Re: [PATCH 1/2] serial: mps2-uart: move to dynamic port allocation

[Greg KH <greg@kroah.com>]

On Fri, Jan 25, 2019 at 02:13:16PM +0000, Vladimir Murzin wrote:
> Some designs, like MPS3, expose number of virtual serial ports which
> already close or exceeds MPS2_MAX_PORTS. Increasing MPS2_MAX_PORTS
> would have negative impact (in terms of memory consumption) on tiny
> MPS2 platform which, in fact, has only one physically populated UART.
> 
> Start with converting existent static port array to idr. As a bonus it
> make driver not to fail in case when no alias was specified in device
> tree.
> 
> Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
> ---
>  drivers/tty/serial/mps2-uart.c | 47 ++++++++++++++++++++++++++++--------------
>  1 file changed, 31 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/tty/serial/mps2-uart.c b/drivers/tty/serial/mps2-uart.c
> index 9f8f637..6da0633 100644
> --- a/drivers/tty/serial/mps2-uart.c
> +++ b/drivers/tty/serial/mps2-uart.c
> @@ -22,6 +22,7 @@
>  #include <linux/serial_core.h>
>  #include <linux/tty_flip.h>
>  #include <linux/types.h>
> +#include <linux/idr.h>
>  
>  #define SERIAL_NAME	"ttyMPS"
>  #define DRIVER_NAME	"mps2-uart"
> @@ -397,7 +398,7 @@ static const struct uart_ops mps2_uart_pops = {
>  	.verify_port = mps2_uart_verify_port,
>  };
>  
> -static struct mps2_uart_port mps2_uart_ports[MPS2_MAX_PORTS];
> +static DEFINE_IDR(ports_idr);

You forgot to call idr_destroy() when your code unloads :(

Yeah, it's not an obvious design pattern, I think someone will fix it up
someday...

thanks,

greg k-h