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x86: cpuid: correct return value on partial operations

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Return the correct return value when the CPUID 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 17:35:25 -07:00
parent 85f1cb6015
commit 9ea2b82ed6
1 changed files with 9 additions and 5 deletions
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14
arch/x86/kernel/cpuid.c
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@ -89,7 +89,8 @@ static ssize_t cpuid_read(struct file *file, char __user *buf,
struct cpuid_regs cmd;
int cpu = iminor(file->f_path.dentry->d_inode);
u64 pos = *ppos;
int err;
ssize_t bytes = 0;
int err = 0;
if (count % 16)
return -EINVAL; /* Invalid chunk size */
@ -99,14 +100,17 @@ static ssize_t cpuid_read(struct file *file, char __user *buf,
cmd.ecx = pos >> 32;
err = smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1);
if (err)
return err;
if (copy_to_user(tmp, &cmd, 16))
return -EFAULT;
break;
if (copy_to_user(tmp, &cmd, 16)) {
err = -EFAULT;
break;
}
tmp += 16;
bytes += 16;
*ppos = ++pos;
}
return tmp - buf;
return bytes ? bytes : err;
}
static int cpuid_open(struct inode *inode, struct file *file)