14 files changed, 131 insertions, 162 deletions

diff --git a/Documentation/block/biodoc.txt b/Documentation/block/biodoc.txt
index 8af392fc6ef0..dc3f49e3e539 100644
--- a/Documentation/block/biodoc.txt
+++ b/Documentation/block/biodoc.txt
@@ -477,9 +477,9 @@ With this multipage bio design:
   the same bi_io_vec array, but with the index and size accordingly modified)
 - A linked list of bios is used as before for unrelated merges (*) - this
   avoids reallocs and makes independent completions easier to handle.
-- Code that traverses the req list needs to make a distinction between
-  segments of a request (bio_for_each_segment) and the distinct completion
-  units/bios (rq_for_each_bio).
+- Code that traverses the req list can find all the segments of a bio
+  by using rq_for_each_segment.  This handles the fact that a request
+  has multiple bios, each of which can have multiple segments.
 - Drivers which can't process a large bio in one shot can use the bi_idx
   field to keep track of the next bio_vec entry to process.
   (e.g a 1MB bio_vec needs to be handled in max 128kB chunks for IDE)
@@ -664,14 +664,14 @@ in lvm or md.
 
 3.2.1 Traversing segments and completion units in a request
 
-The macros bio_for_each_segment() and rq_for_each_bio() should be used for
-traversing the bios in the request list (drivers should avoid directly
-trying to do it themselves). Using these helpers should also make it easier
-to cope with block changes in the future.
+The macro rq_for_each_segment() should be used for traversing the bios
+in the request list (drivers should avoid directly trying to do it
+themselves). Using these helpers should also make it easier to cope
+with block changes in the future.
 
-        rq_for_each_bio(bio, rq)
-                bio_for_each_segment(bio_vec, bio, i)
-                        /* bio_vec is now current segment */
+        struct req_iterator iter;
+        rq_for_each_segment(bio_vec, rq, iter)
+                /* bio_vec is now current segment */
 
 I/O completion callbacks are per-bio rather than per-segment, so drivers
 that traverse bio chains on completion need to keep that in mind. Drivers
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index e35119a72a44..094c0fa5c405 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1244,8 +1244,7 @@ static void blk_recalc_rq_segments(struct request *rq)
         int seg_size;
         int hw_seg_size;
         int cluster;
-        struct bio *bio;
-        int i;
+        struct req_iterator iter;
         int high, highprv = 1;
         struct request_queue *q = rq->q;
 
@@ -1255,8 +1254,7 @@ static void blk_recalc_rq_segments(struct request *rq)
         cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
         hw_seg_size = seg_size = 0;
         phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0;
-        rq_for_each_bio(bio, rq)
-            bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, rq, iter) {
                 /*
                  * the trick here is making sure that a high page is never
                  * considered part of another segment, since that might
@@ -1353,8 +1351,8 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
                   struct scatterlist *sg)
 {
         struct bio_vec *bvec, *bvprv;
-        struct bio *bio;
-        int nsegs, i, cluster;
+        struct req_iterator iter;
+        int nsegs, cluster;
 
         nsegs = 0;
         cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
@@ -1363,11 +1361,7 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
          * for each bio in rq
          */
         bvprv = NULL;
-        rq_for_each_bio(bio, rq) {
-                /*
-                 * for each segment in bio
-                 */
-                bio_for_each_segment(bvec, bio, i) {
+        rq_for_each_segment(bvec, rq, iter) {
                         int nbytes = bvec->bv_len;
 
                         if (bvprv && cluster) {
@@ -1390,8 +1384,7 @@ new_segment:
                                 nsegs++;
                         }
                         bvprv = bvec;
-                } /* segments in bio */
-        } /* bios in rq */
+        } /* segments in rq */
 
         return nsegs;
 }
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 085b7794fb3e..f0a86e201b44 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -2437,22 +2437,19 @@ static void rw_interrupt(void)
 /* Compute maximal contiguous buffer size. */
 static int buffer_chain_size(void)
 {
-        struct bio *bio;
         struct bio_vec *bv;
-        int size, i;
+        int size;
+        struct req_iterator iter;
         char *base;
 
         base = bio_data(current_req->bio);
         size = 0;
 
