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Date: Wed, 4 Dec 2024 17:28:46 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: Yunsheng Lin <linyunsheng@huawei.com>
Cc: <davem@davemloft.net>, <pabeni@redhat.com>, <liuyonglong@huawei.com>,
 <fanghaiqing@huawei.com>, <zhangkun09@huawei.com>, Alexander Lobakin
 <aleksander.lobakin@intel.com>, Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
 Jesper Dangaard Brouer <hawk@kernel.org>, Ilias Apalodimas
 <ilias.apalodimas@linaro.org>, Eric Dumazet <edumazet@google.com>, Simon
 Horman <horms@kernel.org>, <netdev@vger.kernel.org>,
 <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC v4 1/3] page_pool: fix timing for checking and
 disabling napi_local
Message-ID: <20241204172846.5b360d32@kernel.org>
In-Reply-To: <e053e75a-bde1-4e69-9a8d-d1f54be06bdb@huawei.com>
References: <20241120103456.396577-1-linyunsheng@huawei.com>
	<20241120103456.396577-2-linyunsheng@huawei.com>
	<20241202184954.3a4095e3@kernel.org>
	<e053e75a-bde1-4e69-9a8d-d1f54be06bdb@huawei.com>
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On Wed, 4 Dec 2024 19:01:14 +0800 Yunsheng Lin wrote:
> > I don't think this is in the right place.
> > Why not inside page_pool_disable_direct_recycling() ?  
> 
> It is in page_pool_destroy() mostly because:
> 1. Only call synchronize_rcu() when there is inflight pages, which should
>    be an unlikely case, and  synchronize_rcu() might need to be called at
>    least for the case of pool->p.napi not being NULL if it is called inside
>    page_pool_disable_direct_recycling().

Right, my point was that page_pool_disable_direct_recycling() 
is an exported function, its callers also need to be protected.