* [PATCH v2 0/3] Two changes of UFS sysfs
@ 2020-12-24 17:20 Bean Huo
2020-12-24 17:20 ` [PATCH v2 1/3] scsi: ufs: Replace sprintf and snprintf with sysfs_emit Bean Huo
` (2 more replies)
0 siblings, 3 replies; 8+ messages in thread
From: Bean Huo @ 2020-12-24 17:20 UTC (permalink / raw)
To: alim.akhtar, avri.altman, asutoshd, jejb, martin.petersen,
stanley.chu, beanhuo, bvanassche, tomas.winkler, cang
Cc: linux-scsi, linux-kernel, rjw
From: Bean Huo <beanhuo@micron.com>
Changelog:
V1---v2:
1. Add new patch "Let resume callback return -EBUSY after ufshcd_shutdown",
Because the ufshcd_*_resume still returns successful result 0 after
ufshcd_shutdown(). Even add handling of the return value of
pm_runtime_get_sync(), but still there is timeout.
Bean Huo (3):
scsi: ufs: Replace sprintf and snprintf with sysfs_emit
scsi: ufs: Add handling of the return value of pm_runtime_get_sync()
scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown
drivers/scsi/ufs/ufs-sysfs.c | 68 +++++++++++++++++++++++++-----------
drivers/scsi/ufs/ufshcd.c | 12 ++++---
2 files changed, 55 insertions(+), 25 deletions(-)
--
2.17.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2 1/3] scsi: ufs: Replace sprintf and snprintf with sysfs_emit
2020-12-24 17:20 [PATCH v2 0/3] Two changes of UFS sysfs Bean Huo
@ 2020-12-24 17:20 ` Bean Huo
2020-12-24 17:20 ` [PATCH v2 2/3] scsi: ufs: Add handling of the return value of pm_runtime_get_sync() Bean Huo
2020-12-24 17:20 ` [PATCH v2 3/3] scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown Bean Huo
2 siblings, 0 replies; 8+ messages in thread
From: Bean Huo @ 2020-12-24 17:20 UTC (permalink / raw)
To: alim.akhtar, avri.altman, asutoshd, jejb, martin.petersen,
stanley.chu, beanhuo, bvanassche, tomas.winkler, cang
Cc: linux-scsi, linux-kernel, rjw
From: Bean Huo <beanhuo@micron.com>
sprintf and snprintf may cause output defect in sysfs content, it is
better to use new added sysfs_emit function which knows the size of the
temporary buffer.
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Bean Huo <beanhuo@micron.com>
---
drivers/scsi/ufs/ufs-sysfs.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 08e72b7eef6a..0e1438485133 100644
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -67,7 +67,7 @@ static ssize_t rpm_lvl_show(struct device *dev,
{
struct ufs_hba *hba = dev_get_drvdata(dev);
- return sprintf(buf, "%d\n", hba->rpm_lvl);
+ return sysfs_emit(buf, "%d\n", hba->rpm_lvl);
}
static ssize_t rpm_lvl_store(struct device *dev,
@@ -81,7 +81,7 @@ static ssize_t rpm_target_dev_state_show(struct device *dev,
{
struct ufs_hba *hba = dev_get_drvdata(dev);
- return sprintf(buf, "%s\n", ufschd_ufs_dev_pwr_mode_to_string(
+ return sysfs_emit(buf, "%s\n", ufschd_ufs_dev_pwr_mode_to_string(
ufs_pm_lvl_states[hba->rpm_lvl].dev_state));
}
@@ -90,7 +90,7 @@ static ssize_t rpm_target_link_state_show(struct device *dev,
{
struct ufs_hba *hba = dev_get_drvdata(dev);
- return sprintf(buf, "%s\n", ufschd_uic_link_state_to_string(
+ return sysfs_emit(buf, "%s\n", ufschd_uic_link_state_to_string(
ufs_pm_lvl_states[hba->rpm_lvl].link_state));
}
@@ -99,7 +99,7 @@ static ssize_t spm_lvl_show(struct device *dev,
{
struct ufs_hba *hba = dev_get_drvdata(dev);
- return sprintf(buf, "%d\n", hba->spm_lvl);
+ return sysfs_emit(buf, "%d\n", hba->spm_lvl);
}
static ssize_t spm_lvl_store(struct device *dev,
@@ -113,7 +113,7 @@ static ssize_t spm_target_dev_state_show(struct device *dev,
