From: Wolfram Sang Date: Mon, 6 May 2024 11:40:19 +0000 (+0200) Subject: serial: sh-sci: let timeout timer only run when DMA is scheduled X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0c9c1ea583f1b9887d248dc26f6921c4ae826b96;p=linux.git serial: sh-sci: let timeout timer only run when DMA is scheduled The hrtimer for RXDMA timeout was unconditionally restarted in the RXDMA complete handler ignoring the fact that setting up DMA may fail and PIO is used instead. Explicitly stop the timer when DMA is completed and only restart it when setting up DMA was successful. This makes the intention of the timer much clearer, the driver easier to understand and simplifies assumptions about the timer. The latter avoids race conditions if these assumptions were not met or confused. Signed-off-by: Wolfram Sang Link: https://lore.kernel.org/r/20240506114016.30498-9-wsa+renesas@sang-engineering.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 7a7bc18e47055..d31b3aca59878 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1324,14 +1324,14 @@ static void sci_dma_rx_complete(void *arg) dev_dbg(port->dev, "%s(%d) active cookie %d\n", __func__, port->line, s->active_rx); + hrtimer_cancel(&s->rx_timer); + uart_port_lock_irqsave(port, &flags); active = sci_dma_rx_find_active(s); if (active >= 0) count = sci_dma_rx_push(s, s->rx_buf[active], s->buf_len_rx); - start_hrtimer_us(&s->rx_timer, s->rx_timeout); - if (count) tty_flip_buffer_push(&port->state->port); @@ -1354,6 +1354,9 @@ static void sci_dma_rx_complete(void *arg) uart_port_unlock_irqrestore(port, flags); dev_dbg(port->dev, "%s: cookie %d #%d, new active cookie %d\n", __func__, s->cookie_rx[active], active, s->active_rx); + + start_hrtimer_us(&s->rx_timer, s->rx_timeout); + return; fail: