VFS: refactor vfs_read()

integrity_kernel_read() duplicates the file read operations code
in vfs_read(). This patch refactors vfs_read() code creating a
helper function __vfs_read(). It is used by both vfs_read() and
integrity_kernel_read().

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e11d60c..ac3a36e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1527,6 +1527,7 @@
 			      struct iovec *fast_pointer,
 			      struct iovec **ret_pointer);
 
+extern ssize_t __vfs_read(struct file *, char __user *, size_t, loff_t *);
 extern ssize_t vfs_read(struct file *, char __user *, size_t, loff_t *);
 extern ssize_t vfs_write(struct file *, const char __user *, size_t, loff_t *);
 extern ssize_t vfs_readv(struct file *, const struct iovec __user *,