Re: [PATCH] tty: serial: replace spin_lock_irqsave by spin_lock in hard IRQ
From: Johan Hovold <johan@kernel.org>
Date: 2020-11-20 08:23:21
Also in:
linux-arm-kernel, lkml
On Thu, Nov 19, 2020 at 05:01:29PM +0800, Tian Tao wrote:
quoted hunk ↗ jump to hunk
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.
quoted hunk ↗ jump to hunk
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