From patchwork Tue Nov 5 00:42:24 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bart Van Assche X-Patchwork-Id: 11226767 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8143216B1 for ; Tue, 5 Nov 2019 00:42:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FF3D20848 for ; Tue, 5 Nov 2019 00:42:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729917AbfKEAmi (ORCPT ); Mon, 4 Nov 2019 19:42:38 -0500 Received: from mail-pf1-f196.google.com ([209.85.210.196]:41095 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729789AbfKEAmh (ORCPT ); Mon, 4 Nov 2019 19:42:37 -0500 Received: by mail-pf1-f196.google.com with SMTP id p26so13811282pfq.8 for ; Mon, 04 Nov 2019 16:42:37 -0800 (PST) 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=wEnkeVoKnv2xbcigffre63HlK0AiI3h+8776ByTgGcE=; b=Yv9dQgDOkrCItVFMpE+/Q7jZCkrWY4TrjEoVH0K/PM3juHzlBxc4l1NZeh6Xye2F4V CvoPNas152lC2aeYoeILC/LZWBN1/6FS02X19hpUTTh6NPrfZeQ/+5QRZMGE8bSTADXM WS/Fn88iKb6QWgw5qMfOvbfPD8S0cI79mY6IDWCvRtgTpu0DJ5RCfrfY5bHrFFUf7Htl fxiORlSR30ygCjt4Q2BhNN3K+iZFmbg4lUIuFnDnUldqOvkjMGZRAlesY3LoNBt0+VR6 qmHceDgveR0S84KFXGnTzv7yvi4XBdBf3mWnEIz5zIY1tix+4kevneP5PJeQozl9REWd OiUw== X-Gm-Message-State: APjAAAWLTdHOwBik12DYlCR3H66CVVKclkDy+IjZ+t8x9Ui+Q0Py34fY eXWg+fxZClRA+6CwktkQWIo= X-Google-Smtp-Source: APXvYqyGN2KzKdisc58nAmq26TAQYCXw+9M5ZQW7cXO9sHF6mcJ3SGeRs4N0xxR0ReLcTWexJitopg== X-Received: by 2002:a62:6385:: with SMTP id x127mr35317365pfb.244.1572914556819; Mon, 04 Nov 2019 16:42:36 -0800 (PST) Received: from desktop-bart.svl.corp.google.com ([2620:15c:2cd:202:4308:52a3:24b6:2c60]) by smtp.gmail.com with ESMTPSA id a21sm4235449pjv.20.2019.11.04.16.42.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Nov 2019 16:42:36 -0800 (PST) From: Bart Van Assche To: Avri Altman , "James E . J . Bottomley" Cc: "Martin K . Petersen" , linux-scsi@vger.kernel.org, Christoph Hellwig , Bart Van Assche , Yaniv Gardi , Subhash Jadavani , Stanley Chu , Tomas Winkler Subject: [PATCH RFC v2 3/5] ufs: Avoid busy-waiting by eliminating tag conflicts Date: Mon, 4 Nov 2019 16:42:24 -0800 Message-Id: <20191105004226.232635-4-bvanassche@acm.org> X-Mailer: git-send-email 2.24.0.rc1.363.gb1bccd3e3d-goog In-Reply-To: <20191105004226.232635-1-bvanassche@acm.org> References: <20191105004226.232635-1-bvanassche@acm.org> MIME-Version: 1.0 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 | 124 ++++++++++++++++---------------------- drivers/scsi/ufs/ufshcd.h | 9 +-- 2 files changed, 57 insertions(+), 76 deletions(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 3e3c6257a343..c8124db6665e 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 +1596,29 @@ 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; + + if (reserved) + return true; + (*busy)++; + return false; +} + +/* + * Whether or not any non-reserved 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 +1642,7 @@ 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 +1696,7 @@ 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 +2466,9 @@ 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 +2489,6 @@ 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 +2634,6 @@ 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 +2646,8 @@ 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 +2661,11 @@ 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_OUT, 0); + if (IS_ERR(req)) + return PTR_ERR(req); + tag = req->tag - hba->nutmrs; + WARN_ON_ONCE(!ufshcd_valid_tag(hba, tag)); init_completion(&wait); lrbp = &hba->lrb[tag]; @@ -2712,8 +2689,7 @@ 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 +4808,6 @@ 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 +4829,6 @@ 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 +5757,8 @@ 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 +5768,11 @@ 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_OUT, 0); + if (IS_ERR(req)) + return PTR_ERR(req); + tag = req->tag - hba->nutmrs; + WARN_ON_ONCE(!ufshcd_valid_tag(hba, tag)); init_completion(&wait); lrbp = &hba->lrb[tag]; @@ -5868,8 +5846,7 @@ 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; } @@ -6165,9 +6142,6 @@ 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; @@ -6874,6 +6848,11 @@ 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; @@ -7506,6 +7485,10 @@ 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 @@ -8348,9 +8331,6 @@ 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;