libceph: consolidate message prep code

In prepare_write_message_data(), various fields are initialized in
preparation for writing message data out.  Meanwhile, in
read_partial_message(), there is essentially the same block of code,
operating on message variables associated with an incoming message.

Generalize prepare_write_message_data() so it works for both
incoming and outcoming messages, and use it in both spots.  The
did_page_crc is not used for input (so it's harmless to initialize
it).

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

1 files changed, 10 insertions, 18 deletions

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 7788170524e3..e8fa4497f424 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -722,11 +722,9 @@ static void iter_bio_next(struct bio **bio_iter, unsigned int *seg)
 }
 #endif
 
-static void prepare_write_message_data(struct ceph_connection *con)
+static void prepare_message_data(struct ceph_msg *msg,
+                                struct ceph_msg_pos *msg_pos)
 {
-        struct ceph_msg *msg = con->out_msg;
-        struct ceph_msg_pos *msg_pos = &con->out_msg_pos;
-
         BUG_ON(!msg);
         BUG_ON(!msg->hdr.data_len);
 
@@ -742,7 +740,6 @@ static void prepare_write_message_data(struct ceph_connection *con)
 #endif
         msg_pos->data_pos = 0;
         msg_pos->did_page_crc = false;
-        con->out_more = 1;  /* data + footer will follow */
 }
 
 /*
@@ -840,11 +837,13 @@ static void prepare_write_message(struct ceph_connection *con)
 
         /* is there a data payload? */
         con->out_msg->footer.data_crc = 0;
-        if (m->hdr.data_len)
-                prepare_write_message_data(con);
-        else
+        if (m->hdr.data_len) {
+                prepare_message_data(con->out_msg, &con->out_msg_pos);
+                con->out_more = 1;  /* data + footer will follow */
+        } else {
                 /* no, queue up footer too and be done */
                 prepare_write_message_footer(con);
+        }
 
         con_flag_set(con, CON_FLAG_WRITE_PENDING);
 }
@@ -1956,17 +1955,10 @@ static int read_partial_message(struct ceph_connection *con)
                 if (m->middle)
                         m->middle->vec.iov_len = 0;
 
-                msg_pos->page = 0;
-                if (m->pages)
-                        msg_pos->page_pos = m->page_alignment;
-                else
-                        msg_pos->page_pos = 0;
-                msg_pos->data_pos = 0;
+                /* prepare for data payload, if any */
 
-#ifdef CONFIG_BLOCK
-                if (m->bio)
-                        init_bio_iter(m->bio, &m->bio_iter, &m->bio_seg);
-#endif
+                if (data_len)
+                        prepare_message_data(con->in_msg, &con->in_msg_pos);
         }
 
         /* front */