* [PATCH v3] power_supply: power_supply_read_temp only if use_cnt > 0
@ 2016-06-07 20:26 Rhyland Klein
2016-06-08 6:35 ` Krzysztof Kozlowski
0 siblings, 1 reply; 6+ messages in thread
From: Rhyland Klein @ 2016-06-07 20:26 UTC (permalink / raw)
To: Sebastian Reichel, Dmitry Eremin-Solenikov, David Woodhouse
Cc: linux-pm, linux-kernel, Jon Hunter, Krzysztof Kozlowski,
Rhyland Klein, stable
Change power_supply_read_temp() to use power_supply_get_property()
so that it will check the use_cnt and ensure it is > 0. The use_cnt
will be incremented at the end of __power_supply_register, so this
will block to case where get_property can be called before the supply
is fully registered. This fixes the issue show in the stack below:
[ 1.452598] power_supply_read_temp+0x78/0x80
[ 1.458680] thermal_zone_get_temp+0x5c/0x11c
[ 1.464765] thermal_zone_device_update+0x34/0xb4
[ 1.471195] thermal_zone_device_register+0x87c/0x8cc
[ 1.477974] __power_supply_register+0x364/0x424
[ 1.484317] power_supply_register_no_ws+0x10/0x18
[ 1.490833] bq27xxx_battery_setup+0x10c/0x164
[ 1.497003] bq27xxx_battery_i2c_probe+0xd0/0x1b0
[ 1.503435] i2c_device_probe+0x174/0x240
[ 1.509172] driver_probe_device+0x1fc/0x29c
[ 1.515167] __driver_attach+0xa4/0xa8
[ 1.520643] bus_for_each_dev+0x58/0x98
[ 1.526204] driver_attach+0x20/0x28
[ 1.531505] bus_add_driver+0x1c8/0x22c
[ 1.537067] driver_register+0x68/0x108
[ 1.542630] i2c_register_driver+0x38/0x7c
[ 1.548457] bq27xxx_battery_i2c_driver_init+0x18/0x20
[ 1.555321] do_one_initcall+0x38/0x12c
[ 1.560886] kernel_init_freeable+0x148/0x1ec
[ 1.566972] kernel_init+0x10/0xfc
[ 1.572101] ret_from_fork+0x10/0x40
Also make the same change to ps_get_max_charge_cntl_limit() and
ps_get_cur_chrage_cntl_limit() to be safe. Lastly, change the return
value of power_supply_get_property() to -EAGAIN from -ENODEV if
use_cnt <= 0.
Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")
Cc: stable@vger.kernel.org
Signed-off-by: Rhyland Klein <rklein@nvidia.com>
---
v3:
- Changed calls to ->get_property() to use common
power_supply_get_property()
- reworded description, added "Fixes" line
- Changed return value of power_supply_get_property() to -EAGAIN
v2:
- Added cc stable
- changed return to -EAGAIN in case of use_cnt < 1
- Removed WARNING
- return value check added in additional patch:
https://lkml.org/lkml/2016/6/6/706
drivers/power/power_supply_core.c | 26 ++++++++++++++++----------
1 file changed, 16 insertions(+), 10 deletions(-)
diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
index 456987c88baa..cccc630bd68e 100644
--- a/drivers/power/power_supply_core.c
+++ b/drivers/power/power_supply_core.c
@@ -492,7 +492,7 @@ int power_supply_get_property(struct power_supply *psy,
union power_supply_propval *val)
{
if (atomic_read(&psy->use_cnt) <= 0)
- return -ENODEV;
+ return -EAGAIN;
return psy->desc->get_property(psy, psp, val);
}
@@ -564,12 +564,14 @@ static int power_supply_read_temp(struct thermal_zone_device *tzd,
int ret;
WARN_ON(tzd == NULL);
+
psy = tzd->devdata;
- ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
+ ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
+ if (!ret)
+ return ret;
/* Convert tenths of degree Celsius to milli degree Celsius. */
- if (!ret)
- *temp = val.intval * 100;
+ *temp = val.intval * 100;
return ret;
}
@@ -612,10 +614,12 @@ static int ps_get_max_charge_cntl_limit(struct thermal_cooling_device *tcd,
int ret;
psy = tcd->devdata;
- ret = psy->desc->get_property(psy,
- POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX, &val);
+ ret = power_supply_get_property(psy,
+ POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX, &val);
if (!ret)
- *state = val.intval;
+ return ret;
+
+ *state = val.intval;
return ret;
}
@@ -628,10 +632,12 @@ static int ps_get_cur_chrage_cntl_limit(struct thermal_cooling_device *tcd,
