From: Akinobu Mita <akinobu.mita@gmail.com>

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/s390/cio/chp.c |   12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff -puN drivers/s390/cio/chp.c~s390-cio-use-memory_read_from_buffer drivers/s390/cio/chp.c
--- a/drivers/s390/cio/chp.c~s390-cio-use-memory_read_from_buffer
+++ a/drivers/s390/cio/chp.c
@@ -15,6 +15,7 @@
 #include <linux/wait.h>
 #include <linux/mutex.h>
 #include <linux/errno.h>
+#include <linux/fs.h>
 #include <asm/chpid.h>
 #include <asm/sclp.h>
 
@@ -143,21 +144,14 @@ static ssize_t chp_measurement_chars_rea
 {
 	struct channel_path *chp;
 	struct device *device;
-	unsigned int size;
 
 	device = container_of(kobj, struct device, kobj);
 	chp = to_channelpath(device);
 	if (!chp->cmg_chars)
 		return 0;
 
-	size = sizeof(struct cmg_chars);
-
-	if (off > size)
-		return 0;
-	if (off + count > size)
-		count = size - off;
-	memcpy(buf, chp->cmg_chars + off, count);
-	return count;
+	return memory_read_from_buffer(buf, count, &off,
+				chp->cmg_chars, sizeof(struct cmg_chars));
 }
 
 static struct bin_attribute chp_measurement_chars_attr = {
_