xprtrdma: RPC/RDMA must invoke xprt_wake_pending_tasks() in process context

An IB provider can invoke rpcrdma_conn_func() in an IRQ context,
thus rpcrdma_conn_func() cannot be allowed to directly invoke
generic RPC functions like xprt_wake_pending_tasks().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

3 files changed, 21 insertions, 7 deletions

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 400aa1b77d72..c296468a6f96 100644
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -676,15 +676,11 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
         rqst->rq_private_buf = rqst->rq_rcv_buf;
 }
 
-/*
- * This function is called when an async event is posted to
- * the connection which changes the connection state. All it
- * does at this point is mark the connection up/down, the rpc
- * timers do the rest.
- */
 void
-rpcrdma_conn_func(struct rpcrdma_ep *ep)
+rpcrdma_connect_worker(struct work_struct *work)
 {
+        struct rpcrdma_ep *ep =
+                container_of(work, struct rpcrdma_ep, rep_connect_worker.work);
         struct rpc_xprt *xprt = ep->rep_xprt;
 
         spin_lock_bh(&xprt->transport_lock);
@@ -701,6 +697,18 @@ rpcrdma_conn_func(struct rpcrdma_ep *ep)
 }
 
 /*
+ * This function is called when an async event is posted to
+ * the connection which changes the connection state. All it
+ * does at this point is mark the connection up/down, the rpc
+ * timers do the rest.
+ */
+void
+rpcrdma_conn_func(struct rpcrdma_ep *ep)
+{
+        schedule_delayed_work(&ep->rep_connect_worker, 0);
+}
+
+/*
  * This function is called when memory window unbind which we are waiting
  * for completes. Just use rr_func (zeroed by upcall) to signal completion.
  */
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 8f9704e0f03d..9cb88f373c7a 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -742,6 +742,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
         INIT_CQCOUNT(ep);
         ep->rep_ia = ia;
         init_waitqueue_head(&ep->rep_connect_wait);
+        INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker);
 
         /*
          * Create a single cq for receive dto and mw_bind (only ever
@@ -817,6 +818,8 @@ rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
         dprintk("RPC:       %s: entering, connected is %d\n",
                 __func__, ep->rep_connected);
 
+        cancel_delayed_work_sync(&ep->rep_connect_worker);
+
         if (ia->ri_id->qp) {
                 rc = rpcrdma_ep_disconnect(ep, ia);
                 if (rc)
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 98340a31f2bc..c620d1332933 100644
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -43,6 +43,7 @@
 #include <linux/wait.h>                 /* wait_queue_head_t, etc */
 #include <linux/spinlock.h>             /* spinlock_t, etc */
 #include <linux/atomic.h>                       /* atomic_t, etc */
+#include <linux/workqueue.h>            /* struct work_struct */
 
 #include <rdma/rdma_cm.h>               /* RDMA connection api */
 #include <rdma/ib_verbs.h>              /* RDMA verbs api */
@@ -87,6 +88,7 @@ struct rpcrdma_ep {
         struct rpc_xprt         *rep_xprt;      /* for rep_func */
         struct rdma_conn_param  rep_remote_cma;
         struct sockaddr_storage rep_remote_addr;
+        struct delayed_work     rep_connect_worker;
 };
 
 #define INIT_CQCOUNT(ep) atomic_set(&(ep)->rep_cqcount, (ep)->rep_cqinit)
@@ -336,6 +338,7 @@ int rpcrdma_deregister_external(struct rpcrdma_mr_seg *,
 /*
  * RPC/RDMA connection management calls - xprtrdma/rpc_rdma.c
  */
+void rpcrdma_connect_worker(struct work_struct *);
 void rpcrdma_conn_func(struct rpcrdma_ep *);
 void rpcrdma_reply_handler(struct rpcrdma_rep *);