int ret;
psy = tcd->devdata;
- ret = psy->desc->get_property(psy,
- POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT, &val);
+ ret = power_supply_get_property(psy,
+ POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT, &val);
if (!ret)
- *state = val.intval;
+ return ret;
+
+ *state = val.intval;
return ret;
}
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v3] power_supply: power_supply_read_temp only if use_cnt > 0
2016-06-07 20:26 [PATCH v3] power_supply: power_supply_read_temp only if use_cnt > 0 Rhyland Klein
@ 2016-06-08 6:35 ` Krzysztof Kozlowski
2016-06-08 15:26 ` Rhyland Klein
0 siblings, 1 reply; 6+ messages in thread
From: Krzysztof Kozlowski @ 2016-06-08 6:35 UTC (permalink / raw)
To: Rhyland Klein, Sebastian Reichel, Dmitry Eremin-Solenikov,
David Woodhouse
Cc: linux-pm, linux-kernel, Jon Hunter, stable
On 06/07/2016 10:26 PM, Rhyland Klein wrote:
> Change power_supply_read_temp() to use power_supply_get_property()
> so that it will check the use_cnt and ensure it is > 0. The use_cnt
> will be incremented at the end of __power_supply_register, so this
> will block to case where get_property can be called before the supply
> is fully registered. This fixes the issue show in the stack below:
>
> [ 1.452598] power_supply_read_temp+0x78/0x80
> [ 1.458680] thermal_zone_get_temp+0x5c/0x11c
> [ 1.464765] thermal_zone_device_update+0x34/0xb4
> [ 1.471195] thermal_zone_device_register+0x87c/0x8cc
> [ 1.477974] __power_supply_register+0x364/0x424
> [ 1.484317] power_supply_register_no_ws+0x10/0x18
> [ 1.490833] bq27xxx_battery_setup+0x10c/0x164
> [ 1.497003] bq27xxx_battery_i2c_probe+0xd0/0x1b0
> [ 1.503435] i2c_device_probe+0x174/0x240
> [ 1.509172] driver_probe_device+0x1fc/0x29c
> [ 1.515167] __driver_attach+0xa4/0xa8
> [ 1.520643] bus_for_each_dev+0x58/0x98
> [ 1.526204] driver_attach+0x20/0x28
> [ 1.531505] bus_add_driver+0x1c8/0x22c
> [ 1.537067] driver_register+0x68/0x108
> [ 1.542630] i2c_register_driver+0x38/0x7c
> [ 1.548457] bq27xxx_battery_i2c_driver_init+0x18/0x20
> [ 1.555321] do_one_initcall+0x38/0x12c
> [ 1.560886] kernel_init_freeable+0x148/0x1ec
> [ 1.566972] kernel_init+0x10/0xfc
> [ 1.572101] ret_from_fork+0x10/0x40
>
> Also make the same change to ps_get_max_charge_cntl_limit() and
> ps_get_cur_chrage_cntl_limit() to be safe. Lastly, change the return
> value of power_supply_get_property() to -EAGAIN from -ENODEV if
> use_cnt <= 0.
>
> Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")
> Cc: stable@vger.kernel.org
> Signed-off-by: Rhyland Klein <rklein@nvidia.com>
> ---
> v3:
> - Changed calls to ->get_property() to use common
> power_supply_get_property()
> - reworded description, added "Fixes" line
> - Changed return value of power_supply_get_property() to -EAGAIN
>
> v2:
> - Added cc stable
> - changed return to -EAGAIN in case of use_cnt < 1
> - Removed WARNING
> - return value check added in additional patch:
> https://lkml.org/lkml/2016/6/6/706
>
> drivers/power/power_supply_core.c | 26 ++++++++++++++++----------
> 1 file changed, 16 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
> index 456987c88baa..cccc630bd68e 100644
> --- a/drivers/power/power_supply_core.c
> +++ b/drivers/power/power_supply_core.c
> @@ -492,7 +492,7 @@ int power_supply_get_property(struct power_supply *psy,
> union power_supply_propval *val)
> {
> if (atomic_read(&psy->use_cnt) <= 0)
> - return -ENODEV;
> + return -EAGAIN;
Wait, no. I was thinking of changing the return value in
power_supply_read_temp() if we really want EAGAIN:
ret = power_supply_get_property(...);
if (ret)
return -EAGAIN;
On the other hand, here both return values look correct... the call can
be executed too early (not very common) or too late after unbinding the
driver (also kind of specific).
