libceph: don't use bio_iter as a flag

(cherry picked from commit abdaa6a849af1d63153682c11f5bbb22dacb1f6b)

Recently a bug was fixed in which the bio_iter field in a ceph
message was not being properly re-initialized when a message got
re-transmitted:
    commit 43643528cce60ca184fe8197efa8e8da7c89a037
    Author: Yan, Zheng <zheng.z.yan@intel.com>
    rbd: Clear ceph_msg->bio_iter for retransmitted message

We are now only initializing the bio_iter field when we are about to
start to write message data (in prepare_write_message_data()),
rather than every time we are attempting to write any portion of the
message data (in write_partial_msg_pages()).  This means we no
longer need to use the msg->bio_iter field as a flag.

So just don't do that any more.  Trust prepare_write_message_data()
to ensure msg->bio_iter is properly initialized, every time we are
about to begin writing (or re-writing) a message's bio data.

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 0c097b0dba9d33e1d67647fbb7d9c4b03880aa81..f0499fe069a54f0213521d82070b6e1419b6bff9 100644 (file)
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -604,7 +604,7 @@ static void prepare_write_message_data(struct ceph_connection *con)
        else
                con->out_msg_pos.page_pos = 0;
 #ifdef CONFIG_BLOCK
-       if (msg->bio && !msg->bio_iter)
+       if (msg->bio)
                init_bio_iter(msg->bio, &msg->bio_iter, &msg->bio_seg);
 #endif
        con->out_msg_pos.data_pos = 0;
@@ -672,10 +672,6 @@ static void prepare_write_message(struct ceph_connection *con)
                m->hdr.seq = cpu_to_le64(++con->out_seq);
                m->needs_out_seq = false;
        }
-#ifdef CONFIG_BLOCK
-       else
-               m->bio_iter = NULL;
-#endif
 
        dout("prepare_write_message %p seq %lld type %d len %d+%d+%d %d pgs\n",
             m, con->out_seq, le16_to_cpu(m->hdr.type),