v4.19.13 snapshot.
diff --git a/include/linux/task_io_accounting.h b/include/linux/task_io_accounting.h
new file mode 100644
index 0000000..6f6acce
--- /dev/null
+++ b/include/linux/task_io_accounting.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * task_io_accounting: a structure which is used for recording a single task's
+ * IO statistics.
+ *
+ * Don't include this header file directly - it is designed to be dragged in via
+ * sched.h.
+ *
+ * Blame Andrew Morton for all this.
+ */
+
+struct task_io_accounting {
+#ifdef CONFIG_TASK_XACCT
+ /* bytes read */
+ u64 rchar;
+ /* bytes written */
+ u64 wchar;
+ /* # of read syscalls */
+ u64 syscr;
+ /* # of write syscalls */
+ u64 syscw;
+#endif /* CONFIG_TASK_XACCT */
+
+#ifdef CONFIG_TASK_IO_ACCOUNTING
+ /*
+ * The number of bytes which this task has caused to be read from
+ * storage.
+ */
+ u64 read_bytes;
+
+ /*
+ * The number of bytes which this task has caused, or shall cause to be
+ * written to disk.
+ */
+ u64 write_bytes;
+
+ /*
+ * A task can cause "negative" IO too. If this task truncates some
+ * dirty pagecache, some IO which another task has been accounted for
+ * (in its write_bytes) will not be happening. We _could_ just
+ * subtract that from the truncating task's write_bytes, but there is
+ * information loss in doing that.
+ */
+ u64 cancelled_write_bytes;
+#endif /* CONFIG_TASK_IO_ACCOUNTING */
+};