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Date: Thu, 6 Jun 2024 08:22:37 +0200
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Andrew Lunn <andrew@lunn.ch>, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org, "David S. Miller" <davem@davemloft.net>,
	Daniel Bristot de Oliveira <bristot@kernel.org>,
	Boqun Feng <boqun.feng@gmail.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Eric Dumazet <edumazet@google.com>,
	Frederic Weisbecker <frederic@kernel.org>,
	Ingo Molnar <mingo@redhat.com>, Paolo Abeni <pabeni@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Waiman Long <longman@redhat.com>, Will Deacon <will@kernel.org>
Subject: Re: [PATCH v4 net-next 03/14] net: Use nested-BH locking for
 napi_alloc_cache.
Message-ID: <20240606062237.nuBoHreW@linutronix.de>
References: <20240604154425.878636-1-bigeasy@linutronix.de>
 <20240604154425.878636-4-bigeasy@linutronix.de>
 <20240605195420.2f47e6a1@kernel.org>
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In-Reply-To: <20240605195420.2f47e6a1@kernel.org>

On 2024-06-05 19:54:20 [-0700], Jakub Kicinski wrote:
> On Tue,  4 Jun 2024 17:24:10 +0200 Sebastian Andrzej Siewior wrote:
> > @@ -308,6 +311,7 @@ void *__napi_alloc_frag_align(unsigned int fragsz, unsigned int align_mask)
> >  	struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache);
> >  
> >  	fragsz = SKB_DATA_ALIGN(fragsz);
> > +	guard(local_lock_nested_bh)(&napi_alloc_cache.bh_lock);
> >  
> >  	return __page_frag_alloc_align(&nc->page, fragsz, GFP_ATOMIC,
> >  				       align_mask);
> 
> We have decided to advise against the use of guard() in networking, 
> at least for now.

Understood.

> Andrew, wasn't it on your TODO list to send the update to the docs? :)
I can add it to
	Documentation/process/maintainer-netdev.rst

Yes, no, Andrew?

Sebastian