[PATCH] locking: Add WARN_ON_ONCE lock assertion

[PATCH] locking: Add WARN_ON_ONCE lock assertion

[Peter Hurley]

An interface may need to assert a lock invariant and not flood the
system logs; add a lockdep helper macro equivalent to
lockdep_assert_held() which only WARNs once.

cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
---
 include/linux/lockdep.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 008388f9..64c7425 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -362,6 +362,10 @@ extern void lockdep_trace_alloc(gfp_t mask);
 		WARN_ON(debug_locks && !lockdep_is_held(l));	\
 	} while (0)
 
+#define lockdep_assert_held_once(l)	do {				\
+		WARN_ON_ONCE(debug_locks && !lockdep_is_held(l));	\
+	} while (0)
+
 #define lockdep_recursing(tsk)	((tsk)->lockdep_recursion)
 
 #else /* !CONFIG_LOCKDEP */
@@ -412,6 +416,7 @@ struct lock_class_key { };
 #define lockdep_depth(tsk)	(0)
 
 #define lockdep_assert_held(l)			do { (void)(l); } while (0)
+#define lockdep_assert_held_once(l)		do { (void)(l); } while (0)
 
 #define lockdep_recursing(tsk)			(0)
 
-- 
2.1.0

Re: [PATCH] locking: Add WARN_ON_ONCE lock assertion

[Ingo Molnar]

* Peter Hurley <peter@hurleysoftware.com> wrote:

> An interface may need to assert a lock invariant and not flood the
> system logs; add a lockdep helper macro equivalent to
> lockdep_assert_held() which only WARNs once.
> 
> cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Peter Hurley <peter@hurleysoftware.com>

Acked-by: Ingo Molnar <mingo@kernel.org>

Thanks,

	Ingo

Re: [PATCH] locking: Add WARN_ON_ONCE lock assertion

[Greg Kroah-Hartman]

On Tue, Sep 16, 2014 at 10:08:14AM +0200, Ingo Molnar wrote:
> 
> * Peter Hurley <peter@hurleysoftware.com> wrote:
> 
> > An interface may need to assert a lock invariant and not flood the
> > system logs; add a lockdep helper macro equivalent to
> > lockdep_assert_held() which only WARNs once.
> > 
> > cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
> 
> Acked-by: Ingo Molnar <mingo@kernel.org>

Any objection for me taking this through the TTY tree due to the
dependancies on future tty patches that use the function in this patch?

thanks,

greg k-h

Re: [PATCH] locking: Add WARN_ON_ONCE lock assertion

[Ingo Molnar]

* Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:

> On Tue, Sep 16, 2014 at 10:08:14AM +0200, Ingo Molnar wrote:
> > 
> > * Peter Hurley <peter@hurleysoftware.com> wrote:
> > 
> > > An interface may need to assert a lock invariant and not flood the
> > > system logs; add a lockdep helper macro equivalent to
> > > lockdep_assert_held() which only WARNs once.
> > > 
> > > cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
> > 
> > Acked-by: Ingo Molnar <mingo@kernel.org>
> 
> Any objection for me taking this through the TTY tree due to 
> the dependancies on future tty patches that use the function in 
> this patch?

Now that the patch is correct I have no objection whatsoever, 
feel free!

Thanks,

	Ingo

Re: [PATCH] locking: Add WARN_ON_ONCE lock assertion

[Greg Kroah-Hartman]

On Wed, Sep 17, 2014 at 02:32:56PM +0200, Ingo Molnar wrote:
> 
> * Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
> 
> > On Tue, Sep 16, 2014 at 10:08:14AM +0200, Ingo Molnar wrote:
> > > 
> > > * Peter Hurley <peter@hurleysoftware.com> wrote:
> > > 
> > > > An interface may need to assert a lock invariant and not flood the
> > > > system logs; add a lockdep helper macro equivalent to
> > > > lockdep_assert_held() which only WARNs once.
> > > > 
> > > > cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > > > Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
> > > 
> > > Acked-by: Ingo Molnar <mingo@kernel.org>
> > 
> > Any objection for me taking this through the TTY tree due to 
> > the dependancies on future tty patches that use the function in 
> > this patch?
> 
> Now that the patch is correct I have no objection whatsoever, 
> feel free!

Thanks, will do.

greg k-h