On Fri,  4 Jul 2014 18:34:08 +0200
Sebastian Andrzej Siewior [off-list ref] wrote:

There is no access to access a struct uart_8250_port for a specific
line. This is only required outside of the 8250/uart callbacks like for
devices' suspend & remove callbacks. For those the 8250-core provides
wrapper like serial8250_unregister_port() which passes the struct
to the proper function based on the line argument.

For runtime suspend I need access to this struct not only to make
serial_out() work but also to properly restore up->ier and up->mcr.

Please update the patch to clearly describe the locking
assumptions/requirements for the caller (and not to use it unless you
have no other choice)