On Mon, Jun 19, 2023 at 01:01:49PM +0200, Jiri Slaby wrote:
> On 19. 06. 23, 11:45, Dan Carpenter wrote:
> > The atmel_complete_tx_dma() function disables IRQs at the start
> > of the function by calling spin_lock_irqsave(&port->lock, flags);
> > There is no need to disable them a second time using the
> > spin_lock_irq() function and, in fact, doing so is a bug because
> > it will enable IRQs prematurely when we call spin_unlock_irq().
> >
> > Just use spin_lock/unlock() instead without disabling or enabling
> > IRQs.
> >
> > Fixes: 08f738be88bb ("serial: at91: add tx dma support")
> > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > ---
> > drivers/tty/serial/atmel_serial.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> > index 6e9192f122aa..3467a875641a 100644
> > --- a/drivers/tty/serial/atmel_serial.c
> > +++ b/drivers/tty/serial/atmel_serial.c
> > @@ -868,11 +868,11 @@ static void atmel_complete_tx_dma(void *arg)
> > dmaengine_terminate_all(chan);
> > uart_xmit_advance(port, atmel_port->tx_len);
> > - spin_lock_irq(&atmel_port->lock_tx);
> > + spin_lock(&atmel_port->lock_tx);
> > async_tx_ack(atmel_port->desc_tx);
> > atmel_port->cookie_tx = -EINVAL;
> > atmel_port->desc_tx = NULL;
> > - spin_unlock_irq(&atmel_port->lock_tx);
> > + spin_unlock(&atmel_port->lock_tx);
>
> Hmm, can you ensure the DMA engine code calls this with irqs disabled? If
> so, you should document it in the commit log. If not, you shyuld use
> _irqsave() variant.
>
> thanks,
Hi Jiri,
I feel like we are miscommunicating but I don't know how to improve my
commit message... The function itself disables IRQs at the start using
_irqsave(). I have left that as-is.
regards,
dan carpenter