-        rq_for_each_bio(bio, current_req) {
-                bio_for_each_segment(bv, bio, i) {
-                        if (page_address(bv->bv_page) + bv->bv_offset !=
-                            base + size)
-                                break;
+        rq_for_each_segment(bv, current_req, iter) {
+                if (page_address(bv->bv_page) + bv->bv_offset != base + size)
+                        break;
 
-                        size += bv->bv_len;
-                }
+                size += bv->bv_len;
         }
 
         return size >> 9;
@@ -2479,9 +2476,9 @@ 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 *bio;
         char *buffer, *dma_buffer;
-        int size, i;
+        int size;
+        struct req_iterator iter;
 
         max_sector = transfer_size(ssize,
                                    min(max_sector, max_sector_2),
@@ -2514,43 +2511,41 @@ static void copy_buffer(int ssize, int max_sector, int max_sector_2)
 
         size = current_req->current_nr_sectors << 9;
 
-        rq_for_each_bio(bio, current_req) {
-                bio_for_each_segment(bv, bio, i) {
-                        if (!remaining)
-                                break;
+        rq_for_each_segment(bv, current_req, iter) {
+                if (!remaining)
+                        break;
 
-                        size = bv->bv_len;
-                        SUPBOUND(size, remaining);
+                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;
 #ifdef FLOPPY_SANITY_CHECK
-                        if (dma_buffer + size >
-                            floppy_track_buffer + (max_buffer_sectors << 10) ||
-                            dma_buffer < floppy_track_buffer) {
-                                DPRINT("buffer overrun in copy buffer %d\n",
-                                       (int)((floppy_track_buffer -
-                                              dma_buffer) >> 9));
-                                printk("fsector_t=%d buffer_min=%d\n",
-                                       fsector_t, buffer_min);
-                                printk("current_count_sectors=%ld\n",
-                                       current_count_sectors);
-                                if (CT(COMMAND) == FD_READ)
-                                        printk("read\n");
-                                if (CT(COMMAND) == FD_WRITE)
-                                        printk("write\n");
-                                break;
-                        }
-                        if (((unsigned long)buffer) % 512)
-                                DPRINT("%p buffer not aligned\n", buffer);
-#endif
+                if (dma_buffer + size >
+                    floppy_track_buffer + (max_buffer_sectors << 10) ||
+                    dma_buffer < floppy_track_buffer) {
+                        DPRINT("buffer overrun in copy buffer %d\n",
+                               (int)((floppy_track_buffer -
+                                      dma_buffer) >> 9));
+                        printk("fsector_t=%d buffer_min=%d\n",
+                               fsector_t, buffer_min);
+                        printk("current_count_sectors=%ld\n",
+                               current_count_sectors);
                         if (CT(COMMAND) == FD_READ)
-                                memcpy(buffer, dma_buffer, size);
-                        else
-                                memcpy(dma_buffer, buffer, size);
-
-                        remaining -= size;
-                        dma_buffer += size;
+                                printk("read\n");
+                        if (CT(COMMAND) == FD_WRITE)
+                                printk("write\n");
+                        break;
                 }
+                if (((unsigned long)buffer) % 512)
+                        DPRINT("%p buffer not aligned\n", buffer);
+#endif
+                if (CT(COMMAND) == FD_READ)
+                        memcpy(buffer, dma_buffer, size);
+                else
+                        memcpy(dma_buffer, buffer, size);
+
+                remaining -= size;
+                dma_buffer += size;
         }
 #ifdef FLOPPY_SANITY_CHECK
         if (remaining) {
diff --git a/drivers/block/lguest_blk.c b/drivers/block/lguest_blk.c
index 160cf14431ac..1e838ae60a60 100644
--- a/drivers/block/lguest_blk.c
+++ b/drivers/block/lguest_blk.c
@@ -142,12 +142,11 @@ static irqreturn_t lgb_irq(int irq, void *_bd)
  * return the total length. */
 static unsigned int req_to_dma(struct request *req, struct lguest_dma *dma)
 {
-        unsigned int i = 0, idx, len = 0;
-        struct bio *bio;
+        unsigned int i = 0, len = 0;
+        struct req_iterator iter;
+        struct bio_vec *bvec;
 
