Re: [PACTH v2] cdc-wdm: Clear read pipeline in case of error

[Robert Foss]

On 2016-08-09 09:51 AM, Greg KH wrote:
> On Mon, Aug 08, 2016 at 11:48:52AM -0400, robert.foss@xxxxxxxxxxxxx wrote:
> > From: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> >
> > Implemented queued response handling. This queue is processed every time the
> > WDM_READ flag is cleared.
> >
> > In case of a read error, userspace may not actually read the data, since the
> > driver returns an error through wdm_poll. After this, the underlying device may
> > attempt to send us more data, but the queue is not processed. While userspace is
> > also blocked, because the read error is never cleared.
> >
> > After this patch, we proactively process the queue on a read error. If there was
> > an outstanding response to handle, that will clear the error (or go through the
> > same logic again, if another read error occurs). If there was no outstanding
> > response, this will bring the queue size back to 0, unblocking a future response
> > from the underlying device.
> >
> > Tested-by: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> > Signed-off-by: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> > Acked-by: Oliver Neukum <oneukum@xxxxxxxx>

Thanks Oliver!

> > ---
> >
> > Changes since v1:
> > - Only set a new error code it there is no previous error code
>
> This no longer applies to my tree due to a patch sent before yours for
> the same driver.  Can you resync against my usb-testing brance on my
> usb.git tree on git.kernel.org and resend?

Will do!