Messages in this thread | | | Date | Sat, 30 Jan 2021 14:15:29 +0900 | From | William Breathitt Gray <> | Subject | Re: [PATCH v7 3/5] counter: Add character device interface |
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On Thu, Jan 28, 2021 at 10:01:13AM +0100, Oleksij Rempel wrote: > 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@lechnology.com> > > Cc: Gwendal Grignou <gwendal@chromium.org> > > Cc: Dan Carpenter <dan.carpenter@oracle.com> > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> > > --- > ... > > +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 |
Sure, I can rename this to avoid a possible clash with libc's errno. Maybe "status" would be more apt to indicate that this is an exit status for the event -- the code returned may simply be a warning and not necessarily a critical error.
Regarding the datatype for this value, I've opened up the discussion in my reply to David Lechner [1], so perhaps we can continue it there.
[1] https://lkml.org/lkml/2021/1/30/5
William Breathitt Gray [unhandled content-type:application/pgp-signature] | |