"Paul E. McKenney" <paulmck@xxxxxxxxxx> writes: > On Wed, Jun 09, 2021 at 12:33:15PM +0200, Toke Høiland-Jørgensen wrote: >> The bnxt driver has 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. > > And same for the rest of these removals. Someone might be very happy > to have that comment at some later date, and that someone just might > be you. ;-) Bah, why do you have to go and make sensible suggestions like that? ;) Will wait for Martin's review and add this in a v2. BTW, is it OK to include your patch in the series like this, or should I rather request that your tree be merged into bpf-next? -Toke
