x86: Simplify bound checks in the MTRR code

[net-next-2.6.git] / arch / x86 / kernel / cpu / mtrr / if.c

diff --git a/arch/x86/kernel/cpu/mtrr/if.c b/arch/x86/kernel/cpu/mtrr/if.c
index f04e72527604f2e231e81705552cc5ce72a88bc1..3c1b12d461d151303d6e2787c5aa9fddc078c1ad 100644 (file)
--- a/arch/x86/kernel/cpu/mtrr/if.c
+++ b/arch/x86/kernel/cpu/mtrr/if.c
@@ -96,17 +96,24 @@ mtrr_write(struct file *file, const char __user *buf, size_t len, loff_t * ppos)
        unsigned long long base, size;
        char *ptr;
        char line[LINE_SIZE];
+       int length;
        size_t linelen;
 
        if (!capable(CAP_SYS_ADMIN))
                return -EPERM;
-       if (!len)
-               return -EINVAL;
 
        memset(line, 0, LINE_SIZE);
-       if (len > LINE_SIZE)
-               len = LINE_SIZE;
-       if (copy_from_user(line, buf, len - 1))
+
+       length = len;
+       length--;
+
+       if (length > LINE_SIZE - 1)
+               length = LINE_SIZE - 1;
+
+       if (length < 0)
+               return -EINVAL;
+
+       if (copy_from_user(line, buf, length))
                return -EFAULT;
 
        linelen = strlen(line);