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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
	linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Carsten Emde <C.Emde@osadl.org>, John Kacur <jkacur@redhat.com>,
	stable-rt@vger.kernel.org,
	Lothar Wassmann <lw@karo-electronics.de>
Subject: [PATCH RT 1/8] genirq: Unmask oneshot irqs when thread was not woken
Date: Wed, 08 Feb 2012 20:59:27 -0500	[thread overview]
Message-ID: <20120209020159.095037912@goodmis.org> (raw)
In-Reply-To: 20120209015926.851312665@goodmis.org

[-- Attachment #1: 0001-genirq-Unmask-oneshot-irqs-when-thread-was-not-woken.patch --]
[-- Type: text/plain, Size: 1960 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

When the primary handler of an interrupt which is marked IRQ_ONESHOT
does not wake the thread (e.g. due to a spurious interrupt) then
nothing ever unmasks the interrupt line again. Handle it gracefully.

Cc: stable-rt@vger.kernel.org
Reported-by: Lothar Wassmann <lw@karo-electronics.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/irq/chip.c |   25 +++++++++++++++++++++++--
 1 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index dc5114b..3322a34 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -312,6 +312,24 @@ out_unlock:
 }
 EXPORT_SYMBOL_GPL(handle_simple_irq);
 
+/*
+ * Called unconditionally from handle_level_irq() and only for oneshot
+ * interrupts from handle_fasteoi_irq()
+ */
+static void cond_unmask_irq(struct irq_desc *desc)
+{
+	/*
+	 * We need to unmask in the following cases:
+	 * - Standard level irq (IRQF_ONESHOT is not set)
+	 * - Oneshot irq which did not wake the thread (caused by a
+	 *   spurious interrupt or a primary handler handling it
+	 *   completely).
+	 */
+	if (!irqd_irq_disabled(&desc->irq_data) &&
+	    irqd_irq_masked(&desc->irq_data) && !desc->threads_oneshot)
+		unmask_irq(desc);
+}
+
 /**
  *	handle_level_irq - Level type irq handler
  *	@irq:	the interrupt number
@@ -344,8 +362,8 @@ handle_level_irq(unsigned int irq, struct irq_desc *desc)
 
 	handle_irq_event(desc);
 
-	if (!irqd_irq_disabled(&desc->irq_data) && !(desc->istate & IRQS_ONESHOT))
-		unmask_irq(desc);
+	cond_unmask_irq(desc);
+
 out_unlock:
 	raw_spin_unlock(&desc->lock);
 }
@@ -399,6 +417,9 @@ handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
 	preflow_handler(desc);
 	handle_irq_event(desc);
 
+	if (desc->istate & IRQS_ONESHOT)
+		cond_unmask_irq(desc);
+
 out_eoi:
 	desc->irq_data.chip->irq_eoi(&desc->irq_data);
 out_unlock:
-- 
1.7.8.3



  reply	other threads:[~2012-02-09  2:02 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-09  1:59 [PATCH RT 0/8] [ANNOUNCE] 3.0.20-rt36-rc1 Steven Rostedt
2012-02-09  1:59 ` Steven Rostedt [this message]
2012-02-09  1:59 ` [PATCH RT 2/8] genirq: Handle pending irqs in irq_startup() Steven Rostedt
2012-02-09  1:59 ` [PATCH RT 3/8] signal/x86: Delay calling signals in atomic Steven Rostedt
2012-02-09  1:59 ` [PATCH RT 4/8] x86: Do not disable preemption in int3 on 32bit Steven Rostedt
2012-02-09  1:59 ` [PATCH RT 5/8] timer-fd: Prevent live lock Steven Rostedt
2012-02-09  1:59 ` [PATCH RT 6/8] genirq: Allow disabling of softirq processing in irq thread context Steven Rostedt
2012-02-09  1:59 ` [PATCH RT 7/8] futex: Fix bug on when a requeued RT task times out Steven Rostedt
2012-02-09  1:59 ` [PATCH RT 8/8] Linux 3.0.20-rt36-rc1 Steven Rostedt

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