From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 45706CF9C72 for ; Tue, 24 Sep 2024 06:38:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:References:Cc:To:From:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=EvGTGjJSWJclu4eLEDzFU9FIDGDCYQNcXw5pUd3mJoY=; b=toIcW9bZUHjQ491uxnK2UHUXTl S390xuRi0CC44Omrx98F3A3VkF7Uz7sVpDYPSLiKQT3gdef8p9RtOK5jO5HuHcUQooaAkxyJqNWT4 95lUpO06Om0/yvHfK3+RT8pbgqPx5kNxQdMZeWt8hT2A0vzaMCJGTinwNwFEw18rlHWz6f8K44WGH yHohcxe93yLVSX7sONFtytfp0nrUH8TuHLUVaQh8XnqghBZReod/fngdfFjuZKf0RAbm6WO//MuZa YbHK9BobClfEN7PP9Oqjq3GPNc7sII5hVrKcX8dKk3womSlwnMFGGwr5cPfxvJwaQztvV87pZJxfS HltTlf2g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1sszCF-00000001HAL-29Np; Tue, 24 Sep 2024 06:38:51 +0000 Received: from out30-100.freemail.mail.aliyun.com ([115.124.30.100]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1sszCC-00000001H93-0diA for linux-nvme@lists.infradead.org; Tue, 24 Sep 2024 06:38:50 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1727159924; h=Message-ID:Date:MIME-Version:Subject:From:To:Content-Type; bh=EvGTGjJSWJclu4eLEDzFU9FIDGDCYQNcXw5pUd3mJoY=; b=VLWml6jd/1Z0bfG3fB1H2WkuERRSTEnLij3oID71zqcKcVefMWpY7jx1iXzL6R2g+Z0GZQ0OjPxfqIsi0YRJ3ux+Vlt6IVA5FPZoFCUrrEEBn3P3ouWaDvHYK5eQzWuE71vL/Urglf+5d+S5Y5nBu9aFLz/b1queC7MAVWNCkwU= Received: from 30.178.83.97(mailfrom:kanie@linux.alibaba.com fp:SMTPD_---0WFf1vOo_1727159922) by smtp.aliyun-inc.com; Tue, 24 Sep 2024 14:38:43 +0800 Message-ID: <0cddf902-9e60-43ca-b138-630c5485efa0@linux.alibaba.com> Date: Tue, 24 Sep 2024 14:38:40 +0800 MIME-Version: 1.0 User-Agent: =?UTF-8?B?TW96aWxsYSBUaHVuZGVyYmlyZCDmtYvor5XniYg=?= Subject: Re: [PATCH v9 1/1] nvmet: support reservation feature From: Guixin Liu To: Dmitry Bogdanov Cc: hch@lst.de, sagi@grimberg.me, kch@nvidia.com, linux-nvme@lists.infradead.org References: <20240923094708.42445-1-kanie@linux.alibaba.com> <20240923094708.42445-2-kanie@linux.alibaba.com> <20240923163228.GD22571@yadro.com> <114ce6b1-13e7-418e-bd23-8ab32a7b4c8f@linux.alibaba.com> <20240924055433.GE22571@yadro.com> <3b315daf-76a6-4360-aeac-65def22aa196@linux.alibaba.com> In-Reply-To: <3b315daf-76a6-4360-aeac-65def22aa196@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240923_233848_704700_7B7A3601 X-CRM114-Status: GOOD ( 18.50 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org 在 2024/9/24 14:18, Guixin Liu 写道: > > 在 2024/9/24 13:54, Dmitry Bogdanov 写道: >> On Tue, Sep 24, 2024 at 10:49:58AM +0800, Guixin Liu wrote: >>> 在 2024/9/24 00:32, Dmitry Bogdanov 写道: >>>>> This patch implements the reservation feature, includes: >>>>> 1. reservation register(register, unregister and replace). >>>>> 2. reservation acquire(acquire, preempt, preempt and abort). >>>>> 3. reservation release(release and clear). >>>>> 4. reservation report. >>>>> 5. set feature and get feature of reservation notify mask. >>>>> 6. get log page of reservation event. >>>>> >>>>> And also make reservation configurable, one can set ns to support >>>>> reservation before enable ns. The default of resv_enable is false. >>>>> >>>>> Signed-off-by: Guixin Liu >>>>> --- >>>>>    drivers/nvme/target/Makefile    |    2 +- >>>>>    drivers/nvme/target/admin-cmd.c |   