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 83664CF9C5B for ; Tue, 24 Sep 2024 02:50:11 +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:From:References:Cc:To: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=s8jtEhjla4zGgMqrcoXbIG3PeBG54I0VUnvuWBCltvM=; b=r/ejRY4EIoDUOkYgbrZMcQm5ST Tvt1/lUZC62QVYojIdDh5IpPK1nADT8k2TI9XEn5yGj1abX821u+XsTBTf6c77EOUSprTfnZegLxG KSb1OpB/tsgSxHtmeFzsRLbgkP39K0h788QOFI+Kr3EKEWTnMl7If380SDRLtIMIXBYVrjBRSAujJ VGNdqvYHt1O285GKRrq+4J2QBa255/Bida1TWbMrpqXplJ3BE1XQ8UgRVZPrjL4RSNdWKev4V/Xmb LlbWFBg7N7qfLEGdDMLhYqrhkyMRoTpEJWH0l6gP3iZbUKtVx5/gD4qjNWWs/El73moP2LBYRUaMD PaRpcYIQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1ssvcs-00000000vIf-3dch; Tue, 24 Sep 2024 02:50:06 +0000 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1ssvcq-00000000vHv-1BZj for linux-nvme@lists.infradead.org; Tue, 24 Sep 2024 02:50:05 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1727146202; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=s8jtEhjla4zGgMqrcoXbIG3PeBG54I0VUnvuWBCltvM=; b=KQt++YaBBx01l4+GaekHY2Q39Y5b1p+CRFUQR9djokM53bT79HSWpgHCIIm6xchyZmFmqLDXU01+M0lBTw3Nzyyu7NJd/ZyWa+rhJpm5I5hRrg43BNZU8CgvVkA7n1h8DPpYOlqgehxMSvvN1GWOMK+uDw6E93A6fim/RJLwGuM= Received: from 30.178.83.97(mailfrom:kanie@linux.alibaba.com fp:SMTPD_---0WFeKN0A_1727146200) by smtp.aliyun-inc.com; Tue, 24 Sep 2024 10:50:01 +0800 Message-ID: <114ce6b1-13e7-418e-bd23-8ab32a7b4c8f@linux.alibaba.com> Date: Tue, 24 Sep 2024 10:49:58 +0800 MIME-Version: 1.0 User-Agent: =?UTF-8?B?TW96aWxsYSBUaHVuZGVyYmlyZCDmtYvor5XniYg=?= Subject: Re: [PATCH v9 1/1] nvmet: support reservation feature 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> From: Guixin Liu In-Reply-To: <20240923163228.GD22571@yadro.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_195004_669118_5493D2C8 X-CRM114-Status: GOOD ( 24.58 ) 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 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. >> + 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; >> +} >> +