linux-kernel - [RFC PATCH 07/10] clocksource/drivers/h8300_timer8: Remove pointless irq re-entrant safe code

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Date:	Sun,  8 Nov 2015 23:36:36 +0100
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	daniel.lezcano@...aro.org, ysato@...rs.sourceforge.jp
Cc:	tglx@...utronix.de, linux-kernel@...r.kernel.org,
	uclinux-h8-devel@...ts.sourceforge.jp (moderated list:H8/300
	ARCHITECTURE)
Subject: [RFC PATCH 07/10] clocksource/drivers/h8300_timer8: Remove pointless irq re-entrant safe code

The current code assumes the interrupt function is re-entrant.

That is not correct. An interrupt handler is never invoked concurrently. The
interrupt line is masked on all processors.

Remove the chewing flags in the code.

Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
---
 drivers/clocksource/h8300_timer8.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/clocksource/h8300_timer8.c b/drivers/clocksource/h8300_timer8.c
index 680f65b..ba219cf 100644
--- a/drivers/clocksource/h8300_timer8.c
+++ b/drivers/clocksource/h8300_timer8.c
@@ -24,8 +24,6 @@
 #define TCORB	6
 #define _8TCNT	8
 
-#define FLAG_SKIPEVENT (1 << 1)
-#define FLAG_IRQCONTEXT (1 << 2)
 #define FLAG_STARTED (1 << 3)
 
 #define SCALE 64
@@ -67,14 +65,13 @@ static irqreturn_t timer8_interrupt(int irq, void *dev_id)
 
 	ctrl_outb(ctrl_inb(p->mapbase + _8TCSR) & ~0x40,
 		  p->mapbase + _8TCSR);
-	p->flags |= FLAG_IRQCONTEXT;
+
 	ctrl_outw(p->tcora, p->mapbase + TCORA);
-	if (!(p->flags & FLAG_SKIPEVENT)) {
-		if (clockevent_state_oneshot(&p->ced))
-			ctrl_outw(0x0000, p->mapbase + _8TCR);
-		p->ced.event_handler(&p->ced);
-	}
-	p->flags &= ~(FLAG_SKIPEVENT | FLAG_IRQCONTEXT);
+
+	if (clockevent_state_oneshot(&p->ced))
+		ctrl_outw(0x0000, p->mapbase + _8TCR);
+
+	p->ced.event_handler(&p->ced);
 
 	return IRQ_HANDLED;
 }
-- 
1.9.1

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