From patchwork Wed Dec 15 14:37:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Garry X-Patchwork-Id: 524455 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 73D7BC4332F for ; Wed, 15 Dec 2021 14:43:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243508AbhLOOnV (ORCPT ); Wed, 15 Dec 2021 09:43:21 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:4292 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243499AbhLOOnS (ORCPT ); Wed, 15 Dec 2021 09:43:18 -0500 Received: from fraeml738-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4JDdCw5gjsz67wfM; Wed, 15 Dec 2021 22:38:52 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml738-chm.china.huawei.com (10.206.15.219) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Wed, 15 Dec 2021 15:43:13 +0100 Received: from localhost.localdomain (10.69.192.58) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Wed, 15 Dec 2021 14:43:10 +0000 From: John Garry To: , CC: , , , Qi Liu , John Garry Subject: [PATCH 6/8] scsi: hisi_sas: Prevent parallel FLR and controller reset Date: Wed, 15 Dec 2021 22:37:39 +0800 Message-ID: <1639579061-179473-7-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1639579061-179473-1-git-send-email-john.garry@huawei.com> References: <1639579061-179473-1-git-send-email-john.garry@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.69.192.58] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org From: Qi Liu If we issue a controller reset command during executing a FLR a hung task may be found: Call trace: __switch_to+0x158/0x1cc __schedule+0x2e8/0x85c schedule+0x7c/0x110 schedule_timeout+0x190/0x1cc __down+0x7c/0xd4 down+0x5c/0x7c hisi_sas_task_exec+0x510/0x680 [hisi_sas_main] hisi_sas_queue_command+0x24/0x30 [hisi_sas_main] smp_execute_task_sg+0xf4/0x23c [libsas] sas_smp_phy_control+0x110/0x1e0 [libsas] transport_sas_phy_reset+0xc8/0x190 [libsas] phy_reset_work+0x2c/0x40 [libsas] process_one_work+0x1dc/0x48c worker_thread+0x15c/0x464 kthread+0x160/0x170 ret_from_fork+0x10/0x18 This is a race condition which occurs when the FLR completes first. Here the host HISI_SAS_RESETTING_BIT flag out gets of sync as HISI_SAS_RESETTING_BIT is not always cleared with the hisi_hba.sem held, so now only set/unset HISI_SAS_RESETTING_BIT under hisi_hba.sem . Signed-off-by: Qi Liu Signed-off-by: John Garry --- drivers/scsi/hisi_sas/hisi_sas_main.c | 8 +++++--- drivers/scsi/hisi_sas/hisi_sas_v3_hw.c | 1 + 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/hisi_sas/hisi_sas_main.c b/drivers/scsi/hisi_sas/hisi_sas_main.c index 977911580d8f..0e14f90dbb1e 100644 --- a/drivers/scsi/hisi_sas/hisi_sas_main.c +++ b/drivers/scsi/hisi_sas/hisi_sas_main.c @@ -1574,7 +1574,6 @@ void hisi_sas_controller_reset_prepare(struct hisi_hba *hisi_hba) { struct Scsi_Host *shost = hisi_hba->shost; - down(&hisi_hba->sem); hisi_hba->phy_state = hisi_hba->hw->get_phys_state(hisi_hba); scsi_block_requests(shost); @@ -1599,9 +1598,9 @@ void hisi_sas_controller_reset_done(struct hisi_hba *hisi_hba) if (hisi_hba->reject_stp_links_msk) hisi_sas_terminate_stp_reject(hisi_hba); hisi_sas_reset_init_all_devices(hisi_hba); - up(&hisi_hba->sem); scsi_unblock_requests(shost); clear_bit(HISI_SAS_RESETTING_BIT, &hisi_hba->flags); + up(&hisi_hba->sem); hisi_sas_rescan_topology(hisi_hba, hisi_hba->phy_state); } @@ -1612,8 +1611,11 @@ static int hisi_sas_controller_prereset(struct hisi_hba *hisi_hba) if (!hisi_hba->hw->soft_reset) return -1; - if (test_and_set_bit(HISI_SAS_RESETTING_BIT, &hisi_hba->flags)) + down(&hisi_hba->sem); + if (test_and_set_bit(HISI_SAS_RESETTING_BIT, &hisi_hba->flags)) { + up(&hisi_hba->sem); return -1; + } if (hisi_sas_debugfs_enable && hisi_hba->debugfs_itct[0].itct) hisi_hba->hw->debugfs_snapshot_regs(hisi_hba); diff --git a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c index 0ef6c21bf081..11a44d9dd9b2 100644 --- a/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c +++ b/drivers/scsi/hisi_sas/hisi_sas_v3_hw.c @@ -4848,6 +4848,7 @@ static void hisi_sas_reset_prepare_v3_hw(struct pci_dev *pdev) int rc; dev_info(dev, "FLR prepare\n"); + down(&hisi_hba->sem); set_bit(HISI_SAS_RESETTING_BIT, &hisi_hba->flags); hisi_sas_controller_reset_prepare(hisi_hba);