From: Xiang Chen Date: Mon, 20 Dec 2021 11:21:37 +0000 (+0800) Subject: scsi: libsas: Keep host active while processing events X-Git-Tag: v6.6.17~8331^2~53 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=307d9f49cce966c2ba969f58bd6227bc0092afaa;p=platform%2Fkernel%2Flinux-rpi.git scsi: libsas: Keep host active while processing events 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 Signed-off-by: Xiang Chen Signed-off-by: Martin K. Petersen --- diff --git a/drivers/scsi/libsas/sas_event.c b/drivers/scsi/libsas/sas_event.c index 626ef96..3613b9b 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; }