| Message ID | 201309040241.27834.sergei.shtylyov@cogentembedded.com (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Headers | show |
From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> Date: Wed, 4 Sep 2013 02:41:27 +0400 > While implementing NAPI for the driver, I overlooked the race conditions where > interrupt handler might have called napi_schedule_prep() before napi_enable() > was called or after napi_disable() was called. If RX interrupt happens, this > would cause the endless interrupts and messages like: > > sh-eth eth0: ignoring interrupt, status 0x00040000, mask 0x01ff009f. > > The interrupt wouldn't even be masked by the kernel eventually since the handler > would return IRQ_HANDLED all the time. > > As a fix, move napi_enable() call before request_irq() call and napi_disable() > call after free_irq() call. > > Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> Applied and queued up for -stable, thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Index: net/drivers/net/ethernet/renesas/sh_eth.c =================================================================== --- net.orig/drivers/net/ethernet/renesas/sh_eth.c +++ net/drivers/net/ethernet/renesas/sh_eth.c @@ -1857,11 +1857,13 @@ static int sh_eth_open(struct net_device pm_runtime_get_sync(&mdp->pdev->dev); + napi_enable(&mdp->napi); + ret = request_irq(ndev->irq, sh_eth_interrupt, mdp->cd->irq_flags, ndev->name, ndev); if (ret) { dev_err(&ndev->dev, "Can not assign IRQ number\n"); - return ret; + goto out_napi_off; } /* Descriptor set */ @@ -1879,12 +1881,12 @@ static int sh_eth_open(struct net_device if (ret) goto out_free_irq; - napi_enable(&mdp->napi); - return ret; out_free_irq: free_irq(ndev->irq, ndev); +out_napi_off: + napi_disable(&mdp->napi); pm_runtime_put_sync(&mdp->pdev->dev); return ret; } @@ -1976,8 +1978,6 @@ static int sh_eth_close(struct net_devic { struct sh_eth_private *mdp = netdev_priv(ndev); - napi_disable(&mdp->napi); - netif_stop_queue(ndev); /* Disable interrupts by clearing the interrupt mask. */ @@ -1995,6 +1995,8 @@ static int sh_eth_close(struct net_devic free_irq(ndev->irq, ndev); + napi_disable(&mdp->napi); + /* Free all the skbuffs in the Rx queue. */ sh_eth_ring_free(ndev);
While implementing NAPI for the driver, I overlooked the race conditions where interrupt handler might have called napi_schedule_prep() before napi_enable() was called or after napi_disable() was called. If RX interrupt happens, this would cause the endless interrupts and messages like: sh-eth eth0: ignoring interrupt, status 0x00040000, mask 0x01ff009f. The interrupt wouldn't even be masked by the kernel eventually since the handler would return IRQ_HANDLED all the time. As a fix, move napi_enable() call before request_irq() call and napi_disable() call after free_irq() call. Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> --- The patch is against Dave's 'net.git' repo. It should be applied to 3.11.y too. drivers/net/ethernet/renesas/sh_eth.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html