From f39cdaebb89dc3e6dd4f3e75b6d4e87ef12190af Mon Sep 17 00:00:00 2001
From: Anton Blanchard <anton@samba.org>
Date: Wed, 20 Jun 2012 12:53:03 -0700
Subject: [PATCH] fault-inject: avoid call to random32() if fault injection is
disabled
After enabling CONFIG_FAILSLAB I noticed random32 in profiles even if slub
fault injection wasn't enabled at runtime.
should_fail forces a comparison against random32() even if probability is
0:
if (attr->probability <= random32() % 100)
return false;
Add a check up front for probability == 0 and avoid all of the more
complicated checks.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
lib/fault-inject.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index 6805453c18e78..f7210ad6cffd4 100644
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -101,6 +101,10 @@ static inline bool fail_stacktrace(struct fault_attr *attr)
bool should_fail(struct fault_attr *attr, ssize_t size)
{
+ /* No need to check any other properties if the probability is 0 */
+ if (attr->probability == 0)
+ return false;
+
if (attr->task_filter && !fail_task(attr, current))
return false;
--
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