From: Sebastian Andrzej Siewior Date: Fri, 1 Mar 2024 22:45:28 +0100 Subject: [PATCH 15/18] serial: pch: Don't disable interrupts while acquiring lock in ISR. Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz The interrupt service routine is always invoked with disabled interrupts. Remove the _irqsave() from the locking functions in the interrupts service routine/ pch_uart_interrupt(). Link: https://lore.kernel.org/r/20240301215246.891055-16-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior --- drivers/tty/serial/pch_uart.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/drivers/tty/serial/pch_uart.c +++ b/drivers/tty/serial/pch_uart.c @@ -1010,11 +1010,10 @@ static irqreturn_t pch_uart_interrupt(in u8 lsr; int ret = 0; unsigned char iid; - unsigned long flags; int next = 1; u8 msr; - spin_lock_irqsave(&priv->lock, flags); + spin_lock(&priv->lock); handled = 0; while (next) { iid = pch_uart_hal_get_iid(priv); @@ -1074,7 +1073,7 @@ static irqreturn_t pch_uart_interrupt(in handled |= (unsigned int)ret; } - spin_unlock_irqrestore(&priv->lock, flags); + spin_unlock(&priv->lock); return IRQ_RETVAL(handled); }