| Message ID | 1471340976-5379-8-git-send-email-jonathanh@nvidia.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On 16 August 2016 at 11:49, Jon Hunter <jonathanh@nvidia.com> wrote: > In order to remove PM domains safely from the list of PM domains, > it is necessary to adding locking for the PM domain list around any > places where devices or subdomains are added to a PM domain. > > There are places where a reference to a PM domain is obtained via > calling of_genpd_get_from_provider() before adding the device or the > subdomain. In these cases a lock for the PM domain list needs to be > held around the call to of_genpd_get_from_provider() and the call to > add the device/subdomain. To avoid deadlocks by multiple attempts to > obtain the PM domain list lock, add functions genpd_add_device() and > genpd_add_subdomain() which require the user to hold the PM domain > list lock when calling. > > Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> Kind regards Uffe > --- > drivers/base/power/domain.c | 97 ++++++++++++++++++++++++++++++++++----------- > 1 file changed, 73 insertions(+), 24 deletions(-) > > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c > index 50223ae0c9a7..7ce4608bbbe0 100644 > --- a/drivers/base/power/domain.c > +++ b/drivers/base/power/domain.c > @@ -1060,14 +1060,8 @@ static void genpd_free_dev_data(struct device *dev, > dev_pm_put_subsys_data(dev); > } > > -/** > - * __pm_genpd_add_device - Add a device to an I/O PM domain. > - * @genpd: PM domain to add the device to. > - * @dev: Device to be added. > - * @td: Set of PM QoS timing parameters to attach to the device. > - */ > -int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, > - struct gpd_timing_data *td) > +static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, > + struct gpd_timing_data *td) > { > struct generic_pm_domain_data *gpd_data; > int ret = 0; > @@ -1107,6 +1101,24 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, > > return ret; > } > + > +/** > + * __pm_genpd_add_device - Add a device to an I/O PM domain. > + * @genpd: PM domain to add the device to. > + * @dev: Device to be added. > + * @td: Set of PM QoS timing parameters to attach to the device. > + */ > +int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, > + struct gpd_timing_data *td) > +{ > + int ret; > + > + mutex_lock(&gpd_list_lock); > + ret = genpd_add_device(genpd, dev, td); > + mutex_unlock(&gpd_list_lock); > + > + return ret; > +} > EXPORT_SYMBOL_GPL(__pm_genpd_add_device); > > /** > @@ -1160,13 +1172,8 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd, > } > EXPORT_SYMBOL_GPL(pm_genpd_remove_device); > > -/** > - * pm_genpd_add_subdomain - Add a subdomain to an I/O PM domain. > - * @genpd: Master PM domain to add the subdomain to. > - * @subdomain: Subdomain to be added. > - */ > -int pm_genpd_add_subdomain(struct generic_pm_domain *genpd, > - struct generic_pm_domain *subdomain) > +static int genpd_add_subdomain(struct generic_pm_domain *genpd, > + struct generic_pm_domain *subdomain) > { > struct gpd_link *link, *itr; > int ret = 0; > @@ -1209,6 +1216,23 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd, > kfree(link); > return ret; > } > + > +/** > + * pm_genpd_add_subdomain - Add a subdomain to an I/O PM domain. > + * @genpd: Master PM domain to add the subdomain to. > + * @subdomain: Subdomain to be added. > + */ > +int pm_genpd_add_subdomain(struct generic_pm_domain *genpd, > + struct generic_pm_domain *subdomain) > +{ > + int ret; > + > + mutex_lock(&gpd_list_lock); > + ret = genpd_add_subdomain(genpd, subdomain); > + mutex_unlock(&gpd_list_lock); > + > + return ret; > +} > EXPORT_SYMBOL_GPL(pm_genpd_add_subdomain); > > /** > @@ -1575,12 +1599,22 @@ static struct generic_pm_domain *genpd_get_from_provider( > int