On Mon, Apr 12, 2021 at 12:34:21PM +0800, dillon.minfei@xxxxxxxxx wrote: > From: dillon min <dillon.minfei@xxxxxxxxx> > > To avoid potential deadlock in spin_lock usage, change to use > spin_lock_irqsave(), spin_unlock_irqrestore() in process(thread_fn) context. > spin_lock(), spin_unlock() under handler context. > > remove unused local_irq_save/restore call. > > Signed-off-by: dillon min <dillon.minfei@xxxxxxxxx> > --- > Was verified on stm32f469-disco board. need more test on stm32mp platform. > > drivers/tty/serial/stm32-usart.c | 27 +++++++++++++++++---------- > 1 file changed, 17 insertions(+), 10 deletions(-) > > diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c > index b3675cf25a69..c4c859b34367 100644 > --- a/drivers/tty/serial/stm32-usart.c > +++ b/drivers/tty/serial/stm32-usart.c > @@ -214,7 +214,7 @@ static void stm32_usart_receive_chars(struct uart_port *port, bool threaded) > struct tty_port *tport = &port->state->port; > struct stm32_port *stm32_port = to_stm32_port(port); > const struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; > - unsigned long c; > + unsigned long c, flags; > u32 sr; > char flag; > > @@ -276,9 +276,17 @@ static void stm32_usart_receive_chars(struct uart_port *port, bool threaded) > uart_insert_char(port, sr, USART_SR_ORE, c, flag); > } > > - spin_unlock(&port->lock); > + if (threaded) > + spin_unlock_irqrestore(&port->lock, flags); > + else > + spin_unlock(&port->lock); You shouldn't have to check for this, see the other patches on the list recently that fixed this up to not be an issue for irq handlers. thanks, greg k-h
