2020-10-27 01:11:15

by Tian Tao

Subject: [PATCH] thermal: rcar: replace spin_lock_irqsave by spin_lock in hard IRQ

On RT or even on mainline with 'threadirqs' on the command line all
interrupts which are not explicitly requested with IRQF_NO_THREAD
run their handlers in thread context. The same applies to soft interrupts.
That means they are subject to the normal scheduler rules and no other
code is going to acquire that lock from hard interrupt context either,
so the irqsave() here is pointless in all cases.

Signed-off-by: Tian Tao <[email protected]>
---
drivers/thermal/rcar_thermal.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/thermal/rcar_thermal.c b/drivers/thermal/rcar_thermal.c
index 5c2a13b..6ae757d 100644
--- a/drivers/thermal/rcar_thermal.c
+++ b/drivers/thermal/rcar_thermal.c
@@ -409,16 +409,15 @@ static irqreturn_t rcar_thermal_irq(int irq, void *data)
{
struct rcar_thermal_common *common = data;
struct rcar_thermal_priv *priv;
- unsigned long flags;
u32 status, mask;

- spin_lock_irqsave(&common->lock, flags);
+ spin_lock(&common->lock);

mask = rcar_thermal_common_read(common, INTMSK);
status = rcar_thermal_common_read(common, STR);
rcar_thermal_common_write(common, STR, 0x000F0F0F & mask);

- spin_unlock_irqrestore(&common->lock, flags);
+ spin_unlock(&common->lock);

status = status & ~mask;

--
2.7.4

2020-10-28 06:23:21

by Daniel Lezcano

Subject: Re: [PATCH] thermal: rcar: replace spin_lock_irqsave by spin_lock in hard IRQ

On 27/10/2020 02:06, Tian Tao wrote:
> On RT or even on mainline with 'threadirqs' on the command line all
> interrupts which are not explicitly requested with IRQF_NO_THREAD
> run their handlers in thread context. The same applies to soft interrupts.
> That means they are subject to the normal scheduler rules and no other
> code is going to acquire that lock from hard interrupt context either,
> so the irqsave() here is pointless in all cases.
>
> Signed-off-by: Tian Tao <[email protected]>

Applied, thanks


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