1 files changed, 41 insertions, 19 deletions

diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
index 1f3abe0..2e2af5d 100644
--- a/arch/x86/kernel/msr.c
+++ b/arch/x86/kernel/msr.c
@@ -72,21 +72,28 @@ static ssize_t msr_read(struct file *file, char __user *buf,
 	u32 data[2];
 	u32 reg = *ppos;
 	int cpu = iminor(file->f_path.dentry->d_inode);
-	int err;
+	int err = 0;
+	ssize_t bytes = 0;
 
 	if (count % 8)
 		return -EINVAL;	/* Invalid chunk size */
 
 	for (; count; count -= 8) {
 		err = rdmsr_safe_on_cpu(cpu, reg, &data[0], &data[1]);
-		if (err)
-			return -EIO;
-		if (copy_to_user(tmp, &data, 8))
-			return -EFAULT;
+		if (err) {
+			if (err == -EFAULT) /* Fix idiotic error code */
+				err = -EIO;
+			break;
+		}
+		if (copy_to_user(tmp, &data, 8)) {
+			err = -EFAULT;
+			break;
+		}
 		tmp += 2;
+		bytes += 8;
 	}
 
-	return ((char __user *)tmp) - buf;
+	return bytes ? bytes : err;
 }
 
 static ssize_t msr_write(struct file *file, const char __user *buf,
@@ -96,34 +103,49 @@ static ssize_t msr_write(struct file *file, const char __user *buf,
 	u32 data[2];
 	u32 reg = *ppos;
 	int cpu = iminor(file->f_path.dentry->d_inode);
-	int err;
+	int err = 0;
+	ssize_t bytes = 0;
 
 	if (count % 8)
 		return -EINVAL;	/* Invalid chunk size */
 
 	for (; count; count -= 8) {
-		if (copy_from_user(&data, tmp, 8))
-			return -EFAULT;
+		if (copy_from_user(&data, tmp, 8)) {
+			err = -EFAULT;
+			break;
+		}
 		err = wrmsr_safe_on_cpu(cpu, reg, data[0], data[1]);
-		if (err)
-			return -EIO;
+		if (err) {
+			if (err == -EFAULT) /* Fix idiotic error code */
+				err = -EIO;
+			break;
+		}
 		tmp += 2;
+		bytes += 8;
 	}
 
-	return ((char __user *)tmp) - buf;
+	return bytes ? bytes : err;
 }
 
 static int msr_open(struct inode *inode, struct file *file)
 {
 	unsigned int cpu = iminor(file->f_path.dentry->d_inode);
 	struct cpuinfo_x86 *c = &cpu_data(cpu);
+	int ret = 0;
 
-	if (cpu >= NR_CPUS || !cpu_online(cpu))
-		return -ENXIO;	/* No such CPU */
-	if (!cpu_has(c, X86_FEATURE_MSR))
-		return -EIO;	/* MSR not supported */
+	lock_kernel();
+	cpu = iminor(file->f_path.dentry->d_inode);
 
-	return 0;
+	if (cpu >= NR_CPUS || !cpu_online(cpu)) {
+		ret = -ENXIO;	/* No such CPU */
+		goto out;
+	}
+	c = &cpu_data(cpu);
+	if (!cpu_has(c, X86_FEATURE_MSR))
+		ret = -EIO;	/* MSR not supported */
+out:
+	unlock_kernel();
+	return ret;
 }
 
 /*
@@ -141,8 +163,8 @@ static int __cpuinit msr_device_create(int cpu)
 {
 	struct device *dev;
 
-	dev = device_create(msr_class, NULL, MKDEV(MSR_MAJOR, cpu),
-			    "msr%d", cpu);
+	dev = device_create_drvdata(msr_class, NULL, MKDEV(MSR_MAJOR, cpu),
+				    NULL, "msr%d", cpu);
 	return IS_ERR(dev) ? PTR_ERR(dev) : 0;
 }