From: Xiang Chen chenxiang66@hisilicon.com
During the process of event PORT_BYTES_DMAED, it queues work DISCE_DISCOVER_DOMAIN and then flush workqueue ha->disco_q. If new phyup occurs during resming SAS controller, the work PORTE_BYTES_DMAED of new phys occurs before suspended phys', then work DISCE_DISCOVER_DOMAIN of new phy requires the active of SAS controller (It requires to resume SAS controller by function scsi_sysfs_add_sdev() and some other functions such as fucntion add_device_link()). But the active of SAS controller requires the complete of work PORTE_BYTES_DMAED of suspended phys while it is blocked by new phy's work on ha->event_q. So there is a deadlock and it is released only after resume timeout.
To solve the issue, defer works of new phys during suspend and queue those defer works after SAS controller becomes active.
Signed-off-by: Xiang Chen chenxiang66@hisilicon.com Reviewed-by: John Garry john.garry@huawei.com --- drivers/scsi/libsas/sas_event.c | 24 ++++++++++++++++++++++++ drivers/scsi/libsas/sas_init.c | 1 + 2 files changed, 25 insertions(+)
diff --git a/drivers/scsi/libsas/sas_event.c b/drivers/scsi/libsas/sas_event.c index 01e544ca518a..66eab7694832 100644 --- a/drivers/scsi/libsas/sas_event.c +++ b/drivers/scsi/libsas/sas_event.c @@ -139,6 +139,24 @@ static void sas_phy_event_worker(struct work_struct *work) sas_free_event(ev); }
+/* defer works of new phys during suspend */ +static bool sas_defer_event(struct asd_sas_phy *phy, struct asd_sas_event *ev) +{ + struct sas_ha_struct *ha = phy->ha; + unsigned long flags; + bool deferred = false; + + spin_lock_irqsave(&ha->lock, flags); + if (test_bit(SAS_HA_RESUMING, &ha->state) && !phy->suspended) { + struct sas_work *sw = &ev->work; + + list_add_tail(&sw->drain_node, &ha->defer_q); + deferred = true; + } + spin_unlock_irqrestore(&ha->lock, flags); + return deferred; +} + int sas_notify_port_event(struct asd_sas_phy *phy, enum port_event event, gfp_t gfp_flags) { @@ -154,6 +172,9 @@ int sas_notify_port_event(struct asd_sas_phy *phy, enum port_event event,
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) sas_free_event(ev); @@ -177,6 +198,9 @@ int sas_notify_phy_event(struct asd_sas_phy *phy, enum phy_event event,
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) sas_free_event(ev); diff --git a/drivers/scsi/libsas/sas_init.c b/drivers/scsi/libsas/sas_init.c index f7c56677da3e..87ececc31e1b 100644 --- a/drivers/scsi/libsas/sas_init.c +++ b/drivers/scsi/libsas/sas_init.c @@ -446,6 +446,7 @@ static void _sas_resume_ha(struct sas_ha_struct *ha, bool drain) sas_drain_work(ha); clear_bit(SAS_HA_RESUMING, &ha->state);
+ sas_queue_deferred_work(ha);
/* send event PORTE_BROADCAST_RCVD to identify some new inserted * disks for expander