"Paul E. McKenney" [off-list ref] writes:

On Wed, Jun 09, 2021 at 12:33:15PM +0200, Toke Høiland-Jørgensen wrote:

quoted

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