Samba is a suite of programs that allows SMB/CIFS clients to interact with file and print services on a Linux/UNIX server.
smbd is the Samba daemon responsible for handling SMB/CIFS requests.
The smbcontrol utility is used to send messages to running Samba daemons.
The correct way to terminate all running instances of the Samba daemon handling SMB shares is to send a shutdown message to smbd using the command smbcontrol smbd shutdown.
This command ensures that only the smbd processes, which are responsible for handling SMB shares, are terminated without affecting other Samba components like nmbd (NetBIOS name server daemon).
Reference:
Samba documentation: https://www.samba.org/samba/docs/current/man-html/smbcontrol.1.html