Hello William, On Fri, Dec 25, 2020 at 07:15:36PM -0500, William Breathitt Gray wrote: > This patch introduces a character device interface for the Counter > subsystem. Device data is exposed through standard character device read > operations. Device data is gathered when a Counter event is pushed by > the respective Counter device driver. Configuration is handled via ioctl > operations on the respective Counter character device node. > > Cc: David Lechner <david@xxxxxxxxxxxxxx> > Cc: Gwendal Grignou <gwendal@xxxxxxxxxxxx> > Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx> > --- ... > +struct counter_event { > + __aligned_u64 timestamp; > + __aligned_u64 value; > + struct counter_watch watch; > + __u8 errno; This variable clashed in user space, as soon as you include errno.h, with the libc's "magic" definition of errno. What about "err" instead. I'm not sure it an __u8 is the proper type, IIRC usually it's an int. Regards, Oleksij -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |