linux-kernel - [PATCH 2/2] rt/threadirqs: remove pointless irq disabling on irq thread handlers

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Date:	Thu, 12 Feb 2009 23:33:11 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] rt/threadirqs: remove pointless irq disabling on irq thread handlers

The handlers called by the irq thread lock the desc->lock by
using spin_lock_irq.
But at this stage, the irqs are already disabled at the end
of both handle_IRQ_event() processing and cond_resched_hardirq_context().

A single spin_lock is sufficient.

Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
---
 kernel/irq/manage.c |    8 +++-----
 1 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 6e9baf8..8e963a9 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -802,7 +802,7 @@ static void thread_simple_irq(irq_desc_t *desc)
 		spin_unlock(&desc->lock);
 		action_ret = handle_IRQ_event(irq, action);
 		cond_resched_hardirq_context();
-		spin_lock_irq(&desc->lock);
+		spin_lock(&desc->lock);
 		if (!noirqdebug)
 			note_interrupt(irq, desc, action_ret);
 	} while (desc->status & IRQ_PENDING);
@@ -863,7 +863,7 @@ static void thread_edge_irq(irq_desc_t *desc)
 		spin_unlock(&desc->lock);
 		action_ret = handle_IRQ_event(irq, action);
 		cond_resched_hardirq_context();
-		spin_lock_irq(&desc->lock);
+		spin_lock(&desc->lock);
 		if (!noirqdebug)
 			note_interrupt(irq, desc, action_ret);
 	} while ((desc->status & IRQ_PENDING) && !desc->depth);
@@ -892,7 +892,7 @@ static void thread_do_irq(irq_desc_t *desc)
 		spin_unlock(&desc->lock);
 		action_ret = handle_IRQ_event(irq, action);
 		cond_resched_hardirq_context();
-		spin_lock_irq(&desc->lock);
+		spin_lock(&desc->lock);
 		if (!noirqdebug)
 			note_interrupt(irq, desc, action_ret);
 	} while ((desc->status & IRQ_PENDING) && !desc->depth);
@@ -903,8 +903,6 @@ static void thread_do_irq(irq_desc_t *desc)
 
 static void do_hardirq(struct irq_desc *desc)
 {
-	unsigned long flags;
-
 	spin_lock(&desc->lock);
 
 	if (!(desc->status & IRQ_INPROGRESS))
-- 
1.6.1


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