[PATCH v2 0/3] Three minor fixes w.r.t suspend/resume

[PATCH v2 0/3] Three minor fixes w.r.t suspend/resume

[Can Guo]

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.

[PATCH v2 1/3] scsi: ufs: Do not put UFS power into LPM if link is broken

[Can Guo]

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

Fixes: 4db7a23605973 ("scsi: ufs: Fix concurrency of error handler and other error recovery paths")
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 6da1da8..28501bb 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -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.

[PATCH v2 2/3] scsi: ufs: Cancel rpm_dev_flush_recheck_work during system suspend

[Can Guo]

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.

Fixes: 51dd905bd2f61 ("scsi: ufs: Fix WriteBooster flush during runtime suspend")
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 28501bb..a2f9c8e 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -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.

[PATCH v2 3/3] scsi: ufs: Narrow down fast pass in system suspend path

[Can Guo]

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.

Fixes: 0b257734344aa ("scsi: ufs: optimize system suspend handling")
Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index a2f9c8e..c480f88 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -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.

RE: [PATCH v2 0/3] Three minor fixes w.r.t suspend/resume

[Daejun Park]

Hi Can Guo,

>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(-)
> 

This series looks good to me.
Reviewed-by: Daejun Park <daejun7.park@samsung.com>

Thanks,
Daejun

Re: [PATCH v2 0/3] Three minor fixes w.r.t suspend/resume

[Martin K. Petersen]

On Sun, 25 Apr 2021 20:48:37 -0700, Can Guo wrote:

> 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
> 
> [...]

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