USB: mass_storage: eject LUNs on thread exit

Adds a fallback which forces all LUNs ejection (including
non-removable and with prevent_medium_removal flag) when mass storage
function (MSF) worker thread exits and gadget fails to handle the
situation.

Previously, if thread_exits was not specified mass storage function
(MSF) did nothing when exiting thread as it's unclear for *function*
what to do when it's thread terminates so responsibility of handling
this situation was left to the *gadget* using the function.

The g_mass_storage handled the situation by unregistering itself (the
same thing that file storage gadget does).  However, g_multi did
nothing and so MSF did not eject LUNs which prevented file system
unmounting.

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/usb/gadget/mass_storage.c b/drivers/usb/gadget/mass_storage.c
index 19619fb..705cc1f 100644
--- a/drivers/usb/gadget/mass_storage.c
+++ b/drivers/usb/gadget/mass_storage.c
@@ -135,6 +135,12 @@ FSG_MODULE_PARAMETERS(/* no prefix */, mod_data);
 static unsigned long msg_registered = 0;
 static void msg_cleanup(void);
 
+static int msg_thread_exits(struct fsg_common *common)
+{
+	msg_cleanup();
+	return 0;
+}
+
 static int __init msg_do_config(struct usb_configuration *c)
 {
 	struct fsg_common *common;
@@ -147,7 +153,7 @@ static int __init msg_do_config(struct usb_configuration *c)
 	}
 
 	fsg_config_from_params(&config, &mod_data);
-	config.thread_exits = (void(*)(struct fsg_common*))&msg_cleanup;
+	config.thread_exits = msg_thread_exits;
 	common = fsg_common_init(0, c->cdev, &config);
 	if (IS_ERR(common))
 		return PTR_ERR(common);