| Message ID | 0ad496507cd7e6731e46249b1499dfdebe205c16.1569252537.git.leonard.crestez@nxp.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | PM / devfreq: Add dev_pm_qos support | expand |
On Mon, Sep 23, 2019 at 06:51:05PM +0300, Leonard Crestez wrote: > In general it is a better to initialize an object before making it > accessible externally (through device_register). > > This makes it possible to avoid relying on locking a partially > initialized object. > > Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> > --- > drivers/devfreq/devfreq.c | 43 +++++++++++++++++++++++---------------- > 1 file changed, 25 insertions(+), 18 deletions(-) > > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > index 323d43315d1e..b4d2bfebb140 100644 > --- a/drivers/devfreq/devfreq.c > +++ b/drivers/devfreq/devfreq.c > @@ -587,10 +587,12 @@ static void devfreq_dev_release(struct device *dev) > mutex_unlock(&devfreq_list_lock); > > if (devfreq->profile->exit) > devfreq->profile->exit(devfreq->dev.parent); > > + kfree(devfreq->time_in_state); > + kfree(devfreq->trans_table); > mutex_destroy(&devfreq->lock); > kfree(devfreq); > } > > /** > @@ -670,44 +672,43 @@ struct devfreq *devfreq_add_device(struct device *dev, > devfreq->max_freq = devfreq->scaling_max_freq; > > devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev); > atomic_set(&devfreq->suspend_count, 0); > > - dev_set_name(&devfreq->dev, "devfreq%d", > - atomic_inc_return(&devfreq_no)); > - err = device_register(&devfreq->dev); > - if (err) { > - mutex_unlock(&devfreq->lock); > - put_device(&devfreq->dev); > - goto err_out; > - } > - > - devfreq->trans_table = devm_kzalloc(&devfreq->dev, > + devfreq->trans_table = kzalloc( > array3_size(sizeof(unsigned int), > devfreq->profile->max_state, > devfreq->profile->max_state), > GFP_KERNEL); > if (!devfreq->trans_table) { > mutex_unlock(&devfreq->lock); > err = -ENOMEM; > - goto err_devfreq; > + goto err_dev; > } > > - devfreq->time_in_state = devm_kcalloc(&devfreq->dev, > - devfreq->profile->max_state, > - sizeof(unsigned long), > - GFP_KERNEL); > + devfreq->time_in_state = kcalloc(devfreq->profile->max_state, > + sizeof(unsigned long), > + GFP_KERNEL); > if (!devfreq->time_in_state) { > mutex_unlock(&devfreq->lock); > err = -ENOMEM; > - goto err_devfreq; > + goto err_dev; > } > > devfreq->last_stat_updated = jiffies; > > srcu_init_notifier_head(&devfreq->transition_notifier_list); > > + dev_set_name(&devfreq->dev, "devfreq%d", > + atomic_inc_return(&devfreq_no)); > + err = device_register(&devfreq->dev); > + if (err) { > + mutex_unlock(&devfreq->lock); > + put_device(&devfreq->dev); > + goto err_out; As per my comment on v5 I think the goto needs to go to 'err_dev'. The device registration failed, hence devfreq_dev_release() won't be called to free allocated memory. > + } > + > mutex_unlock(&devfreq->lock); > > mutex_lock(&devfreq_list_lock); > > governor = try_then_request_governor(devfreq->governor_name); > @@ -733,14 +734,20 @@ struct devfreq *devfreq_add_device(struct device *dev, > > return devfreq; > > err_init: > mutex_unlock(&devfreq_list_lock); > -err_devfreq: > devfreq_remove_device(devfreq); > - devfreq = NULL; > + return ERR_PTR(err); > + > err_dev: > + /* > + * Cleanup path for errors that happen before registration. > + * Otherwise we rely on devfreq_dev_release nit: add a period at the end of the second sentence. > + */ > + kfree(devfreq->time_in_state); > + kfree(devfreq->trans_table); > kfree(devfreq); > err_out: > return ERR_PTR(err); > } > EXPORT_SYMBOL(devfreq_add_device);
