[PATCH v2 2/2] scsi: ufs: core: add is_sys_suspended state before recovery

[HOYOUNG SEO]

If a LINERESET is reported and the hibern8 exit fails in
__ufshcd_wl_resume() during system resume, the link is recovered twice:

  - the UIC error interrupt schedules eh_work, and ufshcd_err_handler()
    calls ufshcd_link_recovery() because hba->pm_op_in_progress is set;
  - __ufshcd_wl_resume() calls ufshcd_link_recovery() itself after the
    hibern8 exit failure.

Since the early recovery path in ufshcd_err_handler() does not take
hba->host_sem, the two recoveries are not serialized and may reset the
host and the device concurrently.

During system resume, hba->host_sem is held from ufshcd_wl_suspend()
until ufshcd_wl_resume() returns, so the error handler can simply wait
for it. Skip the early link recovery when hba->is_sys_suspended is set.
With the previous patch, the errors already recovered by the resume path
are cleared, so ufshcd_err_handler() stops once host_sem is released
unless new errors occurred. If the resume failed, is_sys_suspended stays
set and the error handler performs a full recovery as usual.

The early link recovery is kept for runtime PM, where host_sem is not
held and the error handler cannot wait for the PM operation to finish.

Signed-off-by: HOYOUNG SEO <hy50.seo@xxxxxxxxxxx>
---
 drivers/ufs/core/ufshcd.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 74dfbb98129e..d085d394858f 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -7053,9 +7053,14 @@ static void ufshcd_err_handler(struct work_struct *work)
 		 * runtime resume. This avoids potential deadlocks that could
 		 * happen if we tried to resume the device while a PM operation
 		 * is already in progress.
+		 *
+		 * During system resume, host_sem is held from
+		 * ufshcd_wl_suspend() until ufshcd_wl_resume() returns, so wait
+		 * for it below instead of recovering the link concurrently with
+		 * the resume path.
 		 */
 		ufshcd_rpm_get_noresume(hba);
-		if (hba->pm_op_in_progress) {
+		if (hba->pm_op_in_progress && !hba->is_sys_suspended) {
 			ufshcd_link_recovery(hba);
 			ufshcd_rpm_put(hba);
 			return;
-- 
2.34.1