greybus: kill greybus_{get,put}_gbuf()

These functions are never used, so we can get rid of them.
Since there's no reference-getting function any more, we no
longer need "gbuf_mutex" to avoid racing gets and puts, so
get rid of that too.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/gbuf.c

@@ -62,8 +62,6 @@ struct gbuf *greybus_alloc_gbuf(struct greybus_host_device *hd,
 }
 EXPORT_SYMBOL_GPL(greybus_alloc_gbuf);
 
-static DEFINE_MUTEX(gbuf_mutex);
-
 static void free_gbuf(struct kref *kref)
 {
 	struct gbuf *gbuf = container_of(kref, struct gbuf, kref);
@@ -71,25 +69,15 @@ static void free_gbuf(struct kref *kref)
 	gbuf->hd->driver->free_gbuf_data(gbuf);
 
 	kmem_cache_free(gbuf_head_cache, gbuf);
-	mutex_unlock(&gbuf_mutex);
 }
 
 void greybus_free_gbuf(struct gbuf *gbuf)
 {
 	/* drop the reference count and get out of here */
-	kref_put_mutex(&gbuf->kref, free_gbuf, &gbuf_mutex);
+	kref_put(&gbuf->kref, free_gbuf);
 }
 EXPORT_SYMBOL_GPL(greybus_free_gbuf);
 
-struct gbuf *greybus_get_gbuf(struct gbuf *gbuf)
-{
-	mutex_lock(&gbuf_mutex);
-	kref_get(&gbuf->kref);
-	mutex_unlock(&gbuf_mutex);
-	return gbuf;
-}
-EXPORT_SYMBOL_GPL(greybus_get_gbuf);
-
 int greybus_submit_gbuf(struct gbuf *gbuf, gfp_t gfp_mask)
 {
 	gbuf->status = -EINPROGRESS;

drivers/staging/greybus/greybus.h

@@ -184,8 +184,6 @@ struct gbuf *greybus_alloc_gbuf(struct greybus_host_device *hd,
 				u16 dest_cport_id, unsigned int size,
 				gfp_t gfp_mask);
 void greybus_free_gbuf(struct gbuf *gbuf);
-struct gbuf *greybus_get_gbuf(struct gbuf *gbuf);
-#define greybus_put_gbuf	greybus_free_gbuf
 
 int greybus_submit_gbuf(struct gbuf *gbuf, gfp_t mem_flags);
 void greybus_kill_gbuf(struct gbuf *gbuf);