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>

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index a37640e..0a18d44 100644 (file)
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -368,7 +368,7 @@ struct fsg_common {
        struct task_struct      *thread_task;
 
        /* Callback function to call when thread exits. */
-       void                    (*thread_exits)(struct fsg_common *common);
+       int                     (*thread_exits)(struct fsg_common *common);
        /* Gadget's private data. */
        void                    *private_data;
 
@@ -392,8 +392,12 @@ struct fsg_config {
        const char              *lun_name_format;
        const char              *thread_name;
 
-       /* Callback function to call when thread exits. */
-       void                    (*thread_exits)(struct fsg_common *common);
+       /* Callback function to call when thread exits.  If no
+        * callback is set or it returns value lower then zero MSF
+        * will force eject all LUNs it operates on (including those
+        * marked as non-removable or with prevent_medium_removal flag
+        * set). */
+       int                     (*thread_exits)(struct fsg_common *common);
        /* Gadget's private data. */
        void                    *private_data;
 
@@ -2615,8 +2619,20 @@ static int fsg_main_thread(void *common_)
        common->thread_task = NULL;
        spin_unlock_irq(&common->lock);
 
-       if (common->thread_exits)
-               common->thread_exits(common);
+       if (!common->thread_exits || common->thread_exits(common) < 0) {
+               struct fsg_lun *curlun = common->luns;
+               unsigned i = common->nluns;
+
+               down_write(&common->filesem);
+               for (; i--; ++curlun) {
+                       if (!fsg_lun_is_open(curlun))
+                               continue;
+
+                       fsg_lun_close(curlun);
+                       curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
+               }
+               up_write(&common->filesem);
+       }
 
        /* Let the unbind and cleanup routines know the thread has exited */
        complete_and_exit(&common->thread_notifier, 0);

diff --git a/drivers/usb/gadget/mass_storage.c b/drivers/usb/gadget/mass_storage.c
index 19619fb..705cc1f 100644 (file)
--- 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);