[PATCH v2 4/5] scsi: ufs: bsg: Abort ufs_bsg_request() when runtime resume fails

[Stanley Jhu <stanleyjhu@google.com>]

ufs_bsg_request() resumes the UFS device W-LUN with
ufshcd_rpm_get_sync() and ignores its return value:

1. The W-LUN is runtime suspended.
2. User space submits a BSG request.
3. ufs_bsg_request() 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_bsg_request() dispatches the BSG command while the W-LUN is
   still suspended.

Use ufshcd_rpm_resume_and_get() and jump to out_complete on error so
the BSG job is completed via bsg_job_done() with the failure code
without dropping an unacquired runtime PM reference.

Fixes: b294ff3e3449 ("scsi: ufs: core: Enable power management for wlun")
Cc: stable@vger.kernel.org # needs "scsi: ufs: core: Introduce ufshcd_rpm_resume_and_get() helper"
Signed-off-by: Stanley Jhu <stanleyjhu@google.com>
---
 drivers/ufs/core/ufs_bsg.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufs_bsg.c b/drivers/ufs/core/ufs_bsg.c
index baf6ae917d36..8df1a2c6abf6 100644
--- a/drivers/ufs/core/ufs_bsg.c
+++ b/drivers/ufs/core/ufs_bsg.c
@@ -150,7 +150,9 @@ static int ufs_bsg_request(struct bsg_job *job)
 		goto out_complete;
 	}
 
-	ufshcd_rpm_get_sync(hba);
+	ret = ufshcd_rpm_resume_and_get(hba);
+	if (ret)
+		goto out_complete;
 
 	msgcode = bsg_request->msgcode;
 	switch (msgcode) {
-- 
2.56.0.313.g2479322e68-goog