Add a tracepoint for afs_read_receive() to allow potential missed wakeups
to be debugged.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
---
 fs/afs/file.c              |  1 +
 include/trace/events/afs.h | 30 ++++++++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/fs/afs/file.c b/fs/afs/file.c
index c296efebb491..fc15497608c6 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -274,6 +274,7 @@ static void afs_read_receive(struct afs_call *call)
 	state = READ_ONCE(call->state);
 	if (state == AFS_CALL_COMPLETE)
 		return;
+	trace_afs_read_recv(op, call);
 
 	while (state < AFS_CALL_COMPLETE && READ_ONCE(call->need_attention)) {
 		WRITE_ONCE(call->need_attention, false);
diff --git a/include/trace/events/afs.h b/include/trace/events/afs.h
index c52fd83ca9b7..2e92487f3f34 100644
--- a/include/trace/events/afs.h
+++ b/include/trace/events/afs.h
@@ -1775,6 +1775,36 @@ TRACE_EVENT(afs_make_call,
 		      __entry->fid.unique)
 	    );
 
+TRACE_EVENT(afs_read_recv,
+	    TP_PROTO(const struct afs_operation *op, const struct afs_call *call),
+
+	    TP_ARGS(op, call),
+
+	    TP_STRUCT__entry(
+		    __field(unsigned int,		rreq)
+		    __field(unsigned int,		sreq)
+		    __field(unsigned int,		op)
+		    __field(unsigned int,		op_flags)
+		    __field(unsigned int,		call)
+		    __field(enum afs_call_state,	call_state)
+			     ),
+
+	    TP_fast_assign(
+		    __entry->op = op->debug_id;
+		    __entry->sreq = op->fetch.subreq->debug_index;
+		    __entry->rreq = op->fetch.subreq->rreq->debug_id;
+		    __entry->op_flags = op->flags;
+		    __entry->call = call->debug_id;
+		    __entry->call_state = call->state;
+			   ),
+
+	    TP_printk("R=%08x[%x] OP=%08x c=%08x cs=%x of=%x",
+		      __entry->rreq, __entry->sreq,
+		      __entry->op,
+		      __entry->call, __entry->call_state,
+		      __entry->op_flags)
+	    );
+
 #endif /* _TRACE_AFS_H */
 
 /* This part must be outside protection */