libceph: implement bio message data item cursor

Implement and use cursor routines for bio message data items for
outbound message data.

(See the previous commit for reasoning in support of the changes
in out_msg_pos_next().)

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index 716c3fdeb257..76b4645e2dff 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -98,6 +98,13 @@ static __inline__ bool ceph_msg_data_type_valid(enum ceph_msg_data_type type)
 struct ceph_msg_data_cursor {
         bool            last_piece;     /* now at last piece of data item */
         union {
+#ifdef CONFIG_BLOCK
+                struct {                                /* bio */
+                        struct bio      *bio;           /* bio from list */
+                        unsigned int    vector_index;   /* vector from bio */
+                        unsigned int    vector_offset;  /* bytes from vector */
+                };
+#endif /* CONFIG_BLOCK */
                 struct {                                /* pagelist */
                         struct page     *page;          /* page from list */
                         size_t          offset;         /* bytes from list */