-        rq_for_each_bio(bio, req) {
-                struct bio_vec *bvec;
-                bio_for_each_segment(bvec, bio, idx) {
+        rq_for_each_segment(bvec, req, iter) {
                         /* We told the block layer not to give us too many. */
                         BUG_ON(i == LGUEST_MAX_DMA_SECTIONS);
                         /* If we had a zero-length segment, it would look like
@@ -160,7 +159,6 @@ static unsigned int req_to_dma(struct request *req, struct lguest_dma *dma)
                         dma->len[i] = bvec->bv_len;
                         len += bvec->bv_len;
                         i++;
-                }
         }
         /* If the array isn't full, we mark the end with a 0 length */
         if (i < LGUEST_MAX_DMA_SECTIONS)
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;
diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c
index aa8b890c80d7..8953e7ce0016 100644
--- a/drivers/block/ps3disk.c
+++ b/drivers/block/ps3disk.c
@@ -91,30 +91,30 @@ static void ps3disk_scatter_gather(struct ps3_storage_device *dev,
                                    struct request *req, int gather)
 {
         unsigned int offset = 0;
-        struct bio *bio;
-        sector_t sector;
+        struct req_iterator iter;
         struct bio_vec *bvec;
-        unsigned int i = 0, j;
+        unsigned int i = 0;
         size_t size;
         void *buf;
 
-        rq_for_each_bio(bio, req) {
-                sector = bio->bi_sector;
+        rq_for_each_segment(bvec, req, iter) {
+                unsigned long flags;
                 dev_dbg(&dev->sbd.core,
                         "%s:%u: bio %u: %u segs %u sectors from %lu\n",
-                        __func__, __LINE__, i, bio_segments(bio),
-                        bio_sectors(bio), sector);
-                bio_for_each_segment(bvec, bio, j) {
+                        __func__, __LINE__, i, bio_segments(iter.bio),
+                        bio_sectors(iter.bio),
+                        (unsigned long)iter.bio->bi_sector);
+
                         size = bvec->bv_len;
-                        buf = __bio_kmap_atomic(bio, j, KM_IRQ0);
+                        buf = bvec_kmap_irq(bvec, &flags);
                         if (gather)
                                 memcpy(dev->bounce_buf+offset, buf, size);
                         else
                                 memcpy(buf, dev->bounce_buf+offset, size);
                         offset += size;
-                        flush_kernel_dcache_page(bio_iovec_idx(bio, j)->bv_page);
-                        __bio_kunmap_atomic(bio, KM_IRQ0);
-                }
+                        flush_kernel_dcache_page(bvec->bv_page);
+                        bvec_kunmap_irq(bvec, &flags);
+
                 i++;
         }
 }
@@ -130,12 +130,13 @@ static int ps3disk_submit_request_sg(struct ps3_storage_device *dev,
 
 #ifdef DEBUG
         unsigned int n = 0;
-        struct bio *bio;
+        struct bio_vec *bv;
+        struct req_iterator iter;
 
-        rq_for_each_bio(bio, req)
+        rq_for_each_segment(bv, req, iter)
                 n++;
         dev_dbg(&dev->sbd.core,
-                "%s:%u: %s req has %u bios for %lu sectors %lu hard sectors\n",
+                "%s:%u: %s req has %u bvecs for %lu sectors %lu hard sectors\n",
                 __func__, __LINE__, op, n, req->nr_sectors,
                 req->hard_nr_sectors);
 #endif
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 964e51634f2d..6af250113c2a 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -150,9 +150,8 @@ static int blkif_queue_request(struct request *req)
         struct blkfront_info *info = req->rq_disk->private_data;
         unsigned long buffer_mfn;
         struct blkif_request *ring_req;
-        struct bio *bio;
+        struct req_iterator iter;
         struct bio_vec *bvec;
-        int idx;
         unsigned long id;
         unsigned int fsect, lsect;
         int ref;
@@ -186,8 +185,7 @@ static int blkif_queue_request(struct request *req)
                 ring_req->operation = BLKIF_OP_WRITE_BARRIER;
 
