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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC085C433F5 for ; Tue, 30 Nov 2021 23:34:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241095AbhK3Xhu (ORCPT ); Tue, 30 Nov 2021 18:37:50 -0500 Received: from mail-pg1-f181.google.com ([209.85.215.181]:39566 "EHLO mail-pg1-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232973AbhK3Xht (ORCPT ); Tue, 30 Nov 2021 18:37:49 -0500 Received: by mail-pg1-f181.google.com with SMTP id r5so21486521pgi.6 for ; Tue, 30 Nov 2021 15:34:30 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=WtZRiMZiXejpaLTrbZn8XfgRNYsyVCWYUCazi6KKYBM=; b=XSarRX3Ai3x5qa5meInd74JygnoSf5knIbJryxtig8Zq7MhEbkTlJYQRTGgrvSBx2I +RfbMTFHJMNfmMBczQZpa9YtzVYc8vV7FdRL2rAySAmVEcPoxr5TBhqZwcbUFqTruXvc LRe9iogMHzuEKb+fQZ5akPwj6tzvMGNfFVrsCG7a1+aZTsiCsOSkDnzMETdYVHALIrNW NYEq0QbGDK9MS7fo78Mfw4IsJuzec2/1cII95R9jsgZjCApOJkcYN9ZqYYGY2LtV5gbC 3lw++JALM2N6PhoG9RHFBy8RXpxcH6JcBGsSDd/c6oF/7UbjhouDPKzIgMkhZULh/GJw SyXg== X-Gm-Message-State: AOAM5307CwAXm+vKBwWH7X2Dmxrg2LTkVrbnfQkFqKeR5UEOre7bNZi0 hCN/ShS8gxo7BYCEGiJC4Es= X-Google-Smtp-Source: ABdhPJxluhLseoBwqtUZPS/tm03gQMfYMuQahhtHJy7XhrWxCw++jOpkTlDk4ygSkLgkxmfUSmwNRw== X-Received: by 2002:a63:9:: with SMTP id 9mr1861652pga.91.1638315269600; Tue, 30 Nov 2021 15:34:29 -0800 (PST) Received: from bvanassche-linux.mtv.corp.google.com ([2620:15c:211:201:ef1f:f086:d1ba:8190]) by smtp.gmail.com with ESMTPSA id mu4sm4127187pjb.8.2021.11.30.15.34.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Nov 2021 15:34:29 -0800 (PST) From: Bart Van Assche To: "Martin K . Petersen" Cc: Jaegeuk Kim , linux-scsi@vger.kernel.org, Bart Van Assche , "James E.J. Bottomley" , Bean Huo , Avri Altman , Can Guo , Adrian Hunter , Stanley Chu , Asutosh Das , Keoseong Park Subject: [PATCH v3 10/17] scsi: ufs: Fix a deadlock in the error handler Date: Tue, 30 Nov 2021 15:33:17 -0800 Message-Id: <20211130233324.1402448-11-bvanassche@acm.org> X-Mailer: git-send-email 2.34.0.rc2.393.gf8c9666880-goog In-Reply-To: <20211130233324.1402448-1-bvanassche@acm.org> References: <20211130233324.1402448-1-bvanassche@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org The following deadlock has been observed on a test setup: * All tags allocated. * The SCSI error handler calls ufshcd_eh_host_reset_handler() * ufshcd_eh_host_reset_handler() queues work that calls ufshcd_err_handler() * ufshcd_err_handler() locks up as follows: Workqueue: ufs_eh_wq_0 ufshcd_err_handler.cfi_jt Call trace: __switch_to+0x298/0x5d8 __schedule+0x6cc/0xa94 schedule+0x12c/0x298 blk_mq_get_tag+0x210/0x480 __blk_mq_alloc_request+0x1c8/0x284 blk_get_request+0x74/0x134 ufshcd_exec_dev_cmd+0x68/0x640 ufshcd_verify_dev_init+0x68/0x35c ufshcd_probe_hba+0x12c/0x1cb8 ufshcd_host_reset_and_restore+0x88/0x254 ufshcd_reset_and_restore+0xd0/0x354 ufshcd_err_handler+0x408/0xc58 process_one_work+0x24c/0x66c worker_thread+0x3e8/0xa4c kthread+0x150/0x1b4 ret_from_fork+0x10/0x30 Fix this lockup by making ufshcd_exec_dev_cmd() allocate a reserved request. Signed-off-by: Bart Van Assche --- drivers/scsi/ufs/ufshcd.c | 53 +++++++++++---------------------------- drivers/scsi/ufs/ufshcd.h | 2 ++ 2 files changed, 16 insertions(+), 39 deletions(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 2d0f59424b00..da4714aaa850 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -128,8 +128,9 @@ EXPORT_SYMBOL_GPL(ufshcd_dump_regs); enum { UFSHCD_MAX_CHANNEL = 0, UFSHCD_MAX_ID = 1, - UFSHCD_CMD_PER_LUN = 32, - UFSHCD_CAN_QUEUE = 32, + UFSHCD_NUM_RESERVED = 1, + UFSHCD_CMD_PER_LUN = 32 - UFSHCD_NUM_RESERVED, + UFSHCD_CAN_QUEUE = 32 - UFSHCD_NUM_RESERVED, }; static const char *const ufshcd_state_name[] = { @@ -2170,6 +2171,7 @@ static inline int