ocfs2: use simple_read_from_buffer()

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 5 insertions, 14 deletions

diff --git a/fs/ocfs2/stack_user.c b/fs/ocfs2/stack_user.c
index c021280dd462..24e0b19c8b69 100644
--- a/fs/ocfs2/stack_user.c
+++ b/fs/ocfs2/stack_user.c
@@ -549,26 +549,17 @@ static ssize_t ocfs2_control_read(struct file *file,
                                   size_t count,
                                   loff_t *ppos)
 {
-        char *proto_string = OCFS2_CONTROL_PROTO;
-        size_t to_write = 0;
-
-        if (*ppos >= OCFS2_CONTROL_PROTO_LEN)
-                return 0;
-
-        to_write = OCFS2_CONTROL_PROTO_LEN - *ppos;
-        if (to_write > count)
-                to_write = count;
-        if (copy_to_user(buf, proto_string + *ppos, to_write))
-                return -EFAULT;
+        ssize_t ret;
 
-        *ppos += to_write;
+        ret = simple_read_from_buffer(buf, count, ppos,
+                        OCFS2_CONTROL_PROTO, OCFS2_CONTROL_PROTO_LEN);
 
         /* Have we read the whole protocol list? */
-        if (*ppos >= OCFS2_CONTROL_PROTO_LEN)
+        if (ret > 0 && *ppos >= OCFS2_CONTROL_PROTO_LEN)
                 ocfs2_control_set_handshake_state(file,
                                                   OCFS2_CONTROL_HANDSHAKE_READ);
 
-        return to_write;
+        return ret;
 }
 
 static int ocfs2_control_release(struct inode *inode, struct file *file)