         ring_req->nr_segments = 0;
-        rq_for_each_bio (bio, req) {
-                bio_for_each_segment (bvec, bio, idx) {
+        rq_for_each_segment(bvec, req, iter) {
                         BUG_ON(ring_req->nr_segments
                                == BLKIF_MAX_SEGMENTS_PER_REQUEST);
                         buffer_mfn = pfn_to_mfn(page_to_pfn(bvec->bv_page));
@@ -213,7 +211,6 @@ static int blkif_queue_request(struct request *req)
                                         .last_sect  = lsect };
 
                         ring_req->nr_segments++;
-                }
         }
 
         info->ring.req_prod_pvt++;
diff --git a/drivers/ide/ide-floppy.c b/drivers/ide/ide-floppy.c
index ae8e1a64b8ad..a775450d7a38 100644
--- a/drivers/ide/ide-floppy.c
+++ b/drivers/ide/ide-floppy.c
@@ -606,13 +606,12 @@ static void idefloppy_input_buffers (ide_drive_t *drive, idefloppy_pc_t *pc, uns
 {
         struct request *rq = pc->rq;
         struct bio_vec *bvec;
-        struct bio *bio;
+        struct req_iterator iter;
         unsigned long flags;
         char *data;
-        int count, i, done = 0;
+        int count, done = 0;
 
-        rq_for_each_bio(bio, rq) {
-                bio_for_each_segment(bvec, bio, i) {
+        rq_for_each_segment(bvec, rq, iter) {
                         if (!bcount)
                                 break;
 
@@ -625,7 +624,6 @@ static void idefloppy_input_buffers (ide_drive_t *drive, idefloppy_pc_t *pc, uns
                         bcount -= count;
                         pc->b_count += count;
                         done += count;
-                }
         }
 
         idefloppy_do_end_request(drive, 1, done >> 9);
@@ -639,14 +637,13 @@ static void idefloppy_input_buffers (ide_drive_t *drive, idefloppy_pc_t *pc, uns
 static void idefloppy_output_buffers (ide_drive_t *drive, idefloppy_pc_t *pc, unsigned int bcount)
 {
         struct request *rq = pc->rq;
-        struct bio *bio;
+        struct req_iterator iter;
         struct bio_vec *bvec;
         unsigned long flags;
-        int count, i, done = 0;
+        int count, done = 0;
         char *data;
 
-        rq_for_each_bio(bio, rq) {
-                bio_for_each_segment(bvec, bio, i) {
+        rq_for_each_segment(bvec, rq, iter) {
                         if (!bcount)
                                 break;
 
@@ -659,7 +656,6 @@ static void idefloppy_output_buffers (ide_drive_t *drive, idefloppy_pc_t *pc, un
                         bcount -= count;
                         pc->b_count += count;
                         done += count;
-                }
         }
 
         idefloppy_do_end_request(drive, 1, done >> 9);
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. */
diff --git a/drivers/s390/char/tape_34xx.c b/drivers/s390/char/tape_34xx.c
index 80e7a537e7d2..ea3e6a345c89 100644
--- a/drivers/s390/char/tape_34xx.c
+++ b/drivers/s390/char/tape_34xx.c
@@ -1134,21 +1134,18 @@ tape_34xx_bread(struct tape_device *device, struct request *req)
 {
         struct tape_request *request;
         struct ccw1 *ccw;
-        int count = 0, i;
+        int count = 0;
         unsigned off;
         char *dst;
         struct bio_vec *bv;
-        struct bio *bio;
+        struct req_iterator iter;
         struct tape_34xx_block_id *     start_block;
 
         DBF_EVENT(6, "xBREDid:");
 
         /* Count the number of blocks for the request. */
-        rq_for_each_bio(bio, req) {
-                bio_for_each_segment(bv, bio, i) {
-                        count += bv->bv_len >> (TAPEBLOCK_HSEC_S2B + 9);
-                }
-        }
+        rq_for_each_segment(bv, req, iter)
+                count += bv->bv_len >> (TAPEBLOCK_HSEC_S2B + 9);
 
