[PATCH 10/19] rnbd-srv: simplify bio mapping in process_rdma

[Christoph Hellwig <hch@xxxxxx>]

The memory mapped in process_rdma is contiguous, so there is no need
to loop over bio_add_page.  Remove rnbd_bio_map_kern and just open code
the bio allocation and mapping in the caller.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 drivers/block/rnbd/rnbd-srv-dev.c | 57 -------------------------------
 drivers/block/rnbd/rnbd-srv-dev.h |  5 ---
 drivers/block/rnbd/rnbd-srv.c     | 20 ++++++++---
 3 files changed, 15 insertions(+), 67 deletions(-)

diff --git a/drivers/block/rnbd/rnbd-srv-dev.c 
b/drivers/block/rnbd/rnbd-srv-dev.c
index b241a099aeae2..98d3e591a0885 100644
--- a/drivers/block/rnbd/rnbd-srv-dev.c
+++ b/drivers/block/rnbd/rnbd-srv-dev.c
@@ -44,60 +44,3 @@ void rnbd_dev_close(struct rnbd_dev *dev)
        blkdev_put(dev->bdev, dev->blk_open_flags);
        kfree(dev);
 }
-
-void rnbd_dev_bi_end_io(struct bio *bio)
-{
-       struct rnbd_dev_blk_io *io = bio->bi_private;
-
-       rnbd_endio(io->priv, blk_status_to_errno(bio->bi_status));
-       bio_put(bio);
-}
-
-/**
- *     rnbd_bio_map_kern       -       map kernel address into bio
- *     @data: pointer to buffer to map
- *     @bs: bio_set to use.
- *     @len: length in bytes
- *     @gfp_mask: allocation flags for bio allocation
- *
- *     Map the kernel address into a bio suitable for io to a block
- *     device. Returns an error pointer in case of error.
- */
-struct bio *rnbd_bio_map_kern(void *data, struct bio_set *bs,
-                             unsigned int len, gfp_t gfp_mask)
-{
-       unsigned long kaddr = (unsigned long)data;
-       unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
-       unsigned long start = kaddr >> PAGE_SHIFT;
-       const int nr_pages = end - start;
-       int offset, i;
-       struct bio *bio;
-
-       bio = bio_alloc_bioset(gfp_mask, nr_pages, bs);
-       if (!bio)
-               return ERR_PTR(-ENOMEM);
-
-       offset = offset_in_page(kaddr);
-       for (i = 0; i < nr_pages; i++) {
-               unsigned int bytes = PAGE_SIZE - offset;
-
-               if (len <= 0)
-                       break;
-
-               if (bytes > len)
-                       bytes = len;
-
-               if (bio_add_page(bio, virt_to_page(data), bytes,
-                                   offset) < bytes) {
-                       /* we don't support partial mappings */
-                       bio_put(bio);
-                       return ERR_PTR(-EINVAL);
-               }
-
-               data += bytes;
-               len -= bytes;
-               offset = 0;
-       }
-
-       return bio;
-}
diff --git a/drivers/block/rnbd/rnbd-srv-dev.h 
b/drivers/block/rnbd/rnbd-srv-dev.h
index 0eb23850afb95..1a14ece0be726 100644
--- a/drivers/block/rnbd/rnbd-srv-dev.h
+++ b/drivers/block/rnbd/rnbd-srv-dev.h
@@ -41,11 +41,6 @@ void rnbd_dev_close(struct rnbd_dev *dev);
 
 void rnbd_endio(void *priv, int error);
 
-void rnbd_dev_bi_end_io(struct bio *bio);
-
-struct bio *rnbd_bio_map_kern(void *data, struct bio_set *bs,
-                             unsigned int len, gfp_t gfp_mask);
-
 static inline int rnbd_dev_get_max_segs(const struct rnbd_dev *dev)
 {
        return queue_max_segments(bdev_get_queue(dev->bdev));
diff --git a/drivers/block/rnbd/rnbd-srv.c b/drivers/block/rnbd/rnbd-srv.c
index 1ee808fc600cf..65c670e96075b 100644
--- a/drivers/block/rnbd/rnbd-srv.c
+++ b/drivers/block/rnbd/rnbd-srv.c
@@ -114,6 +114,14 @@ rnbd_get_sess_dev(int dev_id, struct rnbd_srv_session 
*srv_sess)
        return sess_dev;
 }
 
+static void rnbd_dev_bi_end_io(struct bio *bio)
+{
+       struct rnbd_dev_blk_io *io = bio->bi_private;
+
+       rnbd_endio(io->priv, blk_status_to_errno(bio->bi_status));
+       bio_put(bio);
+}
+
 static int process_rdma(struct rnbd_srv_session *srv_sess,
                        struct rtrs_srv_op *id, void *data, u32 datalen,
                        const void *usr, size_t usrlen)
@@ -144,11 +152,11 @@ static int process_rdma(struct rnbd_srv_session *srv_sess,
        priv->sess_dev = sess_dev;
        priv->id = id;
 
-       /* Generate bio with pages pointing to the rdma buffer */
-       bio = rnbd_bio_map_kern(data, sess_dev->rnbd_dev->ibd_bio_set, datalen, 
GFP_KERNEL);
-       if (IS_ERR(bio)) {
-               err = PTR_ERR(bio);
-               rnbd_srv_err(sess_dev, "Failed to generate bio, err: %d\n", 
err);
+       bio = bio_alloc_bioset(GFP_KERNEL, 1, sess_dev->rnbd_dev->ibd_bio_set);
+       if (bio_add_page(bio, virt_to_page(data), datalen,
+                       offset_in_page(data))) {
+               rnbd_srv_err(sess_dev, "Failed to map data to bio\n");
+               err = -EINVAL;
                goto sess_dev_put;
        }
 
@@ -170,6 +178,8 @@ static int process_rdma(struct rnbd_srv_session *srv_sess,
 
        return 0;
 
+bio_put:
+       bio_put(bio);
 sess_dev_put:
        rnbd_put_sess_dev(sess_dev);
 err:
-- 
2.30.2