Re: [RFC PATCH net-next v8 07/14] page_pool: devmem support

From: David Wei <dw@davidwei.uk>
To: Mina Almasry <almasrymina@google.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-doc@vger.kernel.org, linux-alpha@vger.kernel.org,
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Cc: "David S. Miller" <davem@davemloft.net>,
	"Eric Dumazet" <edumazet@google.com>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Paolo Abeni" <pabeni@redhat.com>,
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	linux-mm@kvack.org, "Matthew Wilcox" <willy@infradead.org>
Subject: Re: [RFC PATCH net-next v8 07/14] page_pool: devmem support
Date: Fri, 26 Apr 2024 17:17:52 -0700	[thread overview]
Message-ID: <8357256a-f0e9-4640-8fec-23341fc607db@davidwei.uk> (raw)
In-Reply-To: <20240403002053.2376017-8-almasrymina@google.com>

On 2024-04-02 5:20 pm, Mina Almasry wrote:
> @@ -69,20 +106,26 @@ net_iov_binding(const struct net_iov *niov)
>   */
>  typedef unsigned long __bitwise netmem_ref;
>  
> +static inline bool netmem_is_net_iov(const netmem_ref netmem)
> +{
> +#if defined(CONFIG_PAGE_POOL) && defined(CONFIG_DMA_SHARED_BUFFER)

I am guessing you added this to try and speed up the fast path? It's
overly restrictive for us since we do not need dmabuf necessarily. I
spent a bit too much time wondering why things aren't working only to
find this :(