>
> return psy->desc->get_property(psy, psp, val);
> }
> @@ -564,12 +564,14 @@ static int power_supply_read_temp(struct thermal_zone_device *tzd,
> int ret;
>
> WARN_ON(tzd == NULL);
> +
> psy = tzd->devdata;
> - ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
> + ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
> + if (!ret)
> + return ret;
I think you wanted reverse:
if (ret)
>
> /* Convert tenths of degree Celsius to milli degree Celsius. */
> - if (!ret)
> - *temp = val.intval * 100;
> + *temp = val.intval * 100;
>
> return ret;
> }
> @@ -612,10 +614,12 @@ static int ps_get_max_charge_cntl_limit(struct thermal_cooling_device *tcd,
> int ret;
>
> psy = tcd->devdata;
> - ret = psy->desc->get_property(psy,
> - POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX, &val);
> + ret = power_supply_get_property(psy,
> + POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX, &val);
> if (!ret)
> - *state = val.intval;
> + return ret;
Wait, again - why are you inverting the logic of 'ret'?
BR,
Krzysztof
> +
> + *state = val.intval;
>
> return ret;
> }
> @@ -628,10 +632,12 @@ static int ps_get_cur_chrage_cntl_limit(struct thermal_cooling_device *tcd,
> int ret;
>
> psy = tcd->devdata;
> - ret = psy->desc->get_property(psy,
> - POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT, &val);
> + ret = power_supply_get_property(psy,
> + POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT, &val);
> if (!ret)
> - *state = val.intval;
> + return ret;
> +
> + *state = val.intval;
>
> return ret;
> }
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] power_supply: power_supply_read_temp only if use_cnt > 0
2016-06-08 6:35 ` Krzysztof Kozlowski
@ 2016-06-08 15:26 ` Rhyland Klein
2016-06-09 10:05 ` Krzysztof Kozlowski
0 siblings, 1 reply; 6+ messages in thread
From: Rhyland Klein @ 2016-06-08 15:26 UTC (permalink / raw)
To: Krzysztof Kozlowski, Sebastian Reichel, Dmitry Eremin-Solenikov,
David Woodhouse
Cc: linux-pm, linux-kernel, Jon Hunter, stable
On 6/8/2016 2:35 AM, Krzysztof Kozlowski wrote:
> On 06/07/2016 10:26 PM, Rhyland Klein wrote:
>> Change power_supply_read_temp() to use power_supply_get_property()
>> so that it will check the use_cnt and ensure it is > 0. The use_cnt
>> will be incremented at the end of __power_supply_register, so this
>> will block to case where get_property can be called before the supply
>> is fully registered. This fixes the issue show in the stack below:
>>
>> [ 1.452598] power_supply_read_temp+0x78/0x80
>> [ 1.458680] thermal_zone_get_temp+0x5c/0x11c
>> [ 1.464765] thermal_zone_device_update+0x34/0xb4
>> [ 1.471195] thermal_zone_device_register+0x87c/0x8cc
>> [ 1.477974] __power_supply_register+0x364/0x424
>> [ 1.484317] power_supply_register_no_ws+0x10/0x18
>> [ 1.490833] bq27xxx_battery_setup+0x10c/0x164
>> [ 1.497003] bq27xxx_battery_i2c_probe+0xd0/0x1b0
>> [ 1.503435] i2c_device_probe+0x174/0x240
>> [ 1.509172] driver_probe_device+0x1fc/0x29c
>> [ 1.515167] __driver_attach+0xa4/0xa8
>> [ 1.520643] bus_for_each_dev+0x58/0x98
>> [ 1.526204] driver_attach+0x20/0x28
>> [ 1.531505] bus_add_driver+0x1c8/0x22c
>> [ 1.537067] driver_register+0x68/0x108
>> [ 1.542630] i2c_register_driver+0x38/0x7c
>> [ 1.548457] bq27xxx_battery_i2c_driver_init+0x18/0x20
>> [ 1.555321] do_one_initcall+0x38/0x12c
>> [ 1.560886] kernel_init_freeable+0x148/0x1ec
>> [ 1.566972] kernel_init+0x10/0xfc
>> [ 1.572101] ret_from_fork+0x10/0x40
>>
>> Also make the same change to ps_get_max_charge_cntl_limit() and
>> ps_get_cur_chrage_cntl_limit() to be safe. Lastly, change the return
>> value of power_supply_get_property() to -EAGAIN from -ENODEV if
>> use_cnt <= 0.
