[PATCH 3/6] kvm tools: Protect IRQ allocations by a mutex

[Sasha Levin <levinsasha928@gmail.com>]

Makes IRQ allocation for new devices thread-safe.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/irq.c |   20 +++++++++++++-------
 1 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/tools/kvm/irq.c b/tools/kvm/irq.c
index 15f4702..f92123d 100644
--- a/tools/kvm/irq.c
+++ b/tools/kvm/irq.c
@@ -1,4 +1,5 @@
 #include "kvm/irq.h"
+#include "kvm/mutex.h"
 
 #include <linux/types.h>
 #include <linux/rbtree.h>
@@ -10,6 +11,7 @@
 static u8		next_line	= 3;
 static u8		next_dev	= 1;
 static struct rb_root	pci_tree	= RB_ROOT;
+static DEFINE_MUTEX(irq_lock);
 
 static struct pci_dev *search(struct rb_root *root, u32 id)
 {
@@ -58,7 +60,9 @@ static int insert(struct rb_root *root, struct pci_dev *data)
 
 int irq__register_device(u32 dev, u8 *num, u8 *pin, u8 *line)
 {
-	struct pci_dev *node;
+	struct pci_dev *node = NULL;
+
+	mutex_lock(&irq_lock);
 
 	node = search(&pci_tree, dev);
 
@@ -66,7 +70,7 @@ int irq__register_device(u32 dev, u8 *num, u8 *pin, u8 *line)
 		/* We haven't found a node - First device of it's kind */
 		node = malloc(sizeof(*node));
 		if (node == NULL)
-			return -1;
+			goto exit_fail;
 
 		*node = (struct pci_dev) {
 			.id	= dev,
@@ -81,17 +85,15 @@ int irq__register_device(u32 dev, u8 *num, u8 *pin, u8 *line)
 
 		INIT_LIST_HEAD(&node->lines);
 
-		if (insert(&pci_tree, node) != 1) {
-			free(node);
-			return -1;
-		}
+		if (insert(&pci_tree, node) != 1)
+			goto exit_fail;
 	}
 
 	if (node) {
 		/* This device already has a pin assigned, give out a new line and device id */
 		struct irq_line *new = malloc(sizeof(*new));
 		if (new == NULL)
-			return -1;
+			goto exit_fail;
 
 		new->line	= next_line++;
 		*line		= new->line;
@@ -100,9 +102,13 @@ int irq__register_device(u32 dev, u8 *num, u8 *pin, u8 *line)
 
 		list_add(&new->node, &node->lines);
 
+		mutex_unlock(&irq_lock);
 		return 0;
 	}
 
+exit_fail:
+	free(node);
+	mutex_unlock(&irq_lock);
 	return -1;
 }
 
-- 
1.7.5.rc3