gro_cells: mark napi struct as not busy poll candidates
[ Upstream commit e88a2766 ] Rolf Neugebauer reported very long delays at netns dismantle. Eric W. Biederman was kind enough to look at this problem and noticed synchronize_net() occurring from netif_napi_del() that was added in linux-4.5 Busy polling makes no sense for tunnels NAPI. If busy poll is used for sessions over tunnels, the poller will need to poll the physical device queue anyway. netif_tx_napi_add() could be used here, but function name is misleading, and renaming it is not stable material, so set NAPI_STATE_NO_BUSY_POLL bit directly. This will avoid inserting gro_cells napi structures in napi_hash[] and avoid the problematic synchronize_net() (per possible cpu) that Rolf reported. Fixes: 93d05d4a ("net: provide generic busy polling to all NAPI drivers") Signed-off-by:Eric Dumazet <edumazet@google.com> Reported-by:
Rolf Neugebauer <rolf.neugebauer@docker.com> Reported-by:
Eric W. Biederman <ebiederm@xmission.com> Acked-by:
Cong Wang <xiyou.wangcong@gmail.com> Tested-by:
Rolf Neugebauer <rolf.neugebauer@docker.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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