From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by dpdk.org (Postfix) with ESMTP id 753F01B4E3 for ; Tue, 26 Jun 2018 14:09:22 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Jun 2018 05:09:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,274,1526367600"; d="scan'208";a="67373272" Received: from aburakov-mobl.ger.corp.intel.com (HELO [10.237.220.28]) ([10.237.220.28]) by fmsmga001.fm.intel.com with ESMTP; 26 Jun 2018 05:09:18 -0700 To: Qi Zhang , thomas@monjalon.net Cc: konstantin.ananyev@intel.com, dev@dpdk.org, bruce.richardson@intel.com, ferruh.yigit@intel.com, benjamin.h.shelton@intel.com, narender.vangati@intel.com References: <20180607123849.14439-1-qi.z.zhang@intel.com> <20180626070832.3055-1-qi.z.zhang@intel.com> <20180626070832.3055-7-qi.z.zhang@intel.com> From: "Burakov, Anatoly" Message-ID: <969f0cb7-4186-d05c-442f-6341f1c44e93@intel.com> Date: Tue, 26 Jun 2018 13:09:17 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180626070832.3055-7-qi.z.zhang@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v4 06/24] ethdev: enable hotplug on multi-process X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 26 Jun 2018 12:09:23 -0000 On 26-Jun-18 8:08 AM, Qi Zhang wrote: > We are going to introduce the solution to handle different hotplug > cases in multi-process situation, it include below scenario: > > 1. Attach a share device from primary > 2. Detach a share device from primary > 3. Attach a share device from secondary > 4. Detach a share device from secondary > 5. Attach a private device from secondary > 6. Detach a private device from secondary > 7. Detach a share device from secondary privately > 8. Attach a share device from secondary privately > > In primary-secondary process model, we assume device is shared by default. > that means attach or detach a device on any process will broadcast to > all other processes through mp channel then device information will be > synchronized on all processes. > > Any failure during attaching process will cause inconsistent status > between processes, so proper rollback action should be considered. > Also it is not safe to detach a share device when other process still use > it, so a handshake mechanism is introduced. > > This patch covers the implementation of case 1,2,5,6,7,8. > Case 3,4 will be implemented on separate patch as well as handshake > mechanism. > > Scenario for Case 1, 2: > > attach device > a) primary attach the new device if failed goto h). > b) primary send attach sync request to all secondary. > c) secondary receive request and attach device and send reply. > d) primary check the reply if all success go to i). > e) primary send attach rollback sync request to all secondary. > f) secondary receive the request and detach device and send reply. > g) primary receive the reply and detach device as rollback action. > h) attach fail > i) attach success > > detach device > a) primary perform pre-detach check, if device is locked, goto i). > b) primary send pre-detach sync request to all secondary. > c) secondary perform pre-detach check and send reply. > d) primary check the reply if any fail goto i). > e) primary send detach sync request to all secondary > f) secondary detach the device and send reply (assume no fail) > g) primary detach the device. > h) detach success > i) detach failed > > Case 5, 6: > Secondary process can attach private device which only visible to itself, > in this case no IPC is involved, primary process is not allowed to have > private device so far. > > Case 7, 8: > Secondary process can also temporally to detach a share device "privately" > then attach it back later, this action also not impact other processes. > > APIs changes: > > rte_eth_dev_attach and rte_eth_dev_attach are extended to support > share device attach/detach in primary-secondary process model, it will > be called in case 1,2,3,4. > > New API rte_eth_dev_attach_private and rte_eth_dev_detach_private are > introduced to cover case 5,6,7,8, this API can only be invoked in secondary > process. > > Signed-off-by: Qi Zhang > --- > +static int > +handle_primary_request(const struct rte_mp_msg *msg, const void *peer) > +{ > + > + struct rte_mp_msg mp_resp; > + const struct eth_dev_mp_req *req = > + (const struct eth_dev_mp_req *)msg->param; > + struct eth_dev_mp_req *resp = > + (struct eth_dev_mp_req *)mp_resp.param; > + struct mp_reply_bundle *bundle; > + int ret = 0; > + > + memset(&mp_resp, 0, sizeof(mp_resp)); > + strlcpy(mp_resp.name, ETH_DEV_MP_ACTION_REQUEST, sizeof(mp_resp.name)); > + mp_resp.len_param = sizeof(*req); > + memcpy(resp, req, sizeof(*resp)); > + > + bundle = calloc(1, sizeof(*bundle)); > + if (bundle == NULL) { > + resp->result = -ENOMEM; > + ret = rte_mp_reply(&mp_resp, peer); > + if (ret) { > + ethdev_log(ERR, "failed to send reply to primary request\n"); > + return ret; > + } > + } > + > + bundle->msg = *msg; > + bundle->peer = peer; > + > + ret = rte_eal_mp_task_add(__handle_primary_request, bundle); > + if (ret) { > + resp->result = ret; > + ret = rte_mp_reply(&mp_resp, peer); > + if (ret) { > + ethdev_log(ERR, "failed to send reply to primary request\n"); > + return ret; > + } > + } What you're doing here is quite dangerous. The parameter "const void *peer" is only guaranteed to be valid at the time of the callback - not necessarily afterwards. So, if you're handing off sending replies to a separate thread, things might blow up because the pointer may no longer be valid. -- Thanks, Anatoly