SMB3: Track total time spent on roundtrips for each SMB3 command

Also track minimum and maximum time by command in /proc/fs/cifs/Stats

Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsglob.h

@@ -714,7 +714,11 @@ struct TCP_Server_Info {
 #ifdef CONFIG_CIFS_STATS2
 	atomic_t in_send; /* requests trying to send */
 	atomic_t num_waiters;   /* blocked waiting to get in sendrecv */
+	atomic_t num_cmds[NUMBER_OF_SMB2_COMMANDS]; /* total requests by cmd */
 	atomic_t smb2slowcmd[NUMBER_OF_SMB2_COMMANDS]; /* count resps > 1 sec */
+	__u64 time_per_cmd[NUMBER_OF_SMB2_COMMANDS]; /* total time per cmd */
+	__u32 slowest_cmd[NUMBER_OF_SMB2_COMMANDS];
+	__u32 fastest_cmd[NUMBER_OF_SMB2_COMMANDS];
 #endif /* STATS2 */
 	unsigned int	max_read;
 	unsigned int	max_write;