{
struct ufs_hba *hba = dev_get_drvdata(dev);
- return sprintf(buf, "%s\n", ufschd_ufs_dev_pwr_mode_to_string(
+ return sysfs_emit(buf, "%s\n", ufschd_ufs_dev_pwr_mode_to_string(
ufs_pm_lvl_states[hba->spm_lvl].dev_state));
}
@@ -122,7 +122,7 @@ static ssize_t spm_target_link_state_show(struct device *dev,
{
struct ufs_hba *hba = dev_get_drvdata(dev);
- return sprintf(buf, "%s\n", ufschd_uic_link_state_to_string(
+ return sysfs_emit(buf, "%s\n", ufschd_uic_link_state_to_string(
ufs_pm_lvl_states[hba->spm_lvl].link_state));
}
@@ -165,7 +165,7 @@ static ssize_t auto_hibern8_show(struct device *dev,
ufshcd_release(hba);
pm_runtime_put_sync(hba->dev);
- return scnprintf(buf, PAGE_SIZE, "%d\n", ufshcd_ahit_to_us(ahit));
+ return sysfs_emit(buf, "%d\n", ufshcd_ahit_to_us(ahit));
}
static ssize_t auto_hibern8_store(struct device *dev,
@@ -233,18 +233,18 @@ static ssize_t ufs_sysfs_read_desc_param(struct ufs_hba *hba,
return -EINVAL;
switch (param_size) {
case 1:
- ret = sprintf(sysfs_buf, "0x%02X\n", *desc_buf);
+ ret = sysfs_emit(sysfs_buf, "0x%02X\n", *desc_buf);
break;
case 2:
- ret = sprintf(sysfs_buf, "0x%04X\n",
+ ret = sysfs_emit(sysfs_buf, "0x%04X\n",
get_unaligned_be16(desc_buf));
break;
case 4:
- ret = sprintf(sysfs_buf, "0x%08X\n",
+ ret = sysfs_emit(sysfs_buf, "0x%08X\n",
get_unaligned_be32(desc_buf));
break;
case 8:
- ret = sprintf(sysfs_buf, "0x%016llX\n",
+ ret = sysfs_emit(sysfs_buf, "0x%016llX\n",
get_unaligned_be64(desc_buf));
break;
}
@@ -609,7 +609,7 @@ static ssize_t _name##_show(struct device *dev, \
SD_ASCII_STD); \
if (ret < 0) \
goto out; \
- ret = snprintf(buf, PAGE_SIZE, "%s\n", desc_buf); \
+ ret = sysfs_emit(buf, "%s\n", desc_buf); \
out: \
pm_runtime_put_sync(hba->dev); \
kfree(desc_buf); \
@@ -659,7 +659,7 @@ static ssize_t _name##_show(struct device *dev, \
pm_runtime_put_sync(hba->dev); \
if (ret) \
return -EINVAL; \
- return sprintf(buf, "%s\n", flag ? "true" : "false"); \
+ return sysfs_emit(buf, "%s\n", flag ? "true" : "false"); \
} \
static DEVICE_ATTR_RO(_name)
@@ -717,7 +717,7 @@ static ssize_t _name##_show(struct device *dev, \
pm_runtime_put_sync(hba->dev); \
if (ret) \
return -EINVAL; \
- return sprintf(buf, "0x%08X\n", value); \
+ return sysfs_emit(buf, "0x%08X\n", value); \
} \
static DEVICE_ATTR_RO(_name)
@@ -856,7 +856,7 @@ static ssize_t dyn_cap_needed_attribute_show(struct device *dev,
pm_runtime_put_sync(hba->dev);
if (ret)
return -EINVAL;
- return sprintf(buf, "0x%08X\n", value);
+ return sysfs_emit(buf, "0x%08X\n", value);
}
static DEVICE_ATTR_RO(dyn_cap_needed_attribute);
--
2.17.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2 2/3] scsi: ufs: Add handling of the return value of pm_runtime_get_sync()
2020-12-24 17:20 [PATCH v2 0/3] Two changes of UFS sysfs Bean Huo
2020-12-24 17:20 ` [PATCH v2 1/3] scsi: ufs: Replace sprintf and snprintf with sysfs_emit Bean Huo
@ 2020-12-24 17:20 ` Bean Huo
2020-12-28 1:50 ` Can Guo
2020-12-24 17:20 ` [PATCH v2 3/3] scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown Bean Huo
2 siblings, 1 reply; 8+ messages in thread
From: Bean Huo @ 2020-12-24 17:20 UTC (permalink / raw)
To: alim.akhtar, avri.altman, asutoshd, jejb, martin.petersen,
stanley.chu, beanhuo, bvanassche, tomas.winkler, cang
Cc: linux-scsi, linux-kernel, rjw
From: Bean Huo <beanhuo@micron.com>
The race issue may exist between UFS access in UFS sysfs context and UFS
shutdown, thus will cause pm_runtime_get_sync() resume failure.