On 23.09.2019 21:11, Matthias Kaehlcke wrote: > On Mon, Sep 23, 2019 at 06:51:05PM +0300, Leonard Crestez wrote: >> In general it is a better to initialize an object before making it >> accessible externally (through device_register). >> >> This makes it possible to avoid relying on locking a partially >> initialized object. >> >> Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> >> --- >> drivers/devfreq/devfreq.c | 43 +++++++++++++++++++++++---------------- >> 1 file changed, 25 insertions(+), 18 deletions(-) >> >> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c >> index 323d43315d1e..b4d2bfebb140 100644 >> --- a/drivers/devfreq/devfreq.c >> +++ b/drivers/devfreq/devfreq.c >> @@ -587,10 +587,12 @@ static void devfreq_dev_release(struct device *dev) >> mutex_unlock(&devfreq_list_lock); >> >> if (devfreq->profile->exit) >> devfreq->profile->exit(devfreq->dev.parent); >> >> + kfree(devfreq->time_in_state); >> + kfree(devfreq->trans_table); >> mutex_destroy(&devfreq->lock); >> kfree(devfreq); >> } >> >> /** >> @@ -670,44 +672,43 @@ struct devfreq *devfreq_add_device(struct device *dev, >> devfreq->max_freq = devfreq->scaling_max_freq; >> >> devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev); >> atomic_set(&devfreq->suspend_count, 0); >> >> - dev_set_name(&devfreq->dev, "devfreq%d", >> - atomic_inc_return(&devfreq_no)); >> - err = device_register(&devfreq->dev); >> - if (err) { >> - mutex_unlock(&devfreq->lock); >> - put_device(&devfreq->dev); >> - goto err_out; >> - } >> - >> - devfreq->trans_table = devm_kzalloc(&devfreq->dev, >> + devfreq->trans_table = kzalloc( >> array3_size(sizeof(unsigned int), >> devfreq->profile->max_state, >> devfreq->profile->max_state), >> GFP_KERNEL); >> if (!devfreq->trans_table) { >> mutex_unlock(&devfreq->lock); >> err = -ENOMEM; >> - goto err_devfreq; >> + goto err_dev; >> } >> >> - devfreq->time_in_state = devm_kcalloc(&devfreq->dev, >> - devfreq->profile->max_state, >> - sizeof(unsigned long), >> - GFP_KERNEL); >> + devfreq->time_in_state = kcalloc(devfreq->profile->max_state, >> + sizeof(unsigned long), >> + GFP_KERNEL); >> if (!devfreq->time_in_state) { >> mutex_unlock(&devfreq->lock); >> err = -ENOMEM; >> - goto err_devfreq; >> + goto err_dev; >> } >> >> devfreq->last_stat_updated = jiffies; >> >> srcu_init_notifier_head(&devfreq->transition_notifier_list); >> >> + dev_set_name(&devfreq->dev, "devfreq%d", >> + atomic_inc_return(&devfreq_no)); >> + err = device_register(&devfreq->dev); >> + if (err) { >> + mutex_unlock(&devfreq->lock); >> + put_device(&devfreq->dev); >> + goto err_out; > > As per my comment on v5 I think the goto needs to go to 'err_dev'. The > device registration failed, hence devfreq_dev_release() won't be > called to free allocated memory. This code is not modified in the patch, it only shows up as +added because diff got confused but there is an identical -removed chunk higher up. The device_register documentation mentions the following: * NOTE: _Never_ directly free @dev after calling this function, even * if it returned an error! Always use put_device() to give up the * reference initialized in this function instead. Cleanup path then goes like this (from a hacked error in device_add): dump_stack+0xdc/0x144 devfreq_dev_release+0x38/0xc0 device_release+0x34/0x90 kobject_put+0x8c/0x1f0 put_device+0x24/0x30 devfreq_add_device+0x540/0x570 devm_devfreq_add_device+0x60/0xd0 imx_ddrc_probe+0x35c/0x4c8 Can I add your "Reviewed-By" for the rest of the series if I fix the nits? -- Regards, Leonard
