diff options
| author | Magnus Karlsson <magnus.karlsson@intel.com> | 2023-01-25 08:48:57 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-01-27 22:27:59 -0800 |
| commit | 2ccce20d51faa0178086163ccb6c84a099a87ab4 (patch) | |
| tree | 1e2b89f0add70cc41d42141bea67a9cd5931a3f9 | |
| parent | 28b4387f0ec08d48634fcc3e3687c93edc1503f9 (diff) | |
| download | linux-2ccce20d51faa0178086163ccb6c84a099a87ab4.tar.gz | |
qede: 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: d1b25b79e162b ("qede: add .ndo_xdp_xmit() and 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/qlogic/qede/qede_fp.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c b/drivers/net/ethernet/qlogic/qede/qede_fp.c index 7c2af482192d74..cb1746bc0e0c5d 100644 --- a/drivers/net/ethernet/qlogic/qede/qede_fp.c +++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c @@ -1438,6 +1438,10 @@ int qede_poll(struct napi_struct *napi, int budget) rx_work_done = (likely(fp->type & QEDE_FASTPATH_RX) && qede_has_rx_work(fp->rxq)) ? qede_rx_int(fp, budget) : 0; + + if (fp->xdp_xmit & QEDE_XDP_REDIRECT) + xdp_do_flush(); + /* Handle case where we are called by netpoll with a budget of 0 */ if (rx_work_done < budget || !budget) { if (!qede_poll_is_more_work(fp)) { @@ -1457,9 +1461,6 @@ int qede_poll(struct napi_struct *napi, int budget) qede_update_tx_producer(fp->xdp_tx); } - if (fp->xdp_xmit & QEDE_XDP_REDIRECT) - xdp_do_flush_map(); - return rx_work_done; } |