2021-04-06 23:41:50

by Luca Fancellu

Subject: [PATCH] xen/evtchn: Change irq_info lock to raw_spinlock_t

Unmask operation must be called with interrupt disabled,
on preempt_rt spin_lock_irqsave/spin_unlock_irqrestore
don't disable/enable interrupts, so use raw_* implementation
and change lock variable in struct irq_info from spinlock_t
to raw_spinlock_t

Cc: [email protected]
Fixes: 25da4618af24 ("xen/events: don't unmask an event channel
when an eoi is pending")

Signed-off-by: Luca Fancellu <[email protected]>
---
drivers/xen/events/events_base.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 8236e2364eeb..7bbfd58958bc 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -110,7 +110,7 @@ struct irq_info {
unsigned short eoi_cpu; /* EOI must happen on this cpu-1 */
unsigned int irq_epoch; /* If eoi_cpu valid: irq_epoch of event */
u64 eoi_time; /* Time in jiffies when to EOI. */
- spinlock_t lock;
+ raw_spinlock_t lock;

union {
unsigned short virq;
@@ -312,7 +312,7 @@ static int xen_irq_info_common_setup(struct irq_info *info,
info->evtchn = evtchn;
info->cpu = cpu;
info->mask_reason = EVT_MASK_REASON_EXPLICIT;
- spin_lock_init(&info->lock);
+ raw_spin_lock_init(&info->lock);

ret = set_evtchn_to_irq(evtchn, irq);
if (ret < 0)
@@ -472,28 +472,28 @@ static void do_mask(struct irq_info *info, u8 reason)
{
unsigned long flags;

- spin_lock_irqsave(&info->lock, flags);
+ raw_spin_lock_irqsave(&info->lock, flags);

if (!info->mask_reason)
mask_evtchn(info->evtchn);

info->mask_reason |= reason;

- spin_unlock_irqrestore(&info->lock, flags);
+ raw_spin_unlock_irqrestore(&info->lock, flags);
}

static void do_unmask(struct irq_info *info, u8 reason)
{
unsigned long flags;

- spin_lock_irqsave(&info->lock, flags);
+ raw_spin_lock_irqsave(&info->lock, flags);

info->mask_reason &= ~reason;

if (!info->mask_reason)
unmask_evtchn(info->evtchn);

- spin_unlock_irqrestore(&info->lock, flags);
+ raw_spin_unlock_irqrestore(&info->lock, flags);
}

#ifdef CONFIG_X86
--
2.17.1

2021-04-07 04:58:43

by Julien Grall

Subject: Re: [PATCH] xen/evtchn: Change irq_info lock to raw_spinlock_t

Hi Luca,

On 06/04/2021 11:51, Luca Fancellu wrote:
> Unmask operation must be called with interrupt disabled,
> on preempt_rt spin_lock_irqsave/spin_unlock_irqrestore
> don't disable/enable interrupts, so use raw_* implementation
> and change lock variable in struct irq_info from spinlock_t
> to raw_spinlock_t
>
> Cc: [email protected]
> Fixes: 25da4618af24 ("xen/events: don't unmask an event channel
> when an eoi is pending")
>
> Signed-off-by: Luca Fancellu <[email protected]>

Reviewed-by: Julien Grall <[email protected]>

Cheers,

--
Julien Grall

2021-04-07 21:00:04

by Wei Liu

Subject: Re: [PATCH] xen/evtchn: Change irq_info lock to raw_spinlock_t

On Tue, Apr 06, 2021 at 11:51:04AM +0100, Luca Fancellu wrote:
> Unmask operation must be called with interrupt disabled,
> on preempt_rt spin_lock_irqsave/spin_unlock_irqrestore
> don't disable/enable interrupts, so use raw_* implementation
> and change lock variable in struct irq_info from spinlock_t
> to raw_spinlock_t
>
> Cc: [email protected]
> Fixes: 25da4618af24 ("xen/events: don't unmask an event channel
> when an eoi is pending")
>
> Signed-off-by: Luca Fancellu <[email protected]>

Reviewed-by: Wei Liu <[email protected]>

2021-04-07 22:07:59

by Boris Ostrovsky

Subject: Re: [PATCH] xen/evtchn: Change irq_info lock to raw_spinlock_t

On 4/6/21 6:51 AM, Luca Fancellu wrote:
> Unmask operation must be called with interrupt disabled,
> on preempt_rt spin_lock_irqsave/spin_unlock_irqrestore
> don't disable/enable interrupts, so use raw_* implementation
> and change lock variable in struct irq_info from spinlock_t
> to raw_spinlock_t
>
> Cc: [email protected]
> Fixes: 25da4618af24 ("xen/events: don't unmask an event channel
> when an eoi is pending")
>
> Signed-off-by: Luca Fancellu <[email protected]>



Applied to for-linus-5.12b


-boris