From: Ingo Molnar <mingo@elte.hu>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
"Paul E. McKenney" <paulmck@us.ibm.com>
Subject: [GIT PULL] core kernel fixes
Date: Sat, 2 Apr 2011 12:21:14 +0200 [thread overview]
Message-ID: <20110402102114.GA15391@elte.hu> (raw)
Linus,
Please pull the latest core-fixes-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git core-fixes-for-linus
Thanks,
Ingo
------------------>
Paul E. McKenney (1):
rcu: create new rcu_access_index() and use in mce
Steven Rostedt (1):
WARN_ON_SMP(): Add comment to explain ({0;})
arch/x86/kernel/cpu/mcheck/mce.c | 2 +-
include/asm-generic/bug.h | 7 +++++++
include/linux/rcupdate.h | 20 ++++++++++++++++++++
3 files changed, 28 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 5a05ef6..3385ea2 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1626,7 +1626,7 @@ out:
static unsigned int mce_poll(struct file *file, poll_table *wait)
{
poll_wait(file, &mce_wait, wait);
- if (rcu_dereference_check_mce(mcelog.next))
+ if (rcu_access_index(mcelog.next))
return POLLIN | POLLRDNORM;
if (!mce_apei_read_done && apei_check_mce())
return POLLIN | POLLRDNORM;
diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index f2d2faf..e5a3f58 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -194,6 +194,13 @@ extern void warn_slowpath_null(const char *file, const int line);
#ifdef CONFIG_SMP
# define WARN_ON_SMP(x) WARN_ON(x)
#else
+/*
+ * Use of ({0;}) because WARN_ON_SMP(x) may be used either as
+ * a stand alone line statement or as a condition in an if ()
+ * statement.
+ * A simple "0" would cause gcc to give a "statement has no effect"
+ * warning.
+ */
# define WARN_ON_SMP(x) ({0;})
#endif
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index af56148..ff422d2 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -339,6 +339,12 @@ extern int rcu_my_thread_group_empty(void);
((typeof(*p) __force __kernel *)(p)); \
})
+#define __rcu_access_index(p, space) \
+ ({ \
+ typeof(p) _________p1 = ACCESS_ONCE(p); \
+ rcu_dereference_sparse(p, space); \
+ (_________p1); \
+ })
#define __rcu_dereference_index_check(p, c) \
({ \
typeof(p) _________p1 = ACCESS_ONCE(p); \
@@ -429,6 +435,20 @@ extern int rcu_my_thread_group_empty(void);
#define rcu_dereference_raw(p) rcu_dereference_check(p, 1) /*@@@ needed? @@@*/
/**
+ * rcu_access_index() - fetch RCU index with no dereferencing
+ * @p: The index to read
+ *
+ * Return the value of the specified RCU-protected index, but omit the
+ * smp_read_barrier_depends() and keep the ACCESS_ONCE(). This is useful
+ * when the value of this index is accessed, but the index is not
+ * dereferenced, for example, when testing an RCU-protected index against
+ * -1. Although rcu_access_index() may also be used in cases where
+ * update-side locks prevent the value of the index from changing, you
+ * should instead use rcu_dereference_index_protected() for this use case.
