[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <Pine.LNX.4.44L0.0706111147160.2611-100000@iolanthe.rowland.org>
Date: Mon, 11 Jun 2007 11:59:58 -0400 (EDT)
From: Alan Stern <stern@...land.harvard.edu>
To: "Rafael J. Wysocki" <rjw@...k.pl>
cc: pm list <linux-pm@...ts.linux-foundation.org>,
David Brownell <david-b@...bell.net>, Greg KH <greg@...ah.com>,
LKML <linux-kernel@...r.kernel.org>, Pavel Machek <pavel@....cz>,
USB development list <linux-usb-devel@...ts.sourceforge.net>
Subject: Re: [RFC][PATCH -mm 1/7] PM: Remove pm_parent from struct dev_pm_info
On Mon, 11 Jun 2007, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rjw@...k.pl>
>
> The pm_parent member of struct dev_pm_info (defined in include/linux/pm.h) is
> only used to check if the device's parent is in the right state while the
> device is being suspended or resumed. However, this can be done just as well
> with the help of the parent pointer in struct device, so pm_parent can be
> removed along with some code that handles it.
> @@ -61,21 +40,26 @@ int device_pm_add(struct device * dev)
> kobject_name(&dev->kobj));
> mutex_lock(&dpm_list_mtx);
> list_add_tail(&dev->power.entry, &dpm_active);
> - device_pm_set_parent(dev, dev->parent);
> - if ((error = dpm_sysfs_add(dev)))
> + /*
> + * The device's parent must not be released until the device itself is
> + * removed from the dpm_active list.
> + */
> + get_device(dev->parent);
> + error = dpm_sysfs_add(dev);
> + if (error)
> list_del(&dev->power.entry);
> mutex_unlock(&dpm_list_mtx);
> return error;
> }
The error pathway here does an unbalanced get_device on dev->parent.
Anyway, I don't think you need to do this get_device at all (or the
coresponding put in device_pm_remove). As long as a device is
registered it retains a reference to its parent, and unregistration
always calls device_pm_remove. The reason it was there in the first
place was because people recognized that dev->power.pm_parent wouldn't
be one of dev's ancestors in the device hierarchy.
Alan Stern
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists