linux-kernel - Re: [PATCH net-next v18 07/14] memory-provider: dmabuf devmem memory provider

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Message-ID: <20240813073917.690ac1cc@kernel.org>
Date: Tue, 13 Aug 2024 07:39:17 -0700
From: Jakub Kicinski <kuba@...nel.org>
To: Pavel Begunkov <asml.silence@...il.com>
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Subject: Re: [PATCH net-next v18 07/14] memory-provider: dmabuf devmem
 memory provider

On Tue, 13 Aug 2024 03:31:13 +0100 Pavel Begunkov wrote:
> I'm getting lost, so repeating myself a bit. What I think
> would be a good approach is if we get an error back from
> the driver if it doesn't support netiov / providers.
> 
> netdev_rx_queue_restart() {
> 	...
> 	err = dev->queue_mgmt_ops->ndo_queue_mem_alloc();
> 	if (err == -EOPNOTSUPP) // the driver doesn't support netiov
> 		return -EOPNOTSUPP;
> 	...
> }
> 
> That can be done if drivers opt in to support providers,
> e.g. via a page pool flag.
> 
> What I think wouldn't be a great option is getting back a
> "success" from the driver even though it ignored

page pool params are not the right place for a supported flag.
Sooner or later we'll want to expose this flag to user space.