From patchwork Wed Dec 2 03:47:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Can Guo X-Patchwork-Id: 336440 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, 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 2B8F4C64E8A for ; Wed, 2 Dec 2020 03:48:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC1BB206A4 for ; Wed, 2 Dec 2020 03:48:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728248AbgLBDs0 (ORCPT ); Tue, 1 Dec 2020 22:48:26 -0500 Received: from labrats.qualcomm.com ([199.106.110.90]:35360 "EHLO labrats.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727033AbgLBDs0 (ORCPT ); Tue, 1 Dec 2020 22:48:26 -0500 IronPort-SDR: +2iklZMFj41B9sTG3ei4cnAn+W0DtC/kjVfHQ8cYhx5c5xhaf8qFx/DZc2Cj5N+LibOvQ3OvXm Oc94MCsQ51cyQZ1JPsnrGF8M5S1T7izuk3iWeKdoimDlvhMlhCm3Tz3Tm1fp/0BC9IJV0xiyfB A6czLUD+fPK0VS38eDediOsqynmmLATR2JvtrNkfSqcroF/XHuqoMDTdMZPKAm0Tzv5ddjbWr9 hGbVb0OKFbikMm8AYtK+HLd6zxvH6N+o1msxwc2fTy6UwAOr4Qo49Toc+YvlANgi7P5uaa7BHp d9Q= X-IronPort-AV: E=Sophos;i="5.78,385,1599548400"; d="scan'208";a="47538811" Received: from unknown (HELO ironmsg05-sd.qualcomm.com) ([10.53.140.145]) by labrats.qualcomm.com with ESMTP; 01 Dec 2020 19:47:25 -0800 X-QCInternal: smtphost Received: from wsp769891wss.qualcomm.com (HELO stor-presley.qualcomm.com) ([192.168.140.85]) by ironmsg05-sd.qualcomm.com with ESMTP; 01 Dec 2020 19:47:23 -0800 Received: by stor-presley.qualcomm.com (Postfix, from userid 359480) id E1DA12106B; Tue, 1 Dec 2020 19:47:23 -0800 (PST) From: Can Guo To: asutoshd@codeaurora.org, nguyenb@codeaurora.org, hongwus@codeaurora.org, rnayak@codeaurora.org, linux-scsi@vger.kernel.org, kernel-team@android.com, saravanak@google.com, salyzyn@google.com, cang@codeaurora.org Cc: Alim Akhtar , Avri Altman , "James E.J. Bottomley" , "Martin K. Petersen" , Stanley Chu , Bean Huo , Bart Van Assche , Satya Tangirala , linux-kernel@vger.kernel.org (open list) Subject: [PATCH v4 2/3] scsi: ufs: Fix a race condition between ufshcd_abort and eh_work Date: Tue, 1 Dec 2020 19:47:07 -0800 Message-Id: <1606880829-27500-3-git-send-email-cang@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1606880829-27500-1-git-send-email-cang@codeaurora.org> References: <1606880829-27500-1-git-send-email-cang@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org In current task abort routine, if task abort happens to the device W-LU, the code directly jumps to ufshcd_eh_host_reset_handler() to perform a full reset and restore then returns FAIL or SUCCESS. Commands sent to the device W-LU are most likely the SSU cmds sent during UFS PM operations. If such SSU cmd enters task abort routine, when ufshcd_eh_host_reset_handler() flushes eh_work, it will get stuck there since err_handler is serialized with PM operations. In order to unblock above call path, we merely clean up the lrb taken by this cmd, queue the eh_work and return SUCCESS. Once the cmd is aborted, the PM operation which sends out the cmd just errors out, then err_handler shall be able to proceed with the full reset and restore. In this scenario, the cmd is aborted even before it is actually cleared by HW, set the lrb->in_use flag to prevent subsequent cmds, including SCSI cmds and dev cmds, from taking the lrb released from abort. The flag shall evetually be cleared in __ufshcd_transfer_req_compl() invoked by the full reset and restore from err_handler. Reviewed-by: Asutosh Das Signed-off-by: Can Guo --- drivers/scsi/ufs/ufshcd.c | 55 ++++++++++++++++++++++++++++++++++++----------- drivers/scsi/ufs/ufshcd.h | 2 ++ 2 files changed, 45 insertions(+), 12 deletions(-) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 7e764e8..cd7394e 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -2539,6 +2539,14 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd) (hba->clk_gating.state != CLKS_ON)); lrbp = &hba->lrb[tag]; + if (unlikely(lrbp->in_use)) { + if (hba->pm_op_in_progress) + set_host_byte(cmd, DID_BAD_TARGET); + else + err = SCSI_MLQUEUE_HOST_BUSY; + ufshcd_release(hba); + goto out; + } WARN_ON(lrbp->cmd); lrbp->cmd = cmd; @@ -2781,6 +2789,11 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, init_completion(&wait); lrbp = &hba->lrb[tag]; + if (unlikely(lrbp->in_use)) { + err = -EBUSY; + goto out; + } + WARN_ON(lrbp->cmd); err = ufshcd_compose_dev_cmd(hba, lrbp, cmd_type, tag); if (unlikely(err)) @@ -2797,6 +2810,7 @@ static int ufshcd_exec_dev_cmd(struct ufs_hba *hba, err = ufshcd_wait_for_dev_cmd(hba, lrbp, timeout); +out: ufshcd_add_query_upiu_trace(hba, tag, err ? "query_complete_err" : "query_complete"); @@ -4932,6 +4946,7 @@ static void __ufshcd_transfer_req_compl(struct ufs_hba *hba, for_each_set_bit(index, &completed_reqs, hba->nutrs) { lrbp = &hba->lrb[index]; + lrbp->in_use = false; lrbp->compl_time_stamp = ktime_get(); cmd = lrbp->cmd; if (cmd) { @@ -6374,8 +6389,12 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba, init_completion(&wait); lrbp = &hba->lrb[tag]; - WARN_ON(lrbp->cmd); + if (unlikely(lrbp->in_use)) { + err = -EBUSY; + goto out; + } + WARN_ON(lrbp->cmd); lrbp->cmd = NULL; lrbp->sense_bufflen = 0; lrbp->sense_buffer = NULL; @@ -6447,6 +6466,7 @@ static int ufshcd_issue_devman_upiu_cmd(struct ufs_hba *hba, } } +out: blk_put_request(req); out_unlock: up_read(&hba->clk_scaling_lock); @@ -6696,16 +6716,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) BUG(); } - /* - * Task abort to the device W-LUN is illegal. When this command - * will fail, due to spec violation, scsi err handling next step - * will be to send LU reset which, again, is a spec violation. - * To avoid these unnecessary/illegal step we skip to the last error - * handling stage: reset and restore. - */ - if (lrbp->lun == UFS_UPIU_UFS_DEVICE_WLUN) - return ufshcd_eh_host_reset_handler(cmd); - ufshcd_hold(hba, false); reg = ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL); /* If command is already aborted/completed, return SUCCESS */ @@ -6726,7 +6736,7 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) * to reduce repeated printouts. For other aborted requests only print * basic details. */ - scsi_print_command(hba->lrb[tag].cmd); + scsi_print_command(cmd); if (!hba->req_abort_count) { ufshcd_update_reg_hist(&hba->ufs_stats.task_abort, 0); ufshcd_print_host_regs(hba); @@ -6745,6 +6755,27 @@ static int ufshcd_abort(struct scsi_cmnd *cmd) goto cleanup; } + /* + * Task abort to the device W-LUN is illegal. When this command + * will fail, due to spec violation, scsi err handling next step + * will be to send LU reset which, again, is a spec violation. + * To avoid these unnecessary/illegal steps, first we clean up + * the lrb taken by this cmd and mark the lrb as in_use, then + * queue the eh_work and bail. + */ + if (lrbp->lun == UFS_UPIU_UFS_DEVICE_WLUN) { + spin_lock_irqsave(host->host_lock, flags); + if (lrbp->cmd) { + __ufshcd_transfer_req_compl(hba, (1UL << tag)); + __set_bit(tag, &hba->outstanding_reqs); + lrbp->in_use = true; + hba->force_reset = true; + ufshcd_schedule_eh_work(hba); + } + spin_unlock_irqrestore(host->host_lock, flags); + goto out; + } + /* Skip task abort in case previous aborts failed and report failure */ if (lrbp->req_abort_skip) err = -EIO; diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h index 1e680bf..66e5338 100644 --- a/drivers/scsi/ufs/ufshcd.h +++ b/drivers/scsi/ufs/ufshcd.h @@ -163,6 +163,7 @@ struct ufs_pm_lvl_states { * @crypto_key_slot: the key slot to use for inline crypto (-1 if none) * @data_unit_num: the data unit number for the first block for inline crypto * @req_abort_skip: skip request abort task flag + * @in_use: indicates that this lrb is still in use */ struct ufshcd_lrb { struct utp_transfer_req_desc *utr_descriptor_ptr; @@ -192,6 +193,7 @@ struct ufshcd_lrb { #endif bool req_abort_skip; + bool in_use; }; /**