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x86: msr: correct return value on partial operations

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Return the correct return value when the MSR driver partially
completes a request (we should return the number of bytes actually
read or written, instead of the error code.)

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
H. Peter Anvin 2008-08-25 17:34:27 -07:00
parent 4b46ca701b
commit 85f1cb6015
1 changed files with 18 additions and 10 deletions
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28
arch/x86/kernel/msr.c
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@ -72,7 +72,8 @@ 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 */
@ -82,14 +83,17 @@ static ssize_t msr_read(struct file *file, char __user *buf,
if (err) {
if (err == -EFAULT) /* Fix idiotic error code */
err = -EIO;
return err;
break;
}
if (copy_to_user(tmp, &data, 8)) {
err = -EFAULT;
break;
}
if (copy_to_user(tmp, &data, 8))
return -EFAULT;
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,
@ -99,24 +103,28 @@ 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) {
if (err == -EFAULT) /* Fix idiotic error code */
err = -EIO;
return err;
break;
}
tmp += 2;
bytes += 8;
}
return ((char __user *)tmp) - buf;
return bytes ? bytes : err;
}
static int msr_open(struct inode *inode, struct file *file)