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| author | Toke Høiland-Jørgensen <toke@redhat.com> | 2021-06-24 18:06:00 +0200 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2021-06-24 19:44:17 +0200 |
| commit | 547aabcac3251c40e4cd09d79dba70f7eab8cca2 (patch) | |
| tree | 63e1435d0a112f80ed38d61526886aae7a00e6bb /drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | |
| parent | 36baafe347a85a9d85f61aac0a9b53c53635829e (diff) | |
| download | lwn-547aabcac3251c40e4cd09d79dba70f7eab8cca2.tar.gz lwn-547aabcac3251c40e4cd09d79dba70f7eab8cca2.zip | |
freescale: Remove rcu_read_lock() around XDP program invocation
The dpaa and dpaa2 drivers have 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>
Reviewed-by: Camelia Groza <camelia.groza@nxp.com>
Cc: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Cc: Madalin Bucur <madalin.bucur@nxp.com>
Cc: Ioana Ciornei <ioana.ciornei@nxp.com>
Link: https://lore.kernel.org/bpf/20210624160609.292325-11-toke@redhat.com
Diffstat (limited to 'drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c')
| -rw-r--r-- | drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c index 8433aa730c42..973352393bd4 100644 --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c @@ -352,8 +352,6 @@ static u32 dpaa2_eth_run_xdp(struct dpaa2_eth_priv *priv, u32 xdp_act = XDP_PASS; int err, offset; - rcu_read_lock(); - xdp_prog = READ_ONCE(ch->xdp.prog); if (!xdp_prog) goto out; @@ -414,7 +412,6 @@ static u32 dpaa2_eth_run_xdp(struct dpaa2_eth_priv *priv, ch->xdp.res |= xdp_act; out: - rcu_read_unlock(); return xdp_act; } |