---

yaml
---
r: 62391
b: refs/heads/master
c: f528e7b
h: refs/heads/master
i:
  62389: 37ebdb9
  62387: 55d5e50
  62383: 66461cf
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: a5ba7971045a90a36cef8f7d5a3075600b475b74
+refs/heads/master: f528e7ba28492e363a64c80c414ded4cadf48f89

trunk/arch/x86_64/kernel/mce.c

@@ -465,6 +465,40 @@ void __cpuinit mcheck_init(struct cpuinfo_x86 *c)
  * Character device to read and clear the MCE log.
  */
 
+static DEFINE_SPINLOCK(mce_state_lock);
+static int open_count;	/* #times opened */
+static int open_exclu;	/* already open exclusive? */
+
+static int mce_open(struct inode *inode, struct file *file)
+{
+	spin_lock(&mce_state_lock);
+
+	if (open_exclu || (open_count && (file->f_flags & O_EXCL))) {
+		spin_unlock(&mce_state_lock);
+		return -EBUSY;
+	}
+
+	if (file->f_flags & O_EXCL)
+		open_exclu = 1;
+	open_count++;
+
+	spin_unlock(&mce_state_lock);
+
+	return 0;
+}
+
+static int mce_release(struct inode *inode, struct file *file)
+{
+	spin_lock(&mce_state_lock);
+
+	open_count--;
+	open_exclu = 0;
+
+	spin_unlock(&mce_state_lock);
+
+	return 0;
+}
+
 static void collect_tscs(void *data) 
 { 
 	unsigned long *cpu_tsc = (unsigned long *)data;
@@ -555,6 +589,8 @@ static int mce_ioctl(struct inode *i, struct file *f,unsigned int cmd, unsigned
 }
 
 static const struct file_operations mce_chrdev_ops = {
+	.open = mce_open,
+	.release = mce_release,
 	.read = mce_read,
 	.ioctl = mce_ioctl,
 };