>>
>> Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Rhyland Klein <rklein@nvidia.com>
>> ---
>> v3:
>> - Changed calls to ->get_property() to use common
>> power_supply_get_property()
>> - reworded description, added "Fixes" line
>> - Changed return value of power_supply_get_property() to -EAGAIN
>>
>> v2:
>> - Added cc stable
>> - changed return to -EAGAIN in case of use_cnt < 1
>> - Removed WARNING
>> - return value check added in additional patch:
>> https://lkml.org/lkml/2016/6/6/706
>>
>> drivers/power/power_supply_core.c | 26 ++++++++++++++++----------
>> 1 file changed, 16 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
>> index 456987c88baa..cccc630bd68e 100644
>> --- a/drivers/power/power_supply_core.c
>> +++ b/drivers/power/power_supply_core.c
>> @@ -492,7 +492,7 @@ int power_supply_get_property(struct power_supply *psy,
>> union power_supply_propval *val)
>> {
>> if (atomic_read(&psy->use_cnt) <= 0)
>> - return -ENODEV;
>> + return -EAGAIN;
>
> Wait, no. I was thinking of changing the return value in
> power_supply_read_temp() if we really want EAGAIN:
> ret = power_supply_get_property(...);
> if (ret)
> return -EAGAIN;
>
> On the other hand, here both return values look correct... the call can
> be executed too early (not very common) or too late after unbinding the
> driver (also kind of specific).
I did have it that way, but it seemed a little weird to me, since both
situations use the same condition (use_cnt <= 0) to trigger. I don't
think we can differentiate, unless I missed something, so I'm not sure
if it makes sense to override the return value after calling
power_supply_get_property() or not.
If I overrode the return value in get_temp, then assuming it was called
after unbinding, it would return the wrong thing (-EAGAIN). If we want
to support both EAGAIN and ENODEV, then maybe we need to use some
additional check to know which to return from power_supply_get_property().
>
>>
>> return psy->desc->get_property(psy, psp, val);
>> }
>> @@ -564,12 +564,14 @@ static int power_supply_read_temp(struct thermal_zone_device *tzd,
>> int ret;
>>
>> WARN_ON(tzd == NULL);
>> +
>> psy = tzd->devdata;
>> - ret = psy->desc->get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
>> + ret = power_supply_get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);
>> + if (!ret)
>> + return ret;
>
> I think you wanted reverse:
> if (ret)
>
Indeed.
>>
>> /* Convert tenths of degree Celsius to milli degree Celsius. */
>> - if (!ret)
>> - *temp = val.intval * 100;
>> + *temp = val.intval * 100;
>>
>> return ret;
>> }
>> @@ -612,10 +614,12 @@ static int ps_get_max_charge_cntl_limit(struct thermal_cooling_device *tcd,
>> int ret;
>>
>> psy = tcd->devdata;
>> - ret = psy->desc->get_property(psy,
>> - POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX, &val);
>> + ret = power_supply_get_property(psy,
>> + POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX, &val);
>> if (!ret)
>> - *state = val.intval;
>> + return ret;
>
> Wait, again - why are you inverting the logic of 'ret'?a
>
copy/paste error repeated... <sigh>
-rhyland
--
nvpublic
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] power_supply: power_supply_read_temp only if use_cnt > 0
2016-06-08 15:26 ` Rhyland Klein
@ 2016-06-09 10:05 ` Krzysztof Kozlowski
2016-06-09 15:31 ` Rhyland Klein
0 siblings, 1 reply; 6+ messages in thread
From: Krzysztof Kozlowski @ 2016-06-09 10:05 UTC (permalink / raw)
To: Rhyland Klein, Sebastian Reichel, Dmitry Eremin-Solenikov,
David Woodhouse
