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Mon, 25 Sep 2023 11:50:23 GMT Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CE75320043; Mon, 25 Sep 2023 11:50:22 +0000 (GMT) Received: from smtpav01.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9433F20040; Mon, 25 Sep 2023 11:50:22 +0000 (GMT) Received: from [9.152.224.54] (unknown [9.152.224.54]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 25 Sep 2023 11:50:22 +0000 (GMT) Message-ID: <3febdf3e-e213-7acf-7dd4-75d177676c3e@linux.ibm.com> Date: Mon, 25 Sep 2023 13:50:22 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH net-next v4 09/18] net/smc: introduce SMC-D loopback device Content-Language: en-US To: Wen Gu , kgraul@linux.ibm.com, wenjia@linux.ibm.com, jaka@linux.ibm.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: schnelle@linux.ibm.com, gbayer@linux.ibm.com, pasic@linux.ibm.com, alibuda@linux.alibaba.com, tonylu@linux.alibaba.com, dust.li@linux.alibaba.com, linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <1695568613-125057-1-git-send-email-guwen@linux.alibaba.com> <1695568613-125057-10-git-send-email-guwen@linux.alibaba.com> From: Alexandra Winter In-Reply-To: <1695568613-125057-10-git-send-email-guwen@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: t_8wHPH4AWvOWU9GE8aKNKofI0SNlpax X-Proofpoint-GUID: RlZnKHlCw6vIphuA58WF_Icozxk9YcXO X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.980,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-09-25_08,2023-09-25_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 lowpriorityscore=0 clxscore=1015 priorityscore=1501 adultscore=0 impostorscore=0 phishscore=0 spamscore=0 mlxlogscore=577 suspectscore=0 mlxscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2309180000 definitions=main-2309250086 X-Spam-Status: No, score=-3.5 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_PASS 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 24.09.23 17:16, Wen Gu wrote: > This patch introduces a kind of loopback device for SMC-D. The device > is created when SMC module is loaded and destroyed when the SMC module > is unloaded. The loopback device is a kernel device used only by the > SMC module and is not restricted by net namespace, so it can be used > for local inter-process or inter-container communication. > > Signed-off-by: Wen Gu > --- > net/smc/Kconfig | 13 ++++ > net/smc/Makefile | 2 +- > net/smc/af_smc.c | 12 +++- > net/smc/smc_loopback.c | 165 +++++++++++++++++++++++++++++++++++++++++++++++++ > net/smc/smc_loopback.h | 33 ++++++++++ > 5 files changed, 223 insertions(+), 2 deletions(-) > create mode 100644 net/smc/smc_loopback.c > create mode 100644 net/smc/smc_loopback.h Hello Wen Gu, thank you for adding the Kconfig, so the distributions can decide when to offer this feature. I propose you add some kind of runtime switch as well. Not every user who loads the SMC module may want to exploit smcd-loopback. Especially in native environements without containers. If no RoCE interfaces or no ISM interfaces exist, the respective handling is skipped in SMC. If loopback is always created unconditionally, there is no way to opt-out.