linux-kernel - [tip: irq/core] irqchip/gic-v3-its: Make vlpi

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Date:   Wed, 20 Nov 2019 13:21:03 -0000
From:   "tip-bot2 for Marc Zyngier" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Heyi Guo <guoheyi@...wei.com>, Marc Zyngier <maz@...nel.org>,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
        linux-kernel@...r.kernel.org
Subject: [tip: irq/core] irqchip/gic-v3-its: Make vlpi_lock a spinlock

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

Commit-ID:     11635fa26dc7a715f3fc1c351846859e90985ae1
Gitweb:        https://git.kernel.org/tip/11635fa26dc7a715f3fc1c351846859e90985ae1
Author:        Marc Zyngier <maz@...nel.org>
AuthorDate:    Fri, 08 Nov 2019 16:58:05 
Committer:     Marc Zyngier <maz@...nel.org>
CommitterDate: Sun, 10 Nov 2019 18:48:35 

irqchip/gic-v3-its: Make vlpi_lock a spinlock

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@...wei.com>
Signed-off-by: Marc Zyngier <maz@...nel.org>
Link: https://lore.kernel.org/r/20191108165805.3071-12-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 9c4f35e..e05673b 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;
@@ -1436,13 +1436,13 @@ 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;
@@ -1485,7 +1485,7 @@ 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;
 }
 
@@ -1495,7 +1495,7 @@ 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);
 
@@ -1508,7 +1508,7 @@ 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;
 }
 
@@ -1518,7 +1518,7 @@ 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;
@@ -1548,7 +1548,7 @@ 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;
 }
 
@@ -2608,7 +2608,7 @@ 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);