Add handling of the return value of pm_runtime_get_sync(). Let it return
in case pm_runtime_get_sync() resume failed.
Signed-off-by: Bean Huo <beanhuo@micron.com>
---
drivers/scsi/ufs/ufs-sysfs.c | 38 ++++++++++++++++++++++++++++++------
1 file changed, 32 insertions(+), 6 deletions(-)
diff --git a/drivers/scsi/ufs/ufs-sysfs.c b/drivers/scsi/ufs/ufs-sysfs.c
index 0e1438485133..8e5e36e01bee 100644
--- a/drivers/scsi/ufs/ufs-sysfs.c
+++ b/drivers/scsi/ufs/ufs-sysfs.c
@@ -154,12 +154,17 @@ static ssize_t auto_hibern8_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
u32 ahit;
+ int ret;
struct ufs_hba *hba = dev_get_drvdata(dev);
if (!ufshcd_is_auto_hibern8_supported(hba))
return -EOPNOTSUPP;
- pm_runtime_get_sync(hba->dev);
+ ret = pm_runtime_get_sync(hba->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(hba->dev);
+ return ret;
+ }
ufshcd_hold(hba, false);
ahit = ufshcd_readl(hba, REG_AUTO_HIBERNATE_IDLE_TIMER);
ufshcd_release(hba);
@@ -225,7 +230,12 @@ static ssize_t ufs_sysfs_read_desc_param(struct ufs_hba *hba,
if (param_size > 8)
return -EINVAL;
- pm_runtime_get_sync(hba->dev);
+ ret = pm_runtime_get_sync(hba->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(hba->dev);
+ return ret;
+ }
+
ret = ufshcd_read_desc_param(hba, desc_id, desc_index,
param_offset, desc_buf, param_size);
pm_runtime_put_sync(hba->dev);
@@ -594,7 +604,11 @@ static ssize_t _name##_show(struct device *dev, \
desc_buf = kzalloc(QUERY_DESC_MAX_SIZE, GFP_ATOMIC); \
if (!desc_buf) \
return -ENOMEM; \
- pm_runtime_get_sync(hba->dev); \
+ ret = pm_runtime_get_sync(hba->dev); \
+ if (ret < 0) { \
+ pm_runtime_put_noidle(hba->dev); \
+ return ret; \
+ } \
ret = ufshcd_query_descriptor_retry(hba, \
UPIU_QUERY_OPCODE_READ_DESC, QUERY_DESC_IDN_DEVICE, \
0, 0, desc_buf, &desc_len); \
@@ -653,7 +667,11 @@ static ssize_t _name##_show(struct device *dev, \
struct ufs_hba *hba = dev_get_drvdata(dev); \
if (ufshcd_is_wb_flags(QUERY_FLAG_IDN##_uname)) \
index = ufshcd_wb_get_query_index(hba); \
- pm_runtime_get_sync(hba->dev); \
+ ret = pm_runtime_get_sync(hba->dev); \
+ if (ret < 0) { \
+ pm_runtime_put_noidle(hba->dev); \
+ return ret; \
+ } \
ret = ufshcd_query_flag(hba, UPIU_QUERY_OPCODE_READ_FLAG, \
QUERY_FLAG_IDN##_uname, index, &flag); \
pm_runtime_put_sync(hba->dev); \
@@ -711,7 +729,11 @@ static ssize_t _name##_show(struct device *dev, \
u8 index = 0; \
if (ufshcd_is_wb_attrs(QUERY_ATTR_IDN##_uname)) \
index = ufshcd_wb_get_query_index(hba); \
- pm_runtime_get_sync(hba->dev); \
+ ret = pm_runtime_get_sync(hba->dev); \
+ if (ret < 0) { \
+ pm_runtime_put_noidle(hba->dev); \
+ return ret; \
+ } \
ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR, \
QUERY_ATTR_IDN##_uname, index, 0, &value); \
pm_runtime_put_sync(hba->dev); \
@@ -850,7 +872,11 @@ static ssize_t dyn_cap_needed_attribute_show(struct device *dev,
u8 lun = ufshcd_scsi_to_upiu_lun(sdev->lun);
int ret;
- pm_runtime_get_sync(hba->dev);
+ ret = pm_runtime_get_sync(hba->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(hba->dev);
+ return ret;
+ }
ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
