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scsi: libsas: Keep host active while processing events

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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>
This commit is contained in:
Xiang Chen 2021-12-20 19:21:37 +08:00 committed by Martin K. Petersen
parent ae9b69e85e
commit 307d9f49cc
1 changed files with 21 additions and 3 deletions
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24
drivers/scsi/libsas/sas_event.c
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@ -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;
}