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[84.238.136.197]) by smtp.gmail.com with ESMTPSA id q15sm6224927wrf.87.2020.05.21.09.58.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 May 2020 09:58:07 -0700 (PDT) Subject: Re: [PATCH 1/3] bridge: mrp: Add br_mrp_unique_ifindex function To: Horatiu Vultur Cc: jiri@resnulli.us, ivecera@redhat.com, davem@davemloft.net, kuba@kernel.org, roopa@cumulusnetworks.com, andrew@lunn.ch, UNGLinuxDriver@microchip.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, bridge@lists.linux-foundation.org References: <20200520130923.3196432-1-horatiu.vultur@microchip.com> <20200520130923.3196432-2-horatiu.vultur@microchip.com> <20200521181337.ory6lxyswatqhoej@soft-dev3.localdomain> From: Nikolay Aleksandrov Message-ID: <39ba5110-2c2a-6fd9-a3e3-000b52a366dc@cumulusnetworks.com> Date: Thu, 21 May 2020 19:58:04 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200521181337.ory6lxyswatqhoej@soft-dev3.localdomain> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 21/05/2020 21:49, Horatiu Vultur wrote: > The 05/21/2020 11:16, Nikolay Aleksandrov wrote: >> On 20/05/2020 16:09, Horatiu Vultur wrote: >>> It is not allow to have the same net bridge port part of multiple MRP >>> rings. Therefore add a check if the port is used already in a different >>> MRP. In that case return failure. >>> >>> Fixes: 9a9f26e8f7ea ("bridge: mrp: Connect MRP API with the switchdev API") >>> Signed-off-by: Horatiu Vultur >>> --- >>> net/bridge/br_mrp.c | 31 +++++++++++++++++++++++++++++++ >>> 1 file changed, 31 insertions(+) >>> >>> diff --git a/net/bridge/br_mrp.c b/net/bridge/br_mrp.c >>> index d7bc09de4c139..a5a3fa59c078a 100644 >>> --- a/net/bridge/br_mrp.c >>> +++ b/net/bridge/br_mrp.c >>> @@ -37,6 +37,32 @@ static struct br_mrp *br_mrp_find_id(struct net_bridge *br, u32 ring_id) >>> return res; >>> } >>> >>> +static bool br_mrp_unique_ifindex(struct net_bridge *br, u32 ifindex) >>> +{ >>> + struct br_mrp *mrp; >>> + bool res = true; >>> + >>> + rcu_read_lock(); >> >> Why do you need the rcu_read_lock() here when lockdep_rtnl_is_held() is used? >> You should be able to just do rtnl_dereference() below as this is used only >> under rtnl. > > Hi Nik, > > Also initially I thought that is not needed, but when I enabled all the > RCU debug configs to see if I use correctly the RCU, I got a warning > regarding suspicious RCU usage. > And that is the reason why I have put it. > Did you try using rtnl_dereference() instead of rcu_dereference() ? >> >>> + list_for_each_entry_rcu(mrp, &br->mrp_list, list, >>> + lockdep_rtnl_is_held()) { >>> + struct net_bridge_port *p; >>> + >>> + p = rcu_dereference(mrp->p_port); >>> + if (p && p->dev->ifindex == ifindex) { >>> + res = false; >>> + break; >>> + } >>> + >>> + p = rcu_dereference(mrp->s_port); >>> + if (p && p->dev->ifindex == ifindex) { >>> + res = false; >>> + break; >>> + } >>> + } >>> + rcu_read_unlock(); >>> + return res; >>> +} >>> + >>> static struct br_mrp *br_mrp_find_port(struct net_bridge *br, >>> struct net_bridge_port *p) >>> { >>> @@ -255,6 +281,11 @@ int br_mrp_add(struct net_bridge *br, struct br_mrp_instance *instance) >>> !br_mrp_get_port(br, instance->s_ifindex)) >>> return -EINVAL; >>> >>> + /* It is not possible to have the same port part of multiple rings */ >>> + if (!br_mrp_unique_ifindex(br, instance->p_ifindex) || >>> + !br_mrp_unique_ifindex(br, instance->s_ifindex)) >>> + return -EINVAL; >>> + >>> mrp = kzalloc(sizeof(*mrp), GFP_KERNEL); >>> if (!mrp) >>> return -ENOMEM; >>> >> >