From: Troy Kisky <troy.ki...@boundarydevices.com> Sent: Sunday, May 08, 2016
2:57 AM
> To: Fugang Duan <fugang.d...@nxp.com>; netdev@vger.kernel.org;
> da...@davemloft.net; lzn...@gmail.com
> Cc: Fabio Estevam <fabio.este...@nxp.com>; l.st...@pengutronix.de;
> and...@lunn.ch; trem...@gmail.com; g...@uclinux.org; linux-arm-
> ker...@lists.infradead.org; johan...@sipsolutions.net;
> stillcompil...@gmail.com; sergei.shtyl...@cogentembedded.com;
> a...@arndb.de; holgerschu...@gmail.com
> Subject: Re: [PATCH net 1/1] net: fec: update dirty_tx even if no skb
>
> On 4/21/2016 10:59 PM, Fugang Duan wrote:
> > From: Troy Kisky <troy.ki...@boundarydevices.com> Sent: Friday, April
> > 22, 2016 10:01 AM
> >> To: netdev@vger.kernel.org; da...@davemloft.net; Fugang Duan
> >> <fugang.d...@nxp.com>; lzn...@gmail.com
> >> Cc: Fabio Estevam <fabio.este...@nxp.com>; l.st...@pengutronix.de;
> >> and...@lunn.ch; trem...@gmail.com; g...@uclinux.org; linux-arm-
> >> ker...@lists.infradead.org; johan...@sipsolutions.net;
> >> stillcompil...@gmail.com; sergei.shtyl...@cogentembedded.com;
> >> a...@arndb.de; holgerschu...@gmail.com; Troy Kisky
> >> <troy.ki...@boundarydevices.com>
> >> Subject: [PATCH net 1/1] net: fec: update dirty_tx even if no skb
> >>
> >> If dirty_tx isn't updated, then dma_unmap_single will be called twice.
> >>
> >> This fixes a
> >> [ 58.420980] ------------[ cut here ]------------
> >> [ 58.425667] WARNING: CPU: 0 PID: 377 at /home/schurig/d/mkarm/linux-
> >> 4.5/lib/dma-debug.c:1096 check_unmap+0x9d0/0xab8()
> >> [ 58.436405] fec 2188000.ethernet: DMA-API: device driver tries to free
> DMA
> >> memory it has not allocated [device address=0x0000000000000000]
> >> [size=66 bytes]
> >>
> >> encountered by Holger
> >>
> >> Signed-off-by: Troy Kisky <troy.ki...@boundarydevices.com>
> >> Tested-by: <holgerschu...@gmail.com>
> >> ---
> >> drivers/net/ethernet/freescale/fec_main.c | 8 +++-----
> >> 1 file changed, 3 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/drivers/net/ethernet/freescale/fec_main.c
> >> b/drivers/net/ethernet/freescale/fec_main.c
> >> index 08243c2..b71654c 100644
> >> --- a/drivers/net/ethernet/freescale/fec_main.c
> >> +++ b/drivers/net/ethernet/freescale/fec_main.c
> >> @@ -1197,10 +1197,8 @@ fec_enet_tx_queue(struct net_device *ndev,
> u16
> >> queue_id)
> >> fec16_to_cpu(bdp->cbd_datlen),
> >> DMA_TO_DEVICE);
> >> bdp->cbd_bufaddr = cpu_to_fec32(0);
> >> - if (!skb) {
> >> - bdp = fec_enet_get_nextdesc(bdp, &txq->bd);
> >> - continue;
> >> - }
> >> + if (!skb)
> >> + goto skb_done;
> >>
> >> /* Check for errors. */
> >> if (status & (BD_ENET_TX_HB | BD_ENET_TX_LC | @@ -1239,7
> >> +1237,7 @@ fec_enet_tx_queue(struct net_device *ndev, u16 queue_id)
> >>
> >> /* Free the sk buffer associated with this last transmit */
> >> dev_kfree_skb_any(skb);
> >> -
> >> +skb_done:
> >> /* Make sure the update to bdp and tx_skbuff are performed
> >> * before dirty_tx
> >> */
> >> --
> >> 2.5.0
> >
> > The patch is fine for me.
> > Can you review below patch that also fix the issue. It can take much
> > effort due to less rmb() and READ_ONCE() operation that is very
> > sensitive for duplex Gbps test for i.MX6SX/i.MX7d SOC. (i.MX6SX can
> > reach at 1.4Gbps, i.MX7D can reach at 1.8Gbps.)
> >
>
>
> Am I supposed to do anything else to get this patch into net ?
I will ack your patch that is fine into net tree.