24 +- >>>>>    drivers/nvme/target/configfs.c  |   27 + >>>>>    drivers/nvme/target/core.c      |   58 +- >>>>>    drivers/nvme/target/nvmet.h     |   49 ++ >>>>>    drivers/nvme/target/pr.c        | 1214 >>>>> +++++++++++++++++++++++++++++++ >>>>>    include/linux/nvme.h            |   54 ++ >>>>>    7 files changed, 1419 insertions(+), 9 deletions(-) >>>>>    create mode 100644 drivers/nvme/target/pr.c >>>> ... >>>>> + >>>>> +static void nvmet_pr_unregister_one(struct nvmet_pr *pr, >>>>> +                                   struct nvmet_pr_registrant *reg) >>>>> +{ >>>>> +       struct nvmet_pr_registrant *first_reg; >>>>> +       struct nvmet_pr_registrant *holder; >>>>> +       u8 original_rtype; >>>>> + >>>>> +       lockdep_assert_held(&pr->pr_lock); >>>>> +       list_del_rcu(®->entry); >>>>> + >>>>> +       holder = rcu_dereference_protected(pr->holder, >>>>> + lockdep_is_held(&pr->pr_lock)); >>>>> +       if (reg != holder) >>>>> +               goto out; >>>>> + >>>>> +       original_rtype = holder->rtype; >>>>> +       if (original_rtype == NVME_PR_WRITE_EXCLUSIVE_ALL_REGS || >>>>> +           original_rtype == NVME_PR_EXCLUSIVE_ACCESS_ALL_REGS) { >>>>> +               first_reg = >>>>> list_first_or_null_rcu(&pr->registrant_list, >>>>> +                               struct nvmet_pr_registrant, entry); >>>>> +               if (first_reg) >>>>> +                       first_reg->rtype = original_rtype; >>>>> +               rcu_assign_pointer(pr->holder, first_reg); >>>>> +       } else { >>>>> +               rcu_assign_pointer(pr->holder, NULL); >>>>> + >>>>> +               if (original_rtype == >>>>> NVME_PR_WRITE_EXCLUSIVE_REG_ONLY || >>>>> +                   original_rtype == >>>>> NVME_PR_WRITE_EXCLUSIVE_REG_ONLY) >>>> copy&past error? >>>> The second check should be against NVME_PR_EXCLUSIVE_ACCESS_REG_ONLY? >>> Indeed, my mistake, it will be fixed in v10. >>>>> + nvmet_pr_resv_released(pr, ®->hostid); >>>>> +       } >>>>> +out: >>>>> +       synchronize_rcu(); >>>>> +       kfree(reg); >>>>> +} >>>>> + >>>>> ...... >>>>> + >>>>> +static u16 nvmet_pr_preempt(struct nvmet_req *req, >>>>> +                           struct nvmet_pr_registrant *reg, >>>>> +                           u8 rtype, >>>>> +                           struct nvmet_pr_acquire_data *d, >>>>> +                           bool abort) >>>>> +{ >>>>> +       struct nvmet_ctrl *ctrl = req->sq->ctrl; >>>>> +       struct nvmet_pr *pr = &req->ns->pr; >>>>> +       struct nvmet_pr_registrant *holder; >>>>> +       enum nvme_pr_type original_rtype; >>>>> +       u64 prkey = le64_to_cpu(d->prkey); >>>>> +       u16 status; >>>>> + >>>>> +       lockdep_assert_held(&pr->pr_lock); >>>>> +       holder = rcu_dereference_protected(pr->holder, >>>>> + lockdep_is_held(&pr->pr_lock)); >>>>> +       if (!holder) >>>>> +               return nvmet_pr_unreg_all_host_by_prkey(req, prkey, >>>>> + &ctrl->hostid, abort); >>>>> + >>>>> +       original_rtype = holder->rtype; >>>>> +       if (original_rtype == NVME_PR_WRITE_EXCLUSIVE_ALL_REGS || >>>>> +           original_rtype == NVME_PR_EXCLUSIVE_ACCESS_ALL_REGS) { >>>>> +               if (!prkey) { >>>>> +                       nvmet_pr_unreg_all_others(req, >>>>> &ctrl->hostid, abort); >>>>> +                       nvmet_pr_set_new_holder(pr, rtype, reg); >>>> You didnot address the reservation atomicity here. You still remove an >>>> old holder and then after a some time you set the new holder. >>>> In this time gap an incomming WRITE command from a non holder will >>>> write >>>> to the media. >>> Right, I will change it in v10. >>>>> +                       return NVME_SC_SUCCESS; >>>>> +               } >>>>> +               return nvmet_pr_unreg_all_host_by_prkey(req, prkey, >>>>> +                               &ctrl->hostid, abort); >>>>> +       } >>>>> + >>>>> +       if (holder == reg) { >>>>> +               status = nvmet_pr_update_reg_attr(pr, holder, >>>>> + nvmet_pr_update_holder_rtype, &rtype); >>>>> +               if (!status && original_rtype != rtype) >>>>> +                       nvmet_pr_resv_released(pr, ®->hostid); >>>>> +               return status; >>>>> +       } >>>>> + >>>>> +       if (prkey == holder->rkey) { >>>>> +               status = nvmet_pr_unreg_all_others_by_prkey(req, >>>>> prkey, >>>>> + &ctrl->hostid, abort); >>>> And here too that timegap with released reservation. >>> I will fix this too, and also the >>> >>> nvmet_pr_unreg_all_others_by_prkey() does not need a return value, >>> >>> I remove it. >>> >>>>> +               if (status) >>>>> +                       return status; >>>>> + >>>>> +               nvmet_pr_set_new_holder(pr, rtype, reg); >>>>> +               if (original_rtype != rtype) >>>>> +                       nvmet_pr_resv_released(pr, ®->hostid); >>>> This function is(may be) already invoked in nvmet_pr_unregister_one. >>>> >>> Not, here the original_rtype is not NVME_PR_WRITE_EXCLUSIVE_REG_ONLY or >>> NVME_PR_EXCLUSIVE_ACCESS_ALL_REGS, so the nvmet_pr_unregister_one will >>> not call nvmet_pr_resv_released. >> nvmet_pr_unregister_one sends an event for original_rtype == *_REG_ONLY >> Here you have only original_rtype != ALL_REGS, so _REG_ONLY is possible. > My mistake, it will be removed in v10, thanks. I take a look again, if we set self new holder before call nvmet_pr_unreg_all_others_by_prkey(), the nvmet_pr_unreg_all_others_by_prkey() will not unregister self, so this will not goto nvmet_pr_unregister_one()'s calling nvmet_pr_resv_released(). >>>>> +               return status; >>>>> +       } >>>>> + >>>>> +       if (prkey) >>>>> +               return nvmet_pr_unreg_all_host_by_prkey(req, prkey, >>>>> + &ctrl->hostid, abort); >>>>> +       return NVME_SC_INVALID_FIELD | NVME_SC_DNR; >>>>> +} >>>>> + >>>>> +static void nvmet_pr_confirm_ns_pc_ref(struct percpu_ref *ref) >>>>> +{ >>>>> +       struct nvmet_pr_per_ctrl_ref *pc_ref = >>>>> +               container_of(ref, struct nvmet_pr_per_ctrl_ref, ref); >>>>> + >>>>> +       complete(&pc_ref->confirm_done); >>>>> +} >>>>> + >>>>> +static void nvmet_pr_do_abort(struct nvmet_req *req) >>>>> +{ >>>>> +       struct nvmet_subsys *subsys = req->sq->ctrl->subsys; >>>>> +       struct nvmet_pr_per_ctrl_ref *pc_ref; >>>>> +       struct nvmet_ctrl *ctrl = NULL; >>>>> + >>>>> +find_next: >>>>> +       