Commit 65ada547 authored by Takashi YOSHII's avatar Takashi YOSHII Committed by Paul Mundt
Browse files

clocksource: sh_cmt: Remove nested spinlock fix 



There are control flow that sh_cmt_set_next() does double
spin-lock. The callers sh_cmt_{start,stop}() already have
lock. But another callers sh_cmt_clock_event_{start,next}()
does not.

Now sh_cmt_set_next() does not lock by itself. All the
callers should hold spin-lock before calling it.

[damm@opensource.se: use __sh_cmt_set_next() to simplify code]
[damm@opensource.se: added stable, suitable for v2.6.35 + v2.6.36]
Cc: stable@kernel.org
Signed-off-by: default avatarTakashi YOSHII <takashi.yoshii.zj@renesas.com>
Signed-off-by: default avatarMagnus Damm <damm@opensource.se>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent b3444d16

drivers/clocksource/sh_cmt.c

+11 −6
Original line number Diff line number Diff line
@@ -283,16 +283,21 @@ static void sh_cmt_clock_event_program_verify(struct sh_cmt_priv *p, 
	} while (delay);

}



static void sh_cmt_set_next(struct sh_cmt_priv *p, unsigned long delta)

static void __sh_cmt_set_next(struct sh_cmt_priv *p, unsigned long delta)

{

	unsigned long flags;



	if (delta > p->max_match_value)

		dev_warn(&p->pdev->dev, "delta out of range\n");



	spin_lock_irqsave(&p->lock, flags);

	p->next_match_value = delta;

	sh_cmt_clock_event_program_verify(p, 0);

}



static void sh_cmt_set_next(struct sh_cmt_priv *p, unsigned long delta)

{

	unsigned long flags;



	spin_lock_irqsave(&p->lock, flags);

	__sh_cmt_set_next(p, delta);

	spin_unlock_irqrestore(&p->lock, flags);

}
@@ -359,7 +364,7 @@ static int sh_cmt_start(struct sh_cmt_priv *p, unsigned long flag) 


	/* setup timeout if no clockevent */

	if ((flag == FLAG_CLOCKSOURCE) && (!(p->flags & FLAG_CLOCKEVENT)))

		sh_cmt_set_next(p, p->max_match_value);

		__sh_cmt_set_next(p, p->max_match_value);

 out:

	spin_unlock_irqrestore(&p->lock, flags);
@@ -381,7 +386,7 @@ static void sh_cmt_stop(struct sh_cmt_priv *p, unsigned long flag) 


	/* adjust the timeout to maximum if only clocksource left */

	if ((flag == FLAG_CLOCKEVENT) && (p->flags & FLAG_CLOCKSOURCE))

		sh_cmt_set_next(p, p->max_match_value);

		__sh_cmt_set_next(p, p->max_match_value);



	spin_unlock_irqrestore(&p->lock, flags);

}

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