binfmt_misc: use simple_read_from_buffer()

Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/binfmt_misc.c

@@ -27,6 +27,7 @@
 #include <linux/namei.h>
 #include <linux/mount.h>
 #include <linux/syscalls.h>
+#include <linux/fs.h>
 
 #include <asm/uaccess.h>
 
@@ -535,31 +536,16 @@ static ssize_t
 bm_entry_read(struct file * file, char __user * buf, size_t nbytes, loff_t *ppos)
 {
 	Node *e = file->f_path.dentry->d_inode->i_private;
-	loff_t pos = *ppos;
 	ssize_t res;
 	char *page;
-	int len;
 
 	if (!(page = (char*) __get_free_page(GFP_KERNEL)))
 		return -ENOMEM;
 
 	entry_status(e, page);
-	len = strlen(page);
 
-	res = -EINVAL;
-	if (pos < 0)
-		goto out;
-	res = 0;
-	if (pos >= len)
-		goto out;
-	if (len < pos + nbytes)
-		nbytes = len - pos;
-	res = -EFAULT;
-	if (copy_to_user(buf, page + pos, nbytes))
-		goto out;
-	*ppos = pos + nbytes;
-	res = nbytes;
-out:
+	res = simple_read_from_buffer(buf, nbytes, ppos, page, strlen(page));
+
 	free_page((unsigned long) page);
 	return res;
 }