Messages in this thread | | | Subject | Re: [PATCH net-next 5/9] sunvnet: add memory barrier before check for tx enable | From | Eric Dumazet <> | Date | Fri, 03 Feb 2017 09:56:25 -0800 |
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On Fri, 2017-02-03 at 09:42 -0800, Shannon Nelson wrote: > In order to allow the underlying LDC and outstanding memory operations > to potentially catch up with the driver's Tx requests, add a memory > barrier before checking again for available tx descriptors. > > Signed-off-by: Shannon Nelson <shannon.nelson@oracle.com> > --- > drivers/net/ethernet/sun/sunvnet_common.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/drivers/net/ethernet/sun/sunvnet_common.c b/drivers/net/ethernet/sun/sunvnet_common.c > index 5d0d386..98e758e 100644 > --- a/drivers/net/ethernet/sun/sunvnet_common.c > +++ b/drivers/net/ethernet/sun/sunvnet_common.c > @@ -1467,6 +1467,7 @@ ldc_start_done: > dr->prod = (dr->prod + 1) & (VNET_TX_RING_SIZE - 1); > if (unlikely(vnet_tx_dring_avail(dr) < 1)) { > netif_tx_stop_queue(txq); > + dma_wmb();
This does not look right.
I believe you need smp_rmb() here.
> if (vnet_tx_dring_avail(dr) > VNET_TX_WAKEUP_THRESH(dr)) > netif_tx_wake_queue(txq); > }
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