diff options
| author | Magnus Karlsson <magnus.karlsson@intel.com> | 2023-01-25 08:49:01 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-01-27 22:27:59 -0800 |
| commit | a3191c4d86c5d3bd35b00dfde6910b88391436a0 (patch) | |
| tree | d7d82a577c7cafd77b5d9b6a2e20d3a7cb0089e0 | |
| parent | b534013798b77f81a36f36dafd59bab9de837619 (diff) | |
dpaa2-eth: execute xdp_do_flush() before napi_complete_done()
Make sure that xdp_do_flush() is always executed before
napi_complete_done(). This is important for two reasons. First, a
redirect to an XSKMAP assumes that a call to xdp_do_redirect() from
napi context X on CPU Y will be followed by a xdp_do_flush() from the
same napi context and CPU. This is not guaranteed if the
napi_complete_done() is executed before xdp_do_flush(), as it tells
the napi logic that it is fine to schedule napi context X on another
CPU. Details from a production system triggering this bug using the
veth driver can be found following the first link below.
The second reason is that the XDP_REDIRECT logic in itself relies on
being inside a single NAPI instance through to the xdp_do_flush() call
for RCU protection of all in-kernel data structures. Details can be
found in the second link below.
Fixes: d678be1dc1ec ("dpaa2-eth: add XDP_REDIRECT support")
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://lore.kernel.org/r/20221220185903.1105011-1-sbohrer@cloudflare.com
Link: https://lore.kernel.org/all/20210624160609.292325-1-toke@redhat.com/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c index 0c35abb7d065..2e79d18fc3c7 100644 --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c @@ -1993,10 +1993,15 @@ static int dpaa2_eth_poll(struct napi_struct *napi, int budget) if (rx_cleaned >= budget || txconf_cleaned >= DPAA2_ETH_TXCONF_PER_NAPI) { work_done = budget; + if (ch->xdp.res & XDP_REDIRECT) + xdp_do_flush(); goto out; } } while (store_cleaned); + if (ch->xdp.res & XDP_REDIRECT) + xdp_do_flush(); + /* Update NET DIM with the values for this CDAN */ dpaa2_io_update_net_dim(ch->dpio, ch->stats.frames_per_cdan, ch->stats.bytes_per_cdan); @@ -2032,9 +2037,7 @@ out: txc_fq->dq_bytes = 0; } - if (ch->xdp.res & XDP_REDIRECT) - xdp_do_flush_map(); - else if (rx_cleaned && ch->xdp.res & XDP_TX) + if (rx_cleaned && ch->xdp.res & XDP_TX) dpaa2_eth_xdp_tx_flush(priv, ch, &priv->fq[flowid]); return work_done; |