[tip: irq/core] irqchip/gic-v3-its: Lock VLPI map array before translating it

[tip-bot2 for Marc Zyngier]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     046b5054f56691c7f5861197a812f3990f66b30e
Gitweb:        https://git.kernel.org/tip/046b5054f56691c7f5861197a812f3990f66b30e
Author:        Marc Zyngier <maz@xxxxxxxxxx>
AuthorDate:    Fri, 08 Nov 2019 16:58:04 
Committer:     Marc Zyngier <maz@xxxxxxxxxx>
CommitterDate: Sun, 10 Nov 2019 18:48:30 

irqchip/gic-v3-its: Lock VLPI map array before translating it

Obtaining the mapping ivformation for a VLPI should always be
done with the vlpi_lock for this device held. Otherwise, we
expose ourselves to races against a concurrent unmap.

Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20191108165805.3071-11-maz@xxxxxxxxxx
---
 drivers/irqchip/irq-gic-v3-its.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 61b8851..9c4f35e 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -1492,12 +1492,14 @@ out:
 static int its_vlpi_get(struct irq_data *d, struct its_cmd_info *info)
 {
 	struct its_device *its_dev = irq_data_get_irq_chip_data(d);
-	struct its_vlpi_map *map = get_vlpi_map(d);
+	struct its_vlpi_map *map;
 	int ret = 0;
 
 	mutex_lock(&its_dev->event_map.vlpi_lock);
 
-	if (!its_dev->event_map.vm || !map->vm) {
+	map = get_vlpi_map(d);
+
+	if (!its_dev->event_map.vm || !map) {
 		ret = -EINVAL;
 		goto out;
 	}