[PATCH v5 3/9] ufs: ufs-qcom: Fix race conditions caused by func ufs_qcom_testbus_config

[PATCH v5 3/9] ufs: ufs-qcom: Fix race conditions caused by func ufs_qcom_testbus_config

[Can Guo]

If ufs_qcom_dump_dbg_regs() calls ufs_qcom_testbus_config() from
ufshcd_suspend/resume and/or clk gate/ungate context, pm_runtime_get_sync()
and ufshcd_hold() will cause racing problems. Fix this by removing the
unnecessary calls of pm_runtime_get_sync() and ufshcd_hold().

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufs-qcom.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index 2e6ddb5..7da27ee 100644
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -1604,9 +1604,6 @@ int ufs_qcom_testbus_config(struct ufs_qcom_host *host)
 	 */
 	}
 	mask <<= offset;
-
-	pm_runtime_get_sync(host->hba->dev);
-	ufshcd_hold(host->hba, false);
 	ufshcd_rmwl(host->hba, TEST_BUS_SEL,
 		    (u32)host->testbus.select_major << 19,
 		    REG_UFS_CFG1);
@@ -1619,8 +1616,6 @@ int ufs_qcom_testbus_config(struct ufs_qcom_host *host)
 	 * committed before returning.
 	 */
 	mb();
-	ufshcd_release(host->hba);
-	pm_runtime_put_sync(host->hba->dev);
 
 	return 0;
 }
-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

[PATCH v5 4/9] scsi: ufs-qcom: Fix schedule while atomic error in ufs_qcom_dump_dbg_regs

[Can Guo]

Dumping testbus registers needs to sleep a bit intermittently as there are
too many of them. Skip them for those contexts where sleep is not allowed.

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufs-qcom.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index 7da27ee..7831b2b 100644
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -1651,13 +1651,16 @@ static void ufs_qcom_dump_dbg_regs(struct ufs_hba *hba)
 	ufshcd_dump_regs(hba, REG_UFS_SYS1CLK_1US, 16 * 4,
 			 "HCI Vendor Specific Registers ");
 
-	/* sleep a bit intermittently as we are dumping too much data */
 	ufs_qcom_print_hw_debug_reg_all(hba, NULL, ufs_qcom_dump_regs_wrapper);
-	udelay(1000);
-	ufs_qcom_testbus_read(hba);
-	udelay(1000);
-	ufs_qcom_print_unipro_testbus(hba);
-	udelay(1000);
+
+	if (in_task()) {
+		/* sleep a bit intermittently as we are dumping too much data */
+		usleep_range(1000, 1100);
+		ufs_qcom_testbus_read(hba);
+		usleep_range(1000, 1100);
+		ufs_qcom_print_unipro_testbus(hba);
+		usleep_range(1000, 1100);
+	}
 }
 
 /**
-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH v5 3/9] ufs: ufs-qcom: Fix race conditions caused by func ufs_qcom_testbus_config

[hongwus]

On 2020-07-23 10:34, Can Guo wrote:
> If ufs_qcom_dump_dbg_regs() calls ufs_qcom_testbus_config() from
> ufshcd_suspend/resume and/or clk gate/ungate context, 
> pm_runtime_get_sync()
> and ufshcd_hold() will cause racing problems. Fix this by removing the
> unnecessary calls of pm_runtime_get_sync() and ufshcd_hold().
> 
> Signed-off-by: Can Guo <cang@codeaurora.org>
> ---
>  drivers/scsi/ufs/ufs-qcom.c | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
> index 2e6ddb5..7da27ee 100644
> --- a/drivers/scsi/ufs/ufs-qcom.c
> +++ b/drivers/scsi/ufs/ufs-qcom.c
> @@ -1604,9 +1604,6 @@ int ufs_qcom_testbus_config(struct ufs_qcom_host 
> *host)
>  	 */
>  	}
>  	mask <<= offset;
> -
> -	pm_runtime_get_sync(host->hba->dev);
> -	ufshcd_hold(host->hba, false);
>  	ufshcd_rmwl(host->hba, TEST_BUS_SEL,
>  		    (u32)host->testbus.select_major << 19,
>  		    REG_UFS_CFG1);
> @@ -1619,8 +1616,6 @@ int ufs_qcom_testbus_config(struct ufs_qcom_host 
> *host)
>  	 * committed before returning.
>  	 */
>  	mb();
> -	ufshcd_release(host->hba);
> -	pm_runtime_put_sync(host->hba->dev);
> 
>  	return 0;
>  }


Reviewed-by: Hongwu Su <hongwus@codeaurora.org>