| Message ID | 20201019101110.019266389@linutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | USB: Cleanup in_interupt/in_irq/in_atomic() usage | expand |
On Mon, Oct 19, 2020 at 12:06:33PM +0200, Thomas Gleixner wrote: > From: Ahmed S. Darwish <a.darwish@linutronix.de> > > 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 <a.darwish@linutronix.de> > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de> > Cc: Johan Hovold <johan@kernel.org> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: linux-usb@vger.kernel.org > > --- > 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
--- 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); + } /* copy user data (which can sleep) before getting spin lock */ count = min(count, port->bulk_out_size-2);