staging: unisys: visorchannel: Describe spinlocks in VISORCHANNEL_Tag struct

Add comments indicating the requirements and use of the insert_lock and
remove_lock in the VISORCHANNEL_Tag structure.
Signed-off-by: NBryan Thompson <bryan.thompson@unisys.com>
Signed-off-by: NBenjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/unisys/visorchannel/visorchannel_funcs.c

@@ -33,9 +33,10 @@ struct VISORCHANNEL_Tag {
 	struct channel_header chan_hdr;
 	uuid_le guid;
 	ulong size;
-	BOOL needs_lock;
-	spinlock_t insert_lock;
-	spinlock_t remove_lock;
+	BOOL needs_lock;	/* channel creator knows if more than one
+				 * thread will be inserting or removing */
+	spinlock_t insert_lock; /* protect head writes in chan_hdr */
+	spinlock_t remove_lock;	/* protect tail writes in chan_hdr */
 
 	struct {
 		struct signal_queue_header req_queue;