From patchwork Mon Dec 20 11:21:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: chenxiang X-Patchwork-Id: 12687665 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 C1D51C433FE for ; Mon, 20 Dec 2021 11:27:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231814AbhLTL1E (ORCPT ); Mon, 20 Dec 2021 06:27:04 -0500 Received: from szxga01-in.huawei.com ([45.249.212.187]:15946 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231806AbhLTL0w (ORCPT ); Mon, 20 Dec 2021 06:26:52 -0500 Received: from dggeme756-chm.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4JHcfS2jdKzZdkQ; Mon, 20 Dec 2021 19:23:44 +0800 (CST) Received: from localhost.localdomain (10.69.192.58) by dggeme756-chm.china.huawei.com (10.3.19.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.20; Mon, 20 Dec 2021 19:26:50 +0800 From: chenxiang To: , CC: , , , Xiang Chen Subject: [PATCH v2 14/15] scsi: libsas: Keep host active while processing events Date: Mon, 20 Dec 2021 19:21:37 +0800 Message-ID: <1639999298-244569-15-git-send-email-chenxiang66@hisilicon.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1639999298-244569-1-git-send-email-chenxiang66@hisilicon.com> References: <1639999298-244569-1-git-send-email-chenxiang66@hisilicon.com> MIME-Version: 1.0 X-Originating-IP: [10.69.192.58] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To dggeme756-chm.china.huawei.com (10.3.19.102) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org From: Xiang Chen Processing events such as PORTE_BROADCAST_RCVD may cause dependency issues for runtime power management support. Such a problem would be that handling a PORTE_BROADCAST_RCVD event requires that the host is resumed to send SMP commands. However, in resuming the host, the phyup events generated from re-enabling the phys are processed in the same workqueue as the original PORTE_BROADCAST_RCVD event. As such, the host will never finish resuming (as it waits for the phyup event processing), and then the PORTE_BROADCAST_RCVD event can't be processed as the SMP commands are blocked, and so we have a deadlock. Solve this problem by ensuring that libsas keeps the host active until completely finished phy or port events, such as PORTE_BYTES_DMAED. As such, we don't have to worry about resuming the host for processing individual SMP commands in this example. Signed-off-by: Xiang Chen Reviewed-by: John Garry --- drivers/scsi/libsas/sas_event.c | 24 +++++++++++++++++++++--- 1 file changed, 21 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/libsas/sas_event.c b/drivers/scsi/libsas/sas_event.c index 626ef96b9348..3613b9b315bc 100644 --- a/drivers/scsi/libsas/sas_event.c +++ b/drivers/scsi/libsas/sas_event.c @@ -50,8 +50,10 @@ void sas_queue_deferred_work(struct sas_ha_struct *ha) list_for_each_entry_safe(sw, _sw, &ha->defer_q, drain_node) { list_del_init(&sw->drain_node); ret = sas_queue_work(ha, sw); - if (ret != 1) + if (ret != 1) { + pm_runtime_put(ha->dev); sas_free_event(to_asd_sas_event(&sw->work)); + } } spin_unlock_irq(&ha->lock); } @@ -126,16 +128,22 @@ void sas_enable_revalidation(struct sas_ha_struct *ha) static void sas_port_event_worker(struct work_struct *work) { struct asd_sas_event *ev = to_asd_sas_event(work); + struct asd_sas_phy *phy = ev->phy; + struct sas_ha_struct *ha = phy->ha; sas_port_event_fns[ev->event](work); + pm_runtime_put(ha->dev); sas_free_event(ev); } static void sas_phy_event_worker(struct work_struct *work) { struct asd_sas_event *ev = to_asd_sas_event(work); + struct asd_sas_phy *phy = ev->phy; + struct sas_ha_struct *ha = phy->ha; sas_phy_event_fns[ev->event](work); + pm_runtime_put(ha->dev); sas_free_event(ev); } @@ -170,14 +178,19 @@ int sas_notify_port_event(struct asd_sas_phy *phy, enum port_event event, if (!ev) return -ENOMEM; + /* Call pm_runtime_put() with pairs in sas_port_event_worker() */ + pm_runtime_get_noresume(ha->dev); + INIT_SAS_EVENT(ev, sas_port_event_worker, phy, event); if (sas_defer_event(phy, ev)) return 0; ret = sas_queue_event(event, &ev->work, ha); - if (ret != 1) + if (ret != 1) { + pm_runtime_put(ha->dev); sas_free_event(ev); + } return ret; } @@ -196,14 +209,19 @@ int sas_notify_phy_event(struct asd_sas_phy *phy, enum phy_event event, if (!ev) return -ENOMEM; + /* Call pm_runtime_put() with pairs in sas_phy_event_worker() */ + pm_runtime_get_noresume(ha->dev); + INIT_SAS_EVENT(ev, sas_phy_event_worker, phy, event); if (sas_defer_event(phy, ev)) return 0; ret = sas_queue_event(event, &ev->work, ha); - if (ret != 1) + if (ret != 1) { + pm_runtime_put(ha->dev); sas_free_event(ev); + } return ret; }