linux-kernel - [PATCH/RFC -rt] local_bh_enable() is safe for irqs

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Message-ID: <87fxyearp7.fsf@vence.hilman.org>
Date:	Fri, 07 Dec 2007 17:41:24 -0800
From:	Kevin Hilman <kevin@...man.org>
To:	linux-rt-users@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH/RFC -rt] local_bh_enable() is safe for irqs_disabled()

In local_bh_enable() there is a WARN_ON(irqs_disabled()), but looking
at the rest of the code, it seems it expects to be used with
interrupts off, so is this warning really necessary?

I hit this warning in the ads7846 touchscreen driver timer function
where enable_irq() may be called with interrupts disabled.  Since
enable_irq now calls local_bh_disable/enable for IRQ resend, this
warning is triggered.

Patch against 2.6.23.9-rt12

Signed-off-by: Kevin Hilman <khilman@...sta.com>

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 4c19017..68149ae 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -207,7 +207,6 @@ void local_bh_enable(void)

 	WARN_ON_ONCE(in_irq());
 #endif
-	WARN_ON_ONCE(irqs_disabled());

 #ifdef CONFIG_TRACE_IRQFLAGS
 	local_irq_save(flags);
--
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