Messages in this thread Patch in this message | | | Subject | Re: [PATCH] tty: serial: replace spin_lock_irqsave by spin_lock in hard IRQ | From | "tiantao (H)" <> | Date | Fri, 20 Nov 2020 19:25:03 +0800 |
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在 2020/11/20 16:23, Johan Hovold 写道: > On Thu, Nov 19, 2020 at 05:01:29PM +0800, Tian Tao wrote: >> The code has been in a irq-disabled context since it is hard IRQ. There >> is no necessity to do it again. >> >> Signed-off-by: Tian Tao <tiantao6@hisilicon.com> >> --- >> drivers/tty/serial/owl-uart.c | 5 ++--- >> 1 file changed, 2 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/tty/serial/owl-uart.c b/drivers/tty/serial/owl-uart.c >> index c149f8c3..472fdaf 100644 >> --- a/drivers/tty/serial/owl-uart.c >> +++ b/drivers/tty/serial/owl-uart.c >> @@ -251,10 +251,9 @@ static void owl_uart_receive_chars(struct uart_port *port) >> static irqreturn_t owl_uart_irq(int irq, void *dev_id) >> { >> struct uart_port *port = dev_id; >> - unsigned long flags; >> u32 stat; >> >> - spin_lock_irqsave(&port->lock, flags); >> + spin_lock(&port->lock); > > Same thing here; this will break with forced irq threading (i.e. > "threadirqs") since the console code can still end up being called from > interrupt context. As the following code shows, owl_uart_irq does not run in the irq threading context. ret = request_irq(port->irq, owl_uart_irq, IRQF_TRIGGER_HIGH, "owl-uart", port); if (ret) return ret;
> >> stat = owl_uart_read(port, OWL_UART_STAT); >> >> @@ -268,7 +267,7 @@ static irqreturn_t owl_uart_irq(int irq, void *dev_id) >> stat |= OWL_UART_STAT_RIP | OWL_UART_STAT_TIP; >> owl_uart_write(port, stat, OWL_UART_STAT); >> >> - spin_unlock_irqrestore(&port->lock, flags); >> + spin_unlock(&port->lock); >> >> return IRQ_HANDLED; >> } > > Johan > > . >
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