Cc: linux-pm, linux-kernel, Jon Hunter, stable
On 06/08/2016 05:26 PM, Rhyland Klein wrote:
> On 6/8/2016 2:35 AM, Krzysztof Kozlowski wrote:
>> On 06/07/2016 10:26 PM, Rhyland Klein wrote:
>>> Change power_supply_read_temp() to use power_supply_get_property()
>>> so that it will check the use_cnt and ensure it is > 0. The use_cnt
>>> will be incremented at the end of __power_supply_register, so this
>>> will block to case where get_property can be called before the supply
>>> is fully registered. This fixes the issue show in the stack below:
>>>
>>> [ 1.452598] power_supply_read_temp+0x78/0x80
>>> [ 1.458680] thermal_zone_get_temp+0x5c/0x11c
>>> [ 1.464765] thermal_zone_device_update+0x34/0xb4
>>> [ 1.471195] thermal_zone_device_register+0x87c/0x8cc
>>> [ 1.477974] __power_supply_register+0x364/0x424
>>> [ 1.484317] power_supply_register_no_ws+0x10/0x18
>>> [ 1.490833] bq27xxx_battery_setup+0x10c/0x164
>>> [ 1.497003] bq27xxx_battery_i2c_probe+0xd0/0x1b0
>>> [ 1.503435] i2c_device_probe+0x174/0x240
>>> [ 1.509172] driver_probe_device+0x1fc/0x29c
>>> [ 1.515167] __driver_attach+0xa4/0xa8
>>> [ 1.520643] bus_for_each_dev+0x58/0x98
>>> [ 1.526204] driver_attach+0x20/0x28
>>> [ 1.531505] bus_add_driver+0x1c8/0x22c
>>> [ 1.537067] driver_register+0x68/0x108
>>> [ 1.542630] i2c_register_driver+0x38/0x7c
>>> [ 1.548457] bq27xxx_battery_i2c_driver_init+0x18/0x20
>>> [ 1.555321] do_one_initcall+0x38/0x12c
>>> [ 1.560886] kernel_init_freeable+0x148/0x1ec
>>> [ 1.566972] kernel_init+0x10/0xfc
>>> [ 1.572101] ret_from_fork+0x10/0x40
>>>
>>> Also make the same change to ps_get_max_charge_cntl_limit() and
>>> ps_get_cur_chrage_cntl_limit() to be safe. Lastly, change the return
>>> value of power_supply_get_property() to -EAGAIN from -ENODEV if
>>> use_cnt <= 0.
>>>
>>> Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")
>>> Cc: stable@vger.kernel.org
>>> Signed-off-by: Rhyland Klein <rklein@nvidia.com>
>>> ---
>>> v3:
>>> - Changed calls to ->get_property() to use common
>>> power_supply_get_property()
>>> - reworded description, added "Fixes" line
>>> - Changed return value of power_supply_get_property() to -EAGAIN
>>>
>>> v2:
>>> - Added cc stable
>>> - changed return to -EAGAIN in case of use_cnt < 1
>>> - Removed WARNING
>>> - return value check added in additional patch:
>>> https://lkml.org/lkml/2016/6/6/706
>>>
>>> drivers/power/power_supply_core.c | 26 ++++++++++++++++----------
>>> 1 file changed, 16 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
>>> index 456987c88baa..cccc630bd68e 100644
>>> --- a/drivers/power/power_supply_core.c
>>> +++ b/drivers/power/power_supply_core.c
>>> @@ -492,7 +492,7 @@ int power_supply_get_property(struct power_supply *psy,
>>> union power_supply_propval *val)
>>> {
>>> if (atomic_read(&psy->use_cnt) <= 0)
>>> - return -ENODEV;
>>> + return -EAGAIN;
>>
>> Wait, no. I was thinking of changing the return value in
>> power_supply_read_temp() if we really want EAGAIN:
>> ret = power_supply_get_property(...);
>> if (ret)
>> return -EAGAIN;
>>
>> On the other hand, here both return values look correct... the call can
>> be executed too early (not very common) or too late after unbinding the
>> driver (also kind of specific).
>
> I did have it that way, but it seemed a little weird to me, since both
> situations use the same condition (use_cnt <= 0) to trigger. I don't
> think we can differentiate, unless I missed something, so I'm not sure
> if it makes sense to override the return value after calling
> power_supply_get_property() or not.