QUERY_ATTR_IDN_DYN_CAP_NEEDED, lun, 0, &value);
pm_runtime_put_sync(hba->dev);
--
2.17.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2 3/3] scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown
2020-12-24 17:20 [PATCH v2 0/3] Two changes of UFS sysfs Bean Huo
2020-12-24 17:20 ` [PATCH v2 1/3] scsi: ufs: Replace sprintf and snprintf with sysfs_emit Bean Huo
2020-12-24 17:20 ` [PATCH v2 2/3] scsi: ufs: Add handling of the return value of pm_runtime_get_sync() Bean Huo
@ 2020-12-24 17:20 ` Bean Huo
2021-01-04 19:26 ` Bean Huo
2021-01-05 1:10 ` Can Guo
2 siblings, 2 replies; 8+ messages in thread
From: Bean Huo @ 2020-12-24 17:20 UTC (permalink / raw)
To: alim.akhtar, avri.altman, asutoshd, jejb, martin.petersen,
stanley.chu, beanhuo, bvanassche, tomas.winkler, cang
Cc: linux-scsi, linux-kernel, rjw
From: Bean Huo <beanhuo@micron.com>
After ufshcd_shutdown(), both UFS device and UFS LINk are powered off,
return '0' will mislead the upper PM layer since the device has not been
successfully resumed yet. This will let pm_runtime_get_sync() caller
mistakenly believe the device/LINK has been resumed, which leads to
request processing timeout that was en-queued later.
To fix this, let ufshcd_system/runtimie_resume() return -EBUSY in case of
hba->is_powered == false.
Signed-off-by: Bean Huo <beanhuo@micron.com>
---
drivers/scsi/ufs/ufshcd.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index e221add25a7e..e1bcac51c01f 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -8950,14 +8950,16 @@ int ufshcd_system_resume(struct ufs_hba *hba)
return -EINVAL;
}
- if (!hba->is_powered || pm_runtime_suspended(hba->dev))
+ if (!hba->is_powered || pm_runtime_suspended(hba->dev)) {
/*
* Let the runtime resume take care of resuming
* if runtime suspended.
*/
+ ret = -EBUSY;
goto out;
- else
+ } else {
ret = ufshcd_resume(hba, UFS_SYSTEM_PM);
+ }
out:
trace_ufshcd_system_resume(dev_name(hba->dev), ret,
ktime_to_us(ktime_sub(ktime_get(), start)),
@@ -9026,10 +9028,12 @@ int ufshcd_runtime_resume(struct ufs_hba *hba)
if (!hba)
return -EINVAL;
- if (!hba->is_powered)
+ if (!hba->is_powered) {
+ ret = -EBUSY;
goto out;
- else
+ } else {
ret = ufshcd_resume(hba, UFS_RUNTIME_PM);
+ }
out:
trace_ufshcd_runtime_resume(dev_name(hba->dev), ret,
ktime_to_us(ktime_sub(ktime_get(), start)),
--
2.17.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2 2/3] scsi: ufs: Add handling of the return value of pm_runtime_get_sync()
2020-12-24 17:20 ` [PATCH v2 2/3] scsi: ufs: Add handling of the return value of pm_runtime_get_sync() Bean Huo
@ 2020-12-28 1:50 ` Can Guo
2021-01-04 17:39 ` Bean Huo
0 siblings, 1 reply; 8+ messages in thread
From: Can Guo @ 2020-12-28 1:50 UTC (permalink / raw)
To: Bean Huo
Cc: alim.akhtar, avri.altman, asutoshd, jejb, martin.petersen,
stanley.chu, beanhuo, bvanassche, tomas.winkler, linux-scsi,
linux-kernel, rjw
On 2020-12-25 01:20, Bean Huo wrote:
> From: Bean Huo <beanhuo@micron.com>
>
> The race issue may exist between UFS access in UFS sysfs context and
> UFS
> shutdown, thus will cause pm_runtime_get_sync() resume failure.
