9P: Add cancelled() to the transport functions.

RDMA needs to post a buffer for each incoming reply.
Hence it needs to keep count of these and needs to be
aware of whether a flushed request has received a reply
or not.

This patch adds the cancelled() callback to the transport modules.
It is called when RFLUSH has been received and that the corresponding
request will never receive a reply.

Signed-off-by: Simon Derr <simon.derr@bull.net>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

2 files changed, 20 insertions, 3 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index d18a0b22f62c..8b93cae2d11d 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -658,12 +658,18 @@ static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
 
         /*
          * if we haven't received a response for oldreq,
-         * remove it from the list.
+         * remove it from the list, and notify the transport
+         * layer that the reply will never arrive.
          */
         spin_lock(&c->lock);
-        if (oldreq->status == REQ_STATUS_FLSH)
+        if (oldreq->status == REQ_STATUS_FLSH) {
                 list_del(&oldreq->req_list);
-        spin_unlock(&c->lock);
+                spin_unlock(&c->lock);
+                if (c->trans_mod->cancelled)
+                        c->trans_mod->cancelled(c, req);
+        } else {
+                spin_unlock(&c->lock);
+        }
 
         p9_free_req(c, req);
         return 0;
diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c
index 8f68df5d2973..928f2bb9bf8d 100644
--- a/net/9p/trans_rdma.c
+++ b/net/9p/trans_rdma.c
@@ -588,6 +588,17 @@ static int rdma_cancel(struct p9_client *client, struct p9_req_t *req)
         return 1;
 }
 
+/* A request has been fully flushed without a reply.
+ * That means we have posted one buffer in excess.
+ */
+static int rdma_cancelled(struct p9_client *client, struct p9_req_t *req)
+{
+        struct p9_trans_rdma *rdma = client->trans;
+
+        atomic_inc(&rdma->excess_rc);
+        return 0;
+}
+
 /**
  * trans_create_rdma - Transport method for creating atransport instance
  * @client: client instance