From: Netanel Belgazal netanel@amazon.com
[ 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 netanel@amazon.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/amazon/ena/ena_netdev.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c +++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c @@ -1238,8 +1238,8 @@ static int ena_io_poll(struct napi_struc struct ena_napi *ena_napi = container_of(napi, struct ena_napi, napi); struct ena_ring *tx_ring, *rx_ring;
- 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; @@ -1256,7 +1256,11 @@ static int ena_io_poll(struct napi_struc }
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 the device is about to reset or down, avoid unmask * the interrupt and return 0 so NAPI won't reschedule