linux-kernel - RE: [char-misc-next RESEND] mei: bus: enable non-blocking RX

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Date:   Tue, 6 Dec 2016 10:08:20 +0000
From:   "Winkler, Tomas" <tomas.winkler@...el.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
CC:     "Usyskin, Alexander" <alexander.usyskin@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [char-misc-next RESEND] mei: bus: enable non-blocking RX

> 
> On Sat, Dec 03, 2016 at 12:15:25AM +0200, Tomas Winkler wrote:
> > From: Alexander Usyskin <alexander.usyskin@...el.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@...el.com>
> > Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
> > ---
> >  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);
> >  	if (ret < 0)
> >  		return ret;
> >
> > @@ -272,7 +272,7 @@ static int mei_nfc_if_version(struct mei_cl *cl,
> >  		return -ENOMEM;
> >
> >  	ret = 0;
> > -	bytes_recv = __mei_cl_recv(cl, (u8 *)reply, if_version_length);
> > +	bytes_recv = __mei_cl_recv(cl, (u8 *)reply, if_version_length, 0);
> 
> I still don't like this, as here are two examples of you having to somehow
> mentally keep track of the "mode" of what is going on.

I know, but I don't have better solution. We try to keep the code documented as much as possible.  
> 
a> But it's your code, you have to maintain it, not me, good luck!

Fair enough
Tomas