Are you trying to fix the race condition by adding these checks or just
adding these checks in case pm_runtime_get_sync() fails?
Can Guo.
> Add handling of the return value of pm_runtime_get_sync(). Let it
> return
> in case pm_runtime_get_sync() resume failed.
>
> Signed-off-by: Bean Huo <beanhuo@micron.com>
> ---
> drivers/scsi/ufs/ufs-sysfs.c | 38 ++++++++++++++++++++++++++++++------
> 1 file changed, 32 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufs-sysfs.c
> b/drivers/scsi/ufs/ufs-sysfs.c
> index 0e1438485133..8e5e36e01bee 100644
> --- a/drivers/scsi/ufs/ufs-sysfs.c
> +++ b/drivers/scsi/ufs/ufs-sysfs.c
> @@ -154,12 +154,17 @@ static ssize_t auto_hibern8_show(struct device
> *dev,
> struct device_attribute *attr, char *buf)
> {
> u32 ahit;
> + int ret;
> struct ufs_hba *hba = dev_get_drvdata(dev);
>
> if (!ufshcd_is_auto_hibern8_supported(hba))
> return -EOPNOTSUPP;
>
> - pm_runtime_get_sync(hba->dev);
> + ret = pm_runtime_get_sync(hba->dev);
> + if (ret < 0) {
> + pm_runtime_put_noidle(hba->dev);
> + return ret;
> + }
> ufshcd_hold(hba, false);
> ahit = ufshcd_readl(hba, REG_AUTO_HIBERNATE_IDLE_TIMER);
> ufshcd_release(hba);
> @@ -225,7 +230,12 @@ static ssize_t ufs_sysfs_read_desc_param(struct
> ufs_hba *hba,
> if (param_size > 8)
> return -EINVAL;
>
> - pm_runtime_get_sync(hba->dev);
> + ret = pm_runtime_get_sync(hba->dev);
> + if (ret < 0) {
> + pm_runtime_put_noidle(hba->dev);
> + return ret;
> + }
> +
> ret = ufshcd_read_desc_param(hba, desc_id, desc_index,
> param_offset, desc_buf, param_size);
> pm_runtime_put_sync(hba->dev);
> @@ -594,7 +604,11 @@ static ssize_t _name##_show(struct device
> *dev, \
> desc_buf = kzalloc(QUERY_DESC_MAX_SIZE, GFP_ATOMIC); \
> if (!desc_buf) \
> return -ENOMEM; \
> - pm_runtime_get_sync(hba->dev); \
> + ret = pm_runtime_get_sync(hba->dev); \
> + if (ret < 0) { \
> + pm_runtime_put_noidle(hba->dev); \
> + return ret; \
> + } \
> ret = ufshcd_query_descriptor_retry(hba, \
> UPIU_QUERY_OPCODE_READ_DESC, QUERY_DESC_IDN_DEVICE, \
> 0, 0, desc_buf, &desc_len); \
> @@ -653,7 +667,11 @@ static ssize_t _name##_show(struct device
> *dev, \
> struct ufs_hba *hba = dev_get_drvdata(dev); \
> if (ufshcd_is_wb_flags(QUERY_FLAG_IDN##_uname)) \
> index = ufshcd_wb_get_query_index(hba); \
> - pm_runtime_get_sync(hba->dev); \
> + ret = pm_runtime_get_sync(hba->dev); \
> + if (ret < 0) { \
> + pm_runtime_put_noidle(hba->dev); \
> + return ret; \
> + } \
> ret = ufshcd_query_flag(hba, UPIU_QUERY_OPCODE_READ_FLAG, \
> QUERY_FLAG_IDN##_uname, index, &flag); \
> pm_runtime_put_sync(hba->dev); \
> @@ -711,7 +729,11 @@ static ssize_t _name##_show(struct device
> *dev, \
> u8 index = 0; \
> if (ufshcd_is_wb_attrs(QUERY_ATTR_IDN##_uname)) \
> index = ufshcd_wb_get_query_index(hba); \
> - pm_runtime_get_sync(hba->dev); \
> + ret = pm_runtime_get_sync(hba->dev); \
> + if (ret < 0) { \
> + pm_runtime_put_noidle(hba->dev); \
> + return ret; \
> + } \
> ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR, \
> QUERY_ATTR_IDN##_uname, index, 0, &value); \
> pm_runtime_put_sync(hba->dev); \
> @@ -850,7 +872,11 @@ static ssize_t
> dyn_cap_needed_attribute_show(struct device *dev,
> u8 lun = ufshcd_scsi_to_upiu_lun(sdev->lun);
> int ret;
>
> - pm_runtime_get_sync(hba->dev);
