On Mon, Oct 19, 2020 at 12:06:33PM +0200, Thomas Gleixner wrote: > From: Ahmed S. Darwish <[email protected]> > > The usage of in_interrupt() in drivers is phased out and Linus clearly > requested that code which changes behaviour depending on context should > either be separated or the context be conveyed in an argument passed by the > caller, which usually knows the context. > > The debug printk() in digi_write() prints in_interrupt() as context > information. TTY writes happen always in preemptible task context and > console writes can happen from almost any context, so in_interrupt() is not > really helpful.
The above statement is not correct, TTY writes can and do happen from other contexts, including soft IRQ (e.g. PPP). > Aside of that issuing a printk() from a console->write() callback is not a > really brilliant idea for obvious reasons. True, but we don't need to sprinkle conditionals for the benefit of people trying to debug USB serial drivers using a USB serial console. They get what they deserve. ;) > Remove the in_interrupt() printout and make the printk() depend on tty. > > Signed-off-by: Ahmed S. Darwish <[email protected]> > Signed-off-by: Sebastian Andrzej Siewior <[email protected]> > Signed-off-by: Thomas Gleixner <[email protected]> > Cc: Johan Hovold <[email protected]> > Cc: Greg Kroah-Hartman <[email protected]> > Cc: [email protected] > > --- > drivers/usb/serial/digi_acceleport.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > --- a/drivers/usb/serial/digi_acceleport.c > +++ b/drivers/usb/serial/digi_acceleport.c > @@ -911,9 +911,10 @@ static int digi_write(struct tty_struct > unsigned char *data = port->write_urb->transfer_buffer; > unsigned long flags = 0; > > - dev_dbg(&port->dev, > - "digi_write: TOP: port=%d, count=%d, in_interrupt=%ld\n", > - priv->dp_port_num, count, in_interrupt()); > + if (tty) { > + dev_dbg(&port->dev, "digi_write: TOP: port=%d, count=%d\n", > + priv->dp_port_num, count); > + } So just drop the in_interrupt() here. Also note that we already have another unconditional dev_dbg() at the end of this function. > > /* copy user data (which can sleep) before getting spin lock */ > count = min(count, port->bulk_out_size-2); > Johan
