[PATCH v1] scsi: ufs: fix rpm racing issue

[peter.wang at mediatek.com]

From: Peter Wang <peter.wang at mediatek.com>

Device WLun may enter RPM_SUSPENDED and the consumer is RPM_ACTIVE.

The error state is
Device Wlun RPM: status:2, usage_count:0
Consumer: 0:0:0:49476 Link: rpm_active:1, RPM: status:2, usage_count:0
Consumer: 0:0:0:49456 Link: rpm_active:1, RPM: status:2, usage_count:0
Consumer: 0:0:0:0 Link: rpm_active:1, RPM: status:2, usage_count:0
Consumer: 0:0:0:1 Link: rpm_active:1, RPM: status:2, usage_count:0
Consumer: 0:0:0:2 Link: rpm_active:1, RPM: status:0, usage_count:0

Because rpm enable before rpm delay set, scsi_autopm_put_device
invoke by scsi_sysfs_add_sdev may cause consumer enter suspend immediately.
Thas will always set rpm_active to 1.
If driver_probe_device invoke pm_runtime_get_suppliers just befor
previous scsi_autopm_put_device, the rpm_active will change to 1
after pm_runtime_put_suppliers.
Set this delay to avoid scsi_autopm_put_device enter suspend immediately.

Signed-off-by: Peter Wang <peter.wang at mediatek.com>
---
 drivers/scsi/ufs/ufshcd.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 3f9caafa91bf..1250792d16be 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5024,10 +5024,14 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
 	 * Block runtime-pm until all consumers are added.
 	 * Refer ufshcd_setup_links().
 	 */
-	if (is_device_wlun(sdev))
+	if (is_device_wlun(sdev)) {
 		pm_runtime_get_noresume(&sdev->sdev_gendev);
-	else if (ufshcd_is_rpm_autosuspend_allowed(hba))
+	} else if (ufshcd_is_rpm_autosuspend_allowed(hba)) {
 		sdev->rpm_autosuspend = 1;
+		pm_runtime_set_autosuspend_delay(&sdev->sdev_gendev,
+			RPM_AUTOSUSPEND_DELAY_MS);
+	}
+
 	/*
 	 * Do not print messages during runtime PM to avoid never-ending cycles
 	 * of messages written back to storage by user space causing runtime
-- 
2.18.0