From 959ad7ec066d9a61557ad6aedf77ea9b54c82df0 Mon Sep 17 00:00:00 2001 From: Toke Høiland-Jørgensen Date: Thu, 24 Jun 2021 18:06:02 +0200 Subject: marvell: Remove rcu_read_lock() around XDP program invocation MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The mvneta and mvpp2 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 Signed-off-by: Daniel Borkmann Cc: Thomas Petazzoni Cc: Russell King Cc: Marcin Wojtas Link: https://lore.kernel.org/bpf/20210624160609.292325-13-toke@redhat.com --- drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c') diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c index 9bca8c8f9f8d..c31677527a02 100644 --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c @@ -3881,8 +3881,6 @@ static int mvpp2_rx(struct mvpp2_port *port, struct napi_struct *napi, int rx_done = 0; u32 xdp_ret = 0; - rcu_read_lock(); - xdp_prog = READ_ONCE(port->xdp_prog); /* Get number of received packets and clamp the to-do */ @@ -4028,8 +4026,6 @@ err_drop_frame: mvpp2_bm_pool_put(port, pool, dma_addr, phys_addr); } - rcu_read_unlock(); - if (xdp_ret & MVPP2_XDP_REDIR) xdp_do_flush_map(); -- cgit v1.2.3