         /* Allocate the ccw request. */
         request = tape_alloc_request(3+count+1, 8);
@@ -1175,8 +1172,7 @@ tape_34xx_bread(struct tape_device *device, struct request *req)
         ccw = tape_ccw_cc(ccw, NOP, 0, NULL);
         ccw = tape_ccw_cc(ccw, NOP, 0, NULL);
 
-        rq_for_each_bio(bio, req) {
-                bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, req, iter) {
                         dst = kmap(bv->bv_page) + bv->bv_offset;
                         for (off = 0; off < bv->bv_len;
                              off += TAPEBLOCK_HSEC_SIZE) {
@@ -1187,7 +1183,6 @@ tape_34xx_bread(struct tape_device *device, struct request *req)
                                 ccw++;
                                 dst += TAPEBLOCK_HSEC_SIZE;
                         }
-                }
         }
 
         ccw = tape_ccw_end(ccw, NOP, 0, NULL);
diff --git a/drivers/s390/char/tape_3590.c b/drivers/s390/char/tape_3590.c
index 7e2b2ab49264..b16ad7a7631d 100644
--- a/drivers/s390/char/tape_3590.c
+++ b/drivers/s390/char/tape_3590.c
@@ -623,21 +623,19 @@ tape_3590_bread(struct tape_device *device, struct request *req)
 {
         struct tape_request *request;
         struct ccw1 *ccw;
-        int count = 0, start_block, i;
+        int count = 0, start_block;
         unsigned off;
         char *dst;
         struct bio_vec *bv;
-        struct bio *bio;
+        struct req_iterator iter;
 
         DBF_EVENT(6, "xBREDid:");
         start_block = req->sector >> TAPEBLOCK_HSEC_S2B;
         DBF_EVENT(6, "start_block = %i\n", start_block);
 
-        rq_for_each_bio(bio, req) {
-                bio_for_each_segment(bv, bio, i) {
-                        count += bv->bv_len >> (TAPEBLOCK_HSEC_S2B + 9);
-                }
-        }
+        rq_for_each_segment(bv, req, iter)
+                count += bv->bv_len >> (TAPEBLOCK_HSEC_S2B + 9);
+
         request = tape_alloc_request(2 + count + 1, 4);
         if (IS_ERR(request))
                 return request;
@@ -653,8 +651,7 @@ tape_3590_bread(struct tape_device *device, struct request *req)
          */
         ccw = tape_ccw_cc(ccw, NOP, 0, NULL);
 
-        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 += TAPEBLOCK_HSEC_SIZE) {
@@ -667,7 +664,6 @@ tape_3590_bread(struct tape_device *device, struct request *req)
                         }
                         if (off > bv->bv_len)
                                 BUG();
-                }
         }
         ccw = tape_ccw_end(ccw, NOP, 0, NULL);
         DBF_EVENT(6, "xBREDccwg\n");
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index b126c6f68e27..a4b13b8a9d09 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -637,10 +637,23 @@ static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio)
 }
 #endif /* CONFIG_MMU */
 
-#define rq_for_each_bio(_bio, rq)       \
+struct req_iterator {
+        int i;
+        struct bio *bio;
+};
+
+/* This should not be used directly - use rq_for_each_segment */
+#define __rq_for_each_bio(_bio, rq)     \
         if ((rq->bio))                  \
                 for (_bio = (rq)->bio; _bio; _bio = _bio->bi_next)
 
+#define rq_for_each_segment(bvl, _rq, _iter)                    \
+        __rq_for_each_bio(_iter.bio, _rq)                       \
+                bio_for_each_segment(bvl, _iter.bio, _iter.i)
+
+#define rq_iter_last(rq, _iter)                                 \
+                (_iter.bio->bi_next == NULL && _iter.i == _iter.bio->bi_vcnt-1)
+
 extern int blk_register_queue(struct gendisk *disk);
 extern void blk_unregister_queue(struct gendisk *disk);
 extern void register_disk(struct gendisk *dev);