libceph: have messages point to their connection

When a ceph message is queued for sending it is placed on a list of
pending messages (ceph_connection->out_queue).  When they are
actually sent over the wire, they are moved from that list to
another (ceph_connection->out_sent).  When acknowledgement for the
message is received, it is removed from the sent messages list.

During that entire time the message is "in the possession" of a
single ceph connection.  Keep track of that connection in the
message.  This will be used in the next patch (and is a helpful
bit of information for debugging anyway).

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>

1 files changed, 25 insertions, 2 deletions

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 98ca23726ea6..68b49b5b8e86 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -414,6 +414,9 @@ static int con_close_socket(struct ceph_connection *con)
 static void ceph_msg_remove(struct ceph_msg *msg)
 {
         list_del_init(&msg->list_head);
+        BUG_ON(msg->con == NULL);
+        msg->con = NULL;
+
         ceph_msg_put(msg);
 }
 static void ceph_msg_remove_list(struct list_head *head)
@@ -433,6 +436,8 @@ static void reset_connection(struct ceph_connection *con)
         ceph_msg_remove_list(&con->out_sent);
 
         if (con->in_msg) {
+                BUG_ON(con->in_msg->con != con);
+                con->in_msg->con = NULL;
                 ceph_msg_put(con->in_msg);
                 con->in_msg = NULL;
         }
@@ -625,8 +630,10 @@ static void prepare_write_message(struct ceph_connection *con)
                         &con->out_temp_ack);
         }
 
+        BUG_ON(list_empty(&con->out_queue));
         m = list_first_entry(&con->out_queue, struct ceph_msg, list_head);
         con->out_msg = m;
+        BUG_ON(m->con != con);
 
         /* put message on sent list */
         ceph_msg_get(m);
@@ -1806,6 +1813,8 @@ static int read_partial_message(struct ceph_connection *con)
                                 "error allocating memory for incoming message";
                         return -ENOMEM;
                 }
+
+                BUG_ON(con->in_msg->con != con);
                 m = con->in_msg;
                 m->front.iov_len = 0;    /* haven't read it yet */
                 if (m->middle)
@@ -1901,6 +1910,8 @@ static void process_message(struct ceph_connection *con)
 {
         struct ceph_msg *msg;
 
+        BUG_ON(con->in_msg->con != con);
+        con->in_msg->con = NULL;
         msg = con->in_msg;
         con->in_msg = NULL;
 
@@ -2260,6 +2271,8 @@ static void ceph_fault(struct ceph_connection *con)
         con_close_socket(con);
 
         if (con->in_msg) {
+                BUG_ON(con->in_msg->con != con);
+                con->in_msg->con = NULL;
                 ceph_msg_put(con->in_msg);
                 con->in_msg = NULL;
         }
@@ -2378,6 +2391,8 @@ void ceph_con_send(struct ceph_connection *con, struct ceph_msg *msg)
 
         /* queue */
         mutex_lock(&con->mutex);
+        BUG_ON(msg->con != NULL);
+        msg->con = con;
         BUG_ON(!list_empty(&msg->list_head));
         list_add_tail(&msg->list_head, &con->out_queue);
         dout("----- %p to %s%lld %d=%s len %d+%d+%d -----\n", msg,
@@ -2403,13 +2418,16 @@ void ceph_con_revoke(struct ceph_connection *con, struct ceph_msg *msg)
 {
         mutex_lock(&con->mutex);
         if (!list_empty(&msg->list_head)) {
-                dout("con_revoke %p msg %p - was on queue\n", con, msg);
+                dout("%s %p msg %p - was on queue\n", __func__, con, msg);
                 list_del_init(&msg->list_head);
+                BUG_ON(msg->con == NULL);
+                msg->con = NULL;
+
                 ceph_msg_put(msg);
                 msg->hdr.seq = 0;
         }
         if (con->out_msg == msg) {
-                dout("con_revoke %p msg %p - was sending\n", con, msg);
+                dout("%s %p msg %p - was sending\n", __func__, con, msg);
                 con->out_msg = NULL;
                 if (con->out_kvec_is_msg) {
                         con->out_skip = con->out_kvec_bytes;
@@ -2478,6 +2496,8 @@ struct ceph_msg *ceph_msg_new(int type, int front_len, gfp_t flags,
         if (m == NULL)
                 goto out;
         kref_init(&m->kref);
+
+        m->con = NULL;
         INIT_LIST_HEAD(&m->list_head);
 
         m->hdr.tid = 0;
@@ -2598,6 +2618,8 @@ static bool ceph_con_in_msg_alloc(struct ceph_connection *con,
                 mutex_unlock(&con->mutex);
                 con->in_msg = con->ops->alloc_msg(con, hdr, &skip);
                 mutex_lock(&con->mutex);
+                if (con->in_msg)
+                        con->in_msg->con = con;
                 if (skip)
                         con->in_msg = NULL;
 
@@ -2611,6 +2633,7 @@ static bool ceph_con_in_msg_alloc(struct ceph_connection *con,
                                type, front_len);
                         return false;
                 }
+                con->in_msg->con = con;
                 con->in_msg->page_alignment = le16_to_cpu(hdr->data_off);
         }
         memcpy(&con->in_msg->hdr, &con->in_hdr, sizeof(con->in_hdr));