> -----Original Message-----
> From: netdev-ow...@vger.kernel.org [mailto:netdev-ow...@vger.kernel.org] On
> Behalf Of Keller, Jacob E
> Sent: Tuesday, March 12, 2019 2:35 PM
> To: Paul Thomas <pthomas8...@gmail.com>; netdev@vger.kernel.org
> Subject: RE: [PATCH] Check for SKBTX_HW_TSTAMP in macb driver
>
> > -----Original Message-----
> > From: netdev-ow...@vger.kernel.org [mailto:netdev-ow...@vger.kernel.org] On
> > Behalf Of Paul Thomas
> > Sent: Tuesday, March 12, 2019 12:51 PM
> > To: netdev@vger.kernel.org
> > Cc: Paul Thomas <pthomas8...@gmail.com>
> > Subject: [PATCH] Check for SKBTX_HW_TSTAMP in macb driver
> >
> > Make sure SKBTX_HW_TSTAMP (i.e. SOF_TIMESTAMPING_TX_HARDWARE) has
> been
> > enabled for this skb
> > This is a concept for discussion, more testing is needed.
> > It does fix the issue where normal socks that aren't expecting a timestamp
> > will not
> > wake
> > up on select.
> > ---
> > drivers/net/ethernet/cadence/macb_main.c | 12 +++++++-----
> > 1 file changed, 7 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/cadence/macb_main.c
> > b/drivers/net/ethernet/cadence/macb_main.c
> > index ad099fd01b45..b2f184fc1370 100644
> > --- a/drivers/net/ethernet/cadence/macb_main.c
> > +++ b/drivers/net/ethernet/cadence/macb_main.c
> > @@ -898,11 +898,13 @@ static void macb_tx_interrupt(struct macb_queue
> *queue)
> >
> > /* First, update TX stats if needed */
> > if (skb) {
> > - if (gem_ptp_do_txstamp(queue, skb, desc) == 0) {
> > - /* skb now belongs to timestamp buffer
> > - * and will be removed later
> > - */
> > - tx_skb->skb = NULL;
> > + if(unlikely(skb_shinfo(skb)->tx_flags &
> > SKBTX_HW_TSTAMP)) {
>
> This should be && for logical AND. Technically a bitwise & will likely work,
> but it's not
> what you intended.
>
> Thanks,
> Jake
>
Sorry, I misread the code.
You have two conditionals inside, and I misread where you were doing the
checking of the SKBTX_HW_TSTAMP flag.
I would do the following :
if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_HWTSTAMP) &&
gem_ptp_do_txstamp(queue, skb, desc)) {
....
}
Rather than have two nested if statements, relying on the short circuiting to
exit early.
The patch looks technically correct to me now that I'm reading it properly.
Jake
> > + if (gem_ptp_do_txstamp(queue, skb, desc)
> > == 0) {
> > + /* skb now belongs to timestamp
> > buffer
> > + * and will be removed later
> > + */
> > + tx_skb->skb = NULL;
> > + }
> > }
> > netdev_vdbg(bp->dev, "skb %u (data %p) TX
> > complete\n",
> > macb_tx_ring_wrap(bp, tail),
> > --
> > 2.17.1
