diff options
| author | Magnus Karlsson <magnus.karlsson@intel.com> | 2023-01-25 08:49:00 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-01-27 22:27:59 -0800 |
| commit | b534013798b77f81a36f36dafd59bab9de837619 (patch) | |
| tree | 244650c9b1a47c630f47dc09968a566fa6955bd8 | |
| parent | ad7e615f646c9b5b2cf655cdfb9d91a28db4f25a (diff) | |
dpaa_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: a1e031ffb422 ("dpaa_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/
Acked-by: Camelia Groza <camelia.groza@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | drivers/net/ethernet/freescale/dpaa/dpaa_eth.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c index 3f8032947d86..027fff9f7db0 100644 --- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c @@ -2410,6 +2410,9 @@ static int dpaa_eth_poll(struct napi_struct *napi, int budget) cleaned = qman_p_poll_dqrr(np->p, budget); + if (np->xdp_act & XDP_REDIRECT) + xdp_do_flush(); + if (cleaned < budget) { napi_complete_done(napi, cleaned); qman_p_irqsource_add(np->p, QM_PIRQ_DQRI); @@ -2417,9 +2420,6 @@ static int dpaa_eth_poll(struct napi_struct *napi, int budget) qman_p_irqsource_add(np->p, QM_PIRQ_DQRI); } - if (np->xdp_act & XDP_REDIRECT) - xdp_do_flush(); - return cleaned; } |