Subject: Re: [PATCH v4] bnx2x: Fix error recovering in switch configuration

From: Jakub Kicinski <[email-masked]>
Date: Mon, 31 Jul 2023 17:47:16 -0700

On Fri, 28 Jul 2023 16:11:33 -0500 Thinh Tran wrote:
> As the BCM57810 and other I/O adapters are connected
> through a PCIe switch, the bnx2x driver causes unexpected
> system hang/crash while handling PCIe switch errors, if
> its error handler is called after other drivers' handlers.
> 
> In this case, after numbers of bnx2x_tx_timout(), the
> bnx2x_nic_unload() is  called, frees up resources and
> calls bnx2x_napi_disable(). Then when EEH calls its
> error handler, the bnx2x_io_error_detected() and
> bnx2x_io_slot_reset() also calling bnx2x_napi_disable()
> and freeing the resources.
> 
> 
> Signed-off-by: Thinh Tran <[email-masked]>
> Reviewed-by: Manish Chopra <[email-masked]>
> Tested-by: Abdul Haleem <[email-masked]>
> Tested-by: David Christensen <[email-masked]>
> 
> Reviewed-by: Simon Horman <[email-masked]>

nit: no empty lines between tags

There should be a "---" line between the tags and changelog.

>   v4:
>    - factoring common code into new function bnx2x_stop_nic()
>      that disables and releases IRQs and NAPIs 
>   v3:
>     - no changes, just repatched to the latest driver level
>     - updated the reviewed-by Manish in October, 2022
> 
>   v2:
>    - Check the state of the NIC before calling disable nappi
>      and freeing the IRQ
>    - Prevent recurrence of TX timeout by turning off the carrier,
>      calling netif_carrier_off() in bnx2x_tx_timeout()
>    - Check and bail out early if fp->page_pool already freed
>
> ---
>  drivers/net/ethernet/broadcom/bnx2x/bnx2x.h   |  2 ++

> @@ -3095,14 +3097,8 @@ int bnx2x_nic_unload(struct bnx2x *bp, int unload_mode, bool keep_link)
>  		if (!CHIP_IS_E1x(bp))
>  			bnx2x_pf_disable(bp);
>  
> -		/* Disable HW interrupts, NAPI */
> -		bnx2x_netif_stop(bp, 1);
> -		/* Delete all NAPI objects */
> -		bnx2x_del_all_napi(bp);
> -		if (CNIC_LOADED(bp))
> -			bnx2x_del_all_napi_cnic(bp);
> -		/* Release IRQs */
> -		bnx2x_free_irq(bp);

Could you split the change into two patches - one factoring out the
code into bnx2x_stop_nic() and the other adding the nic_stopped
variable? First one should be pure code refactoring with no functional
changes. That'd make the reviewing process easier.

> +		/* Disable HW interrupts, delete NAPIs, Release IRQs */
> +		bnx2x_stop_nic(bp);
>  
>  		/* Report UNLOAD_DONE to MCP */
>  		bnx2x_send_unload_done(bp, false);
> @@ -4987,6 +4983,12 @@ void bnx2x_tx_timeout(struct net_device *dev, unsigned int txqueue)
>  {
>  	struct bnx2x *bp = netdev_priv(dev);
>  
> +	/* Immediately indicate link as down */
> +	bp->link_vars.link_up = 0;
> +	bp->force_link_down = true;
> +	netif_carrier_off(dev);
> +	BNX2X_ERR("Indicating link is down due to Tx-timeout\n");

Is this code move to make the shutdown more immediate?
That could also be a separate patch.

>  	/* We want the information of the dump logged,
>  	 * but calling bnx2x_panic() would kill all chances of recovery.
>  	 */
> diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h
> index d8b1824c334d..f5ecbe8d604a 100644
> --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h
> +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h
> @@ -1015,6 +1015,9 @@ static inline void bnx2x_free_rx_sge_range(struct bnx2x *bp,
>  {
>  	int i;
>  
> +	if (!fp->page_pool.page)
> +		return;
> +
>  	if (fp->mode == TPA_MODE_DISABLED)
>  		return;
>  
> @@ -1399,5 +1402,20 @@ void bnx2x_set_os_driver_state(struct bnx2x *bp, u32 state);
>   */
>  int bnx2x_nvram_read(struct bnx2x *bp, u32 offset, u8 *ret_buf,
>  		     int buf_size);
> +static inline void bnx2x_stop_nic(struct bnx2x *bp)

can't it live in bnx2x_cmn.c ? Why make it a static inline?

> +{
> +	if (!bp->nic_stopped) {
> +		/* Disable HW interrupts, NAPI */
> +		bnx2x_netif_stop(bp, 1);
> +		/* Delete all NAPI objects */
> +		bnx2x_del_all_napi(bp);
> +		if (CNIC_LOADED(bp))
> +			bnx2x_del_all_napi_cnic(bp);
> +		/* Release IRQs */
> +		bnx2x_free_irq(bp);
> +		bp->nic_stopped = true;
> +	}
> +}
> +
>  

nit: double new line

> --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_vfpf.c
> +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_vfpf.c
> @@ -529,13 +529,8 @@ void bnx2x_vfpf_close_vf(struct bnx2x *bp)
>  	bnx2x_vfpf_finalize(bp, &req->first_tlv);
>  
>  free_irq:
> -	/* Disable HW interrupts, NAPI */
> -	bnx2x_netif_stop(bp, 0);

This used to say 

	bnx2x_netif_stop(bp, 0);

but bnx2x_stop_nic() will do:

	bnx2x_netif_stop(bp, 1);

is it okay to shut down the HW here ? (whatever that entails)

> -	/* Delete all NAPI objects */
> -	bnx2x_del_all_napi(bp);
> -
> -	/* Release IRQs */
> -	bnx2x_free_irq(bp);
> +	/* Disable HW interrupts, delete NAPIs, Release IRQs */
> +	bnx2x_stop_nic(bp);
-- 
pw-bot: cr