linux-kernel - Re: [PATCH 14/24] thunderbolt: Let the connection manager handle all notifications

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Date:   Thu, 25 May 2017 10:02:08 +0300
From:   Mika Westerberg <mika.westerberg@...ux.intel.com>
To:     Lukas Wunner <lukas@...ner.de>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andreas Noever <andreas.noever@...il.com>,
        Michael Jamet <michael.jamet@...el.com>,
        Yehezkel Bernat <yehezkel.bernat@...el.com>,
        Amir Levy <amir.jer.levy@...el.com>,
        Andy Lutomirski <luto@...nel.org>, Mario.Limonciello@...l.com,
        Jared.Dominguez@...l.com,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 14/24] thunderbolt: Let the connection manager handle all
 notifications

On Wed, May 24, 2017 at 04:00:49PM +0200, Lukas Wunner wrote:
> On Thu, May 18, 2017 at 05:39:04PM +0300, Mika Westerberg wrote:
> > @@ -320,18 +330,42 @@ static void tb_ctl_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
> >  	}
> >  
> >  	frame->size -= 4; /* remove checksum */
> > -	if (*(__be32 *) (pkg->buffer + frame->size)
> > -			!= tb_crc(pkg->buffer, frame->size)) {
> > -		tb_ctl_err(pkg->ctl,
> > -			   "RX: checksum mismatch, dropping packet\n");
> > -		goto rx;
> > -	}
> > +	crc32 = tb_crc(pkg->buffer, frame->size);
> >  	be32_to_cpu_array(pkg->buffer, pkg->buffer, frame->size / 4);
> >  
> > -	if (frame->eof == TB_CFG_PKG_EVENT) {
> > -		tb_ctl_handle_plug_event(pkg->ctl, pkg);
> > +	switch (frame->eof) {
> > +	case TB_CFG_PKG_READ:
> > +	case TB_CFG_PKG_WRITE:
> > +	case TB_CFG_PKG_ERROR:
> > +	case TB_CFG_PKG_OVERRIDE:
> > +	case TB_CFG_PKG_RESET:
> > +		if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
> > +			tb_ctl_err(pkg->ctl,
> > +				   "RX: checksum mismatch, dropping packet\n");
> > +			goto rx;
> > +		}
> 
> Any harm keeping the crc32 check above the switch/case statement?
> (And thus also execute it for unknown packets?)

Not all packets carry crc32, only these configuration space packets.

> > +	case TB_CFG_PKG_EVENT:
> > +		if (*(__be32 *)(pkg->buffer + frame->size) != crc32) {
> > +			tb_ctl_err(pkg->ctl,
> > +				   "RX: checksum mismatch, dropping packet\n");
> > +			goto rx;
> > +		}
> > +		tb_ctl_handle_event(pkg->ctl, frame->eof, pkg, frame->size);
> > +		goto rx;
> > +
> > +	default:
> > +		tb_ctl_dbg(pkg->ctl, "RX: unknown package %#x, dropping\n",
> 
> The packet / package terminology is a bit inconsistent here.
> Andreas originally used package.  What's the term used by the TB spec?

IIRC it uses packet.