On Mon, Sep 23, 2019 at 06:56:28PM +0000, Leonard Crestez wrote: > On 23.09.2019 21:11, Matthias Kaehlcke wrote: > > On Mon, Sep 23, 2019 at 06:51:05PM +0300, Leonard Crestez wrote: > >> In general it is a better to initialize an object before making it > >> accessible externally (through device_register). > >> > >> This makes it possible to avoid relying on locking a partially > >> initialized object. > >> > >> Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> > >> --- > >> drivers/devfreq/devfreq.c | 43 +++++++++++++++++++++++---------------- > >> 1 file changed, 25 insertions(+), 18 deletions(-) > >> > >> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > >> index 323d43315d1e..b4d2bfebb140 100644 > >> --- a/drivers/devfreq/devfreq.c > >> +++ b/drivers/devfreq/devfreq.c > >> @@ -587,10 +587,12 @@ static void devfreq_dev_release(struct device *dev) > >> mutex_unlock(&devfreq_list_lock); > >> > >> if (devfreq->profile->exit) > >> devfreq->profile->exit(devfreq->dev.parent); > >> > >> + kfree(devfreq->time_in_state); > >> + kfree(devfreq->trans_table); > >> mutex_destroy(&devfreq->lock); > >> kfree(devfreq); > >> } > >> > >> /** > >> @@ -670,44 +672,43 @@ struct devfreq *devfreq_add_device(struct device *dev, > >> devfreq->max_freq = devfreq->scaling_max_freq; > >> > >> devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev); > >> atomic_set(&devfreq->suspend_count, 0); > >> > >> - dev_set_name(&devfreq->dev, "devfreq%d", > >> - atomic_inc_return(&devfreq_no)); > >> - err = device_register(&devfreq->dev); > >> - if (err) { > >> - mutex_unlock(&devfreq->lock); > >> - put_device(&devfreq->dev); > >> - goto err_out; > >> - } > >> - > >> - devfreq->trans_table = devm_kzalloc(&devfreq->dev, > >> + devfreq->trans_table = kzalloc( > >> array3_size(sizeof(unsigned int), > >> devfreq->profile->max_state, > >> devfreq->profile->max_state), > >> GFP_KERNEL); > >> if (!devfreq->trans_table) { > >> mutex_unlock(&devfreq->lock); > >> err = -ENOMEM; > >> - goto err_devfreq; > >> + goto err_dev; > >> } > >> > >> - devfreq->time_in_state = devm_kcalloc(&devfreq->dev, > >> - devfreq->profile->max_state, > >> - sizeof(unsigned long), > >> - GFP_KERNEL); > >> + devfreq->time_in_state = kcalloc(devfreq->profile->max_state, > >> + sizeof(unsigned long), > >> + GFP_KERNEL); > >> if (!devfreq->time_in_state) { > >> mutex_unlock(&devfreq->lock); > >> err = -ENOMEM; > >> - goto err_devfreq; > >> + goto err_dev; > >> } > >> > >> devfreq->last_stat_updated = jiffies; > >> > >> srcu_init_notifier_head(&devfreq->transition_notifier_list); > >> > >> + dev_set_name(&devfreq->dev, "devfreq%d", > >> + atomic_inc_return(&devfreq_no)); > >> + err = device_register(&devfreq->dev); > >> + if (err) { > >> + mutex_unlock(&devfreq->lock); > >> + put_device(&devfreq->dev); > >> + goto err_out; > > > > As per my comment on v5 I think the goto needs to go to 'err_dev'. The > > device registration failed, hence devfreq_dev_release() won't be > > called to free allocated memory. > > This code is not modified in the patch, it only shows up as +added > because diff got confused but there is an identical -removed chunk > higher up. > > The device_register documentation mentions the following: > > * NOTE: _Never_ directly free @dev after calling this function, even > * if it returned an error! Always use put_device() to give up the > * reference initialized in this function instead. > > Cleanup path then goes like this (from a hacked error in device_add): > dump_stack+0xdc/0x144 > > > devfreq_dev_release+0x38/0xc0 > > > device_release+0x34/0x90 > > > kobject_put+0x8c/0x1f0 > > > put_device+0x24/0x30 > > > devfreq_add_device+0x540/0x570 > > > devm_devfreq_add_device+0x60/0xd0 > > > imx_ddrc_probe+0x35c/0x4c8 Good to know, thanks for the pointer! > Can I add your "Reviewed-By" for the rest of the series if I fix the nits? By now you should have it for most patches. For this one: Reviewed-by: Matthias Kaehlcke <mka@chromium.org> There is one doubt I have left on "PM / devfreq: Add PM QoS support" that I posted on v5: "IIUC you rely on the notifiers being removed by devfreq_dev_release(). Does dev_pm_qos_remove_notifier() behave gracefully if the notifier is not initialized/added or do we need to use BLOCKING_NOTIFIER_INIT() or similar?" Could you clarify this replying to the thread? Besides that and the nits (which are optional to fix) the patch looks good to me.
