dell_rbu: use memory_read_from_buffer()

Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Abhay Salunke <Abhay_Salunke@dell.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/firmware/dell_rbu.c

@@ -507,11 +507,6 @@ static ssize_t read_packet_data(char *buffer, loff_t pos, size_t count)
 
 static ssize_t read_rbu_mono_data(char *buffer, loff_t pos, size_t count)
 {
-	unsigned char *ptemp = NULL;
-	size_t bytes_left = 0;
-	size_t data_length = 0;
-	ssize_t ret_count = 0;
-
 	/* check to see if we have something to return */
 	if ((rbu_data.image_update_buffer == NULL) ||
 		(rbu_data.bios_image_size == 0)) {
@@ -519,28 +514,11 @@ static ssize_t read_rbu_mono_data(char *buffer, loff_t pos, size_t count)
 			"bios_image_size %lu\n",
 			rbu_data.image_update_buffer,
 			rbu_data.bios_image_size);
-		ret_count = -ENOMEM;
-		goto read_rbu_data_exit;
-	}
-
-	if (pos > rbu_data.bios_image_size) {
-		ret_count = 0;
-		goto read_rbu_data_exit;
+		return -ENOMEM;
 	}
 
-	bytes_left = rbu_data.bios_image_size - pos;
-	data_length = min(bytes_left, count);
-
-	ptemp = rbu_data.image_update_buffer;
-	memcpy(buffer, (ptemp + pos), data_length);
-
-	if ((pos + count) > rbu_data.bios_image_size)
-		/* this was the last copy */
-		ret_count = bytes_left;
-	else
-		ret_count = count;
-      read_rbu_data_exit:
-	return ret_count;
+	return memory_read_from_buffer(buffer, count, &pos,
+			rbu_data.image_update_buffer, rbu_data.bios_image_size);
 }
 
 static ssize_t read_rbu_data(struct kobject *kobj,