[PATCH v2 5/5] scsi: ufs: hwmon, debugfs: Propagate runtime PM resume errors

[Stanley Jhu]

ufs_hwmon_read(), ufs_hwmon_write(), and ufs_debugfs_get_user_access()
resume the UFS device W-LUN with ufshcd_rpm_get_sync() and ignore its
return value. For example, for a hwmon temperature read:

1. The W-LUN is runtime suspended.
2. User space reads temp1_input of the UFS hwmon device.
3. ufs_hwmon_read() calls ufshcd_rpm_get_sync().
4. The W-LUN runtime resume fails and the W-LUN stays suspended.
5. ufshcd_rpm_get_sync() returns a negative errno, which is ignored.
6. ufs_hwmon_read() sends an attribute query UPIU while the W-LUN is
   still suspended.

ufs_hwmon_write() and the debugfs writers that use
ufs_debugfs_get_user_access() (exception_event_mask and tx_eq_ctrl)
follow the same sequence.

Convert all three call sites to ufshcd_rpm_resume_and_get() and
release hba->host_sem before returning the error, ahead of
__acquire(ufs_debugfs) in ufs_debugfs_get_user_access().

Fixes: b294ff3e3449 ("scsi: ufs: core: Enable power management for wlun")
Fixes: e88e2d32200a ("scsi: ufs: core: Probe for temperature notification support")
Fixes: adbabdcf0db0 ("scsi: ufs: core: Add support to retrain TX Equalization via debugfs")
Cc: stable@xxxxxxxxxxxxxxx # needs "scsi: ufs: core: Introduce ufshcd_rpm_resume_and_get() helper"
Signed-off-by: Stanley Jhu <stanleyjhu@xxxxxxxxxx>
---
 drivers/ufs/core/ufs-debugfs.c |  8 +++++++-
 drivers/ufs/core/ufs-hwmon.c   | 12 ++++++++++--
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/ufs/core/ufs-debugfs.c b/drivers/ufs/core/ufs-debugfs.c
index 9f83628f3e2c..44a1a9692324 100644
--- a/drivers/ufs/core/ufs-debugfs.c
+++ b/drivers/ufs/core/ufs-debugfs.c
@@ -70,12 +70,18 @@ token_context_lock(ufs_debugfs);
 static int ufs_debugfs_get_user_access(struct ufs_hba *hba)
 	__cond_acquires(0, ufs_debugfs)
 {
+	int err;
+
 	down(&hba->host_sem);
 	if (!ufshcd_is_user_access_allowed(hba)) {
 		up(&hba->host_sem);
 		return -EBUSY;
 	}
-	ufshcd_rpm_get_sync(hba);
+	err = ufshcd_rpm_resume_and_get(hba);
+	if (err) {
+		up(&hba->host_sem);
+		return err;
+	}
 	__acquire(ufs_debugfs);
 	return 0;
 }
diff --git a/drivers/ufs/core/ufs-hwmon.c b/drivers/ufs/core/ufs-hwmon.c
index aa0b60a0ee8a..2b9673d92573 100644
--- a/drivers/ufs/core/ufs-hwmon.c
+++ b/drivers/ufs/core/ufs-hwmon.c
@@ -61,7 +61,11 @@ static int ufs_hwmon_read(struct device *dev, enum hwmon_sensor_types type, u32
 		return -EBUSY;
 	}
 
-	ufshcd_rpm_get_sync(hba);
+	err = ufshcd_rpm_resume_and_get(hba);
+	if (err) {
+		up(&hba->host_sem);
+		return err;
+	}
 
 	switch (attr) {
 	case hwmon_temp_enable:
@@ -113,7 +117,11 @@ static int ufs_hwmon_write(struct device *dev, enum hwmon_sensor_types type, u32
 		return -EBUSY;
 	}
 
-	ufshcd_rpm_get_sync(hba);
+	err = ufshcd_rpm_resume_and_get(hba);
+	if (err) {
+		up(&hba->host_sem);
+		return err;
+	}
 
 	if (val == 1)
 		err = ufshcd_update_ee_usr_mask(hba, MASK_EE_URGENT_TEMP, 0);
-- 
2.56.0.313.g2479322e68-goog