| Message ID | 20231002140805.568-1-ansuelsmth@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | fcdfc462881d8acf9db77f483b2c821e286ca97b |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] net: ethernet: mediatek: disable irq before schedule napi | expand |
Hello: This patch was applied to netdev/net.git (main) by Paolo Abeni <pabeni@redhat.com>: On Mon, 2 Oct 2023 16:08:05 +0200 you wrote: > While searching for possible refactor of napi_schedule_prep and > __napi_schedule it was notice that the mtk eth driver disable the > interrupt for rx and tx AFTER napi is scheduled. > > While this is a very hard to repro case it might happen to have > situation where the interrupt is disabled and never enabled again as the > napi completes and the interrupt is enabled before. > > [...] Here is the summary with links: - [net] net: ethernet: mediatek: disable irq before schedule napi https://git.kernel.org/netdev/net/c/fcdfc462881d You are awesome, thank you!
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c index 82b51072aad8..7669b446915a 100644 --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c @@ -3172,8 +3172,8 @@ static irqreturn_t mtk_handle_irq_rx(int irq, void *_eth) eth->rx_events++; if (likely(napi_schedule_prep(ð->rx_napi))) { - __napi_schedule(ð->rx_napi); mtk_rx_irq_disable(eth, eth->soc->txrx.rx_irq_done_mask); + __napi_schedule(ð->rx_napi); } return IRQ_HANDLED; @@ -3185,8 +3185,8 @@ static irqreturn_t mtk_handle_irq_tx(int irq, void *_eth) eth->tx_events++; if (likely(napi_schedule_prep(ð->tx_napi))) { - __napi_schedule(ð->tx_napi); mtk_tx_irq_disable(eth, MTK_TX_DONE_INT); + __napi_schedule(ð->tx_napi); } return IRQ_HANDLED;
While searching for possible refactor of napi_schedule_prep and __napi_schedule it was notice that the mtk eth driver disable the interrupt for rx and tx AFTER napi is scheduled. While this is a very hard to repro case it might happen to have situation where the interrupt is disabled and never enabled again as the napi completes and the interrupt is enabled before. This is caused by the fact that a napi driven by interrupt expect a logic with: 1. interrupt received. napi prepared -> interrupt disabled -> napi scheduled 2. napi triggered. ring cleared -> interrupt enabled -> wait for new interrupt To prevent this case, disable the interrupt BEFORE the napi is scheduled. Fixes: 656e705243fd ("net-next: mediatek: add support for MT7623 ethernet") Cc: stable@vger.kernel.org Signed-off-by: Christian Marangi <ansuelsmth@gmail.com> --- drivers/net/ethernet/mediatek/mtk_eth_soc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)