On Fri, Jun 29, 2018 at 4:26 PM Geert Uytterhoeven
<geert+renesas@xxxxxxxxx> wrote:
> When the sh-sci driver detects an issue with DMA during operation, it
> falls backs to PIO, and releases all DMA resources.
>
> As releasing DMA resources immediately has no advantages, but
> complicates the code, and is susceptible to races, it is better to
> postpone this to port shutdown.
>
> This allows to remove the locking from sci_rx_dma_release() and
> sci_tx_dma_release(), but requires keeping a copy of the DMA channel
> pointers for release during port shutdown.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> --- a/drivers/tty/serial/sh-sci.c
> +++ b/drivers/tty/serial/sh-sci.c
> @@ -1212,25 +1214,17 @@ static int sci_dma_rx_find_active(struct sci_port *s)
> return -1;
> }
>
> -static void sci_rx_dma_release(struct sci_port *s, bool enable_pio)
> +static void sci_rx_dma_release(struct sci_port *s)
> {
> - struct dma_chan *chan = s->chan_rx;
> + struct dma_chan *chan = s->chan_rx_saved;
> struct uart_port *port = &s->port;
Brown paper bag #2: unused variable port. Let's blame it on the warm Friday
afternoon.
So yes, there will be a v2, eventually...
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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