mutex_lock(&subsys->lock); >>>>> +       list_for_each_entry(ctrl, &subsys->ctrls, subsys_entry) { >>>>> +               if (ctrl->pr_abort) >>>>> +                       goto do_abort; >>>>> +       } >>>>> +       mutex_unlock(&subsys->lock); >>>>> +       return; >>>>> + >>>>> +do_abort: >>>>> +       mutex_unlock(&subsys->lock); >>>>> +       /* >>>>> +        * The target dose not support abort, just wait ref to 0. >>>> typo "dose"->"does" >>>> >>> Sure. >>>>> +        */ >>>>> +       pc_ref = xa_load(&req->ns->pr_per_ctrl_refs, ctrl->cntlid); >>>>> +       percpu_ref_kill_and_confirm(&pc_ref->ref, >>>>> nvmet_pr_confirm_ns_pc_ref); >>>>> +       wait_for_completion(&pc_ref->confirm_done); >>>>> +       wait_for_completion(&pc_ref->free_done); >>>>> +       reinit_completion(&pc_ref->confirm_done); >>>>> +       reinit_completion(&pc_ref->free_done); >>>>> +       percpu_ref_resurrect(&pc_ref->ref); >>>>> + >>>>> +       ctrl->pr_abort = false; >>>> pr_abort flag is per controller, but this function is per namespace. >>>> The use case of preempt_and_abort is to preempt reservation of a >>>> "zomby" host >>>> for the all namespaces. It means that preempt_and_abort command >>>> will be sent >>>> for the each namespace and there will be several parallel abort >>>> processes for >>>> the same controllers. And you should not mix them. >>>> >>>> May be doing ref_kill instead of setting ctlr->pr_abort=true will more >>>> accuratelly set the barier for incoming IO. You may use Mark >>>> feature in >>>> XArrays to mark pc_ref to wait the completion for and use >>>> xa_for_each_marked >>>> for going through such pc_refs. >>> Good idea, thanks very much, will changed in v10. >>> >>> Best Regards, >>> >>> Guixin Liu >>> >>>>> +       nvmet_ctrl_put(ctrl); >>>>> +       goto find_next; >>>>> +} >>>>> + >>>>> +static u16 __nvmet_execute_pr_acquire(struct nvmet_req *req, >>>>> +                                     struct nvmet_pr_registrant >>>>> *reg, >>>>> +                                     u8 acquire_act, >>>>> +                                     u8 rtype, >>>>> +                                     struct nvmet_pr_acquire_data >>>>> *d) >>>>> +{ >>>>> +       u16 status; >>>>> + >>>>> +       switch (acquire_act) { >>>>> +       case NVME_PR_ACQUIRE_ACT_ACQUIRE: >>>>> +               status = nvmet_pr_acquire(req, reg, rtype); >>>>> +               goto out; >>>>> +       case NVME_PR_ACQUIRE_ACT_PREEMPT: >>>>> +               status = nvmet_pr_preempt(req, reg, rtype, d, false); >>>>> +               goto inc_gen; >>>>> +       case NVME_PR_ACQUIRE_ACT_PREEMPT_AND_ABORT: >>>>> +               status = nvmet_pr_preempt(req, reg, rtype, d, true); >>>>> +               if (!status) >>>>> +                       nvmet_pr_do_abort(req); >>>>> +               goto inc_gen; >>>>> +       default: >>>>> +               req->error_loc = offsetof(struct >>>>> nvme_common_command, cdw10); >>>>> +               status = NVME_SC_INVALID_OPCODE | NVME_SC_DNR; >>>>> +               goto out; >>>>> +       } >>>>> +inc_gen: >>>>> +       if (!status) >>>>> + atomic_inc(&req->ns->pr.generation); >>>>> +out: >>>>> +       return status; >>>>> +} >>>>> +