From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D58095383 for ; Fri, 5 May 2023 16:57:28 +0000 (UTC) Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB55E19922 for ; Fri, 5 May 2023 09:57:21 -0700 (PDT) Received: by mail-pl1-x629.google.com with SMTP id d9443c01a7336-1ab1ce53ca6so14495495ad.0 for ; Fri, 05 May 2023 09:57:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20221208.gappssmtp.com; s=20221208; t=1683305841; x=1685897841; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=MRnH3Cqyhep5CEq8cjj0HvIYZ//rx8xK1w3m3boBFtg=; b=Cyf/IQwjmN9nQoPYngzzVl136RZUda/4n2mxEslQE6sZXsNPA8HPj7FUmIk4yH/+Ul CGE5+hMHUuhvWiMrdhcQ/HHILkaTdCVWE2E1FFRP15KyTbmDfuaSgT46WsKX6jjnhdCc qZN4gR2llEQKeHIA3LEIWEO2NOvJd0J2Yv2QhCa8uDlEG4Z6y2RzMgVkL01DBdbuaqoE t7wEXYL4RYq3GDXOjJ5w3vEJguzJSKRMLOSN65oWtMlSTHjTj4gmbgwHmETw67ZtZINV 88UsYbpmdrEPjoEyvb7s9l3l5iSdgBRIPPuuERshVM37DqaUym8OWO4n72s9AR5DfuMD 4w1Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683305841; x=1685897841; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=MRnH3Cqyhep5CEq8cjj0HvIYZ//rx8xK1w3m3boBFtg=; b=YxrhgktEwUZ9zXNsmZ8kboMU2j5egn5q/32dDR+gIjUDTSEPzgPOtvnLikVPyncDCt 0FwMVwPe+w1NuySK5BvflvgbJQy32jarZ/ymYtMMc9I3hNTlwQsDdrJyscXFiT0Y9cHn Lob4AdOovEKjUKhFPv3sKG9NU1u53lpPUZud6HN7BlNcYOKv4tly7v4GqAhvLdFrPYKV +hJYu0KR2hvhpuxpNJVr3COs/volZF9zRpLAzL2vVkcllBbV9eLy7b7/TQr3Od5ql0If +SBVeCk+TGMbqyAcgRzfsPJQ7sRIFy7ZarPZ5bwKU1oO9TH222zDYj3nfScfm/a2Jn9E 5Row== X-Gm-Message-State: AC+VfDyWH0cSQ2A8WYr+zeczC66ofdryvKVrFtdscUP2rBFt6uMXHbU0 b83Q4ZmJUdkJPF4zYLXtRsFnKw== X-Google-Smtp-Source: ACHHUZ7LKP3CgdJgRxrVJzoZS412nCrFH/uVDLZE6eaj78oMi5iMd/a/L1rEOrB3ZxMOJ5q/i06cTg== X-Received: by 2002:a17:902:be01:b0:1a8:1c9a:f68 with SMTP id r1-20020a170902be0100b001a81c9a0f68mr1814959pls.36.1683305841239; Fri, 05 May 2023 09:57:21 -0700 (PDT) Received: from hermes.local (204-195-120-218.wavecable.com. [204.195.120.218]) by smtp.gmail.com with ESMTPSA id w1-20020a170902904100b001a69c1c78e7sm2017229plz.71.2023.05.05.09.57.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 May 2023 09:57:20 -0700 (PDT) Date: Fri, 5 May 2023 09:57:17 -0700 From: Stephen Hemminger To: Chuck Lever Cc: netdev@vger.kernel.org, linux-rdma@vger.kernel.org, BMT@zurich.ibm.com, tom@talpey.com Subject: Re: [PATCH RFC 2/3] net/lo: Ensure lo devices have a MAC address Message-ID: <20230505095717.6ad2b4ca@hermes.local> In-Reply-To: <168330135435.5953.3471584034284499194.stgit@oracle-102.nfsv4bat.org> References: <168330051600.5953.11366152375575299483.stgit@oracle-102.nfsv4bat.org> <168330135435.5953.3471584034284499194.stgit@oracle-102.nfsv4bat.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Fri, 05 May 2023 11:42:44 -0400 Chuck Lever wrote: > From: Chuck Lever > > A non-zero MAC address enables a network device to be assigned as > the underlying device for a virtual RDMA device. Without a non- > zero MAC address, cma_acquire_dev_by_src_ip() is unable to find the > underlying egress device that corresponds to a source IP address, > and rdma_resolve_address() fails. > > Signed-off-by: Chuck Lever > --- > drivers/net/loopback.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c > index f6d53e63ef4e..1ce4f19d8065 100644 > --- a/drivers/net/loopback.c > +++ b/drivers/net/loopback.c > @@ -192,6 +192,8 @@ static void gen_lo_setup(struct net_device *dev, > dev->needs_free_netdev = true; > dev->priv_destructor = dev_destructor; > > + eth_hw_addr_random(dev); > + > netif_set_tso_max_size(dev, GSO_MAX_SIZE); > } > > > > This enough of a change, it will probably break somebody. If you need dummy endpoint (ie multiple loopback), a common way is to use dummy devices for that.