Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.4 359/434] net: wireless: intel: iwlwifi: fix GRO_NORMAL packet stalling | Date | Sun, 29 Dec 2019 18:26:52 +0100 |
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From: Alexander Lobakin <alobakin@dlink.ru>
[ Upstream commit b167191e2a851cb2e4c6ef8b91c83ff73ef41872 ]
Commit 6570bc79c0df ("net: core: use listified Rx for GRO_NORMAL in napi_gro_receive()") has applied batched GRO_NORMAL packets processing to all napi_gro_receive() users, including mac80211-based drivers.
However, this change has led to a regression in iwlwifi driver [1][2] as it is required for NAPI users to call napi_complete_done() or napi_complete() and the end of every polling iteration, whilst iwlwifi doesn't use NAPI scheduling at all and just calls napi_gro_flush(). In that particular case, packets which have not been already flushed from napi->rx_list stall in it until at least next Rx cycle.
Fix this by adding a manual flushing of the list to iwlwifi driver right before napi_gro_flush() call to mimic napi_complete() logics.
I prefer to open-code gro_normal_list() rather than exporting it for 2 reasons: * to prevent from using it and napi_gro_flush() in any new drivers, as it is the *really* bad way to use NAPI that should be avoided; * to keep gro_normal_list() static and don't lose any CC optimizations.
I also don't add the "Fixes:" tag as the mentioned commit was only a trigger that only exposed an improper usage of NAPI in this particular driver.
[1] https://lore.kernel.org/netdev/PSXP216MB04388962C411CD0B17A86F47804A0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM [2] https://bugzilla.kernel.org/show_bug.cgi?id=205647
Signed-off-by: Alexander Lobakin <alobakin@dlink.ru> Acked-by: Luca Coelho <luciano.coelho@intel.com> Reported-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au> Tested-by: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au> Reviewed-by: Edward Cree <ecree@solarflare.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- drivers/net/wireless/intel/iwlwifi/pcie/rx.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c index 19dd075f2f63..041dd75ac72b 100644 --- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c +++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c @@ -1429,6 +1429,7 @@ out_err: static void iwl_pcie_rx_handle(struct iwl_trans *trans, int queue) { struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans); + struct napi_struct *napi; struct iwl_rxq *rxq; u32 r, i, count = 0; bool emergency = false; @@ -1534,8 +1535,16 @@ out: if (unlikely(emergency && count)) iwl_pcie_rxq_alloc_rbs(trans, GFP_ATOMIC, rxq); - if (rxq->napi.poll) - napi_gro_flush(&rxq->napi, false); + napi = &rxq->napi; + if (napi->poll) { + if (napi->rx_count) { + netif_receive_skb_list(&napi->rx_list); + INIT_LIST_HEAD(&napi->rx_list); + napi->rx_count = 0; + } + + napi_gro_flush(napi, false); + } iwl_pcie_rxq_restock(trans, rxq); } -- 2.20.1
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