+ */
+#define rcu_access_index(p) __rcu_access_index((p), __rcu)
+
+/**
* rcu_dereference_index_check() - rcu_dereference for indices with debug checking
* @p: The pointer to read, prior to dereferencing
* @c: The conditions under which the dereference will take place
next reply other threads:[~2011-04-02 10:21 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-02 10:21 Ingo Molnar [this message]
-- strict thread matches above, loose matches on Subject: below --
2020-01-29 11:53 [GIT PULL] core kernel fixes Ingo Molnar
2020-01-29 19:10 ` pr-tracker-bot
2019-05-18 8:51 Ingo Molnar
2019-05-19 17:45 ` pr-tracker-bot
2019-05-16 15:51 Ingo Molnar
2019-05-16 18:20 ` pr-tracker-bot
2018-07-21 11:58 Ingo Molnar
2017-12-06 22:01 Ingo Molnar
2017-11-05 14:33 Ingo Molnar
2017-11-05 18:09 ` Linus Torvalds
2017-11-05 19:53 ` Josh Poimboeuf
2017-11-05 20:12 ` Linus Torvalds
2017-11-05 21:01 ` Josh Poimboeuf
2017-07-21 10:01 Ingo Molnar
2016-10-18 10:14 Ingo Molnar
2016-07-13 10:55 Ingo Molnar
2016-04-03 10:45 Ingo Molnar
2015-02-06 18:28 Ingo Molnar
2012-10-23 10:57 Ingo Molnar
2012-08-03 16:31 Ingo Molnar
2012-08-03 16:55 ` Darren Hart
2012-08-03 17:01 ` Ingo Molnar
2012-08-03 17:24 ` Darren Hart
2012-06-15 18:45 Ingo Molnar
2012-01-26 18:05 Ingo Molnar
2011-08-04 20:45 Ingo Molnar
2011-03-25 12:52 Ingo Molnar
2011-01-21 2:11 Ingo Molnar
2011-01-15 15:15 Ingo Molnar
2010-10-05 19:12 Ingo Molnar
2010-10-05 20:15 ` Linus Torvalds
2010-10-05 21:09 ` Paul E. McKenney
2010-10-05 21:45 ` Linus Torvalds
2010-10-05 22:05 ` Paul E. McKenney
2010-10-06 2:56 ` Eric Dumazet
2010-10-06 4:59 ` Paul E. McKenney
2010-10-06 18:20 ` Ingo Molnar
2010-10-06 21:27 ` Paul E. McKenney
2010-10-07 8:11 ` Ingo Molnar
2010-10-07 17:42 ` Paul E. McKenney
2010-09-08 13:04 Ingo Molnar
2010-03-26 14:53 Ingo Molnar
2010-03-13 16:35 Ingo Molnar
2009-12-18 18:52 Ingo Molnar
2009-11-10 17:53 Ingo Molnar
2009-10-23 14:53 Ingo Molnar
2009-10-13 18:29 Ingo Molnar
2009-10-08 19:06 Ingo Molnar
2009-10-08 19:16 ` Linus Torvalds
2009-10-08 19:20 ` Ingo Molnar
2009-09-21 13:13 Ingo Molnar
2009-08-13 18:54 Ingo Molnar
2009-08-09 16:07 Ingo Molnar
2009-08-09 18:41 ` Darren Hart
2009-07-10 16:28 Ingo Molnar
2009-07-10 19:06 ` Linus Torvalds
2009-07-10 19:31 ` Ingo Molnar
2009-07-10 19:52 ` Linus Torvalds
2009-07-10 20:02 ` Ingo Molnar
2009-07-13 14:52 ` Joerg Roedel
2009-06-20 17:30 Ingo Molnar
2009-06-20 18:49 ` Linus Torvalds
2009-06-20 19:01 ` Linus Torvalds
2009-06-20 20:27 ` Ingo Molnar
2009-06-21 17:12 ` Thomas Gleixner
2009-06-21 17:37 ` Linus Torvalds
2009-06-21 17:57 ` Linus Torvalds
2009-06-21 19:26 ` Thomas Gleixner
2009-05-18 14:23 Ingo Molnar
2009-05-18 15:48 ` Linus Torvalds
2009-05-18 19:20 ` Thomas Gleixner
2009-05-19 20:52 ` Linus Torvalds
2009-05-19 21:45 ` Thomas Gleixner
2009-05-19 22:20 ` Darren Hart
2009-05-05 9:33 Ingo Molnar
2009-01-30 23:12 [git pull] " Ingo Molnar
2009-01-26 17:24 Ingo Molnar
2009-01-11 14:36 Ingo Molnar
2008-12-04 19:39 Ingo Molnar
2008-11-29 19:36 Ingo Molnar
2008-11-18 14:14 Ingo Molnar
2008-11-07 16:28 Ingo Molnar
2008-10-30 23:29 Ingo Molnar
2008-10-15 12:50 [git pull] core kernel updates for v2.6.28 Ingo Molnar
2008-10-16 22:32 ` Linus Torvalds
2008-10-17 6:23 ` [git pull] core kernel fixes Ingo Molnar
2008-08-28 11:44 Ingo Molnar
2008-08-18 18:35 Ingo Molnar
2008-07-24 15:13 Ingo Molnar
2008-06-30 15:32 Ingo Molnar
2008-06-30 17:02 ` Vegard Nossum
2008-06-30 18:20 ` Ingo Molnar
2008-06-30 18:43 ` Vegard Nossum
2008-06-30 19:46 ` Thomas Gleixner
2008-06-30 19:51 ` Vegard Nossum
2008-06-30 19:54 ` Thomas Gleixner
2008-06-23 19:45 Ingo Molnar
2008-06-19 15:16 Ingo Molnar
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