USB: add USB-Persist facility
This patch (as886) adds the controversial USB-persist facility,
allowing USB devices to persist across a power loss during system
suspend.
The facility is controlled by a new Kconfig option (with appropriate
warnings about the potential dangers); when the option is off the
behavior will remain the same as it is now. But when the option is
on, people will be able to use suspend-to-disk and keep their USB
filesystems intact -- something particularly valuable for small
machines where the root filesystem is on a USB device!
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index df5dc18..be4cd8f 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -236,7 +236,7 @@
mutex_lock(&us->dev_mutex);
}
-static void storage_post_reset(struct usb_interface *iface)
+static void storage_post_reset(struct usb_interface *iface, int reset_resume)
{
struct us_data *us = usb_get_intfdata(iface);
@@ -249,7 +249,11 @@
/* FIXME: Notify the subdrivers that they need to reinitialize
* the device */
- mutex_unlock(&us->dev_mutex);
+
+ /* If this is a reset-resume then the pre_reset routine wasn't
+ * called, so we don't need to unlock the mutex. */
+ if (!reset_resume)
+ mutex_unlock(&us->dev_mutex);
}
/*