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Date: Sun, 12 Oct 2014 14:58:57 -0500
From: Felipe Balbi <balbi@ti.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
CC: David Cohen <david.a.cohen@linux.intel.com>, <balbi@ti.com>,
        <gregkh@linuxfoundation.org>, <mina86@mina86.com>,
        <r.baldyga@samsung.com>, <linux-usb@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <stable@vger.kernel.org>,
        Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Subject: Re: [PATCH v2] usb: ffs: fix regression when
 quirk_ep_out_aligned_size flag is set
Message-ID: <20141012195857.GA5153@saruman>
Reply-To: <balbi@ti.com>
References: <1412727486-479-1-git-send-email-david.a.cohen@linux.intel.com>
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 <20141012191228.GR7996@ZenIV.linux.org.uk>
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On Sun, Oct 12, 2014 at 08:12:28PM +0100, Al Viro wrote:
> On Wed, Oct 08, 2014 at 02:12:18PM -0700, David Cohen wrote:
> >  		use_mm(io_data->mm);
> >  		for (i =3D 0; i < io_data->nr_segs; i++) {
> > +			size_t len =3D min_t(size_t, ret - pos,
> > +					io_data->iovec[i].iov_len);
> > +			if (!len)
> > +				break;
> >  			if (unlikely(copy_to_user(io_data->iovec[i].iov_base,
> > -						 &io_data->buf[pos],
> > -						 io_data->iovec[i].iov_len))) {
> > +						 &io_data->buf[pos], len))) {
> >  				ret =3D -EFAULT;
> >  				break;
> >  			}
> > -			pos +=3D io_data->iovec[i].iov_len;
> > +			pos +=3D len;
>=20
> Hmm...  This is really asking for something like
> 	if (copy_to_iter(io_data->buf, ret, <something>) !=3D ret)
> 		ret =3D -EFAULT;
> with <something> being an iov_iter instead of iovec.  It would be really
> nice to have that thing switched to ->read_iter/->write_iter, dropping
> ->read/->write/->aio_read/->aio_write; I'm not familiar enough with that
> code to do it on my own, though, so it would require some help from
> maintainers...

cool, Michal, if you're too busy lately, I can look at that one myself.
I suppose the test application we have under tool/usb is good enough for
validation ?

cheers

--=20
balbi

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