Three minor fixes w.r.t suspend/resume

1st change can fix a possible OCP issue when AH8 error happens.
2nd and 3rd change can fix race conditions btw suspend/resume and other contexts.

Can Guo (3):
scsi: ufs: Do not put UFS power into LPM if link is broken
scsi: ufs: Cancel rpm_dev_flush_recheck_work during system suspend
scsi: ufs: Narrow down fast pass in system suspend path

Change since V1:
- Incorporated Daejun's comment.

 drivers/scsi/ufs/ufshcd.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

During resume, if link is broken due to AH8 failure, make sure ufshcd_resume() do not put UFS power back into LPM.

---
 drivers/scsi/ufs/ufshcd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

index 6da1da8..28501bb 100644
@@ -8660,7 +8660,7 @@ static void ufshcd_vreg_set_lpm(struct ufs_hba *hba)
 	} else if (!ufshcd_is_ufs_dev_active(hba)) {
 		ufshcd_toggle_vreg(hba->dev, hba->vreg_info.vcc, false);
 		vcc_off = true;
-		if (!ufshcd_is_link_active(hba)) {
+		if (ufshcd_is_link_hibern8(hba) || ufshcd_is_link_off(hba)) {
 			ufshcd_config_vreg_lpm(hba, hba->vreg_info.vccq);
 			ufshcd_config_vreg_lpm(hba, hba->vreg_info.vccq2);
 		}

@@ -8682,7 +8682,7 @@ static int ufshcd_vreg_set_hpm(struct ufs_hba *hba)
 	    !hba->dev_info.is_lu_power_on_wp) {
 		ret = ufshcd_setup_vreg(hba, true);
 	} else if (!ufshcd_is_ufs_dev_active(hba)) {
-		if (!ret && !ufshcd_is_link_active(hba)) {
+		if (!ufshcd_is_link_active(hba)) {
 			ret = ufshcd_config_vreg_hpm(hba, hba->vreg_info.vccq);
 			if (ret)
 				goto vcc_disable;

Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

During ufs system suspend, leaving rpm_dev_flush_recheck_work running or pending is risky, because concurrency may happen btw system suspend/resume and runtime resume routine. Fix it by cancelling rpm_dev_flush_recheck_work synchronously during system suspend.

---
 drivers/scsi/ufs/ufshcd.c | 2 ++
 1 file changed, 2 insertions(+)

index 28501bb..a2f9c8e 100644
@@ -9044,6 +9044,8 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
 	if (!hba->is_powered)
 		return 0;
 
+	cancel_delayed_work_sync(&hba->rpm_dev_flush_recheck_work);
+
 	if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) ==
 	     hba->curr_dev_pwr_mode) &&
 	    (ufs_get_pm_lvl_to_link_pwr_state(hba->spm_lvl) ==

Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

If spm_lvl is set to 0 or 1, when system suspend kicks start and hba is runtime active, system suspend may just bail without doing anything (the fast pass), leaving other contexts still running, e.g., clock gating and clock scaling. When system resume kicks start, concurrency can happen btw ufshcd_resume() and these contexts, leading to various stability issues. Fix it by adding a check against hba's runtime status and allowing fast pass only if hba is runtime suspended, otherwise let system suspend go ahead call ufshcd_suspend(). This can guarantee that these contexts are stopped by either runtime suspend or system suspend.

---
 drivers/scsi/ufs/ufshcd.c | 1 +
 1 file changed, 1 insertion(+)

index a2f9c8e..c480f88 100644
@@ -9050,6 +9050,7 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
 	     hba->curr_dev_pwr_mode) &&
 	    (ufs_get_pm_lvl_to_link_pwr_state(hba->spm_lvl) ==
 	     hba->uic_link_state) &&
+	     pm_runtime_suspended(hba->dev) &&
 	     !hba->dev_info.b_rpm_dev_flush_capable)
 		goto out;
 

Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

Hi Can Guo,

This series looks good to me.

Thanks,
Daejun

Applied to 5.13/scsi-fixes, thanks!

[1/3] scsi: ufs: Do not put UFS power into LPM if link is broken

      https://git.kernel.org/mkp/scsi/c/23043dd87b15
[2/3] scsi: ufs: Cancel rpm_dev_flush_recheck_work during system suspend
      https://git.kernel.org/mkp/scsi/c/637822e63b79
[3/3] scsi: ufs: Narrow down fast pass in system suspend path
      https://git.kernel.org/mkp/scsi/c/ce4f62f9dd8c

Martin K. Petersen	Oracle Linux Engineering