summaryrefslogtreecommitdiff
path: root/arch/x86/xen/spinlock.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/xen/spinlock.c')
-rw-r--r--arch/x86/xen/spinlock.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 441c88262169..1c8a8816a402 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -9,6 +9,7 @@
#include <linux/log2.h>
#include <linux/gfp.h>
#include <linux/slab.h>
+#include <linux/atomic.h>
#include <asm/paravirt.h>
#include <asm/qspinlock.h>
@@ -21,6 +22,7 @@
static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
static DEFINE_PER_CPU(char *, irq_name);
+static DEFINE_PER_CPU(atomic_t, xen_qlock_wait_nest);
static bool xen_pvspin = true;
static void xen_qlock_kick(int cpu)
@@ -39,25 +41,25 @@ static void xen_qlock_kick(int cpu)
*/
static void xen_qlock_wait(u8 *byte, u8 val)
{
- unsigned long flags;
int irq = __this_cpu_read(lock_kicker_irq);
+ atomic_t *nest_cnt = this_cpu_ptr(&xen_qlock_wait_nest);
/* If kicker interrupts not initialized yet, just spin */
if (irq == -1 || in_nmi())
return;
- /* Guard against reentry. */
- local_irq_save(flags);
+ /* Detect reentry. */
+ atomic_inc(nest_cnt);
- /* If irq pending already clear it. */
- if (xen_test_irq_pending(irq)) {
+ /* If irq pending already and no nested call clear it. */
+ if (atomic_read(nest_cnt) == 1 && xen_test_irq_pending(irq)) {
xen_clear_irq_pending(irq);
} else if (READ_ONCE(*byte) == val) {
/* Block until irq becomes pending (or a spurious wakeup) */
xen_poll_irq(irq);
}
- local_irq_restore(flags);
+ atomic_dec(nest_cnt);
}
static irqreturn_t dummy_handler(int irq, void *dev_id)