Re: [PATCH 9/9] scsi: ufs: Properly release resources if a task is aborted successfully

Re: [PATCH 9/9] scsi: ufs: Properly release resources if a task is aborted successfully

[Can Guo]

Hi Markus,

On 2020-08-07 17:33, Markus Elfring wrote:
>> … To fix it, …
> 
> I propose to replace this wording by the tag “Fixes”.
> 
> 
>> … "mannually", …
> 
> Please avoid a typo:
> … "manually", …
> 
> 
> Regards,
> Markus

Thanks, will fix these in next version.

Regards,
Can Guo.

Re: [9/9] scsi: ufs: Properly release resources if a task is aborted successfully

[Can Guo]

Hi Markus,

On 2020-08-10 02:00, Markus Elfring wrote:
>> Thanks, will fix these in next version.
> 
> Thanks for your adjustment of the proposed commit message.
> Should the corresponding patch be marked with an other version number?
> https://lore.kernel.org/linux-arm-kernel/1596975355-39813-10-git-send-email-cang@codeaurora.org/
> https://lore.kernel.org/patchwork/patch/1285629/
> https://lkml.org/lkml/2020/8/9/87
> 
> Should a cover letter be provided for such a patch series?
> 
> Regards,
> Markus

I am not sure if you got my mails, this patch is included in
a patch series with other 8 changes and they do have a cover
letter. Let me re-send them to you.

Thanks,

Can Guo.

[PATCH v11 0/9] Fix up and simplify error recovery mechanism

[Can Guo]

The changes have been tested with error injections of multiple error types (and
all kinds of mixture of them) during runtime, e.g. hibern8 enter/ exit error,
power mode change error and fatal/non-fatal error from IRQ context. During the
test, error injections happen randomly across all contexts, e.g. clk scaling,
clk gate/ungate, runtime suspend/resume and IRQ.

There are a few more fixes to resolve other minor problems based on the main
change, such as LINERESET handling and racing btw error handler and system
suspend/resume/shutdown, but they will be pushed after this series is taken,
due to there are already too many lines in these changes.

Change since v10:
- Incorporated Markus Elfring's comments

Change since v9:
- Fixed compilation warning from option [-Werror=implicit-fallthrough=] in patch "scsi: ufs: Fix a racing problem btw error handler and runtime PM ops"

Change since v8:
- Added one more fix to ufshcd_abort as requested by Stanley Chu

Change since v7:
- Incorporated Asutosh's comments
- Refined patch "scsi: ufs: Recover hba runtime PM error in error handler"

Change since v6:
- Modified change "scsi: ufs-qcom: Fix schedule while atomic error in ufs_qcom_dump_dbg_regs" to "scsi: ufs-qcom: Remove testbus dump in ufs_qcom_dump_dbg_regs"

Change since v5:
- Dropped change "scsi: ufs: Fix imbalanced scsi_block_reqs_cnt caused by ufshcd_hold()" as it is not quite related with this series
- Refined func ufshcd_err_handling_prepare in change "scsi: ufs: Recover hba runtime PM error in error handler"

Change since v4:
- Split the original change "ufs: ufs-qcom: Fix a few BUGs in func ufs_qcom_dump_dbg_regs()" to 2 small changes

Change since v3:
- Split the original change "scsi: ufs: Fix up and simplify error recovery mechanism" into 5 changes

Change since v2:
- Incorporate Bart's comment to change "scsi: ufs: Add checks before setting clk-gating states"
- Revised the commit msg of change "scsi: ufs: Fix up and simplify error recovery mechanism"

Change since v1:
- Fixed a compilation error in case that CONFIG_PM is N

Can Guo (9):
  scsi: ufs: Add checks before setting clk-gating states
  ufs: ufs-qcom: Fix race conditions caused by func
    ufs_qcom_testbus_config
  scsi: ufs-qcom: Remove testbus dump in ufs_qcom_dump_dbg_regs
  scsi: ufs: Add some debug infos to ufshcd_print_host_state
  scsi: ufs: Fix concurrency of error handler and other error recovery
    paths
  scsi: ufs: Recover hba runtime PM error in error handler
  scsi: ufs: Move dumps in IRQ handler to error handler
  scsi: ufs: Fix a racing problem btw error handler and runtime PM ops
  scsi: ufs: Properly release resources if a task is aborted
    successfully

 drivers/scsi/ufs/ufs-qcom.c  |  37 ----
 drivers/scsi/ufs/ufs-sysfs.c |   1 +
 drivers/scsi/ufs/ufshcd.c    | 509 +++++++++++++++++++++++++++----------------
 drivers/scsi/ufs/ufshcd.h    |  14 ++
 4 files changed, 339 insertions(+), 222 deletions(-)

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

[PATCH 9/9] scsi: ufs: Properly release resources if a task is aborted successfully

[Can Guo]

In current UFS task abort hook, namely ufshcd_abort(), if one task is
aborted successfully, clk_gating.active_reqs held by this task is not
decreased, which makes clk_gating.active_reqs stay above zero forever,
thus clock gating would never happen. Instead of releasing resources of
one task "manually", use the existing func __ufshcd_transfer_req_compl().
This change can also eliminate possible racing of scsi_dma_unmap() from
the real completion in IRQ handler path.

