From ffccc78a5862100e1859f74fa8eea0b85b7591f1 Mon Sep 17 00:00:00 2001 From: Sherry Sun Date: Fri, 3 Dec 2021 11:04:41 +0800 Subject: [PATCH] tty: serial: fsl_lpuart: add timeout for wait_event_interruptible in .shutdown() Use wait_event_interruptible in lpuart_dma_shutdown isn't a reasonable behavior, since it may cause the system hang here if the condition !sport->dma_tx_in_progress never to be true in some corner case, such as when enable the flow control, the dma tx request may never be completed due to the peer's CTS setting when run .shutdown(). So here change to use wait_event_interruptible_timeout instead of wait_event_interruptible, the tx dma will be forcibly terminated if the tx dma request cannot be completed within 300ms. Considering the worst tx dma case is to have a 4K bytes tx buffer, which would require about 300ms to complete when the baudrate is 115200. Signed-off-by: Sherry Sun Link: https://lore.kernel.org/r/20211203030441.22873-1-sherry.sun@nxp.com Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/fsl_lpuart.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c index b1e7190..eaa6161 100644 --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -1793,8 +1793,8 @@ static void lpuart_dma_shutdown(struct lpuart_port *sport) } if (sport->lpuart_dma_tx_use) { - if (wait_event_interruptible(sport->dma_wait, - !sport->dma_tx_in_progress) != false) { + if (wait_event_interruptible_timeout(sport->dma_wait, + !sport->dma_tx_in_progress, msecs_to_jiffies(300)) <= 0) { sport->dma_tx_in_progress = false; dmaengine_terminate_all(sport->dma_tx_chan); } -- 2.7.4