Messages in this thread | | | Date | Thu, 5 Jul 2012 09:25:56 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [PATCH] [SCSI] scsi_pm: set device runtime state before parent suspended |
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On Thu, 5 Jul 2012, Lin Ming wrote:
> There is a race in scsi_bus_resume_common when set device's runtime > state to active after pm_runtime_put_sync(dev->parent). > > Parent device may have been suspended so pm_runtime_set_active(dev) will > fail with -EBUSY. > > Signed-off-by: Lin Ming <ming.m.lin@intel.com> > CC: <stable@vger.kernel.org> > --- > drivers/scsi/scsi_pm.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c > index d4201de..d2a80de 100644 > --- a/drivers/scsi/scsi_pm.c > +++ b/drivers/scsi/scsi_pm.c > @@ -85,14 +85,14 @@ static int scsi_bus_resume_common(struct device *dev) > */ > pm_runtime_get_sync(dev->parent); > err = scsi_dev_type_resume(dev); > + if (err == 0) { > + pm_runtime_disable(dev); > + pm_runtime_set_active(dev); > + pm_runtime_enable(dev); > + } > pm_runtime_put_sync(dev->parent); > } > > - if (err == 0) { > - pm_runtime_disable(dev); > - pm_runtime_set_active(dev); > - pm_runtime_enable(dev); > - }
This isn't quite right. We still want to execute the pm_runtime_disable, _set_active, and _enable even when scsi_is_sdev_device(dev) is false.
I guess the revised code should look more like this:
/* * Parent device may have runtime suspended as soon as * it is woken up during the system resume. * * Resume it on behalf of child. */ pm_runtime_get_sync(dev->parent);
if (scsi_is_sdev_device(dev)) err = scsi_dev_type_resume(dev); if (err == 0) { pm_runtime_disable(dev); pm_runtime_set_active(dev); pm_runtime_enable(dev); }
pm_runtime_put_sync(dev->parent);
Alan Stern
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