From: Oliver Neukum <oneukum@suse.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Subject: USB: usb.h: tweak struct urb to remove wasted space
Date: Mon, 04 Mar 2019 19:31:37 +0100 [thread overview]
Message-ID: <1551724297.11201.4.camel@suse.com> (raw)
On Sa, 2019-03-02 at 15:36 +0100, Greg Kroah-Hartman wrote:
> On Sat, Mar 02, 2019 at 02:51:41PM +0100, Oliver Neukum wrote:
> > On Sa, 2019-03-02 at 09:00 +0100, Greg Kroah-Hartman wrote:
> > > On Fri, Mar 01, 2019 at 08:44:13PM +0100, Oliver Neukum wrote:
> > > > On Fr, 2019-03-01 at 18:22 +0100, Greg Kroah-Hartman wrote:
> > > > > By moving one field around in 'struct urb' we reduce the size of the
> > > > > structure by 8 bytes.
> > > >
> > > > If you are going for this I have to ask why unlink and status
> > > > are full size ints anyway.
> > >
> > > History, they hold a "normal" negative error code. I guess we could
> > > turn them into s16, if it really matters, but that feels odd to me.
> >
> > Returning internal error codes to user space is a bug.
>
> Where does status and unlink end up going to userspace? Maybe through
> usbfs?
Nowhere, I hope. Sorry for the confusion. I hope I fixed that some time
ago. My point here is that using the external errnos for internal error
report is not an advantage. In fact, it is a bad idea. A byte would be
ample to record internal errors.
Regards
Oliver
next reply other threads:[~2019-03-04 18:31 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-04 18:31 Oliver Neukum [this message]
-- strict thread matches above, loose matches on Subject: below --
2019-03-02 14:36 USB: usb.h: tweak struct urb to remove wasted space Greg Kroah-Hartman
2019-03-02 13:51 Oliver Neukum
2019-03-02 8:00 Greg Kroah-Hartman
2019-03-01 19:44 Oliver Neukum
2019-03-01 17:22 Greg Kroah-Hartman
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