Fixes: 5a0b0cb9bee76 ("ufs: Add support for clock gating")
Signed-off-by: Can Guo <cang@codeaurora.org>
CC: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 9ebb5cd..efb40b1 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6636,11 +6636,8 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 		goto out;
 	}
 
-	scsi_dma_unmap(cmd);
-
 	spin_lock_irqsave(host->host_lock, flags);
-	ufshcd_outstanding_req_clear(hba, tag);
-	hba->lrb[tag].cmd = NULL;
+	__ufshcd_transfer_req_compl(hba, (1UL << tag));
 	spin_unlock_irqrestore(host->host_lock, flags);
 
 out:
-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

[PATCH v10 0/9] Fix up and simplify error recovery mechanism

[Can Guo]

The changes have been tested with error injections of multiple error types (and
all kinds of mixture of them) during runtime, e.g. hibern8 enter/ exit error,
power mode change error and fatal/non-fatal error from IRQ context. During the
test, error injections happen randomly across all contexts, e.g. clk scaling,
clk gate/ungate, runtime suspend/resume and IRQ.

There are a few more fixes to resolve other minor problems based on the main
change, such as LINERESET handling and racing btw error handler and system
suspend/resume/shutdown, but they will be pushed after this series is taken,
due to there are already too many lines in these changes.

Change since v9:
- Fixed compilation warning from option [-Werror=implicit-fallthrough=] in patch "scsi: ufs: Fix a racing problem btw error handler and runtime PM ops"

Change since v8:
- Added one more fix to ufshcd_abort as requested by Stanley Chu

Change since v7:
- Incorporated Asutosh's comments
- Refined patch "scsi: ufs: Recover hba runtime PM error in error handler"

Change since v6:
- Modified change "scsi: ufs-qcom: Fix schedule while atomic error in ufs_qcom_dump_dbg_regs" to "scsi: ufs-qcom: Remove testbus dump in ufs_qcom_dump_dbg_regs"

Change since v5:
- Dropped change "scsi: ufs: Fix imbalanced scsi_block_reqs_cnt caused by ufshcd_hold()" as it is not quite related with this series
- Refined func ufshcd_err_handling_prepare in change "scsi: ufs: Recover hba runtime PM error in error handler"

Change since v4:
- Split the original change "ufs: ufs-qcom: Fix a few BUGs in func ufs_qcom_dump_dbg_regs()" to 2 small changes

Change since v3:
- Split the original change "scsi: ufs: Fix up and simplify error recovery mechanism" into 5 changes

Change since v2:
- Incorporate Bart's comment to change "scsi: ufs: Add checks before setting clk-gating states"
- Revised the commit msg of change "scsi: ufs: Fix up and simplify error recovery mechanism"

Change since v1:
- Fixed a compilation error in case that CONFIG_PM is N


Can Guo (9):
  scsi: ufs: Add checks before setting clk-gating states
  ufs: ufs-qcom: Fix race conditions caused by func
    ufs_qcom_testbus_config
  scsi: ufs-qcom: Remove testbus dump in ufs_qcom_dump_dbg_regs
  scsi: ufs: Add some debug infos to ufshcd_print_host_state
  scsi: ufs: Fix concurrency of error handler and other error recovery
    paths
  scsi: ufs: Recover hba runtime PM error in error handler
  scsi: ufs: Move dumps in IRQ handler to error handler
  scsi: ufs: Fix a racing problem btw error handler and runtime PM ops
  scsi: ufs: Properly release resources if a task is aborted
    successfully

 drivers/scsi/ufs/ufs-qcom.c  |  37 ----
 drivers/scsi/ufs/ufs-sysfs.c |   1 +
 drivers/scsi/ufs/ufshcd.c    | 509 +++++++++++++++++++++++++++----------------
 drivers/scsi/ufs/ufshcd.h    |  14 ++
 4 files changed, 339 insertions(+), 222 deletions(-)

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

[PATCH 9/9] scsi: ufs: Properly release resources if a task is aborted successfully

[Can Guo]

In current UFS task abort hook, namely ufshcd_abort(), if a task is
aborted successfully, clock scaling busy time statistics is not updated
and, most important, clk_gating.active_reqs is not decreased, which makes
clk_gating.active_reqs stay above zero forever, thus clock gating would
never happen. To fix it, instead of releasing resources "mannually", use
the existing func __ufshcd_transfer_req_compl(). This can also eliminate
racing of scsi_dma_unmap() from the real completion in IRQ handler path.

Signed-off-by: Can Guo <cang@codeaurora.org>
CC: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index b2947ab..9541fc7 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6636,11 +6636,8 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 		goto out;
 	}
 
-	scsi_dma_unmap(cmd);
-
 	spin_lock_irqsave(host->host_lock, flags);
-	ufshcd_outstanding_req_clear(hba, tag);
-	hba->lrb[tag].cmd = NULL;
+	__ufshcd_transfer_req_compl(hba, (1UL << tag));
 	spin_unlock_irqrestore(host->host_lock, flags);
 
 out:
-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.