Re: [PATCH 4.19 008/114] nfp: flower: add rcu locks when accessing netdev for tunnels

Hi!

From: Pieter Jansen van Vuuren pieter.jansenvanvuuren@netronome.com

[ Upstream commit cb07d915bf278a7a3938b983bbcb4921366b5eff ]

Add rcu locks when accessing netdev when processing route request and tunnel keep alive messages received from hardware.

/* Get the neighbour entry for the lookup */ n = dst_neigh_lookup(&rt->dst, &flow.daddr); ip_rt_put(rt); if (!n)

• goto route_fail_warning;
  

• nfp_tun_write_neigh(n->dev, app, &flow, n, GFP_KERNEL);

• goto fail_rcu_unlock;
  

• nfp_tun_write_neigh(n->dev, app, &flow, n, GFP_ATOMIC); neigh_release(n);
• rcu_read_unlock(); return;

This will make allocations more likely to fail. I thought it is okay to sleep in rcu lock critical sections...?