On Fri, Aug 16, 2019 at 7:56 AM Stephen Boyd <swb...@chromium.org> wrote: > > The device_set_wakeup_enable() function can be called on a device that > hasn't been registered with device_add() yet. This allows the device to > be in a state where wakeup is enabled for it but the device isn't > published to userspace in sysfs yet. > > After commit 986845e747af ("PM / wakeup: Show wakeup sources stats in > sysfs"), calling device_set_wakeup_enable() will fail for a device that > hasn't been registered with the driver core via device_add(). This is > because we try to create sysfs entries for the device and associate a > wakeup class kobject with it before the device has been registered. > Let's follow a similar approach that device_set_wakeup_capable() takes > here and register the wakeup class either from > device_set_wakeup_enable() when the device is already registered, or > from dpm_sysfs_add() when the device is being registered with the driver > core via device_add(). > > Fixes: 986845e747af ("PM / wakeup: Show wakeup sources stats in sysfs") > Reported-by: Qian Cai <c...@lca.pw> > Cc: Qian Cai <c...@lca.pw> > Cc: Tri Vo <tr...@android.com> > Signed-off-by: Stephen Boyd <swb...@chromium.org> > --- > drivers/base/power/sysfs.c | 10 +++++++++- > drivers/base/power/wakeup.c | 10 ++++++---- > 2 files changed, 15 insertions(+), 5 deletions(-) > > diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c > index 1b9c281cbe41..27ee00f50bd7 100644 > --- a/drivers/base/power/sysfs.c > +++ b/drivers/base/power/sysfs.c > @@ -5,6 +5,7 @@ > #include <linux/export.h> > #include <linux/pm_qos.h> > #include <linux/pm_runtime.h> > +#include <linux/pm_wakeup.h> > #include <linux/atomic.h> > #include <linux/jiffies.h> > #include "power.h" > @@ -661,14 +662,21 @@ int dpm_sysfs_add(struct device *dev) > if (rc) > goto err_runtime; > } > + if (dev->power.wakeup) {
This conditional checks for the situation when wakeup source registration have been previously attempted, but failed at wakeup_source_sysfs_add(). My concern is that it's not easy to understand what this check does without knowing exactly what device_wakeup_enable() does to dev->power.wakeup before we reach this point. > + rc = wakeup_source_sysfs_add(dev, dev->power.wakeup); > + if (rc) > + goto err_wakeup; > + } > if (dev->power.set_latency_tolerance) { > rc = sysfs_merge_group(&dev->kobj, > &pm_qos_latency_tolerance_attr_group); > if (rc) > - goto err_wakeup; > + goto err_wakeup_source; > } > return 0; > > + err_wakeup_source: > + wakeup_source_sysfs_remove(dev->power.wakeup); > err_wakeup: > sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group); > err_runtime: > diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c > index f7925820b5ca..5817b51d2b15 100644 > --- a/drivers/base/power/wakeup.c > +++ b/drivers/base/power/wakeup.c > @@ -220,10 +220,12 @@ struct wakeup_source *wakeup_source_register(struct > device *dev, > > ws = wakeup_source_create(name); > if (ws) { > - ret = wakeup_source_sysfs_add(dev, ws); > - if (ret) { > - wakeup_source_free(ws); > - return NULL; > + if (!dev || device_is_registered(dev)) { Is there a possible race condition here? If dev->power.wakeup check in dpm_sysfs_add() is done at the same time as device_is_registered(dev) check here, then wakeup_source_sysfs_add() won't ever be called? > + ret = wakeup_source_sysfs_add(dev, ws); > + if (ret) { > + wakeup_source_free(ws); > + return NULL; > + } > } > wakeup_source_add(ws); > } > -- > Sent by a computer through tubes >