On 23.09.2019 22:11, Matthias Kaehlcke wrote: > On Mon, Sep 23, 2019 at 06:56:28PM +0000, Leonard Crestez wrote: >> On 23.09.2019 21:11, Matthias Kaehlcke wrote: >>> On Mon, Sep 23, 2019 at 06:51:05PM +0300, Leonard Crestez wrote: >>>> In general it is a better to initialize an object before making it >>>> accessible externally (through device_register). >>>> >>>> This makes it possible to avoid relying on locking a partially >>>> initialized object. >>>> >>>> Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> >>>> --- >>>> drivers/devfreq/devfreq.c | 43 +++++++++++++++++++++++---------------- >>>> 1 file changed, 25 insertions(+), 18 deletions(-) >>>> >>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c >>>> index 323d43315d1e..b4d2bfebb140 100644 >>>> --- a/drivers/devfreq/devfreq.c >>>> +++ b/drivers/devfreq/devfreq.c >>>> @@ -587,10 +587,12 @@ static void devfreq_dev_release(struct device *dev) >>>> mutex_unlock(&devfreq_list_lock); >>>> >>>> if (devfreq->profile->exit) >>>> devfreq->profile->exit(devfreq->dev.parent); >>>> >>>> + kfree(devfreq->time_in_state); >>>> + kfree(devfreq->trans_table); >>>> mutex_destroy(&devfreq->lock); >>>> kfree(devfreq); >>>> } >>>> >>>> /** >>>> @@ -670,44 +672,43 @@ struct devfreq *devfreq_add_device(struct device *dev, >>>> devfreq->max_freq = devfreq->scaling_max_freq; >>>> >>>> devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev); >>>> atomic_set(&devfreq->suspend_count, 0); >>>> >>>> - dev_set_name(&devfreq->dev, "devfreq%d", >>>> - atomic_inc_return(&devfreq_no)); >>>> - err = device_register(&devfreq->dev); >>>> - if (err) { >>>> - mutex_unlock(&devfreq->lock); >>>> - put_device(&devfreq->dev); >>>> - goto err_out; >>>> - } >>>> - >>>> - devfreq->trans_table = devm_kzalloc(&devfreq->dev, >>>> + devfreq->trans_table = kzalloc( >>>> array3_size(sizeof(unsigned int), >>>> devfreq->profile->max_state, >>>> devfreq->profile->max_state), >>>> GFP_KERNEL); >>>> if (!devfreq->trans_table) { >>>> mutex_unlock(&devfreq->lock); >>>> err = -ENOMEM; >>>> - goto err_devfreq; >>>> + goto err_dev; >>>> } >>>> >>>> - devfreq->time_in_state = devm_kcalloc(&devfreq->dev, >>>> - devfreq->profile->max_state, >>>> - sizeof(unsigned long), >>>> - GFP_KERNEL); >>>> + devfreq->time_in_state = kcalloc(devfreq->profile->max_state, >>>> + sizeof(unsigned long), >>>> + GFP_KERNEL); >>>> if (!devfreq->time_in_state) { >>>> mutex_unlock(&devfreq->lock); >>>> err = -ENOMEM; >>>> - goto err_devfreq; >>>> + goto err_dev; >>>> } >>>> >>>> devfreq->last_stat_updated = jiffies; >>>> >>>> srcu_init_notifier_head(&devfreq->transition_notifier_list); >>>> >>>> + dev_set_name(&devfreq->dev, "devfreq%d", >>>> + atomic_inc_return(&devfreq_no)); >>>> + err = device_register(&devfreq->dev); >>>> + if (err) { >>>> + mutex_unlock(&devfreq->lock); >>>> + put_device(&devfreq->dev); >>>> + goto err_out; >>> >>> As per my comment on v5 I think the goto needs to go to 'err_dev'. The >>> device registration failed, hence devfreq_dev_release() won't be >>> called to free allocated memory. >> >> This code is not modified in the patch, it only shows up as +added >> because diff got confused but there is an identical -removed chunk >> higher up. >> >> The device_register documentation mentions the following: >> >> * NOTE: _Never_ directly free @dev after calling this function, even >> * if it returned an error! Always use put_device() to give up the >> * reference initialized in this function instead. >> >> Cleanup path then goes like this (from a hacked error in device_add): >> dump_stack+0xdc/0x144 >> >> >> devfreq_dev_release+0x38/0xc0 >> >> >> device_release+0x34/0x90 >> >> >> kobject_put+0x8c/0x1f0 >> >> >> put_device+0x24/0x30 >> >> >> devfreq_add_device+0x540/0x570 >> >> >> devm_devfreq_add_device+0x60/0xd0 >> >> >> imx_ddrc_probe+0x35c/0x4c8 > > Good to know, thanks for the pointer! > >> Can I add your "Reviewed-By" for the rest of the series if I fix the nits? > > By now you should have it for most patches. For this one: > > Reviewed-by: Matthias Kaehlcke <mka@chromium.org> > > There is one doubt I have left on "PM / devfreq: Add PM QoS support" that I > posted on v5: > > "IIUC you rely on the notifiers being removed by devfreq_dev_release(). > Does dev_pm_qos_remove_notifier() behave gracefully if the notifier is > not initialized/added or do we need to use BLOCKING_NOTIFIER_INIT() or > similar?" Sorry for missing that. > Could you clarify this replying to the thread? Besides that and the > nits (which are optional to fix) the patch looks good to me. The blocking_notifier_head structs are managed by PM QoS inside dev_pm_qos_constraints_allocate and dev_pm_qos_constraints_destroy. The devfreq subsystem only registers a notifier_block, that's a NULL-terminated singly-linked list for which zero-initialization from kzalloc should be sufficient. But now that I look at this again I should warn and return NOTIFY_DONE from devfreq_qos_notifier_call instead of propagating a negative errno. -- Regards, Leonard
On Mon, Sep 23, 2019 at 07:56:51PM +0000, Leonard Crestez wrote: > On 23.09.2019 22:11, Matthias Kaehlcke wrote: > > On Mon, Sep 23, 2019 at 06:56:28PM +0000, Leonard Crestez wrote: > >> On 23.09.2019 21:11, Matthias Kaehlcke wrote: > >>> On Mon, Sep 23, 2019 at 06:51:05PM +0300, Leonard Crestez wrote: > >>>> In general it is a better to initialize an object before making it > >>>> accessible externally (through device_register). > >>>> > >>>> This makes it possible to avoid relying on locking a partially > >>>> initialized object. > >>>> > >>>> Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> > >>>> --- > >>>> drivers/devfreq/devfreq.c | 43 +++++++++++++++++++++++---------------- > >>>> 1 file changed, 25 insertions(+), 18 deletions(-) > >>>> > >>>> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c > >>>> index 323d43315d1e..b4d2bfebb140 100644 > >>>> --- a/drivers/devfreq/devfreq.c > >>>> +++ b/drivers/devfreq/devfreq.c > >>>> @@ -587,10 +587,12 @@ static void devfreq_dev_release(struct device *dev) > >>>> mutex_unlock(&devfreq_list_lock); > >>>> > >>>> if (devfreq->profile->exit) > >>>> devfreq->profile->exit(devfreq->dev.parent); > >>>> > >>>> + kfree(devfreq->time_in_state); > >>>> + kfree(devfreq->trans_table); > >>>> mutex_destroy(&devfreq->lock); > >>>> kfree(devfreq); > >>>> } > >>>> > >>>> /** > >>>> @@ -670,44 +672,43 @@ struct devfreq *devfreq_add_device(struct device *dev, > >>>> devfreq->max_freq = devfreq->scaling_max_freq; > >>>> > >>>> devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev); > >>>> atomic_set(&devfreq->suspend_count, 