From: Netanel Belgazal Date: Tue, 10 Dec 2019 11:27:44 +0000 (+0000) Subject: net: ena: fix napi handler misbehavior when the napi budget is zero X-Git-Tag: v4.9.208~6 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=971932afde4ee53a7d386e898db0021111e0603b;p=thirdparty%2Fkernel%2Fstable.git net: ena: fix napi handler misbehavior when the napi budget is zero [ Upstream commit 24dee0c7478d1a1e00abdf5625b7f921467325dc ] In netpoll the napi handler could be called with budget equal to zero. Current ENA napi handler doesn't take that into consideration. The napi handler handles Rx packets in a do-while loop. Currently, the budget check happens only after decrementing the budget, therefore the napi handler, in rare cases, could run over MAX_INT packets. In addition to that, this moves all budget related variables to int calculation and stop mixing u32 to avoid ambiguity Fixes: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)") Signed-off-by: Netanel Belgazal Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c index 0780900b37c72..961f31c8356b7 100644 --- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -1105,8 +1105,8 @@ static int ena_io_poll(struct napi_struct *napi, int budget) struct ena_ring *tx_ring, *rx_ring; struct ena_eth_io_intr_reg intr_reg; - u32 tx_work_done; - u32 rx_work_done; + int tx_work_done; + int rx_work_done = 0; int tx_budget; int napi_comp_call = 0; int ret; @@ -1122,7 +1122,11 @@ static int ena_io_poll(struct napi_struct *napi, int budget) } tx_work_done = ena_clean_tx_irq(tx_ring, tx_budget); - rx_work_done = ena_clean_rx_irq(rx_ring, napi, budget); + /* On netpoll the budget is zero and the handler should only clean the + * tx completions. + */ + if (likely(budget)) + rx_work_done = ena_clean_rx_irq(rx_ring, napi, budget); if ((budget > rx_work_done) && (tx_budget > tx_work_done)) { napi_complete_done(napi, rx_work_done);