[PATCH 11/11] irqchip/gic-v3-its: Make vlpi_lock a spinlock

Marc Zyngier
2019-11-05T16:31:51Z

The VLPI map is currently a mutex, and that's a bad idea as
this lock can be taken in non-preemptible contexts. Convert
it to a raw spinlock, and turn the memory allocation of the
VLPI map to be atomic.

Reported-by: Heyi Guo <guoheyi@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
drivers/irqchip/irq-gic-v3-its.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 58ce231d5ade..93a39fcc2c96 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -132,7 +132,7 @@ struct event_lpi_map {
u16 *col_map;
irq_hw_number_t lpi_base;
int nr_lpis;
- struct mutex vlpi_lock;
+ raw_spinlock_t vlpi_lock;
struct its_vm *vm;
struct its_vlpi_map *vlpi_maps;
int nr_vlpis;
@@ -1433,13 +1433,13 @@ static int its_vlpi_map(struct irq_data *d, struct its_cmd_info *info)
if (!info->map)
return -EINVAL;

- mutex_lock(&its_dev->event_map.vlpi_lock);
+ raw_spin_lock(&its_dev->event_map.vlpi_lock);

if (!its_dev->event_map.vm) {
struct its_vlpi_map *maps;

maps = kcalloc(its_dev->event_map.nr_lpis, sizeof(*maps),
- GFP_KERNEL);
+ GFP_ATOMIC);
if (!maps) {
ret = -ENOMEM;
goto out;
@@ -1482,7 +1482,7 @@ static int its_vlpi_map(struct irq_data *d, struct its_cmd_info *info)
}

out:
- mutex_unlock(&its_dev->event_map.vlpi_lock);
+ raw_spin_unlock(&its_dev->event_map.vlpi_lock);
return ret;
}

@@ -1492,7 +1492,7 @@ static int its_vlpi_get(struct irq_data *d, struct its_cmd_info *info)
struct its_vlpi_map *map;
int ret = 0;

- mutex_lock(&its_dev->event_map.vlpi_lock);
+ raw_spin_lock(&its_dev->event_map.vlpi_lock);

map = get_vlpi_map(d);

@@ -1505,7 +1505,7 @@ static int its_vlpi_get(struct irq_data *d, struct its_cmd_info *info)
*info->map = *map;

out:
- mutex_unlock(&its_dev->event_map.vlpi_lock);
+ raw_spin_unlock(&its_dev->event_map.vlpi_lock);
return ret;
}

@@ -1515,7 +1515,7 @@ static int its_vlpi_unmap(struct irq_data *d)
u32 event = its_get_event_id(d);
int ret = 0;

- mutex_lock(&its_dev->event_map.vlpi_lock);
+ raw_spin_lock(&its_dev->event_map.vlpi_lock);

if (!its_dev->event_map.vm || !irqd_is_forwarded_to_vcpu(d)) {
ret = -EINVAL;
@@ -1545,7 +1545,7 @@ static int its_vlpi_unmap(struct irq_data *d)
}

out:
- mutex_unlock(&its_dev->event_map.vlpi_lock);
+ raw_spin_unlock(&its_dev->event_map.vlpi_lock);
return ret;
}

@@ -2605,7 +2605,7 @@ static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
dev->event_map.col_map = col_map;
dev->event_map.lpi_base = lpi_base;
dev->event_map.nr_lpis = nr_lpis;
- mutex_init(&dev->event_map.vlpi_lock);
+ raw_spin_lock_init(&dev->event_map.vlpi_lock);
dev->device_id = dev_id;
INIT_LIST_HEAD(&dev->entry);

--
2.20.1