ufshcd_hba_capabilities(struct ufs_hba *hba) hba->nutrs = (hba->capabilities & MASK_TRANSFER_REQUESTS_SLOTS) + 1; hba->nutmrs = ((hba->capabilities & MASK_TASK_MANAGEMENT_REQUEST_SLOTS) >> 16) + 1; + hba->reserved_slot = hba->nutrs - 1; /* Read crypto capabilities */ err = ufshcd_hba_init_crypto_capabilities(hba); @@ -2912,30 +2914,15 @@ static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba, static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, enum dev_cmd_type cmd_type, int timeout) { - struct request_queue *q = hba->cmd_queue; DECLARE_COMPLETION_ONSTACK(wait); - struct request *req; + const u32 tag = hba->reserved_slot; struct ufshcd_lrb *lrbp; int err; - int tag; - down_read(&hba->clk_scaling_lock); + /* Protects use of hba->reserved_slot. */ + lockdep_assert_held(&hba->dev_cmd.lock); - /* - * Get free slot, sleep if slots are unavailable. - * Even though we use wait_event() which sleeps indefinitely, - * the maximum wait time is bounded by SCSI request timeout. - */ - req = blk_mq_alloc_request(q, REQ_OP_DRV_OUT, 0); - if (IS_ERR(req)) { - err = PTR_ERR(req); - goto out_unlock; - } - tag = req->tag; - WARN_ONCE(tag < 0, "Invalid tag %d\n", tag); - /* Set the timeout such that the SCSI error handler is not activated. */ - req->timeout = msecs_to_jiffies(2 * timeout); - blk_mq_start_request(req); + down_read(&hba->clk_scaling_lock); lrbp = &hba->lrb[tag]; WARN_ON(lrbp->cmd); @@ -2953,8 +2940,6 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, (struct utp_upiu_req *)lrbp->ucd_rsp_ptr); out: - blk_mq_free_request(req); -out_unlock: up_read(&hba->clk_scaling_lock); return err; } @@ -6689,23 +6674,16 @@ 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->cmd_queue; DECLARE_COMPLETION_ONSTACK(wait); - struct request *req; + const u32 tag = hba->reserved_slot; struct ufshcd_lrb *lrbp; int err = 0; - int tag; u8 upiu_flags; - down_read(&hba->clk_scaling_lock); + /* Protects use of hba->reserved_slot. */ + lockdep_assert_held(&hba->dev_cmd.lock); - req = blk_mq_alloc_request(q, REQ_OP_DRV_OUT, 0); - if (IS_ERR(req)) { - err = PTR_ERR(req); - goto out_unlock; - } - tag = req->tag; - WARN_ONCE(tag < 0, "Invalid tag %d\n", tag); + down_read(&hba->clk_scaling_lock); lrbp = &hba->lrb[tag]; WARN_ON(lrbp->cmd); @@ -6774,9 +6752,6 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba, ufshcd_add_query_upiu_trace(hba, err ? UFS_QUERY_ERR : UFS_QUERY_COMP, (struct utp_upiu_req *)lrbp->ucd_rsp_ptr); - blk_mq_free_request(req); - -out_unlock: up_read(&hba->clk_scaling_lock); return err; } @@ -9507,8 +9482,8 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq) /* Configure LRB */ ufshcd_host_memory_configure(hba); - host->can_queue = hba->nutrs; - host->cmd_per_lun = hba->nutrs; + host->can_queue = hba->nutrs - UFSHCD_NUM_RESERVED; + host->cmd_per_lun = hba->nutrs - UFSHCD_NUM_RESERVED; host->max_id = UFSHCD_MAX_ID; host->max_lun = UFS_MAX_LUNS; host->max_channel = UFSHCD_MAX_CHANNEL; diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h index ecc6c545a19d..c3c2792f309f 100644 --- a/drivers/scsi/ufs/ufshcd.h +++ b/drivers/scsi/ufs/ufshcd.h @@ -745,6 +745,7 @@ struct ufs_hba_monitor { * @capabilities: UFS Controller Capabilities * @nutrs: Transfer Request Queue depth supported by controller * @nutmrs: Task Management Queue depth supported by controller + * @reserved_slot: Used to submit device commands. Protected by @dev_cmd.lock. * @ufs_version: UFS Version to which controller complies * @vops: pointer to variant specific operations * @priv: pointer to variant specific private data @@ -836,6 +837,7 @@ struct ufs_hba { u32 capabilities; int nutrs; int nutmrs; + u32 reserved_slot; u32 ufs_version; const struct ufs_hba_variant_ops *vops; struct ufs_hba_variant_params *vps;