0); > >>>> > >>>> - dev_set_name(&devfreq->dev, "devfreq%d", > >>>> - atomic_inc_return(&devfreq_no)); > >>>> - err = device_register(&devfreq->dev); > >>>> - if (err) { > >>>> - mutex_unlock(&devfreq->lock); > >>>> - put_device(&devfreq->dev); > >>>> - goto err_out; > >>>> - } > >>>> - > >>>> - devfreq->trans_table = devm_kzalloc(&devfreq->dev, > >>>> + devfreq->trans_table = kzalloc( > >>>> array3_size(sizeof(unsigned int), > >>>> devfreq->profile->max_state, > >>>> devfreq->profile->max_state), > >>>> GFP_KERNEL); > >>>> if (!devfreq->trans_table) { > >>>> mutex_unlock(&devfreq->lock); > >>>> err = -ENOMEM; > >>>> - goto err_devfreq; > >>>> + goto err_dev; > >>>> } > >>>> > >>>> - devfreq->time_in_state = devm_kcalloc(&devfreq->dev, > >>>> - devfreq->profile->max_state, > >>>> - sizeof(unsigned long), > >>>> - GFP_KERNEL); > >>>> + devfreq->time_in_state = kcalloc(devfreq->profile->max_state, > >>>> + sizeof(unsigned long), > >>>> + GFP_KERNEL); > >>>> if (!devfreq->time_in_state) { > >>>> mutex_unlock(&devfreq->lock); > >>>> err = -ENOMEM; > >>>> - goto err_devfreq; > >>>> + goto err_dev; > >>>> } > >>>> > >>>> devfreq->last_stat_updated = jiffies; > >>>> > >>>> srcu_init_notifier_head(&devfreq->transition_notifier_list); > >>>> > >>>> + dev_set_name(&devfreq->dev, "devfreq%d", > >>>> + atomic_inc_return(&devfreq_no)); > >>>> + err = device_register(&devfreq->dev); > >>>> + if (err) { > >>>> + mutex_unlock(&devfreq->lock); > >>>> + put_device(&devfreq->dev); > >>>> + goto err_out; > >>> > >>> As per my comment on v5 I think the goto needs to go to 'err_dev'. The > >>> device registration failed, hence devfreq_dev_release() won't be > >>> called to free allocated memory. > >> > >> This code is not modified in the patch, it only shows up as +added > >> because diff got confused but there is an identical -removed chunk > >> higher up. > >> > >> The device_register documentation mentions the following: > >> > >> * NOTE: _Never_ directly free @dev after calling this function, even > >> * if it returned an error! Always use put_device() to give up the > >> * reference initialized in this function instead. > >> > >> Cleanup path then goes like this (from a hacked error in device_add): > >> dump_stack+0xdc/0x144 > >> > >> > >> devfreq_dev_release+0x38/0xc0 > >> > >> > >> device_release+0x34/0x90 > >> > >> > >> kobject_put+0x8c/0x1f0 > >> > >> > >> put_device+0x24/0x30 > >> > >> > >> devfreq_add_device+0x540/0x570 > >> > >> > >> devm_devfreq_add_device+0x60/0xd0 > >> > >> > >> imx_ddrc_probe+0x35c/0x4c8 > > > > Good to know, thanks for the pointer! > > > >> Can I add your "Reviewed-By" for the rest of the series if I fix the nits? > > > > By now you should have it for most patches. For this one: > > > > Reviewed-by: Matthias Kaehlcke <mka@chromium.org> > > > > There is one doubt I have left on "PM / devfreq: Add PM QoS support" that I > > posted on v5: > > > > "IIUC you rely on the notifiers being removed by devfreq_dev_release(). > > Does dev_pm_qos_remove_notifier() behave gracefully if the notifier is > > not initialized/added or do we need to use BLOCKING_NOTIFIER_INIT() or > > similar?" > > Sorry for missing that. > > Could you clarify this replying to the thread? Besides that and the > > nits (which are optional to fix) the patch looks good to me. > > The blocking_notifier_head structs are managed by PM QoS inside > dev_pm_qos_constraints_allocate and dev_pm_qos_constraints_destroy. The > devfreq subsystem only registers a notifier_block, that's a > NULL-terminated singly-linked list for which zero-initialization from > kzalloc should be sufficient. Right, thanks for the clarification! > But now that I look at this again I should warn and return NOTIFY_DONE > from devfreq_qos_notifier_call instead of propagating a negative errno. Ack
