Re: Patch "s390/qeth: move netif_napi_add_tx() and napi_enable() from under BH" has been added to the 6.13-stable tree

[Alexandra Winter <wintera@linux.ibm.com>]

On 18.02.25 13:36, Sasha Levin wrote:
> This is a note to let you know that I've just added the patch titled
> 
>     s390/qeth: move netif_napi_add_tx() and napi_enable() from under BH
> 
> to the 6.13-stable tree which can be found at:
>     http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> 
> The filename of the patch is:
>      s390-qeth-move-netif_napi_add_tx-and-napi_enable-fro.patch
> and it can be found in the queue-6.13 subdirectory.
> 
> If you, or anyone else, feels it should not be added to the stable tree,
> please let <stable@vger.kernel.org> know about it.
> 

Hello Sasha,
this is a fix for a regression that was introduced with v6.14-rc1.
So I do not think it needs to go into 6.13 stable tree.
But it does not hurt either.


> 
> 
> commit 48eda8093b86b426078bd245a9b4fbc5d057c436
> Author: Alexandra Winter <wintera@linux.ibm.com>
> Date:   Wed Feb 12 17:36:59 2025 +0100
> 
>     s390/qeth: move netif_napi_add_tx() and napi_enable() from under BH
>     
>     [ Upstream commit 0d0b752f2497471ddd2b32143d167d42e18a8f3c ]
>     
>     Like other drivers qeth is calling local_bh_enable() after napi_schedule()
>     to kick-start softirqs [0].
>     Since netif_napi_add_tx() and napi_enable() now take the netdev_lock()
>     mutex [1], move them out from under the BH protection. Same solution as in
>     commit a60558644e20 ("wifi: mt76: move napi_enable() from under BH")
>     
>     Fixes: 1b23cdbd2bbc ("net: protect netdev->napi_list with netdev_lock()")
>     Link: https://lore.kernel.org/netdev/20240612181900.4d9d18d0@kernel.org/ [0]
>     Link: https://lore.kernel.org/netdev/20250115035319.559603-1-kuba@kernel.org/ [1]
>     Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
>     Acked-by: Joe Damato <jdamato@fastly.com>
>     Link: https://patch.msgid.link/20250212163659.2287292-1-wintera@linux.ibm.com
>     Signed-off-by: Jakub Kicinski <kuba@kernel.org>
>     Signed-off-by: Sasha Levin <sashal@kernel.org>
> 
> diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
> index a3adaec5504e4..20328d695ef92 100644
> --- a/drivers/s390/net/qeth_core_main.c
> +++ b/drivers/s390/net/qeth_core_main.c
> @@ -7050,14 +7050,16 @@ int qeth_open(struct net_device *dev)
>  	card->data.state = CH_STATE_UP;
>  	netif_tx_start_all_queues(dev);
>  
> -	local_bh_disable();
>  	qeth_for_each_output_queue(card, queue, i) {
>  		netif_napi_add_tx(dev, &queue->napi, qeth_tx_poll);
>  		napi_enable(&queue->napi);
> -		napi_schedule(&queue->napi);
>  	}
> -
>  	napi_enable(&card->napi);
> +
> +	local_bh_disable();
> +	qeth_for_each_output_queue(card, queue, i) {
> +		napi_schedule(&queue->napi);
> +	}
>  	napi_schedule(&card->napi);
>  	/* kick-start the NAPI softirq: */
>  	local_bh_enable();