>
> If I overrode the return value in get_temp, then assuming it was called
> after unbinding, it would return the wrong thing (-EAGAIN). If we want
> to support both EAGAIN and ENODEV, then maybe we need to use some
> additional check to know which to return from power_supply_get_property().
Right, currently it is not possible to differentiate these two cases.
After quick look, I think the difference with EAGAIN would be only in
error message printed or not. It is not critical so maybe keep it with
ENODEV?
Best regards,
Krzysztof
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] power_supply: power_supply_read_temp only if use_cnt > 0
2016-06-09 10:05 ` Krzysztof Kozlowski
@ 2016-06-09 15:31 ` Rhyland Klein
2016-06-09 20:58 ` Sebastian Reichel
0 siblings, 1 reply; 6+ messages in thread
From: Rhyland Klein @ 2016-06-09 15:31 UTC (permalink / raw)
To: Krzysztof Kozlowski, Sebastian Reichel, Dmitry Eremin-Solenikov,
David Woodhouse
Cc: linux-pm, linux-kernel, Jon Hunter, stable
On 6/9/2016 6:05 AM, Krzysztof Kozlowski wrote:
> On 06/08/2016 05:26 PM, Rhyland Klein wrote:
>> On 6/8/2016 2:35 AM, Krzysztof Kozlowski wrote:
>>> On 06/07/2016 10:26 PM, Rhyland Klein wrote:
>>>> Change power_supply_read_temp() to use power_supply_get_property()
>>>> so that it will check the use_cnt and ensure it is > 0. The use_cnt
>>>> will be incremented at the end of __power_supply_register, so this
>>>> will block to case where get_property can be called before the supply
>>>> is fully registered. This fixes the issue show in the stack below:
>>>>
>>>> [ 1.452598] power_supply_read_temp+0x78/0x80
>>>> [ 1.458680] thermal_zone_get_temp+0x5c/0x11c
>>>> [ 1.464765] thermal_zone_device_update+0x34/0xb4
>>>> [ 1.471195] thermal_zone_device_register+0x87c/0x8cc
>>>> [ 1.477974] __power_supply_register+0x364/0x424
>>>> [ 1.484317] power_supply_register_no_ws+0x10/0x18
>>>> [ 1.490833] bq27xxx_battery_setup+0x10c/0x164
>>>> [ 1.497003] bq27xxx_battery_i2c_probe+0xd0/0x1b0
>>>> [ 1.503435] i2c_device_probe+0x174/0x240
>>>> [ 1.509172] driver_probe_device+0x1fc/0x29c
>>>> [ 1.515167] __driver_attach+0xa4/0xa8
>>>> [ 1.520643] bus_for_each_dev+0x58/0x98
>>>> [ 1.526204] driver_attach+0x20/0x28
>>>> [ 1.531505] bus_add_driver+0x1c8/0x22c
>>>> [ 1.537067] driver_register+0x68/0x108
>>>> [ 1.542630] i2c_register_driver+0x38/0x7c
>>>> [ 1.548457] bq27xxx_battery_i2c_driver_init+0x18/0x20
>>>> [ 1.555321] do_one_initcall+0x38/0x12c
>>>> [ 1.560886] kernel_init_freeable+0x148/0x1ec
>>>> [ 1.566972] kernel_init+0x10/0xfc
>>>> [ 1.572101] ret_from_fork+0x10/0x40
>>>>
>>>> Also make the same change to ps_get_max_charge_cntl_limit() and
>>>> ps_get_cur_chrage_cntl_limit() to be safe. Lastly, change the return
>>>> value of power_supply_get_property() to -EAGAIN from -ENODEV if
>>>> use_cnt <= 0.