> + ret = pm_runtime_get_sync(hba->dev);
> + if (ret < 0) {
> + pm_runtime_put_noidle(hba->dev);
> + return ret;
> + }
> ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
> QUERY_ATTR_IDN_DYN_CAP_NEEDED, lun, 0, &value);
> pm_runtime_put_sync(hba->dev);
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 2/3] scsi: ufs: Add handling of the return value of pm_runtime_get_sync()
2020-12-28 1:50 ` Can Guo
@ 2021-01-04 17:39 ` Bean Huo
0 siblings, 0 replies; 8+ messages in thread
From: Bean Huo @ 2021-01-04 17:39 UTC (permalink / raw)
To: Can Guo
Cc: alim.akhtar, avri.altman, asutoshd, jejb, martin.petersen,
stanley.chu, beanhuo, bvanassche, tomas.winkler, linux-scsi,
linux-kernel, rjw
On Mon, 2020-12-28 at 09:50 +0800, Can Guo wrote:
> > The race issue may exist between UFS access in UFS sysfs context
> > and
> > UFS
> > shutdown, thus will cause pm_runtime_get_sync() resume failure.
>
> Are you trying to fix the race condition by adding these checks or
> just
> adding these checks in case pm_runtime_get_sync() fails?
>
> Can Guo.
Can,
thanks for your review. Sorry, I didn't quite get your point.
This patch is just to add checkup in case pm_runtime_get_sync() failed.
what else should be added?
Bean
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 3/3] scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown
2020-12-24 17:20 ` [PATCH v2 3/3] scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown Bean Huo
@ 2021-01-04 19:26 ` Bean Huo
2021-01-05 1:10 ` Can Guo
1 sibling, 0 replies; 8+ messages in thread
From: Bean Huo @ 2021-01-04 19:26 UTC (permalink / raw)
To: rjw
Cc: linux-scsi, linux-kernel, rjw, alim.akhtar, avri.altman,
asutoshd, jejb, martin.petersen, stanley.chu, beanhuo,
bvanassche, tomas.winkler, cang
Hi Rafael
Would you please help to review this patch assoociated with PM resume
callback implementation?
Original code that ufshcd_system/runtime_resume returns '0' in case
resume failed due to the UFS device and UFS LINk are powered off(hba-
>is_powered == false).
In the patch 2/3 Add handling of the return value of
pm_runtime_get_sync() is to fix race exists between shudown path and
device access through sysfs node.
Thanks,
Bean
On Thu, 2020-12-24 at 18:20 +0100, Bean Huo wrote:
> From: Bean Huo <beanhuo@micron.com>
>
> After ufshcd_shutdown(), both UFS device and UFS LINk are powered
> off,
> return '0' will mislead the upper PM layer since the device has not
> been
> successfully resumed yet. This will let pm_runtime_get_sync() caller
> mistakenly believe the device/LINK has been resumed, which leads to
> request processing timeout that was en-queued later.
>
> To fix this, let ufshcd_system/runtimie_resume() return -EBUSY in
> case of
> hba->is_powered == false.
>
> Signed-off-by: Bean Huo <beanhuo@micron.com>
> ---
> drivers/scsi/ufs/ufshcd.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index e221add25a7e..e1bcac51c01f 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -8950,14 +8950,16 @@ int ufshcd_system_resume(struct ufs_hba *hba)
> return -EINVAL;
> }
>
> - if (!hba->is_powered || pm_runtime_suspended(hba->dev))
> + if (!hba->is_powered || pm_runtime_suspended(hba->dev)) {
> /*
> * Let the runtime resume take care of resuming
> * if runtime suspended.
