From patchwork Thu Mar 10 15:37:07 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yaniv Gardi X-Patchwork-Id: 8558481 Return-Path: X-Original-To: patchwork-linux-arm-msm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 0B06D9F2B4 for ; Thu, 10 Mar 2016 15:42:58 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 32C8C2034C for ; Thu, 10 Mar 2016 15:42:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C891F20375 for ; Thu, 10 Mar 2016 15:42:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752806AbcCJPmd (ORCPT ); Thu, 10 Mar 2016 10:42:33 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:51397 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753279AbcCJPhn (ORCPT ); Thu, 10 Mar 2016 10:37:43 -0500 Received: from smtp.codeaurora.org (localhost [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 8148360F71; Thu, 10 Mar 2016 15:37:42 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 6F72260F31; Thu, 10 Mar 2016 15:37:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from lx-ygardi.mea.qualcomm.com (unknown [185.23.60.4]) (using TLSv1.1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: ygardi@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 3B86460ECE; Thu, 10 Mar 2016 15:37:39 +0000 (UTC) From: Yaniv Gardi To: James.Bottomley@HansenPartnership.com Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-arm-msm@vger.kernel.org, santoshsy@gmail.com, linux-scsi-owner@vger.kernel.org, ygardi@codeaurora.org, Gilad Broner , Vinayak Holikatti , "James E.J. Bottomley" , "Martin K. Petersen" Subject: [PATCH v8 03/17] scsi: ufs: implement scsi host timeout handler Date: Thu, 10 Mar 2016 17:37:07 +0200 Message-Id: <1457624241-20525-4-git-send-email-ygardi@codeaurora.org> X-Mailer: git-send-email 1.8.5.2 In-Reply-To: <1457624241-20525-1-git-send-email-ygardi@codeaurora.org> References: <1457624241-20525-1-git-send-email-ygardi@codeaurora.org> X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP A race condition exists between request requeueing and scsi layer error handling: When UFS driver queuecommand returns a busy status for a request, it will be requeued and its tag will be freed and set to -1. At the same time it is possible that the request will timeout and scsi layer will start error handling for it. The scsi layer reuses the request and its tag to send error related commands to the device, however its tag is no longer valid. As this request was never really sent to the device, there is no point to start error handling with the device. Implement the scsi error handling timeout callback and bypass SCSI error handling for request that were not actually sent to the device. For such requests simply reset the block layer timer. Otherwise, let SCSI layer perform the usual error handling. Reviewed-by: Hannes Reinecke Signed-off-by: Gilad Broner Signed-off-by: Yaniv Gardi --- drivers/scsi/ufs/ufshcd.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index de7280c..3400ceb 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -4568,6 +4568,41 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie) ufshcd_probe_hba(hba); } +static enum blk_eh_timer_return ufshcd_eh_timed_out(struct scsi_cmnd *scmd) +{ + unsigned long flags; + struct Scsi_Host *host; + struct ufs_hba *hba; + int index; + bool found = false; + + if (!scmd || !scmd->device || !scmd->device->host) + return BLK_EH_NOT_HANDLED; + + host = scmd->device->host; + hba = shost_priv(host); + if (!hba) + return BLK_EH_NOT_HANDLED; + + spin_lock_irqsave(host->host_lock, flags); + + for_each_set_bit(index, &hba->outstanding_reqs, hba->nutrs) { + if (hba->lrb[index].cmd == scmd) { + found = true; + break; + } + } + + spin_unlock_irqrestore(host->host_lock, flags); + + /* + * Bypass SCSI error handling and reset the block layer timer if this + * SCSI command was not actually dispatched to UFS driver, otherwise + * let SCSI layer handle the error as usual. + */ + return found ? BLK_EH_NOT_HANDLED : BLK_EH_RESET_TIMER; +} + static struct scsi_host_template ufshcd_driver_template = { .module = THIS_MODULE, .name = UFSHCD, @@ -4580,6 +4615,7 @@ static struct scsi_host_template ufshcd_driver_template = { .eh_abort_handler = ufshcd_abort, .eh_device_reset_handler = ufshcd_eh_device_reset_handler, .eh_host_reset_handler = ufshcd_eh_host_reset_handler, + .eh_timed_out = ufshcd_eh_timed_out, .this_id = -1, .sg_tablesize = SG_ALL, .cmd_per_lun = UFSHCD_CMD_PER_LUN,