SUNRPC: Trace calls to .rpc_call_done

Introduce a single tracepoint that can replace simple dprintk call
sites in upper layer "rpc_call_done" callbacks. Example:

   kworker/u24:2-1254  [001]   771.026677: rpc_stats_latency:    task:00000001@00000002 xid=0x16a6f3c0 rpcbindv2 GETPORT backlog=446 rtt=101 execute=555
   kworker/u24:2-1254  [001]   771.026677: rpc_task_call_done:   task:00000001@00000002 flags=ASYNC|DYNAMIC|SOFT|SOFTCONN|SENT runstate=RUNNING|ACTIVE status=0 action=rpcb_getport_done
   kworker/u24:2-1254  [001]   771.026678: rpcb_setport:         task:00000001@00000002 status=0 port=20048
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/lockd/clntproc.c

@@ -794,9 +794,6 @@ static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
 		goto retry_cancel;
 	}
 
-	dprintk("lockd: cancel status %u (task %u)\n",
-			status, task->tk_pid);
-
 	switch (status) {
 	case NLM_LCK_GRANTED:
 	case NLM_LCK_DENIED_GRACE_PERIOD:

fs/lockd/svc4proc.c

@@ -269,8 +269,6 @@ nlm4svc_proc_granted(struct svc_rqst *rqstp)
  */
 static void nlm4svc_callback_exit(struct rpc_task *task, void *data)
 {
-	dprintk("lockd: %5u callback returned %d\n", task->tk_pid,
-			-task->tk_status);
 }
 
 static void nlm4svc_callback_release(void *data)

fs/lockd/svcproc.c

@@ -301,8 +301,6 @@ nlmsvc_proc_granted(struct svc_rqst *rqstp)
  */
 static void nlmsvc_callback_exit(struct rpc_task *task, void *data)
 {
-	dprintk("lockd: %5u callback returned %d\n", task->tk_pid,
-			-task->tk_status);
 }
 
 void nlmsvc_release_call(struct nlm_rqst *call)

fs/nfs/filelayout/filelayout.c

@@ -293,8 +293,6 @@ static void filelayout_read_call_done(struct rpc_task *task, void *data)
 {
 	struct nfs_pgio_header *hdr = data;
 
-	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
-
 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
 	    task->tk_status == 0) {
 		nfs41_sequence_done(task, &hdr->res.seq_res);

fs/nfs/flexfilelayout/flexfilelayout.c

@@ -1414,8 +1414,6 @@ static void ff_layout_read_call_done(struct rpc_task *task, void *data)
 {
 	struct nfs_pgio_header *hdr = data;
 
-	dprintk("--> %s task->tk_status %d\n", __func__, task->tk_status);
-
 	if (test_bit(NFS_IOHDR_REDO, &hdr->flags) &&
 	    task->tk_status == 0) {
 		nfs4_sequence_done(task, &hdr->res.seq_res);

fs/nfs/pagelist.c

@@ -864,9 +864,6 @@ static void nfs_pgio_result(struct rpc_task *task, void *calldata)
 	struct nfs_pgio_header *hdr = calldata;
 	struct inode *inode = hdr->inode;
 
-	dprintk("NFS: %s: %5u, (status %d)\n", __func__,
-		task->tk_pid, task->tk_status);
-
 	if (hdr->rw_ops->rw_done(task, hdr, inode) != 0)
 		return;
 	if (task->tk_status < 0)

fs/nfs/write.c

@@ -1840,9 +1840,6 @@ static void nfs_commit_done(struct rpc_task *task, void *calldata)
 {
 	struct nfs_commit_data	*data = calldata;
 
-        dprintk("NFS: %5u nfs_commit_done (status %d)\n",
-                                task->tk_pid, task->tk_status);
-
 	/* Call the NFS version-specific code */
 	NFS_PROTO(data->inode)->commit_done(task, data);
 	trace_nfs_commit_done(task, data);

include/trace/events/sunrpc.h

@@ -378,6 +378,7 @@ DEFINE_RPC_RUNNING_EVENT(complete);
 DEFINE_RPC_RUNNING_EVENT(timeout);
 DEFINE_RPC_RUNNING_EVENT(signalled);
 DEFINE_RPC_RUNNING_EVENT(end);
+DEFINE_RPC_RUNNING_EVENT(call_done);
 
 DECLARE_EVENT_CLASS(rpc_task_queued,
 

net/sunrpc/sched.c

@@ -837,6 +837,7 @@ void rpc_exit_task(struct rpc_task *task)
 	else if (task->tk_client)
 		rpc_count_iostats(task, task->tk_client->cl_metrics);
 	if (task->tk_ops->rpc_call_done != NULL) {
+		trace_rpc_task_call_done(task, task->tk_ops->rpc_call_done);
 		task->tk_ops->rpc_call_done(task, task->tk_calldata);
 		if (task->tk_action != NULL) {
 			/* Always release the RPC slot and buffer memory */