| Message ID | 1465331163-16884-1-git-send-email-rklein@nvidia.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
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; > } > -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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
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 -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 >
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
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; }
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(-)