nwflash: use simple_read_from_buffer()

Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Tim Schmielau <tim@physik3.uni-rostock.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/char/nwflash.c

@@ -122,35 +122,20 @@ static int flash_ioctl(struct inode *inodep, struct file *filep, unsigned int cm
 static ssize_t flash_read(struct file *file, char __user *buf, size_t size,
 			  loff_t *ppos)
 {
-	unsigned long p = *ppos;
-	unsigned int count = size;
-	int ret = 0;
+	ssize_t ret;
 
 	if (flashdebug)
 		printk(KERN_DEBUG "flash_read: flash_read: offset=0x%lX, "
 		       "buffer=%p, count=0x%X.\n", p, buf, count);
-
-	if (count)
-		ret = -ENXIO;
-
-	if (p < gbFlashSize) {
-		if (count > gbFlashSize - p)
-			count = gbFlashSize - p;
-
 	/*
 	 * We now lock against reads and writes. --rmk
 	 */
 	if (mutex_lock_interruptible(&nwflash_mutex))
 		return -ERESTARTSYS;
 
-		ret = copy_to_user(buf, (void *)(FLASH_BASE + p), count);
-		if (ret == 0) {
-			ret = count;
-			*ppos += count;
-		} else
-			ret = -EFAULT;
+	ret = simple_read_from_buffer(buf, size, ppos, FLASH_BASE, gbFlashSize);
 	mutex_unlock(&nwflash_mutex);
-	}
+
 	return ret;
 }