7 +1176,7 @@ dasd_eckd_build_cp(struct dasd_device * device, struct request *req)
         struct LO_eckd_data *LO_data;
         struct dasd_ccw_req *cqr;
         struct ccw1 *ccw;
-        struct bio *bio;
+        struct req_iterator iter;
         struct bio_vec *bv;
         char *dst;
         unsigned int blksize, blk_per_trk, off;
@@ -1185,7 +1185,6 @@ dasd_eckd_build_cp(struct dasd_device * device, struct request *req)
         sector_t first_trk, last_trk;
         unsigned int first_offs, last_offs;
         unsigned char cmd, rcmd;
-        int i;
 
         private = (struct dasd_eckd_private *) device->private;
         if (rq_data_dir(req) == READ)
@@ -1206,8 +1205,7 @@ dasd_eckd_build_cp(struct dasd_device * device, struct request *req)
         /* Check struct bio and count the number of blocks for the request. */
         count = 0;
         cidaw = 0;
-        rq_for_each_bio(bio, req) {
-                bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, req, iter) {
                         if (bv->bv_len & (blksize - 1))
                                 /* Eckd can only do full blocks. */
                                 return ERR_PTR(-EINVAL);
@@ -1217,7 +1215,6 @@ dasd_eckd_build_cp(struct dasd_device * device, struct request *req)
                                             bv->bv_len))
                                 cidaw += bv->bv_len >> (device->s2b_shift + 9);
 #endif
-                }
         }
         /* Paranoia. */
         if (count != last_rec - first_rec + 1)
@@ -1257,7 +1254,7 @@ dasd_eckd_build_cp(struct dasd_device * device, struct request *req)
                 locate_record(ccw++, LO_data++, first_trk, first_offs + 1,
                               last_rec - recid + 1, cmd, device, blksize);
         }
-        rq_for_each_bio(bio, req) bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, req, iter) {
                 dst = page_address(bv->bv_page) + bv->bv_offset;
                 if (dasd_page_cache) {
                         char *copy = kmem_cache_alloc(dasd_page_cache,
@@ -1328,12 +1325,12 @@ dasd_eckd_free_cp(struct dasd_ccw_req *cqr, struct request *req)
 {
         struct dasd_eckd_private *private;
         struct ccw1 *ccw;
-        struct bio *bio;
+        struct req_iterator iter;
         struct bio_vec *bv;
         char *dst, *cda;
         unsigned int blksize, blk_per_trk, off;
         sector_t recid;
-        int i, status;
+        int status;
 
         if (!dasd_page_cache)
                 goto out;
@@ -1346,7 +1343,7 @@ dasd_eckd_free_cp(struct dasd_ccw_req *cqr, struct request *req)
         ccw++;
         if (private->uses_cdl == 0 || recid > 2*blk_per_trk)
                 ccw++;
-        rq_for_each_bio(bio, req) bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, req, iter) {
                 dst = page_address(bv->bv_page) + bv->bv_offset;
                 for (off = 0; off < bv->bv_len; off += blksize) {
                         /* Skip locate record. */
diff --git a/drivers/s390/block/dasd_fba.c b/drivers/s390/block/dasd_fba.c
index da16ead8aff2..119b8d2d5f17 100644
--- a/drivers/s390/block/dasd_fba.c
+++ b/drivers/s390/block/dasd_fba.c
@@ -234,14 +234,13 @@ dasd_fba_build_cp(struct dasd_device * device, struct request *req)
         struct LO_fba_data *LO_data;
         struct dasd_ccw_req *cqr;
         struct ccw1 *ccw;
-        struct bio *bio;
+        struct req_iterator iter;
         struct bio_vec *bv;
         char *dst;
         int count, cidaw, cplength, datasize;
         sector_t recid, first_rec, last_rec;
         unsigned int blksize, off;
         unsigned char cmd;
-        int i;
 
         private = (struct dasd_fba_private *) device->private;
         if (rq_data_dir(req) == READ) {
@@ -257,8 +256,7 @@ dasd_fba_build_cp(struct dasd_device * device, struct request *req)
         /* Check struct bio and count the number of blocks for the request. */
         count = 0;
         cidaw = 0;
-        rq_for_each_bio(bio, req) {
-                bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, req, iter) {
                         if (bv->bv_len & (blksize - 1))
                                 /* Fba can only do full blocks. */
                                 return ERR_PTR(-EINVAL);
@@ -268,7 +266,6 @@ dasd_fba_build_cp(struct dasd_device * device, struct request *req)
                                             bv->bv_len))
                                 cidaw += bv->bv_len / blksize;
 #endif
-                }
         }
         /* Paranoia. */
         if (count != last_rec - first_rec + 1)
@@ -304,7 +301,7 @@ dasd_fba_build_cp(struct dasd_device * device, struct request *req)
                 locate_record(ccw++, LO_data++, rq_data_dir(req), 0, count);
         }
         recid = first_rec;
-        rq_for_each_bio(bio, req) bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, req, iter) {
                 dst = page_address(bv->bv_page) + bv->bv_offset;
                 if (dasd_page_cache) {
                         char *copy = kmem_cache_alloc(dasd_page_cache,
@@ -359,11 +356,11 @@ dasd_fba_free_cp(struct dasd_ccw_req *cqr, struct request *req)
 {
         struct dasd_fba_private *private;
         struct ccw1 *ccw;
-        struct bio *bio;
+        struct req_iterator iter;
         struct bio_vec *bv;
         char *dst, *cda;
         unsigned int blksize, off;
-        int i, status;
+        int status;
 
         if (!dasd_page_cache)
                 goto out;
@@ -374,7 +371,7 @@ dasd_fba_free_cp(struct dasd_ccw_req *cqr, struct request *req)
         ccw++;
         if (private->rdc_data.mode.bits.data_chain != 0)
                 ccw++;
-        rq_for_each_bio(bio, req) bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, req, iter) {
                 dst = page_address(bv->bv_page) + bv->bv_offset;
                 for (off = 0; off < bv->bv_len; off += blksize) {
                         /* Skip locate record. */