>>>>
>>>> Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")
>>>> Cc: stable@vger.kernel.org
>>>> Signed-off-by: Rhyland Klein <rklein@nvidia.com>
>>>> ---
>>>> v3:
>>>> - Changed calls to ->get_property() to use common
>>>> power_supply_get_property()
>>>> - reworded description, added "Fixes" line
>>>> - Changed return value of power_supply_get_property() to -EAGAIN
>>>>
>>>> v2:
>>>> - Added cc stable
>>>> - changed return to -EAGAIN in case of use_cnt < 1
>>>> - Removed WARNING
>>>> - return value check added in additional patch:
>>>> https://lkml.org/lkml/2016/6/6/706
>>>>
>>>> drivers/power/power_supply_core.c | 26 ++++++++++++++++----------
>>>> 1 file changed, 16 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
>>>> index 456987c88baa..cccc630bd68e 100644
>>>> --- a/drivers/power/power_supply_core.c
>>>> +++ b/drivers/power/power_supply_core.c
>>>> @@ -492,7 +492,7 @@ int power_supply_get_property(struct power_supply *psy,
>>>> union power_supply_propval *val)
>>>> {
>>>> if (atomic_read(&psy->use_cnt) <= 0)
>>>> - return -ENODEV;
>>>> + return -EAGAIN;
>>>
>>> Wait, no. I was thinking of changing the return value in
>>> power_supply_read_temp() if we really want EAGAIN:
>>> ret = power_supply_get_property(...);
>>> if (ret)
>>> return -EAGAIN;
>>>
>>> On the other hand, here both return values look correct... the call can
>>> be executed too early (not very common) or too late after unbinding the
>>> driver (also kind of specific).
>>
>> I did have it that way, but it seemed a little weird to me, since both
>> situations use the same condition (use_cnt <= 0) to trigger. I don't
>> think we can differentiate, unless I missed something, so I'm not sure
>> if it makes sense to override the return value after calling
>> power_supply_get_property() or not.
>>
>> If I overrode the return value in get_temp, then assuming it was called
>> after unbinding, it would return the wrong thing (-EAGAIN). If we want
>> to support both EAGAIN and ENODEV, then maybe we need to use some
>> additional check to know which to return from power_supply_get_property().
>
> Right, currently it is not possible to differentiate these two cases.
> After quick look, I think the difference with EAGAIN would be only in
> error message printed or not. It is not critical so maybe keep it with
> ENODEV?
I'm ok with that. Sebastian, are you ok with that? If so, I'll post a v4
without the -EAGAIN change.
-rhyland
>
> Best regards,
> Krzysztof
>
--
nvpublic
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v3] power_supply: power_supply_read_temp only if use_cnt > 0
2016-06-09 15:31 ` Rhyland Klein
@ 2016-06-09 20:58 ` Sebastian Reichel
0 siblings, 0 replies; 6+ messages in thread
From: Sebastian Reichel @ 2016-06-09 20:58 UTC (permalink / raw)
To: Rhyland Klein
Cc: Krzysztof Kozlowski, Dmitry Eremin-Solenikov, David Woodhouse,
linux-pm, linux-kernel, Jon Hunter, stable
[-- Attachment #1: Type: text/plain, Size: 4812 bytes --]
Hi,
On Thu, Jun 09, 2016 at 11:31:37AM -0400, Rhyland Klein wrote:
> On 6/9/2016 6:05 AM, Krzysztof Kozlowski wrote:
> > On 06/08/2016 05:26 PM, Rhyland Klein wrote:
> >> On 6/8/2016 2:35 AM, Krzysztof Kozlowski wrote:
> >>> On 06/07/2016 10:26 PM, Rhyland Klein wrote:
> >>>> Change power_supply_read_temp() to use power_supply_get_property()
> >>>> so that it will check the use_cnt and ensure it is > 0. The use_cnt
> >>>> will be incremented at the end of __power_supply_register, so this
> >>>> will block to case where get_property can be called before the supply
> >>>> is fully registered. This fixes the issue show in the stack below:
> >>>>
> >>>> [ 1.452598] power_supply_read_temp+0x78/0x80
> >>>> [ 1.458680] thermal_zone_get_temp+0x5c/0x11c
> >>>> [ 1.464765] thermal_zone_device_update+0x34/0xb4
> >>>> [ 1.471195] thermal_zone_device_register+0x87c/0x8cc
> >>>> [ 1.477974] __power_supply_register+0x364/0x424
> >>>> [ 1.484317] power_supply_register_no_ws+0x10/0x18
> >>>> [ 1.490833] bq27xxx_battery_setup+0x10c/0x164
> >>>> [ 1.497003] bq27xxx_battery_i2c_probe+0xd0/0x1b0
> >>>> [ 1.503435] i2c_device_probe+0x174/0x240
> >>>> [ 1.509172] driver_probe_device+0x1fc/0x29c
> >>>> [ 1.515167] __driver_attach+0xa4/0xa8
> >>>> [ 1.520643] bus_for_each_dev+0x58/0x98
> >>>> [ 1.526204] driver_attach+0x20/0x28
> >>>> [ 1.531505] bus_add_driver+0x1c8/0x22c
> >>>> [ 1.537067] driver_register+0x68/0x108
> >>>> [ 1.542630] i2c_register_driver+0x38/0x7c
> >>>> [ 1.548457] bq27xxx_battery_i2c_driver_init+0x18/0x20
> >>>> [ 1.555321] do_one_initcall+0x38/0x12c
> >>>> [ 1.560886] kernel_init_freeable+0x148/0x1ec
> >>>> [ 1.566972] kernel_init+0x10/0xfc
> >>>> [ 1.572101] ret_from_fork+0x10/0x40
> >>>>
> >>>> Also make the same change to ps_get_max_charge_cntl_limit() and
> >>>> ps_get_cur_chrage_cntl_limit() to be safe. Lastly, change the return
> >>>> value of power_supply_get_property() to -EAGAIN from -ENODEV if
> >>>> use_cnt <= 0.
