smb3: add dynamic trace point for smb3_cmd_enter

Add tracepoint before sending an SMB3 command on the wire (ie add
an smb3_cmd_enter tracepoint). This allows us to look in much
more detail at response times (between request and response).

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

fs/cifs/trace.h

@@ -275,6 +275,7 @@ DEFINE_EVENT(smb3_cmd_done_class, smb3_##name,    \
 		__u64	mid),			\
 	TP_ARGS(tid, sesid, cmd, mid))
 
+DEFINE_SMB3_CMD_DONE_EVENT(cmd_enter);
 DEFINE_SMB3_CMD_DONE_EVENT(cmd_done);
 DEFINE_SMB3_CMD_DONE_EVENT(ses_expired);