linux-kernel - [tip:core/urgent] WARN_ON_SMP(): Allow use in if() statements on UP

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <tip-2092e6be82ec71ecbf5a8ceeef004bbcbdb78812@git.kernel.org>
Date:	Fri, 25 Mar 2011 10:48:52 GMT
From:	tip-bot for Steven Rostedt <srostedt@...hat.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
	torvalds@...ux-foundation.org, dvhart@...ux.intel.com,
	peterz@...radead.org, akpm@...ux-foundation.org,
	rostedt@...dmis.org, srostedt@...hat.com, tglx@...utronix.de,
	laijs@...fujitsu.com, mingo@...e.hu
Subject: [tip:core/urgent] WARN_ON_SMP(): Allow use in if() statements on UP

Commit-ID:  2092e6be82ec71ecbf5a8ceeef004bbcbdb78812
Gitweb:     http://git.kernel.org/tip/2092e6be82ec71ecbf5a8ceeef004bbcbdb78812
Author:     Steven Rostedt <srostedt@...hat.com>
AuthorDate: Thu, 17 Mar 2011 15:21:06 -0400
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Fri, 25 Mar 2011 11:32:09 +0100

WARN_ON_SMP(): Allow use in if() statements on UP

Both WARN_ON() and WARN_ON_SMP() should be able to be used in
an if statement.

	if (WARN_ON_SMP(foo)) { ... }

Because WARN_ON_SMP() is defined as a do { } while (0) on UP,
it can not be used this way.

Convert it to the same form that WARN_ON() is, even when
CONFIG_SMP is off.

Signed-off-by: Steven Rostedt <rostedt@...dmis.org>
Acked-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Peter Zijlstra <peterz@...radead.org>
Acked-by: Darren Hart <dvhart@...ux.intel.com>
Cc: Lai Jiangshan <laijs@...fujitsu.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>
LKML-Reference: <20110317192208.444147791@...dmis.org>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 include/asm-generic/bug.h |   28 +++++++++++++++++++++++++++-
 1 files changed, 27 insertions(+), 1 deletions(-)

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index c2c9ba0..f2d2faf 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -165,10 +165,36 @@ extern void warn_slowpath_null(const char *file, const int line);
 #define WARN_ON_RATELIMIT(condition, state)			\
 		WARN_ON((condition) && __ratelimit(state))
 
+/*
+ * WARN_ON_SMP() is for cases that the warning is either
+ * meaningless for !SMP or may even cause failures.
+ * This is usually used for cases that we have
+ * WARN_ON(!spin_is_locked(&lock)) checks, as spin_is_locked()
+ * returns 0 for uniprocessor settings.
+ * It can also be used with values that are only defined
+ * on SMP:
+ *
+ * struct foo {
+ *  [...]
+ * #ifdef CONFIG_SMP
+ *	int bar;
+ * #endif
+ * };
+ *
+ * void func(struct foo *zoot)
+ * {
+ *	WARN_ON_SMP(!zoot->bar);
+ *
+ * For CONFIG_SMP, WARN_ON_SMP() should act the same as WARN_ON(),
+ * and should be a nop and return false for uniprocessor.
+ *
+ * if (WARN_ON_SMP(x)) returns true only when CONFIG_SMP is set
+ * and x is true.
+ */
 #ifdef CONFIG_SMP
 # define WARN_ON_SMP(x)			WARN_ON(x)
 #else
-# define WARN_ON_SMP(x)			do { } while (0)
+# define WARN_ON_SMP(x)			({0;})
 #endif
 
 #endif
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/