of_genpd_add_device(struct of_phandle_args *genpdspec, struct device *dev) > { > struct generic_pm_domain *genpd; > + int ret; > + > + mutex_lock(&gpd_list_lock); > > genpd = genpd_get_from_provider(genpdspec); > - if (IS_ERR(genpd)) > - return PTR_ERR(genpd); > + if (IS_ERR(genpd)) { > + ret = PTR_ERR(genpd); > + goto out; > + } > > - return pm_genpd_add_device(genpd, dev); > + ret = genpd_add_device(genpd, dev, NULL); > + > +out: > + mutex_unlock(&gpd_list_lock); > + > + return ret; > } > EXPORT_SYMBOL_GPL(of_genpd_add_device); > > @@ -1597,16 +1631,28 @@ int of_genpd_add_subdomain(struct of_phandle_args *parent_spec, > struct of_phandle_args *subdomain_spec) > { > struct generic_pm_domain *parent, *subdomain; > + int ret; > + > + mutex_lock(&gpd_list_lock); > > parent = genpd_get_from_provider(parent_spec); > - if (IS_ERR(parent)) > - return PTR_ERR(parent); > + if (IS_ERR(parent)) { > + ret = PTR_ERR(parent); > + goto out; > + } > > subdomain = genpd_get_from_provider(subdomain_spec); > - if (IS_ERR(subdomain)) > - return PTR_ERR(subdomain); > + if (IS_ERR(subdomain)) { > + ret = PTR_ERR(subdomain); > + goto out; > + } > + > + ret = genpd_add_subdomain(parent, subdomain); > + > +out: > + mutex_unlock(&gpd_list_lock); > > - return pm_genpd_add_subdomain(parent, subdomain); > + return ret; > } > EXPORT_SYMBOL_GPL(of_genpd_add_subdomain); > > @@ -1705,9 +1751,11 @@ int genpd_dev_pm_attach(struct device *dev) > return -ENOENT; > } > > + mutex_lock(&gpd_list_lock); > pd = genpd_get_from_provider(&pd_args); > of_node_put(pd_args.np); > if (IS_ERR(pd)) { > + mutex_unlock(&gpd_list_lock); > dev_dbg(dev, "%s() failed to find PM domain: %ld\n", > __func__, PTR_ERR(pd)); > return -EPROBE_DEFER; > @@ -1716,13 +1764,14 @@ int genpd_dev_pm_attach(struct device *dev) > dev_dbg(dev, "adding to PM domain %s\n", pd->name); > > for (i = 1; i < GENPD_RETRY_MAX_MS; i <<= 1) { > - ret = pm_genpd_add_device(pd, dev); > + ret = genpd_add_device(pd, dev, NULL); > if (ret != -EAGAIN) > break; > > mdelay(i); > cond_resched(); > } > + mutex_unlock(&gpd_list_lock); > > if (ret < 0) { > dev_err(dev, "failed to add to PM domain %s: %d", > -- > 2.1.4 > -- 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
diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index 50223ae0c9a7..7ce4608bbbe0 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -1060,14 +1060,8 @@ static void genpd_free_dev_data(struct device *dev, dev_pm_put_subsys_data(dev); } -/** - * __pm_genpd_add_device - Add a device to an I/O PM domain. - * @genpd: PM domain to add the device to. - * @dev: Device to be added. - * @td: Set of PM QoS timing parameters to attach to the device. - */ -int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, - struct gpd_timing_data *td) +static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, + struct gpd_timing_data *td) { struct generic_pm_domain_data *gpd_data; int ret = 0; @@ -1107,6 +1101,24 @@ int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, return ret; } + +/** + * __pm_genpd_add_device - Add a device to an I/O PM domain. + * @genpd: PM domain to add the device to. + * @dev: Device to be added. + * @td: Set of PM QoS timing parameters to attach to the device. + */ +int __pm_genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, + struct gpd_timing_data *td) +{ + int ret; + + mutex_lock(&gpd_list_lock); + ret = genpd_add_device(genpd, dev, td); + mutex_unlock(&gpd_list_lock); + + return ret; +} EXPORT_SYMBOL_GPL(__pm_genpd_add_device); /** @@ -1160,13 +1172,8 @@ int pm_genpd_remove_device(struct generic_pm_domain *genpd, } EXPORT_SYMBOL_GPL(pm_genpd_remove_device); -/** - * pm_genpd_add_subdomain - Add a subdomain to an I/O PM domain. - * @genpd: Master PM domain to add the subdomain to. - * @subdomain: Subdomain