diff options
| author | Toke Høiland-Jørgensen <toke@redhat.com> | 2021-06-24 19:05:57 +0300 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-06-24 20:43:28 +0300 |
| commit | 0939e0537896e421e391fa4b1a0b052907808e0d (patch) | |
| tree | 94ab414ba688756b8a15d053190635bafaef6b30 /drivers/net/ethernet/amazon/ena | |
| parent | 77151ccf10659d4066074f278402032f3265f0cc (diff) | |
| download | linux-0939e0537896e421e391fa4b1a0b052907808e0d.tar.xz | |
ena: Remove rcu_read_lock() around XDP program invocation
The ena driver has rcu_read_lock()/rcu_read_unlock() pairs around XDP
program invocations. However, the actual lifetime of the objects referred
by the XDP program invocation is longer, all the way through to the call to
xdp_do_flush(), making the scope of the rcu_read_lock() too small. This
turns out to be harmless because it all happens in a single NAPI poll
cycle (and thus under local_bh_disable()), but it makes the rcu_read_lock()
misleading.
Rather than extend the scope of the rcu_read_lock(), just get rid of it
entirely. With the addition of RCU annotations to the XDP_REDIRECT map
types that take bh execution into account, lockdep even understands this to
be safe, so there's really no reason to keep it around.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Saeed Bishara <saeedb@amazon.com>
Cc: Guy Tzalik <gtzalik@amazon.com>
Link: https://lore.kernel.org/bpf/20210624160609.292325-8-toke@redhat.com
Diffstat (limited to 'drivers/net/ethernet/amazon/ena')
| -rw-r--r-- | drivers/net/ethernet/amazon/ena/ena_netdev.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c index 3bb0e66b2c7e..44ef6b88f715 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -382,7 +382,6 @@ static int ena_xdp_execute(struct ena_ring *rx_ring, struct xdp_buff *xdp) struct xdp_frame *xdpf; u64 *xdp_stat; - rcu_read_lock(); xdp_prog = READ_ONCE(rx_ring->xdp_bpf_prog); if (!xdp_prog) @@ -439,8 +438,6 @@ static int ena_xdp_execute(struct ena_ring *rx_ring, struct xdp_buff *xdp) ena_increase_stat(xdp_stat, 1, &rx_ring->syncp); out: - rcu_read_unlock(); - return verdict; } |