From: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> commit e77cab77f2cb3a1ca2ba8df4af45bb35617ac16d upstream. A very common pattern in the drivers is to advance xmit tail index and do bookkeeping of Tx'ed characters. Create uart_xmit_advance() to handle it. Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> Cc: stable <stable@xxxxxxxxxx> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20220901143934.8850-2-ilpo.jarvinen@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- include/linux/serial_core.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -294,6 +294,23 @@ struct uart_state { /* number of characters left in xmit buffer before we ask for more */ #define WAKEUP_CHARS 256 +/** + * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars + * @up: uart_port structure describing the port + * @chars: number of characters sent + * + * This function advances the tail of circular xmit buffer by the number of + * @chars transmitted and handles accounting of transmitted bytes (into + * @up's icount.tx). + */ +static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars) +{ + struct circ_buf *xmit = &up->state->xmit; + + xmit->tail = (xmit->tail + chars) & (UART_XMIT_SIZE - 1); + up->icount.tx += chars; +} + struct module; struct tty_driver;
