Merge tag 'for-linus-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs

Pull 9p changes from Eric Van Hensbergen:
 "A bunch of updates and cleanup within the transport layer,
  particularly with a focus on RDMA"

* tag 'for-linus-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  9pnet_rdma: check token type before int conversion
  9pnet: trans_fd : allocate struct p9_trans_fd and struct p9_conn together.
  9pnet: p9_client->conn field is unused. Remove it.
  9P: Get rid of REQ_STATUS_FLSH
  9pnet_rdma: add cancelled()
  9pnet_rdma: update request status during send
  9P: Add cancelled() to the transport functions.
  net: Mark function as static in 9p/client.c
  9P: Add memory barriers to protect request fields over cb/rpc threads handoff

1 files changed, 18 insertions, 7 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index 9186550d77a6..0004cbaac4a4 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -415,9 +415,17 @@ static void p9_free_req(struct p9_client *c, struct p9_req_t *r)
  * req: request received
  *
  */
-void p9_client_cb(struct p9_client *c, struct p9_req_t *req)
+void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
 {
         p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc->tag);
+
+        /*
+         * This barrier is needed to make sure any change made to req before
+         * the other thread wakes up will indeed be seen by the waiting side.
+         */
+        smp_wmb();
+        req->status = status;
+
         wake_up(req->wq);
         p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag);
 }
@@ -655,16 +663,13 @@ static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
         if (IS_ERR(req))
                 return PTR_ERR(req);
 
-
         /*
          * if we haven't received a response for oldreq,
          * remove it from the list
          */
-        if (oldreq->status == REQ_STATUS_FLSH) {
-                spin_lock(&c->lock);
-                list_del(&oldreq->req_list);
-                spin_unlock(&c->lock);
-        }
+        if (oldreq->status == REQ_STATUS_SENT)
+                if (c->trans_mod->cancelled)
+                        c->trans_mod->cancelled(c, oldreq);
 
         p9_free_req(c, req);
         return 0;
@@ -751,6 +756,12 @@ again:
         err = wait_event_interruptible(*req->wq,
                                        req->status >= REQ_STATUS_RCVD);
 
+        /*
+         * Make sure our req is coherent with regard to updates in other
+         * threads - echoes to wmb() in the callback
+         */
+        smp_rmb();
+
         if ((err == -ERESTARTSYS) && (c->status == Connected)
                                   && (type == P9_TFLUSH)) {
                 sigpending = 1;