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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C285CA9ECB for ; Thu, 31 Oct 2019 22:55:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E2E320862 for ; Thu, 31 Oct 2019 22:55:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728381AbfJaWzh (ORCPT ); Thu, 31 Oct 2019 18:55:37 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:39132 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728207AbfJaWzg (ORCPT ); Thu, 31 Oct 2019 18:55:36 -0400 Received: by mail-pl1-f194.google.com with SMTP id t12so3410637plo.6 for ; Thu, 31 Oct 2019 15:55:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=PYDrgCzhPi9ZmJz9epJ31IC3Mt69mb2vcSIa0K1oUbc=; b=GaLjItwtxqC9StwiO0FlexeJmPTm42il6yjqJpvpgfb8pUq/RCD/X5ZNwXQ0fUl4Oa n4h3SLqAkDKMKNZA0O+HczBuCHOgBqp3UCBK+yYlgw7k7qN6VYp583v2sHRaM5/VXGMi Usrh7ef2K2p/t8Kqujg+mmlvxfXcVjqS/NUPS68SyIMLJZ0QF3ZRFoTDj5oaeLsdtVQ0 Z7y4Q7V4WZoLeUl0TansycXs+Gh/1SxnxkGA6ttwAqgi+byAtSj+wG6hjJfWMG0iBsMt +W5NReTLUgcIhc7fGGUlyN0Bf366AL2gN6K9cuPhc002LSmFSznHL2LwDdq2jLf2nlJh rbfg== X-Gm-Message-State: APjAAAUzcN2c3YCygweeUvR1J6EL+/bzulaKDI3F3cBfJ5Snu+PYe9ba OokLh6iXKKybr6vkPTBjiiOGyNbd X-Google-Smtp-Source: APXvYqxc+liBQ/SwCjzZDDrJ/digN6FqjtcAdkj/VazmkbNdkoiNBVSrWjX5YHbXjrOqH6dwHdTD7Q== X-Received: by 2002:a17:902:aa82:: with SMTP id d2mr5243797plr.24.1572562535799; Thu, 31 Oct 2019 15:55:35 -0700 (PDT) Received: from desktop-bart.svl.corp.google.com ([2620:15c:2cd:202:4308:52a3:24b6:2c60]) by smtp.gmail.com with ESMTPSA id d139sm8391711pfd.162.2019.10.31.15.55.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 31 Oct 2019 15:55:34 -0700 (PDT) From: Bart Van Assche To: "Martin K . Petersen" , "James E . J . Bottomley" Cc: linux-scsi@vger.kernel.org, Christoph Hellwig , Bart Van Assche , Yaniv Gardi , Subhash Jadavani , Stanley Chu , Avri Altman , Tomas Winkler Subject: [PATCH 1/4] ufs: Avoid busy-waiting by eliminating tag conflicts Date: Thu, 31 Oct 2019 15:55:25 -0700 Message-Id: <20191031225528.233895-2-bvanassche@acm.org> X-Mailer: git-send-email 2.24.0.rc0.303.g954a862665-goog In-Reply-To: <20191031225528.233895-1-bvanassche@acm.org> References: <20191031225528.233895-1-bvanassche@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Instead of tracking which tags are in use in the ufs_hba.lrb_in_use bitmask, rely on the block layer tag allocation mechanism. This patch removes the following busy-waiting loop if ufshcd_issue_devman_upiu_cmd() and the block layer accidentally allocate the same tag for a SCSI request: * ufshcd_queuecommand() returns SCSI_MLQUEUE_HOST_BUSY. * The SCSI core requeues the SCSI command. Cc: Yaniv Gardi Cc: Subhash Jadavani Cc: Stanley Chu Cc: Avri Altman Cc: Tomas Winkler Signed-off-by: Bart Van Assche --- drivers/scsi/ufs/ufshcd.c | 117 +++++++++++++++----------------------- drivers/scsi/ufs/ufshcd.h | 9 +-- 2 files changed, 50 insertions(+), 76 deletions(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 9fc05a535624..da9677fb2d5d 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -497,8 +497,8 @@ static void ufshcd_print_tmrs(struct ufs_hba *hba, unsigned long bitmap) static void ufshcd_print_host_state(struct ufs_hba *hba) { dev_err(hba->dev, "UFS Host state=%d\n", hba->ufshcd_state); - dev_err(hba->dev, "lrb in use=0x%lx, outstanding reqs=0x%lx tasks=0x%lx\n", - hba->lrb_in_use, hba->outstanding_reqs, hba->outstanding_tasks); + dev_err(hba->dev, "outstanding reqs=0x%lx tasks=0x%lx\n", + hba->outstanding_reqs, hba->outstanding_tasks); dev_err(hba->dev, "saved_err=0x%x, saved_uic_err=0x%x\n", hba->saved_err, hba->saved_uic_err); dev_err(hba->dev, "Device power mode=%d, UIC link state=%d\n", @@ -1596,6 +1596,24 @@ int ufshcd_hold(struct ufs_hba *hba, bool async) } EXPORT_SYMBOL_GPL(ufshcd_hold); +static bool ufshcd_is_busy(struct request *req, void *priv, bool reserved) +{ + int *busy = priv; + + (*busy)++; + return false; +} + +/* Whether or not any tag is in use by a request that is in progress. */ +static bool