Documentation/memory-barriers.txt: Add long atomic examples to memory-barriers.txt

Although the atomic_long_t functions are quite useful, they are
a bit obscure.  This commit therefore adds the common ones
alongside their atomic_t counterparts in
Documentation/memory-barriers.txt.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: NJosh Triplett <josh@joshtriplett.org>
Reviewed-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-arch@vger.kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1386799151-2219-2-git-send-email-paulmck@linux.vnet.ibm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Documentation/memory-barriers.txt

@@ -1728,21 +1728,23 @@ explicit lock operations, described later).  These include:
 
 	xchg();
 	cmpxchg();
-	atomic_xchg();
-	atomic_cmpxchg();
-	atomic_inc_return();
-	atomic_dec_return();
-	atomic_add_return();
-	atomic_sub_return();
-	atomic_inc_and_test();
-	atomic_dec_and_test();
-	atomic_sub_and_test();
-	atomic_add_negative();
-	atomic_add_unless();	/* when succeeds (returns 1) */
+	atomic_xchg();			atomic_long_xchg();
+	atomic_cmpxchg();		atomic_long_cmpxchg();
+	atomic_inc_return();		atomic_long_inc_return();
+	atomic_dec_return();		atomic_long_dec_return();
+	atomic_add_return();		atomic_long_add_return();
+	atomic_sub_return();		atomic_long_sub_return();
+	atomic_inc_and_test();		atomic_long_inc_and_test();
+	atomic_dec_and_test();		atomic_long_dec_and_test();
+	atomic_sub_and_test();		atomic_long_sub_and_test();
+	atomic_add_negative();		atomic_long_add_negative();
 	test_and_set_bit();
 	test_and_clear_bit();
 	test_and_change_bit();
 
+	/* when succeeds (returns 1) */
+	atomic_add_unless();		atomic_long_add_unless();
+
 These are used for such things as implementing LOCK-class and UNLOCK-class
 operations and adjusting reference counters towards object destruction, and as
 such the implicit memory barrier effects are necessary.