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Date: Wed, 6 May 2026 19:34:20 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Bobby Eshleman <bobbyeshleman@gmail.com>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>, "David S. Miller"
 <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Paolo Abeni
 <pabeni@redhat.com>, Simon Horman <horms@kernel.org>, Jonathan Corbet
 <corbet@lwn.net>, Shuah Khan <skhan@linuxfoundation.org>, Alex Shi
 <alexs@kernel.org>, Yanteng Si <si.yanteng@linux.dev>, Dongliang Mu
 <dzm91@hust.edu.cn>, Michael Chan <michael.chan@broadcom.com>, Pavan Chebbi
 <pavan.chebbi@broadcom.com>, Joshua Washington <joshwash@google.com>,
 Harshitha Ramamurthy <hramamurthy@google.com>, Saeed Mahameed
 <saeedm@nvidia.com>, Tariq Toukan <tariqt@nvidia.com>, Mark Bloch
 <mbloch@nvidia.com>, Leon Romanovsky <leon@kernel.org>, Alexander Duyck
 <alexanderduyck@fb.com>, kernel-team@meta.com, Daniel Borkmann
 <daniel@iogearbox.net>, Nikolay Aleksandrov <razor@blackwall.org>, Shuah
 Khan <shuah@kernel.org>, netdev@vger.kernel.org, linux-doc@vger.kernel.org,
 linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
 bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, Stanislav Fomichev
 <sdf@fomichev.me>, Mina Almasry <almasrymina@google.com>, Bobby Eshleman
 <bobbyeshleman@meta.com>
Subject: Re: [PATCH net-next v2 2/6] net: devmem: support TX over
 NETMEM_TX_NO_DMA devices
Message-ID: <20260506193420.575e1806@kernel.org>
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On Mon, 04 May 2026 17:27:49 -0700 Bobby Eshleman wrote:
> +	if (bind_dev != netdev)
> +		netdev_lock(bind_dev);
> +	dma_dev = netdev_queue_get_dma_dev(bind_dev, 0, NETDEV_QUEUE_TYPE_TX);
> +	if (bind_dev != netdev)
> +		netdev_unlock(bind_dev);
> +	binding = net_devmem_bind_dmabuf(bind_dev,
> +					 bind_dev != netdev ? netdev : NULL,
> +					 dma_dev, DMA_TO_DEVICE, dmabuf_fd,
> +					 priv, info->extack);

Not sure if it matters but are we intentionally releasing the bind_dev
lock before calling net_devmem_bind_dmabuf() ? Previously more code here
was covered by the physical netdev's lock.