ufshcd_any_tag_in_use(struct ufs_hba *hba) +{ + struct request_queue *q = hba->tag_alloc_queue; + int busy = 0; + + blk_mq_tagset_busy_iter(q->tag_set, ufshcd_is_busy, &busy); + return busy; +} + static void ufshcd_gate_work(struct work_struct *work) { struct ufs_hba *hba = container_of(work, struct ufs_hba, @@ -1619,7 +1637,7 @@ static void ufshcd_gate_work(struct work_struct *work) if (hba->clk_gating.active_reqs || hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL - || hba->lrb_in_use || hba->outstanding_tasks + || ufshcd_any_tag_in_use(hba) || hba->outstanding_tasks || hba->active_uic_cmd || hba->uic_async_done) goto rel_lock; @@ -1673,7 +1691,7 @@ static void __ufshcd_release(struct ufs_hba *hba) if (hba->clk_gating.active_reqs || hba->clk_gating.is_suspended || hba->ufshcd_state != UFSHCD_STATE_OPERATIONAL - || hba->lrb_in_use || hba->outstanding_tasks + || ufshcd_any_tag_in_use(hba) || hba->outstanding_tasks || hba->active_uic_cmd || hba->uic_async_done || ufshcd_eh_in_progress(hba)) return; @@ -2443,22 +2461,9 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) hba->req_abort_count = 0; - /* acquire the tag to make sure device cmds don't use it */ - if (test_and_set_bit_lock(tag, &hba->lrb_in_use)) { - /* - * Dev manage command in progress, requeue the command. - * Requeuing the command helps in cases where the request *may* - * find different tag instead of waiting for dev manage command - * completion. - */ - err = SCSI_MLQUEUE_HOST_BUSY; - goto out; - } - err = ufshcd_hold(hba, true); if (err) { err = SCSI_MLQUEUE_HOST_BUSY; - clear_bit_unlock(tag, &hba->lrb_in_use); goto out; } WARN_ON(hba->clk_gating.state != CLKS_ON); @@ -2479,7 +2484,6 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) err = ufshcd_map_sg(hba, lrbp); if (err) { lrbp->cmd = NULL; - clear_bit_unlock(tag, &hba->lrb_in_use); goto out; } /* Make sure descriptors are ready before ringing the doorbell */ @@ -2625,44 +2629,6 @@ static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba, return err; } -/** - * ufshcd_get_dev_cmd_tag - Get device management command tag - * @hba: per-adapter instance - * @tag_out: pointer to variable with available slot value - * - * Get a free slot and lock it until device management command - * completes. - * - * Returns false if free slot is unavailable for locking, else - * return true with tag value in @tag. - */ -static bool ufshcd_get_dev_cmd_tag(struct ufs_hba *hba, int *tag_out) -{ - int tag; - bool ret = false; - unsigned long tmp; - - if (!tag_out) - goto out; - - do { - tmp = ~hba->lrb_in_use; - tag = find_last_bit(&tmp, hba->nutrs); - if (tag >= hba->nutrs) - goto out; - } while (test_and_set_bit_lock(tag, &hba->lrb_in_use)); - - *tag_out = tag; - ret = true; -out: - return ret; -} - -static inline void ufshcd_put_dev_cmd_tag(struct ufs_hba *hba, int tag) -{ - clear_bit_unlock(tag, &hba->lrb_in_use); -} - /** * ufshcd_exec_dev_cmd - API for sending device management requests * @hba: UFS hba @@ -2675,6 +2641,8 @@ static inline void ufshcd_put_dev_cmd_tag(struct ufs_hba *hba, int tag) static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, enum dev_cmd_type cmd_type, int timeout) { + struct request_queue *q = hba->tag_alloc_queue; + struct request *req; struct ufshcd_lrb *lrbp; int err; int tag; @@ -2688,7 +2656,10 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, * Even though we use wait_event() which sleeps indefinitely, * the maximum wait time is bounded by SCSI request timeout. */ - wait_event(hba->dev_cmd.tag_wq, ufshcd_get_dev_cmd_tag(hba, &tag)); + req = blk_get_request(q, REQ_OP_DRV_IN, 0); + if (IS_ERR(req)) + return PTR_ERR(req); + tag = req->tag; init_completion(&wait); lrbp = &hba->lrb[tag]; @@ -2712,8 +2683,7 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, err ? "query_complete_err" : "query_complete"); out_put_tag: - ufshcd_put_dev_cmd_tag(hba, tag); - wake_up(&hba->dev_cmd.tag_wq); + blk_put_request(req); up_read(&hba->clk_scaling_lock); return err; } @@ -4832,7 +4802,6 @@ static void __ufshcd_transfer_req_compl(struct ufs_hba *hba, cmd->result = result; /* Mark completed command as NULL in LRB */ lrbp->cmd = NULL; - clear_bit_unlock(index, &hba->lrb_in_use); /* Do not touch lrbp after scsi done */ cmd->scsi_done(cmd); __ufshcd_release(hba); @@ -4854,9 +4823,6 @@ static void __ufshcd_transfer_req_compl(struct ufs_hba *hba, hba->outstanding_reqs ^= completed_reqs; ufshcd_clk_scaling_update_busy(hba); - - /* we might have free'd some tags above */ - wake_up(&hba->dev_cmd.tag_wq); } /** @@ -5785,6 +5751,8 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba, enum dev_cmd_type cmd_type, enum query_opcode desc_op) { + struct request_queue *q = hba->tag_alloc_queue; + struct request *req; struct ufshcd_lrb *lrbp; int err = 0; int tag; @@ -5794,7 +5762,10 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba, down_read(&hba->clk_scaling_lock); - wait_event(hba->dev_cmd.tag_wq, ufshcd_get_dev_cmd_tag(hba, &tag)); + req = blk_get_request(q, REQ_OP_DRV_IN, 0); + if (IS_ERR(req)) + return PTR_ERR(req); + tag = req->tag; init_completion(&wait); lrbp = &hba->lrb[tag]; @@ -5868,8 +5839,7 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba, } } - ufshcd_put_dev_cmd_tag(hba, tag); - wake_up(&hba->dev_cmd.tag_wq); + blk_put_request(req); up_read(&hba->clk_scaling_lock); return err; } @@ -6164,9 +6134,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) hba->lrb[tag].cmd = NULL; spin_unlock_irqrestore(host->host_lock, flags); - clear_bit_unlock(tag, &hba->lrb_in_use); - wake_up(&hba->dev_cmd.tag_wq); - out: if (!err) { err = SUCCESS; @@ -6873,6 +6840,11 @@ static int ufshcd_probe_hba(struct ufs_hba *hba) int ret; ktime_t start = ktime_get(); + ret = -ENOMEM; + hba->tag_alloc_queue = blk_mq_init_queue(&hba->host->tag_set); + if (!hba->tag_alloc_queue) + goto out; + ret = ufshcd_link_startup(hba); if (ret) goto out; @@ -7505,6 +7477,10 @@ static void ufshcd_hba_exit(struct ufs_hba *hba) ufshcd_setup_hba_vreg(hba, false); hba->is_powered = false; } + + if (hba->tag_alloc_queue) + blk_cleanup_queue(hba->tag_alloc_queue); + hba->tag_alloc_queue = NULL; } static int @@ -8346,9 +8322,6 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq) init_rwsem(&hba->clk_scaling_lock); - /* Initialize device management tag acquire wait queue */ - init_waitqueue_head(&hba->dev_cmd.tag_wq); - ufshcd_init_clk_gating(hba); ufshcd_init_clk_scaling(hba); diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h index e3593cce23c1..8fa33fb71237 100644 --- a/drivers/scsi/ufs/ufshcd.h +++ b/drivers/scsi/ufs/ufshcd.h @@ -212,13 +212,11 @@ struct ufs_query { * @type: device management command type - Query, NOP OUT * @lock: lock to allow one command at a time * @complete: internal commands completion - * @tag_wq: wait queue until free command slot is available */ struct ufs_dev_cmd { enum dev_cmd_type type; struct mutex lock; struct completion *complete; - wait_queue_head_t tag_wq; struct ufs_query query; }; @@ -480,7 +478,10 @@ struct ufs_stats { * @host: Scsi_Host instance of the driver * @dev: device handle * @lrb: local reference block - * @lrb_in_use: lrb in use + * @tag_alloc_queue: None of the exported block layer functions allows to + * allocate a tag directly from a tag set. The purpose of this request queue + * is to support allocating tags from hba->host->tag_set before any LUNs have + * been associated with this HBA. * @outstanding_tasks: Bits representing outstanding task requests * @outstanding_reqs: Bits representing outstanding transfer requests * @capabilities: UFS Controller Capabilities @@ -538,6 +539,7 @@ struct ufs_hba { struct Scsi_Host *host; struct device *dev; + struct request_queue *tag_alloc_queue; /* * This field is to keep a reference to "scsi_device" corresponding to * "UFS device" W-LU. @@ -558,7 +560,6 @@ struct ufs_hba { u32 ahit; struct ufshcd_lrb *lrb; - unsigned long lrb_in_use; unsigned long outstanding_tasks; unsigned long outstanding_reqs; -- 2.24.0.rc0.303.g954a862665-goog