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![Xiang Chen](/assets/img/avatar_default.png)
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. Link: https://lore.kernel.org/r/1639999298-244569-15-git-send-email-chenxiang66@hisilicon.com Reviewed-by: John Garry <john.garry@huawei.com> Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
228 lines
5.1 KiB
C
228 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Serial Attached SCSI (SAS) Event processing
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*
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* Copyright (C) 2005 Adaptec, Inc. All rights reserved.
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* Copyright (C) 2005 Luben Tuikov <luben_tuikov@adaptec.com>
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*/
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#include <linux/export.h>
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#include <scsi/scsi_host.h>
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#include "sas_internal.h"
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int sas_queue_work(struct sas_ha_struct *ha, struct sas_work *sw)
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{
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/* it's added to the defer_q when draining so return succeed */
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int rc = 1;
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if (!test_bit(SAS_HA_REGISTERED, &ha->state))
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return 0;
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if (test_bit(SAS_HA_DRAINING, &ha->state)) {
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/* add it to the defer list, if not already pending */
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if (list_empty(&sw->drain_node))
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list_add_tail(&sw->drain_node, &ha->defer_q);
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} else
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rc = queue_work(ha->event_q, &sw->work);
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return rc;
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}
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static int sas_queue_event(int event, struct sas_work *work,
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struct sas_ha_struct *ha)
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{
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unsigned long flags;
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int rc;
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spin_lock_irqsave(&ha->lock, flags);
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rc = sas_queue_work(ha, work);
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spin_unlock_irqrestore(&ha->lock, flags);
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return rc;
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}
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void sas_queue_deferred_work(struct sas_ha_struct *ha)
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{
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struct sas_work *sw, *_sw;
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int ret;
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spin_lock_irq(&ha->lock);
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list_for_each_entry_safe(sw, _sw, &ha->defer_q, drain_node) {
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list_del_init(&sw->drain_node);
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ret = sas_queue_work(ha, sw);
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if (ret != 1) {
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pm_runtime_put(ha->dev);
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sas_free_event(to_asd_sas_event(&sw->work));
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}
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}
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spin_unlock_irq(&ha->lock);
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}
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void __sas_drain_work(struct sas_ha_struct *ha)
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{
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set_bit(SAS_HA_DRAINING, &ha->state);
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/* flush submitters */
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spin_lock_irq(&ha->lock);
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spin_unlock_irq(&ha->lock);
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drain_workqueue(ha->event_q);
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drain_workqueue(ha->disco_q);
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clear_bit(SAS_HA_DRAINING, &ha->state);
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sas_queue_deferred_work(ha);
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}
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int sas_drain_work(struct sas_ha_struct *ha)
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{
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int err;
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err = mutex_lock_interruptible(&ha->drain_mutex);
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if (err)
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return err;
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if (test_bit(SAS_HA_REGISTERED, &ha->state))
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__sas_drain_work(ha);
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mutex_unlock(&ha->drain_mutex);
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return 0;
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}
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EXPORT_SYMBOL_GPL(sas_drain_work);
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void sas_disable_revalidation(struct sas_ha_struct *ha)
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{
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mutex_lock(&ha->disco_mutex);
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set_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state);
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mutex_unlock(&ha->disco_mutex);
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}
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void sas_enable_revalidation(struct sas_ha_struct *ha)
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{
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int i;
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mutex_lock(&ha->disco_mutex);
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clear_bit(SAS_HA_ATA_EH_ACTIVE, &ha->state);
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for (i = 0; i < ha->num_phys; i++) {
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struct asd_sas_port *port = ha->sas_port[i];
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const int ev = DISCE_REVALIDATE_DOMAIN;
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struct sas_discovery *d = &port->disc;
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struct asd_sas_phy *sas_phy;
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if (!test_and_clear_bit(ev, &d->pending))
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continue;
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spin_lock(&port->phy_list_lock);
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if (list_empty(&port->phy_list)) {
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spin_unlock(&port->phy_list_lock);
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continue;
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}
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sas_phy = container_of(port->phy_list.next, struct asd_sas_phy,
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port_phy_el);
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spin_unlock(&port->phy_list_lock);
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sas_notify_port_event(sas_phy,
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PORTE_BROADCAST_RCVD, GFP_KERNEL);
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}
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mutex_unlock(&ha->disco_mutex);
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}
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static void sas_port_event_worker(struct work_struct *work)
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{
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struct asd_sas_event *ev = to_asd_sas_event(work);
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struct asd_sas_phy *phy = ev->phy;
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struct sas_ha_struct *ha = phy->ha;
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sas_port_event_fns[ev->event](work);
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pm_runtime_put(ha->dev);
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sas_free_event(ev);
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}
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static void sas_phy_event_worker(struct work_struct *work)
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{
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struct asd_sas_event *ev = to_asd_sas_event(work);
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struct asd_sas_phy *phy = ev->phy;
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struct sas_ha_struct *ha = phy->ha;
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sas_phy_event_fns[ev->event](work);
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pm_runtime_put(ha->dev);
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sas_free_event(ev);
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}
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/* defer works of new phys during suspend */
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static bool sas_defer_event(struct asd_sas_phy *phy, struct asd_sas_event *ev)
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{
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struct sas_ha_struct *ha = phy->ha;
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unsigned long flags;
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bool deferred = false;
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spin_lock_irqsave(&ha->lock, flags);
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if (test_bit(SAS_HA_RESUMING, &ha->state) && !phy->suspended) {
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struct sas_work *sw = &ev->work;
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list_add_tail(&sw->drain_node, &ha->defer_q);
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deferred = true;
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}
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spin_unlock_irqrestore(&ha->lock, flags);
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return deferred;
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}
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int sas_notify_port_event(struct asd_sas_phy *phy, enum port_event event,
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gfp_t gfp_flags)
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{
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struct sas_ha_struct *ha = phy->ha;
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struct asd_sas_event *ev;
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int ret;
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BUG_ON(event >= PORT_NUM_EVENTS);
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ev = sas_alloc_event(phy, gfp_flags);
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if (!ev)
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return -ENOMEM;
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/* Call pm_runtime_put() with pairs in sas_port_event_worker() */
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pm_runtime_get_noresume(ha->dev);
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INIT_SAS_EVENT(ev, sas_port_event_worker, phy, event);
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if (sas_defer_event(phy, ev))
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return 0;
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ret = sas_queue_event(event, &ev->work, ha);
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if (ret != 1) {
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pm_runtime_put(ha->dev);
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sas_free_event(ev);
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(sas_notify_port_event);
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int sas_notify_phy_event(struct asd_sas_phy *phy, enum phy_event event,
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gfp_t gfp_flags)
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{
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struct sas_ha_struct *ha = phy->ha;
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struct asd_sas_event *ev;
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int ret;
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BUG_ON(event >= PHY_NUM_EVENTS);
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ev = sas_alloc_event(phy, gfp_flags);
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if (!ev)
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return -ENOMEM;
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/* Call pm_runtime_put() with pairs in sas_phy_event_worker() */
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pm_runtime_get_noresume(ha->dev);
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INIT_SAS_EVENT(ev, sas_phy_event_worker, phy, event);
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if (sas_defer_event(phy, ev))
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return 0;
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ret = sas_queue_event(event, &ev->work, ha);
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if (ret != 1) {
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pm_runtime_put(ha->dev);
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sas_free_event(ev);
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}
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return ret;
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}
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EXPORT_SYMBOL_GPL(sas_notify_phy_event);
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