The netsec driver has a rcu_read_lock()/rcu_read_unlock() pair around the
full RX loop, covering everything up to and including xdp_do_flush(). This
is actually the correct behaviour, but because it all happens in a single
NAPI poll cycle (and thus under local_bh_disable()), it is also technically
redundant.
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 the rcu_read_lock() around anymore, so
let's just remove it.
Cc: Jassi Brar <jaswinder.singh@xxxxxxxxxx>
Cc: Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx>
Acked-by: Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx>
Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
---
drivers/net/ethernet/socionext/netsec.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
index dfc85cc68173..e07b7c870046 100644
--- a/drivers/net/ethernet/socionext/netsec.c
+++ b/drivers/net/ethernet/socionext/netsec.c
@@ -958,7 +958,6 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
xdp_init_buff(&xdp, PAGE_SIZE, &dring->xdp_rxq);
- rcu_read_lock();
xdp_prog = READ_ONCE(priv->xdp_prog);
dma_dir = page_pool_get_dma_dir(dring->page_pool);
@@ -1019,6 +1018,10 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
pkt_len, false);
if (xdp_prog) {
+ /* This code is invoked within a single NAPI poll cycle
+ * and thus under local_bh_disable(), which provides the
+ * needed RCU protection.
+ */
xdp_result = netsec_run_xdp(priv, xdp_prog, &xdp);
if (xdp_result != NETSEC_XDP_PASS) {
xdp_act |= xdp_result;
@@ -1069,8 +1072,6 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
}
netsec_finalize_xdp_rx(priv, xdp_act, xdp_xmit);
- rcu_read_unlock();
-
return done;
}
--
2.32.0
