USB: usbmon: use simple_read_from_buffer()

Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: NPete Zaitcev <zaitcev@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/mon/mon_stat.c

@@ -9,6 +9,7 @@
 
 #include <linux/kernel.h>
 #include <linux/usb.h>
+#include <linux/fs.h>
 #include <asm/uaccess.h>
 
 #include "usb_mon.h"
@@ -42,19 +43,8 @@ static ssize_t mon_stat_read(struct file *file, char __user *buf,
 				size_t nbytes, loff_t *ppos)
 {
 	struct snap *sp = file->private_data;
-	loff_t pos = *ppos;
-	int cnt;
 
-	if (pos < 0 || pos >= sp->slen)
-		return 0;
-	if (nbytes == 0)
-		return 0;
-	if ((cnt = sp->slen - pos) > nbytes)
-		cnt = nbytes;
-	if (copy_to_user(buf, sp->str + pos, cnt))
-		return -EFAULT;
-	*ppos = pos + cnt;
-	return cnt;
+	return simple_read_from_buffer(buf, nbytes, ppos, sp->str, sp->slen);
 }
 
 static int mon_stat_release(struct inode *inode, struct file *file)