> >>>>
> >>>> Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core")
> >>>> Cc: stable@vger.kernel.org
> >>>> Signed-off-by: Rhyland Klein <rklein@nvidia.com>
> >>>> ---
> >>>> v3:
> >>>> - Changed calls to ->get_property() to use common
> >>>> power_supply_get_property()
> >>>> - reworded description, added "Fixes" line
> >>>> - Changed return value of power_supply_get_property() to -EAGAIN
> >>>>
> >>>> v2:
> >>>> - Added cc stable
> >>>> - changed return to -EAGAIN in case of use_cnt < 1
> >>>> - Removed WARNING
> >>>> - return value check added in additional patch:
> >>>> https://lkml.org/lkml/2016/6/6/706
> >>>>
> >>>> drivers/power/power_supply_core.c | 26 ++++++++++++++++----------
> >>>> 1 file changed, 16 insertions(+), 10 deletions(-)
> >>>>
> >>>> diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c
> >>>> index 456987c88baa..cccc630bd68e 100644
> >>>> --- a/drivers/power/power_supply_core.c
> >>>> +++ b/drivers/power/power_supply_core.c
> >>>> @@ -492,7 +492,7 @@ int power_supply_get_property(struct power_supply *psy,
> >>>> union power_supply_propval *val)
> >>>> {
> >>>> if (atomic_read(&psy->use_cnt) <= 0)
> >>>> - return -ENODEV;
> >>>> + return -EAGAIN;
> >>>
> >>> Wait, no. I was thinking of changing the return value in
> >>> power_supply_read_temp() if we really want EAGAIN:
> >>> ret = power_supply_get_property(...);
> >>> if (ret)
> >>> return -EAGAIN;
> >>>
> >>> On the other hand, here both return values look correct... the call can
> >>> be executed too early (not very common) or too late after unbinding the
> >>> driver (also kind of specific).
> >>
> >> I did have it that way, but it seemed a little weird to me, since both
> >> situations use the same condition (use_cnt <= 0) to trigger. I don't
> >> think we can differentiate, unless I missed something, so I'm not sure
> >> if it makes sense to override the return value after calling
> >> power_supply_get_property() or not.
> >>
> >> If I overrode the return value in get_temp, then assuming it was called
> >> after unbinding, it would return the wrong thing (-EAGAIN). If we want
> >> to support both EAGAIN and ENODEV, then maybe we need to use some
> >> additional check to know which to return from power_supply_get_property().
> >
> > Right, currently it is not possible to differentiate these two cases.
> > After quick look, I think the difference with EAGAIN would be only in
> > error message printed or not. It is not critical so maybe keep it with
> > ENODEV?
>
> I'm ok with that. Sebastian, are you ok with that? If so, I'll post a v4
> without the -EAGAIN change.
Yes.
-- Sebastian
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^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-06-09 20:58 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-06-07 20:26 [PATCH v3] power_supply: power_supply_read_temp only if use_cnt > 0 Rhyland Klein
2016-06-08 6:35 ` Krzysztof Kozlowski
2016-06-08 15:26 ` Rhyland Klein
2016-06-09 10:05 ` Krzysztof Kozlowski
2016-06-09 15:31 ` Rhyland Klein
2016-06-09 20:58 ` Sebastian Reichel
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