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Date: Tue, 13 May 2014 12:05:07 +0300
From: "Michael S. Tsirkin" <mst@redhat.com>
Message-ID: <20140513090507.GA29760@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] usb: fix up post load checks
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To: Gerd Hoffmann <kraxel@redhat.com>
Cc: qemu-devel@nongnu.org, dgilbert@redhat.com

On Tue, May 13, 2014 at 10:44:45AM +0200, Gerd Hoffmann wrote:
> On Di, 2014-05-13 at 11:32 +0300, Michael S. Tsirkin wrote:
> > On Tue, May 13, 2014 at 09:50:09AM +0200, Gerd Hoffmann wrote:
> > >   Hi,
> > > 
> > > > +        (dev->setup_state == SETUP_STATE_DATA &&
> > > 
> > > Fails to build, SETUP_STATE_DATA is not defined here.
> > > 
> > > I think we can simply drop that check, index should never ever be larger
> > > than len, no matter what the state is.
> > > 
> > > cheers,
> > >   Gerd
> > 
> > I'm confused by usb_generic_async_ctrl_complete which can modify len
> > without touching index.
> 
> only in setup state, before any data from/to the buffer is transfered,
> so index is still zero at that point.


And SETUP_STATE_PARAM?

> flow is this:
> 
> state_setup: len = $buflen, index = 0
> state_data:  xfer %buf data, increase index up to len while doing so.
> state_ack:   index == len
> state_idle:  likewise.
> 
> cheers,
>   Gerd
>