Date: Tue, 26 May 2015 19:41:18 -0700
From: Greg KH <gregkh@linuxfoundation.org>
To: David Cohen <david.a.cohen@linux.intel.com>
Cc: =?iso-8859-1?Q?Bj=F8rn?= Mork <bjorn@mork.no>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Tal Shorer <tal.shorer@gmail.com>,
        Sudip Mukherjee <sudipm.mukherjee@gmail.com>,
        Sasha Levin <sasha.levin@oracle.com>,
        USB list <linux-usb@vger.kernel.org>,
        "<linux-kernel@vger.kernel.org>" <linux-kernel@vger.kernel.org>,
        Felipe Balbi <balbi@ti.com>, Lu Baolu <baolu.lu@linux.intel.com>
Subject: Re: [PATCH] usb: ulpi: don't register drivers if bus doesn't exist
Message-ID: <20150527024118.GD7038@kroah.com>
References: <1432150406-20550-1-git-send-email-sasha.levin@oracle.com>
 <20150524071948.GA20923@kroah.com>
 <20150524080940.GA4033@sudip-PC>
 <CAFDyS3M1ZqrkGXGqdhTjyJp1eheJsDKLuBC-piC8jBUC=zt45Q@mail.gmail.com>
 <20150525114010.GA30679@kuha.fi.intel.com>
 <20150525161312.GB9772@kroah.com>
 <87a8wsoan6.fsf@nemi.mork.no>
 <20150526175401.GA26397@psi-dev26.jf.intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20150526175401.GA26397@psi-dev26.jf.intel.com>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1513
Lines: 38

On Tue, May 26, 2015 at 10:54:01AM -0700, David Cohen wrote:
> Hi,
> 
> On Mon, May 25, 2015 at 07:00:13PM +0200, Bj?rn Mork wrote:
> > Greg KH <gregkh@linuxfoundation.org> writes:
> > 
> > > If there are other bus drivers that do this, I'll go fix them up,
> > > pointers to those files would be appreciated.
> > 
> > git grep -E 'if .*\.p\W' found a couple of interesting candidates you
> > might want to check out:
> > 
> >  drivers/i2c/i2c-core.c: if (unlikely(WARN_ON(!i2c_bus_type.p))) {
> >  drivers/i2c/i2c-core.c: if (unlikely(WARN_ON(!i2c_bus_type.p)))
> >  drivers/spmi/spmi.c:    if (WARN_ON(!spmi_bus_type.p))
> > 
> > And this looks somewhat suspicious too, but could very well be OK for
> > all I know (very close to nothing :)
> > 
> >  drivers/gpio/gpiolib-sysfs.c:   if (!gpio_class.p) {
> >  drivers/gpio/gpiolib-sysfs.c:   if (!gpio_class.p)
> 
> I think we need a clear statement on how to proceed on this case.

Don't mess with bus->p.  I can rename it to
"do_not_touch_this_isnt_for_you" if people think that would make it more
obvious that a private data structure shouldn't be messed with in any
way.  Outside of the driver core, you have no knowledge that even if it
is a pointer, what that means with regards to anything.

thanks,

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/