From: Toke Høiland-Jørgensen Date: Thu, 24 Jun 2021 16:06:07 +0000 (+0200) Subject: netsec: Remove rcu_read_lock() around XDP program invocation X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=7b6ee873ff20c22af355661b241defa7f6ed7582;p=linux.git netsec: Remove rcu_read_lock() around XDP program invocation 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. Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Daniel Borkmann Acked-by: Ilias Apalodimas Cc: Jassi Brar Link: https://lore.kernel.org/bpf/20210624160609.292325-18-toke@redhat.com --- diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c index dfc85cc68173c..20d148c019d8d 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); @@ -1069,8 +1068,6 @@ next: } netsec_finalize_xdp_rx(priv, xdp_act, xdp_xmit); - rcu_read_unlock(); - return done; }