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 323d43315d1e..b4d2bfebb140 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -587,10 +587,12 @@ static void devfreq_dev_release(struct device *dev) mutex_unlock(&devfreq_list_lock); if (devfreq->profile->exit) devfreq->profile->exit(devfreq->dev.parent); + kfree(devfreq->time_in_state); + kfree(devfreq->trans_table); mutex_destroy(&devfreq->lock); kfree(devfreq); } /** @@ -670,44 +672,43 @@ struct devfreq *devfreq_add_device(struct device *dev, devfreq->max_freq = devfreq->scaling_max_freq; devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev); atomic_set(&devfreq->suspend_count, 0); - dev_set_name(&devfreq->dev, "devfreq%d", - atomic_inc_return(&devfreq_no)); - err = device_register(&devfreq->dev); - if (err) { - mutex_unlock(&devfreq->lock); - put_device(&devfreq->dev); - goto err_out; - } - - devfreq->trans_table = devm_kzalloc(&devfreq->dev, + devfreq->trans_table = kzalloc( array3_size(sizeof(unsigned int), devfreq->profile->max_state, devfreq->profile->max_state), GFP_KERNEL); if (!devfreq->trans_table) { mutex_unlock(&devfreq->lock); err = -ENOMEM; - goto err_devfreq; + goto err_dev; } - devfreq->time_in_state = devm_kcalloc(&devfreq->dev, - devfreq->profile->max_state, - sizeof(unsigned long), - GFP_KERNEL); + devfreq->time_in_state = kcalloc(devfreq->profile->max_state, + sizeof(unsigned long), + GFP_KERNEL); if (!devfreq->time_in_state) { mutex_unlock(&devfreq->lock); err = -ENOMEM; - goto err_devfreq; + goto err_dev; } devfreq->last_stat_updated = jiffies; srcu_init_notifier_head(&devfreq->transition_notifier_list); + dev_set_name(&devfreq->dev, "devfreq%d", + atomic_inc_return(&devfreq_no)); + err = device_register(&devfreq->dev); + if (err) { + mutex_unlock(&devfreq->lock); + put_device(&devfreq->dev); + goto err_out; + } + mutex_unlock(&devfreq->lock); mutex_lock(&devfreq_list_lock); governor = try_then_request_governor(devfreq->governor_name); @@ -733,14 +734,20 @@ struct devfreq *devfreq_add_device(struct device *dev, return devfreq; err_init: mutex_unlock(&devfreq_list_lock); -err_devfreq: devfreq_remove_device(devfreq); - devfreq = NULL; + return ERR_PTR(err); + err_dev: + /* + * Cleanup path for errors that happen before registration. + * Otherwise we rely on devfreq_dev_release + */ + kfree(devfreq->time_in_state); + kfree(devfreq->trans_table); kfree(devfreq); err_out: return ERR_PTR(err); } EXPORT_SYMBOL(devfreq_add_device);
In general it is a better to initialize an object before making it accessible externally (through device_register). This makes it possible to avoid relying on locking a partially initialized object. Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com> --- drivers/devfreq/devfreq.c | 43 +++++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 18 deletions(-)