Re: [char-misc-next 4/4 V2] mei: bus: enable non-blocking RX

'Greg Kroah-Hartman'
2016-11-30T11:57:18Z

On Tue, Nov 29, 2016 at 08:09:38PM +0000, Winkler, Tomas wrote:
>
> > On Mon, Nov 28, 2016 at 11:03:20PM +0000, Winkler, Tomas wrote:
> > > >
> > > >
> > > > >
> > > > > On Sat, Nov 19, 2016 at 02:16:11PM +0200, Tomas Winkler wrote:
> > > > > > From: Alexander Usyskin <alexander.usyskin@intel.com>
> > > > > >
> > > > > > Enable non-blocking receive for drivers on mei bus, this allows
> > > > > > checking for data availability by mei client drivers. This is
> > > > > > most effective for fixed address clients, that lacks flow control.
> > > > > >
> > > > > > This function adds new API function mei_cldev_recv_nonblock(),
> > > > > > it retuns -EGAIN if function will block.
> > > > > >
> > > > > > Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
> > > > > > Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
> > > > > > ---
> > > > > > V2: use _nonblock() function suffix instead of NONBLOCK flag
> > > > > >
> > > > > > drivers/misc/mei/bus-fixup.c | 4 ++--
> > > > > > drivers/misc/mei/bus.c | 31 +++++++++++++++++++++++++++++--
> > > > > > drivers/misc/mei/mei_dev.h | 7 ++++++-
> > > > > > include/linux/mei_cl_bus.h | 6 ++++--
> > > > > > 4 files changed, 41 insertions(+), 7 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/misc/mei/bus-fixup.c
> > > > > > b/drivers/misc/mei/bus-fixup.c index 7f2cef9011ae..18e05ca7584f
> > > > > > 100644
> > > > > > --- a/drivers/misc/mei/bus-fixup.c
> > > > > > +++ b/drivers/misc/mei/bus-fixup.c
> > > > > > @@ -141,7 +141,7 @@ static int mei_osver(struct mei_cl_device
> > *cldev)
> > > > > > if (ret < 0)
> > > > > > return ret;
> > > > > >
> > > > > > - ret = __mei_cl_recv(cldev->cl, buf, length);
> > > > > > + ret = __mei_cl_recv(cldev->cl, buf, length, 0);
> > > > >
> > > > > What is 0 here? Again, mode...
> > > >
> > > > Yes, it means no change in behavior, but this is an internal function.
> >
> > So, it makes no sense, are you not going to have to read this code again in 10
> > years? New developers? Make the code make sense please.
>
>
> Sorry Greg, the code does make sense to me, the whole kernel passes nonblock around as flag starting from the syscall (O_NONBLOCK)
> it doesn't make sense to write two functions that differ in one 'if' statement.
> I understand that you are in some crusade against flags, but you are not proposing a concrete solution and I don't have one either.
> I can solve it in the external wrapper, but internally it's just a same function.

What is wrong with your email client that it doesn't wrap things
properly?

Anyway, I don't remember anymore, please resend and I will review it
then.

greg k-h