netdev - Re: [PATCH net] s390/qeth: move netif_napi_add_tx() and napi

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Message-ID: <7ea4bc1b-96d8-47a3-8ca2-2baa862d8888@linux.ibm.com>
Date: Thu, 13 Feb 2025 08:37:01 +0100
From: Alexandra Winter <wintera@...ux.ibm.com>
To: Joe Damato <jdamato@...tly.com>, David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Andrew Lunn <andrew+netdev@...n.ch>, netdev@...r.kernel.org,
        linux-s390@...r.kernel.org, Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Alexander Gordeev <agordeev@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        Sven Schnelle <svens@...ux.ibm.com>,
        Thorsten Winkler <twinkler@...ux.ibm.com>,
        Simon Horman <horms@...nel.org>, Kuniyuki Iwashima <kuniyu@...zon.com>
Subject: Re: [PATCH net] s390/qeth: move netif_napi_add_tx() and napi_enable()
 from under BH



On 12.02.25 20:35, Joe Damato wrote:
> On Wed, Feb 12, 2025 at 05:36:59PM +0100, Alexandra Winter wrote:
>> 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()")
> Hm, I wonder if the fixes should be for commit 413f0271f396 ("net:
> protect NAPI enablement with netdev_lock()") instead ?


I was wondering about that too. netif_napi_add_tx() got  the lock in
1b23cdbd2bbc and napi_enable() got the lock in 413f0271f396.
I don't think I can have 2 Fixes tags, can I?
(And I don't think it makes sense to split these few lines up into 2 commits)
I chose 1b23cdbd2bbc because it is the earlier one.