From patchwork Sun Sep 13 14:52:45 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yaniv Gardi X-Patchwork-Id: 7169881 Return-Path: X-Original-To: patchwork-linux-scsi@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 8EB8FBEEC1 for ; Sun, 13 Sep 2015 14:58:17 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id AB29320690 for ; Sun, 13 Sep 2015 14:58:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9CC2D2063E for ; Sun, 13 Sep 2015 14:58:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753243AbbIMO54 (ORCPT ); Sun, 13 Sep 2015 10:57:56 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:49015 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753918AbbIMOxu (ORCPT ); Sun, 13 Sep 2015 10:53:50 -0400 Received: from smtp.codeaurora.org (localhost [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id B95E31403D4; Sun, 13 Sep 2015 14:53:49 +0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 486) id A92EE1403DF; Sun, 13 Sep 2015 14:53:49 +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, T_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 DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: ygardi@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 359281403D4; Sun, 13 Sep 2015 14:53:46 +0000 (UTC) From: Yaniv Gardi To: James.Bottomley@HansenPartnership.com, pebolle@tiscali.nl, hch@infradead.org 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, subhashj@codeaurora.org, ygardi@codeaurora.org, gbroner@codeaurora.org, draviv@codeaurora.org, Vinayak Holikatti , "James E.J. Bottomley" Subject: [PATCH v1 05/17] scsi: ufs: implement scsi host timeout handler Date: Sun, 13 Sep 2015 17:52:45 +0300 Message-Id: <1442155977-7686-6-git-send-email-ygardi@codeaurora.org> X-Mailer: git-send-email 1.8.5.2 In-Reply-To: <1442155977-7686-1-git-send-email-ygardi@codeaurora.org> References: <1442155977-7686-1-git-send-email-ygardi@codeaurora.org> X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@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. 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 7d20dac..6171da8 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -4602,6 +4602,41 @@ 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, @@ -4614,6 +4649,7 @@ 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,