From 0c9c1ea583f1b9887d248dc26f6921c4ae826b96 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Mon, 6 May 2024 13:40:19 +0200 Subject: [PATCH] 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 --- drivers/tty/serial/sh-sci.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 7a7bc18e4705..d31b3aca5987 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: