+ while (!iov->iov_len)
+ iov++;
+
+ while (len > 0) {
+ unsigned long this_len;
+
+ this_len = min_t(unsigned long, len, iov->iov_len);
+ fault_in_pages_readable(iov->iov_base, this_len);
+ len -= this_len;
+ iov++;
+ }
+}
+
+static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf)
+{
+ struct page *page = buf->page;
+
+ /*
+ * If nobody else uses this page, and we don't already have a
+ * temporary page, let's keep track of it as a one-deep
+ * allocation cache. (Otherwise just release our reference to it)
+ */
+ if (page_count(page) == 1 && !pipe->tmp_page)
+ pipe->tmp_page = page;
+ else
+ page_cache_release(page);
+}
+
+void *generic_pipe_buf_map(struct pipe_inode_info *pipe,
+ struct pipe_buffer *buf, int atomic)
+{
+ if (atomic) {
+ buf->flags |= PIPE_BUF_FLAG_ATOMIC;
+ return kmap_atomic(buf->page, KM_USER0);
+ }
+