From be176234d0a845c075736490f34268b6a952c18f Mon Sep 17 00:00:00 2001 From: Christian Marangi Date: Mon, 9 Oct 2023 15:37:53 +0200 Subject: [PATCH] net: tc35815: rework network interface interrupt logic Rework network interface logic. Before this change, the code flow was: 1. Disable interrupt 2. Try to schedule a NAPI 3. Check if it was possible (NAPI is not already scheduled) 4. emit BUG() if we receive interrupt while a NAPI is scheduled If some application busy poll or set gro_flush_timeout low enough, it's possible to reach the BUG() condition. Given that the condition may happen and it wouldn't be a bug, rework the logic to permit such case and prevent stall with interrupt never enabled again. Disable the interrupt only if the NAPI can be scheduled (aka it's not already scheduled) and drop the printk and BUG() call. With these change, in the event of a NAPI already scheduled, the interrupt is simply ignored with nothing done. Suggested-by: Eric Dumazet Signed-off-by: Christian Marangi Link: https://lore.kernel.org/r/20231009133754.9834-4-ansuelsmth@gmail.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/toshiba/tc35815.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/toshiba/tc35815.c b/drivers/net/ethernet/toshiba/tc35815.c index 14cf6ecf6d0d..6e3758dfbdbd 100644 --- a/drivers/net/ethernet/toshiba/tc35815.c +++ b/drivers/net/ethernet/toshiba/tc35815.c @@ -1434,14 +1434,10 @@ static irqreturn_t tc35815_interrupt(int irq, void *dev_id) u32 dmactl = tc_readl(&tr->DMA_Ctl); if (!(dmactl & DMA_IntMask)) { - /* disable interrupts */ - tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl); - if (napi_schedule_prep(&lp->napi)) + if (napi_schedule_prep(&lp->napi)) { + /* disable interrupts */ + tc_writel(dmactl | DMA_IntMask, &tr->DMA_Ctl); __napi_schedule(&lp->napi); - else { - printk(KERN_ERR "%s: interrupt taken in poll\n", - dev->name); - BUG(); } (void)tc_readl(&tr->Int_Src); /* flush */ return IRQ_HANDLED;