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: stable@vger.kernel.org
Fixes: 25da4618 ("xen/events: don't unmask an event channel when an eoi is pending")
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>
Reviewed-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20210406105105.10141-1-luca.fancellu@arm.comSigned-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>

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