In the current xdp_xmit implementation, if any single frame fails to
transmit due to insufficient buffer descriptors, the function nevertheless
reports success in sending all frames. This results in erroneously
indicating that frames were transmitted when in fact they were dropped.
This patch fixes the issue by ensureing the return value properly
indicates the actual number of frames successfully transmitted, rather than
potentially reporting success for all frames when some could not transmit.
Fixes: 6d6b39f180b8 ("net: fec: add initial XDP support")
Signed-off-by: Gagandeep Singh <[email protected]>
Signed-off-by: Shenwei Wang <[email protected]>
---
v4:
- resend for net
- the tx frame shouldn't be returned when error occurs.
- changed the function return values by using the standard errno.
v3:
- resend the v2 fix for "net" as the standalone patch.
v2:
- only keep the bug fix part of codes according to Horatiu's comments.
- restructure the functions to avoid the forward declaration.
drivers/net/ethernet/freescale/fec_main.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 160c1b3525f5..36a3ee304482 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -3798,7 +3798,7 @@ static int fec_enet_txq_xmit_frame(struct fec_enet_private *fep,
entries_free = fec_enet_get_free_txdesc_num(txq);
if (entries_free < MAX_SKB_FRAGS + 1) {
netdev_err(fep->netdev, "NOT enough BD for SG!\n");
- return NETDEV_TX_OK;
+ return -EBUSY;
}
/* Fill in a Tx ring entry */
@@ -3812,7 +3812,7 @@ static int fec_enet_txq_xmit_frame(struct fec_enet_private *fep,
dma_addr = dma_map_single(&fep->pdev->dev, frame->data,
frame->len, DMA_TO_DEVICE);
if (dma_mapping_error(&fep->pdev->dev, dma_addr))
- return FEC_ENET_XDP_CONSUMED;
+ return -ENOMEM;
status |= (BD_ENET_TX_INTR | BD_ENET_TX_LAST);
if (fep->bufdesc_ex)
@@ -3856,6 +3856,7 @@ static int fec_enet_xdp_xmit(struct net_device *dev,
struct fec_enet_private *fep = netdev_priv(dev);
struct fec_enet_priv_tx_q *txq;
int cpu = smp_processor_id();
+ unsigned int sent_frames = 0;
struct netdev_queue *nq;
unsigned int queue;
int i;
@@ -3866,8 +3867,11 @@ static int fec_enet_xdp_xmit(struct net_device *dev,
__netif_tx_lock(nq, cpu);
- for (i = 0; i < num_frames; i++)
- fec_enet_txq_xmit_frame(fep, txq, frames[i]);
+ for (i = 0; i < num_frames; i++) {
+ if (fec_enet_txq_xmit_frame(fep, txq, frames[i]) != 0)
+ break;
+ sent_frames++;
+ }
/* Make sure the update to bdp and tx_skbuff are performed. */
wmb();
@@ -3877,7 +3881,7 @@ static int fec_enet_xdp_xmit(struct net_device *dev,
__netif_tx_unlock(nq);
- return num_frames;
+ return sent_frames;
}
static const struct net_device_ops fec_netdev_ops = {
--
2.34.1
On Mon, 8 May 2023 09:38:31 -0500 Shenwei Wang wrote:
> In the current xdp_xmit implementation, if any single frame fails to
> transmit due to insufficient buffer descriptors, the function nevertheless
> reports success in sending all frames. This results in erroneously
> indicating that frames were transmitted when in fact they were dropped.
>
> This patch fixes the issue by ensureing the return value properly
> indicates the actual number of frames successfully transmitted, rather than
> potentially reporting success for all frames when some could not transmit.
>
> Fixes: 6d6b39f180b8 ("net: fec: add initial XDP support")
> Signed-off-by: Gagandeep Singh <[email protected]>
> Signed-off-by: Shenwei Wang <[email protected]>
Unfortunately the previous version was silently applied, it seems:
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=26312c685ae0bca61e06ac75ee158b1e69546415
Could you send an incremental fix, on top of that patch?
--
pw-bot: cr
> -----Original Message-----
> From: Jakub Kicinski <[email protected]>
> Sent: Monday, May 8, 2023 8:46 PM
> To: Shenwei Wang <[email protected]>
> Cc: Wei Fang <[email protected]>; David S. Miller <[email protected]>;
> Eric Dumazet <[email protected]>; Paolo Abeni <[email protected]>;
> Clark Wang <[email protected]>; dl-linux-imx <[email protected]>;
> Alexei Starovoitov <[email protected]>; Daniel Borkmann <[email protected]>;
> Jesper Dangaard Brouer <[email protected]>; John Fastabend
> <[email protected]>; Alexander Lobakin
> <[email protected]>; [email protected]; linux-
> [email protected]; [email protected]; Gagandeep Singh
> <[email protected]>
> Subject: [EXT] Re: [RESEND PATCH v4 net 1/1] net: fec: correct the counting of
> XDP sent frames
>
> Caution: This is an external email. Please take care when clicking links or
> opening attachments. When in doubt, report the message using the 'Report this
> email' button
>
>
> On Mon, 8 May 2023 09:38:31 -0500 Shenwei Wang wrote:
> > In the current xdp_xmit implementation, if any single frame fails to
> > transmit due to insufficient buffer descriptors, the function
> > nevertheless reports success in sending all frames. This results in
> > erroneously indicating that frames were transmitted when in fact they were
> dropped.
> >
> > This patch fixes the issue by ensureing the return value properly
> > indicates the actual number of frames successfully transmitted, rather
> > than potentially reporting success for all frames when some could not transmit.
> >
> > Fixes: 6d6b39f180b8 ("net: fec: add initial XDP support")
> > Signed-off-by: Gagandeep Singh <[email protected]>
> > Signed-off-by: Shenwei Wang <[email protected]>
>
> Unfortunately the previous version was silently applied, it seems:
>
> https://git.kernel/
> .org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fnetdev%2Fnet.git%2Fcommit
> %2F%3Fid%3D26312c685ae0bca61e06ac75ee158b1e69546415&data=05%7C01
> %7Cshenwei.wang%40nxp.com%7C50d9af4da79646cf2d2b08db502f2b7d%7C6
> 86ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C638191935747226987%7C
> Unknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6I
> k1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=O2uy5iy4QJa9v8TN9t
> qM7jqIgVhBY7pMxl4K58abj9s%3D&reserved=0
>
> Could you send an incremental fix, on top of that patch?
Certainly, I will.
Thanks,
Shenwei
> --
> pw-bot: cr