sys_sendfile() call,

    do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
        in_file->f_op->sendfile(out_file, in_file, ppos, count);

But,

ssize_t generic_file_sendfile(struct file *in_file, struct file *out_file,
			      loff_t *ppos, size_t count)

fist arg of generic_file_sendfile() should be for output. This patch
fixes this typo.