> */
> + ret = -EBUSY;
> goto out;
> - else
> + } else {
> ret = ufshcd_resume(hba, UFS_SYSTEM_PM);
> + }
> out:
> trace_ufshcd_system_resume(dev_name(hba->dev), ret,
> ktime_to_us(ktime_sub(ktime_get(), start)),
> @@ -9026,10 +9028,12 @@ int ufshcd_runtime_resume(struct ufs_hba
> *hba)
> if (!hba)
> return -EINVAL;
>
> - if (!hba->is_powered)
> + if (!hba->is_powered) {
> + ret = -EBUSY;
> goto out;
> - else
> + } else {
> ret = ufshcd_resume(hba, UFS_RUNTIME_PM);
> + }
> out:
> trace_ufshcd_runtime_resume(dev_name(hba->dev), ret,
> ktime_to_us(ktime_sub(ktime_get(), start)),
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 3/3] scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown
2020-12-24 17:20 ` [PATCH v2 3/3] scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown Bean Huo
2021-01-04 19:26 ` Bean Huo
@ 2021-01-05 1:10 ` Can Guo
1 sibling, 0 replies; 8+ messages in thread
From: Can Guo @ 2021-01-05 1:10 UTC (permalink / raw)
To: Bean Huo
Cc: alim.akhtar, avri.altman, asutoshd, jejb, martin.petersen,
stanley.chu, beanhuo, bvanassche, tomas.winkler, linux-scsi,
linux-kernel, rjw
On 2020-12-25 01:20, Bean Huo wrote:
> From: Bean Huo <beanhuo@micron.com>
>
> After ufshcd_shutdown(), both UFS device and UFS LINk are powered off,
> return '0' will mislead the upper PM layer since the device has not
> been
> successfully resumed yet. This will let pm_runtime_get_sync() caller
> mistakenly believe the device/LINK has been resumed, which leads to
> request processing timeout that was en-queued later.
>
> To fix this, let ufshcd_system/runtimie_resume() return -EBUSY in case
> of
> hba->is_powered == false.
This change won't work as you expect...
During/after shutdown, for UFS's case only,
pm_runtime_get_sync(hba->dev) will most likely return 0,
because it is already RUNTIME_ACTIVE, pm_runtime_get_sync()
will directly return 0... meaning your change won't even be
exercised.
Check Stanley's change -
https://lore.kernel.org/patchwork/patch/1341389/
Can Guo.
>
> Signed-off-by: Bean Huo <beanhuo@micron.com>
> ---
> drivers/scsi/ufs/ufshcd.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index e221add25a7e..e1bcac51c01f 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -8950,14 +8950,16 @@ int ufshcd_system_resume(struct ufs_hba *hba)
> return -EINVAL;
> }
>
> - if (!hba->is_powered || pm_runtime_suspended(hba->dev))
> + if (!hba->is_powered || pm_runtime_suspended(hba->dev)) {
> /*
> * Let the runtime resume take care of resuming
> * if runtime suspended.
> */
> + ret = -EBUSY;
> goto out;
> - else
> + } else {
> ret = ufshcd_resume(hba, UFS_SYSTEM_PM);
> + }
> out:
> trace_ufshcd_system_resume(dev_name(hba->dev), ret,
> ktime_to_us(ktime_sub(ktime_get(), start)),
> @@ -9026,10 +9028,12 @@ int ufshcd_runtime_resume(struct ufs_hba *hba)
> if (!hba)
> return -EINVAL;
>
> - if (!hba->is_powered)
> + if (!hba->is_powered) {
> + ret = -EBUSY;
> goto out;
> - else
> + } else {
> ret = ufshcd_resume(hba, UFS_RUNTIME_PM);
> + }
> out:
> trace_ufshcd_runtime_resume(dev_name(hba->dev), ret,
> ktime_to_us(ktime_sub(ktime_get(), start)),
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2021-01-05 1:10 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-12-24 17:20 [PATCH v2 0/3] Two changes of UFS sysfs Bean Huo
2020-12-24 17:20 ` [PATCH v2 1/3] scsi: ufs: Replace sprintf and snprintf with sysfs_emit Bean Huo
2020-12-24 17:20 ` [PATCH v2 2/3] scsi: ufs: Add handling of the return value of pm_runtime_get_sync() Bean Huo
2020-12-28 1:50 ` Can Guo
2021-01-04 17:39 ` Bean Huo
2020-12-24 17:20 ` [PATCH v2 3/3] scsi: ufs: Let resume callback return -EBUSY after ufshcd_shutdown Bean Huo
2021-01-04 19:26 ` Bean Huo
2021-01-05 1:10 ` Can Guo
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