to be added. - */ -int pm_genpd_add_subdomain(struct generic_pm_domain *genpd, - struct generic_pm_domain *subdomain) +static int genpd_add_subdomain(struct generic_pm_domain *genpd, + struct generic_pm_domain *subdomain) { struct gpd_link *link, *itr; int ret = 0; @@ -1209,6 +1216,23 @@ int pm_genpd_add_subdomain(struct generic_pm_domain *genpd, kfree(link); return ret; } + +/** + * pm_genpd_add_subdomain - Add a subdomain to an I/O PM domain. + * @genpd: Master PM domain to add the subdomain to. + * @subdomain: Subdomain to be added. + */ +int pm_genpd_add_subdomain(struct generic_pm_domain *genpd, + struct generic_pm_domain *subdomain) +{ + int ret; + + mutex_lock(&gpd_list_lock); + ret = genpd_add_subdomain(genpd, subdomain); + mutex_unlock(&gpd_list_lock); + + return ret; +} EXPORT_SYMBOL_GPL(pm_genpd_add_subdomain); /** @@ -1575,12 +1599,22 @@ static struct generic_pm_domain *genpd_get_from_provider( int of_genpd_add_device(struct of_phandle_args *genpdspec, struct device *dev) { struct generic_pm_domain *genpd; + int ret; + + mutex_lock(&gpd_list_lock); genpd = genpd_get_from_provider(genpdspec); - if (IS_ERR(genpd)) - return PTR_ERR(genpd); + if (IS_ERR(genpd)) { + ret = PTR_ERR(genpd); + goto out; + } - return pm_genpd_add_device(genpd, dev); + ret = genpd_add_device(genpd, dev, NULL); + +out: + mutex_unlock(&gpd_list_lock); + + return ret; } EXPORT_SYMBOL_GPL(of_genpd_add_device); @@ -1597,16 +1631,28 @@ int of_genpd_add_subdomain(struct of_phandle_args *parent_spec, struct of_phandle_args *subdomain_spec) { struct generic_pm_domain *parent, *subdomain; + int ret; + + mutex_lock(&gpd_list_lock); parent = genpd_get_from_provider(parent_spec); - if (IS_ERR(parent)) - return PTR_ERR(parent); + if (IS_ERR(parent)) { + ret = PTR_ERR(parent); + goto out; + } subdomain = genpd_get_from_provider(subdomain_spec); - if (IS_ERR(subdomain)) - return PTR_ERR(subdomain); + if (IS_ERR(subdomain)) { + ret = PTR_ERR(subdomain); + goto out; + } + + ret = genpd_add_subdomain(parent, subdomain); + +out: + mutex_unlock(&gpd_list_lock); - return pm_genpd_add_subdomain(parent, subdomain); + return ret; } EXPORT_SYMBOL_GPL(of_genpd_add_subdomain); @@ -1705,9 +1751,11 @@ int genpd_dev_pm_attach(struct device *dev) return -ENOENT; } + mutex_lock(&gpd_list_lock); pd = genpd_get_from_provider(&pd_args); of_node_put(pd_args.np); if (IS_ERR(pd)) { + mutex_unlock(&gpd_list_lock); dev_dbg(dev, "%s() failed to find PM domain: %ld\n", __func__, PTR_ERR(pd)); return -EPROBE_DEFER; @@ -1716,13 +1764,14 @@ int genpd_dev_pm_attach(struct device *dev) dev_dbg(dev, "adding to PM domain %s\n", pd->name); for (i = 1; i < GENPD_RETRY_MAX_MS; i <<= 1) { - ret = pm_genpd_add_device(pd, dev); + ret = genpd_add_device(pd, dev, NULL); if (ret != -EAGAIN) break; mdelay(i); cond_resched(); } + mutex_unlock(&gpd_list_lock); if (ret < 0) { dev_err(dev, "failed to add to PM domain %s: %d",
In order to remove PM domains safely from the list of PM domains, it is necessary to adding locking for the PM domain list around any places where devices or subdomains are added to a PM domain. There are places where a reference to a PM domain is obtained via calling of_genpd_get_from_provider() before adding the device or the subdomain. In these cases a lock for the PM domain list needs to be held around the call to of_genpd_get_from_provider() and the call to add the device/subdomain. To avoid deadlocks by multiple attempts to obtain the PM domain list lock, add functions genpd_add_device() and genpd_add_subdomain() which require the user to hold the PM domain list lock when calling. Signed-off-by: Jon Hunter <jonathanh@nvidia.com> --- drivers/base/power/domain.c | 97 ++++++++++++++++++++++++++++++++++----------- 1 file changed, 73 insertions(+), 24 deletions(-)