linux-kernel - [PATCH] Introduce down

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-next>] [day] [month] [year] [list]

Message-Id: <200805211600.16415.rusty@rustcorp.com.au>
Date:	Wed, 21 May 2008 16:00:15 +1000
From:	Rusty Russell <rusty@...tcorp.com.au>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org,
	Stephen Rothwell <sfr@...b.auug.org.au>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Christoph Hellwig <hch@...radead.org>,
	Matthew Wilcox <matthew@....cx>
Subject: [PATCH] Introduce down_nowait()

I planned on removing the much-disliked down_trylock() (with its
backwards return codes) in 2.6.27, but it's creating something of a
logjam with other patches in -mm and linux-next.

Andrew suggested introducing "down_nowait" as a wrapper now, to make
the transition easier.

Signed-off-by: Rusty Russell <rusty@...tcorp.com.au>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Christoph Hellwig <hch@...radead.org>
Cc: Matthew Wilcox <matthew@....cx>
Cc: Stephen Rothwell <sfr@...b.auug.org.au>

diff -r 92664ae4130b include/linux/semaphore.h
--- a/include/linux/semaphore.h	Wed May 21 14:54:40 2008 +1000
+++ b/include/linux/semaphore.h	Wed May 21 15:07:31 2008 +1000
@@ -48,4 +48,18 @@ extern int __must_check down_timeout(str
 extern int __must_check down_timeout(struct semaphore *sem, long jiffies);
 extern void up(struct semaphore *sem);
 
+/**
+ * down_nowait - try to down a semaphore, but don't block
+ * @sem: the semaphore
+ *
+ * This is equivalent to down_trylock(), but has the same return codes as
+ * spin_trylock and mutex_trylock: 1 if semaphore acquired, 0 if not.
+ *
+ * down_trylock() with its confusing return codes will be deprecated
+ * soon.  It will not be missed.
+ */
+static inline int __must_check down_nowait(struct semaphore *sem)
+{
+        return !down_trylock(sem);
+}
 #endif /* __LINUX_SEMAPHORE_H */
--
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/