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| author | Alan Stern <stern@rowland.harvard.edu> | 2010-01-08 12:56:19 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-03-02 14:54:08 -0800 |
| commit | 62e299e61a6ffe8131fa85a984c3058b68586f5d (patch) | |
| tree | d10709c5b5e6d280e1329c7ed4f30f990246893e /drivers/usb/core/sysfs.c | |
| parent | 0f3dda9f7ff2db8dbf4d6fbab4d4438251446002 (diff) | |
| download | op-kernel-dev-62e299e61a6ffe8131fa85a984c3058b68586f5d.zip op-kernel-dev-62e299e61a6ffe8131fa85a984c3058b68586f5d.tar.gz | |
USB: change locking for device-level autosuspend
This patch (as1323) changes the locking requirements for
usb_autosuspend_device(), usb_autoresume_device(), and
usb_try_autosuspend_device(). This isn't a very important change;
mainly it's meant to make the locking more uniform.
The most tricky part of the patch involves changes to usbdev_open().
To avoid an ABBA locking problem, it was necessary to reduce the
region protected by usbfs_mutex. Since that mutex now protects only
against simultaneous open and remove, this posed no difficulty -- its
scope was larger than necessary.
And it turns out that usbfs_mutex is no longer needed in
usbdev_release() at all. The list of usbfs "ps" structures is now
protected by the device lock instead of by usbfs_mutex.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/core/sysfs.c')
| -rw-r--r-- | drivers/usb/core/sysfs.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c index 1b3c00b..d8f3bfe 100644 --- a/drivers/usb/core/sysfs.c +++ b/drivers/usb/core/sysfs.c @@ -352,6 +352,7 @@ set_autosuspend(struct device *dev, struct device_attribute *attr, return -EINVAL; value *= HZ; + usb_lock_device(udev); udev->autosuspend_delay = value; if (value >= 0) usb_try_autosuspend_device(udev); @@ -359,6 +360,7 @@ set_autosuspend(struct device *dev, struct device_attribute *attr, if (usb_autoresume_device(udev) == 0) usb_autosuspend_device(udev); } + usb_unlock_device(udev); return count; } |
