From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj2-f1.google.com (mail-pj2-f1.google.com [74.125.227.129]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ED8B225392A for ; Tue, 11 Aug 2026 00:26:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.227.129 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786407972; cv=none; b=VJqOKYbNnqotCjJNkPe9vMY+B4Wfe15Mn570PZ4l6b7CGI9iGbnmF02SXjnGM3XAWWLgiMpq50np6lKBaLMxZKgTWNNscNGZmQ/qUsk/wdo1EpzVpsdASHAW2NJPcqa+Hrawqjnhj5zmrZi4Mptxcj8+lM5VSFi80h7+nCKcGuc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786407972; c=relaxed/simple; bh=P/fL8kGnlyscba7QW/lYS9gXhr6STGQSI5DJXPhuQoQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jHwHEYmRS1UDWNZkmPgeLvTgoFu9eFW6Xbb/B1dP2JgyeY/c9ovxrIiKfZc/LZF4IToKQSHaIXbuvQdr1M1hPrkF3dmAD+O3oq5U0pjil3b2gri4lLGVeiYEw2kFiG9L6fCqMMz/pcETkpIi34dwV0gJZRyX6dvaNj4T7/ngmS4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=P0qDMiqX; arc=none smtp.client-ip=74.125.227.129 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="P0qDMiqX" Received: by mail-pj2-f1.google.com with SMTP id 98e67ed59e1d1-383390e7584so296978a91.0 for ; Mon, 10 Aug 2026 17:26:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1786407970; x=1787012770; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=IhRbvmHYXhFQ9Cyt9TR3UOP/9MRjlVWpX8ibWI5vEl4=; b=P0qDMiqXSqFDLAqwFKu6JsOfNIXkrWDOB6TM77m0bxZuQ3vtj7gT/1lphoWthjyYaf 87ZGqjzU/UFnkRJcQ9IoYQWuAMGmIUDAhKYyTk6nIXn9Uh/2FC2GTFb6kbANs9HYcYjf P4RrEs4ufPqQDvGAIfS0cE7Ve3OYjG7rPGrO3ls7UnJM0DVzcMnkTcr5wxgknBLwNgv/ NtD6/4Du7NXjAMVIZ6M7E7lri2u9k0yjSR1yZaGAXp/iK7zp4j8yTgEGS9mCV8DSKTqs QiejSsbLMevb1bZwtWbBFyRFLdnHBHv4y/z2olMMISYJTNXjOvr/FdYFbziSHRxiBQi7 pcxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786407970; x=1787012770; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=IhRbvmHYXhFQ9Cyt9TR3UOP/9MRjlVWpX8ibWI5vEl4=; b=cKoys/DHLMspGijf9US+bP17XizVlbTLYwslj/9zJKs8OWbn9jXFUn0oXfR1IdkOKk jhMNDFgy1jlL6amf7XrAdvLp8M3tYCe+L2MX3TPqXwJmU/CYMBNrHM6UGsvPd5h0QDLT ZmarVa4FG0n/jdA8asfo3WtJKTHCIpMXdgT1Eb/8oZVMLNaMHkLn3bvra5pH1bqoLY0L Rj+6mki3UGQIVcGi5omzidtpIT846c4mHZ4XSAUBx6UslNGuaJ+nWK5P6gW2WFOY08cv BMaONvDdoUXe6bO/4ecO+iAs09kY2/hvnxK8H0YY5r9ofbzJCG1eG5UqSgjMoWzZRKr7 dBaA== X-Forwarded-Encrypted: i=1; AHgh+Rr/URkezB88Yr+3fNbHLfEer/C1xx0WRJk4Ijy5lUyt6S9kcvJCrTmfdsRCJjiT75DVyS/Kwo/Ll/CPlM8=@vger.kernel.org X-Gm-Message-State: AOJu0YxG2UtpdNgc7qK9FpqA6GVxM5Bxe7n22Nvx/w+3S3rNc+sxS43c VuuG/74rKHhhZG3TQQno3ReiKJuKTYukMh3z0d19GF+PQHSOv3N+mbcP X-Gm-Gg: AR+sD105/zBX3KNDSI7+UAaty7vWi4ERRiVDlPVglkqtZIpsnwdqYqOVAHL13oSkaYP 8vCpVPm1DRxOzdhVFM5u+j12jGG60QNPMUHUIqqNksRcEa2kidDs9J9baqHxNUxo+TLgrT7jvAz vvVlHF+/9qdG2G0eyUCdubSclwl4KQqsTalCnb8LB5sCFRBvzFTxSNTSTYiVa/H7Qy8TVtLoJcf qc4WZYegjScNnviBkZe2iS610TnZoL96hvzmZqDE6yyKhwHultqDFB4q9IK6XUqCwDieT6Frpbp pIws1OvpOCUNNONk0zSCyS95OD1gxP4Noev/yVzbv/aQ6zWX6AJ1usMlV7xnqquvZ/JcWbTBtWC +/il7gYNbzwyrX3HGWUpX3cJ7jPn3Ic1jvpo6B+oaQgUyzwGRUdwxIxkQiK2Ss6T2XRYvUX6D93 KcLb7fMuhWLGK499kkdXdlxHTYKcf9bFcEYv/IkMbUxzsuGyU0jE9zyQ== X-Received: by 2002:a17:90b:2d0e:b0:390:b3c5:e2c9 with SMTP id 98e67ed59e1d1-392d61cf225mr976242a91.17.1786407970093; Mon, 10 Aug 2026 17:26:10 -0700 (PDT) Received: from localhost ([2a03:2880:2ff:4c::]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-392d4050827sm1306069a91.2.2026.08.10.17.26.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 10 Aug 2026 17:26:09 -0700 (PDT) Date: Mon, 10 Aug 2026 17:25:54 -0700 From: Stanislav Fomichev To: Dragos Tatulea Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , tariqt@nvidia.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next] net: devmem: add netdev_has_dmabuf_binding() helper Message-ID: References: <20260810175446.3945358-2-dtatulea@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260810175446.3945358-2-dtatulea@nvidia.com> On 08/10, Dragos Tatulea wrote: > Currently there is no way to check if there is a dmabuf bound on a TX > queue. RX side has netif_rxq_has_unreadable_mp() which gives a hint of > it. > > To help with that, this patch add a helper to check whether a devmem > dmabuf binding is active on a given netdev, optionally filtered by the > DMA device the dmabuf was mapped against. > > This API is necessary for the upcoming support of data direct in mlx5e > to allow blocking accidental swapping of DMA devices while devmem is active. > > Signed-off-by: Dragos Tatulea > --- > include/net/netmem.h | 19 +++++++++++++++++++ > net/core/devmem.c | 20 ++++++++++++++++++++ > 2 files changed, 39 insertions(+) > > diff --git a/include/net/netmem.h b/include/net/netmem.h > index bccacd21b6c3..0e332e04ea16 100644 > --- a/include/net/netmem.h > +++ b/include/net/netmem.h > @@ -363,16 +363,35 @@ static inline unsigned long netmem_get_dma_addr(netmem_ref netmem) > return netmem_to_nmdesc(netmem)->dma_addr; > } > > +struct net_device; > + > #if defined(CONFIG_NET_DEVMEM) > static inline bool net_is_devmem_iov(const struct net_iov *niov) > { > return niov->type == NET_IOV_DMABUF; > } > + > +/** > + * netdev_has_dmabuf_binding - is there a dmabuf binding for a > + * given @dev and @dma_dev > + * > + * @dev: netdev to check bindings > + * @dma_dev: dma device to check, when NULL it will not be checked > + * > + * Return: true if a binding is found under @dev and possibily @dma_dev > + */ > +bool netdev_has_dmabuf_binding(struct net_device *dev, struct device *dma_dev); > #else > static inline bool net_is_devmem_iov(const struct net_iov *niov) > { > return false; > } > + > +static inline bool netdev_has_dmabuf_binding(struct net_device *dev, > + struct device *dma_dev) > +{ > + return false; > +} > #endif > > void __get_netmem(netmem_ref netmem); > diff --git a/net/core/devmem.c b/net/core/devmem.c > index 957d6b96216b..f13a0e343684 100644 > --- a/net/core/devmem.c > +++ b/net/core/devmem.c > @@ -364,6 +364,26 @@ struct net_devmem_dmabuf_binding *net_devmem_lookup_dmabuf(u32 id) > return binding; > } > > +bool netdev_has_dmabuf_binding(struct net_device *dev, struct device *dma_dev) > +{ > + struct net_devmem_dmabuf_binding *binding; > + unsigned long id; > + bool found = false; xmas tree. Other than that LGTM. Presumably it's better to ship via your upcoming series to show the actual usage?