From 7faaa5f0bf4db6ac4908038e2139adc46c165ff4 Mon Sep 17 00:00:00 2001 From: Mika Kukkonen Date: Thu, 10 May 2007 22:22:17 -0700 Subject: [PATCH] Bug in mm/thrash.c function grab_swap_token() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Following bug was uncovered by compiling with '-W' flag: CC mm/thrash.o mm/thrash.c: In function ‘grab_swap_token’: mm/thrash.c:52: warning: comparison of unsigned expression < 0 is always false Variable token_priority is unsigned, so decrementing first and then checking the result does not work; fixed by reversing the test, patch attached (compile tested only). I am not sure if likely() makes much sense in this new situation, but I'll let somebody else to make a decision on that. Signed-off-by: Mika Kukkonen Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/thrash.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/mm/thrash.c b/mm/thrash.c index 9ef9071f99b..c4c5205a9c3 100644 --- a/mm/thrash.c +++ b/mm/thrash.c @@ -48,9 +48,8 @@ void grab_swap_token(void) if (current_interval < current->mm->last_interval) current->mm->token_priority++; else { - current->mm->token_priority--; - if (unlikely(current->mm->token_priority < 0)) - current->mm->token_priority = 0; + if (likely(current->mm->token_priority > 0)) + current->mm->token_priority--; } /* Check if we deserve the token */ if (current->mm->token_priority >