Subject: Re: [PATCH v2 -next] sfc: Add missing pci_disable_device() for error path

From: Martin Habets <[email-masked]>
Date: Thu, 15 Aug 2024 09:21:12 +0100

On Thu, Aug 15, 2024 at 03:04:36AM +0000, Yi Yang wrote:
> This error path needs to disable the pci device before returning.

Can you explain why this is needed? What goes wrong without this patch?

> 
> Fixes: 6e173d3b4af9 ("sfc: Copy shared files needed for Siena (part 1)")
> Fixes: 5a6681e22c14 ("sfc: separate out SFC4000 ("Falcon") support into new sfc-falcon driver")
> Fixes: 89c758fa47b5 ("sfc: Add power-management and wake-on-LAN support")
> Signed-off-by: Yi Yang <[email-masked]>
> ---
> 
> v2: add pci_disable_device() for efx_pm_resume() (drivers/net/ethernet/sfc/efx.c)
> and ef4_pm_resume() (drivers/net/ethernet/sfc/falcon/efx.c)
> 
>  drivers/net/ethernet/sfc/efx.c        | 6 ++++--
>  drivers/net/ethernet/sfc/falcon/efx.c | 6 ++++--
>  drivers/net/ethernet/sfc/siena/efx.c  | 6 ++++--
>  3 files changed, 12 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
> index 6f1a01ded7d4..bf6567093001 100644
> --- a/drivers/net/ethernet/sfc/efx.c
> +++ b/drivers/net/ethernet/sfc/efx.c
> @@ -1278,13 +1278,15 @@ static int efx_pm_resume(struct device *dev)
>  	pci_set_master(efx->pci_dev);
>  	rc = efx->type->reset(efx, RESET_TYPE_ALL);
>  	if (rc)
> -		return rc;
> +		goto fail;
>  	down_write(&efx->filter_sem);
>  	rc = efx->type->init(efx);
>  	up_write(&efx->filter_sem);
>  	if (rc)
> -		return rc;
> +		goto fail;
>  	rc = efx_pm_thaw(dev);

This always falls through into the failure path, even if efx_pm_thaw
succeeds.
Same for the other files.

Martin

> +fail:
> +	pci_disable_device(pci_dev);
>  	return rc;
>  }
>  
> diff --git a/drivers/net/ethernet/sfc/falcon/efx.c b/drivers/net/ethernet/sfc/falcon/efx.c
> index 8925745f1c17..2c3cf1c9a1a7 100644
> --- a/drivers/net/ethernet/sfc/falcon/efx.c
> +++ b/drivers/net/ethernet/sfc/falcon/efx.c
> @@ -3027,11 +3027,13 @@ static int ef4_pm_resume(struct device *dev)
>  	pci_set_master(efx->pci_dev);
>  	rc = efx->type->reset(efx, RESET_TYPE_ALL);
>  	if (rc)
> -		return rc;
> +		goto fail;
>  	rc = efx->type->init(efx);
>  	if (rc)
> -		return rc;
> +		goto fail;
>  	rc = ef4_pm_thaw(dev);
> +fail:
> +	pci_disable_device(pci_dev);
>  	return rc;
>  }
>  
> diff --git a/drivers/net/ethernet/sfc/siena/efx.c b/drivers/net/ethernet/sfc/siena/efx.c
> index 59d3a6043379..dce9a5174e4a 100644
> --- a/drivers/net/ethernet/sfc/siena/efx.c
> +++ b/drivers/net/ethernet/sfc/siena/efx.c
> @@ -1240,13 +1240,15 @@ static int efx_pm_resume(struct device *dev)
>  	pci_set_master(efx->pci_dev);
>  	rc = efx->type->reset(efx, RESET_TYPE_ALL);
>  	if (rc)
> -		return rc;
> +		goto fail;
>  	down_write(&efx->filter_sem);
>  	rc = efx->type->init(efx);
>  	up_write(&efx->filter_sem);
>  	if (rc)
> -		return rc;
> +		goto fail;
>  	rc = efx_pm_thaw(dev);
> +fail:
> +	pci_disable_device(pci_dev);
>  	return rc;
>  }
>  
> -- 
> 2.25.1
>