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authorMatthew Wilcox <willy@infradead.org>2017-11-07 16:30:10 -0500
committerMatthew Wilcox <willy@infradead.org>2018-10-21 10:45:53 -0400
commitf8d5d0cc145cc21bfc56ef807dc28102aebbf228 (patch)
tree0fcba575e83fb02fd2cb49df1ce1cc55bcd927d3 /lib/xarray.c
parent02c02bf12c5d838603eed44195d3e91f094e2ab2 (diff)
xarray: Add definition of struct xarray
This is a direct replacement for struct radix_tree_root. Some of the struct members have changed name; convert those, and use a #define so that radix_tree users continue to work without change. Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Josef Bacik <jbacik@fb.com>
Diffstat (limited to 'lib/xarray.c')
-rw-r--r--lib/xarray.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/lib/xarray.c b/lib/xarray.c
new file mode 100644
index 000000000000..862f4c64c754
--- /dev/null
+++ b/lib/xarray.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * XArray implementation
+ * Copyright (c) 2017 Microsoft Corporation
+ * Author: Matthew Wilcox <willy@infradead.org>
+ */
+
+#include <linux/export.h>
+#include <linux/xarray.h>
+
+/*
+ * Coding conventions in this file:
+ *
+ * @xa is used to refer to the entire xarray.
+ * @xas is the 'xarray operation state'. It may be either a pointer to
+ * an xa_state, or an xa_state stored on the stack. This is an unfortunate
+ * ambiguity.
+ * @index is the index of the entry being operated on
+ * @mark is an xa_mark_t; a small number indicating one of the mark bits.
+ * @node refers to an xa_node; usually the primary one being operated on by
+ * this function.
+ * @offset is the index into the slots array inside an xa_node.
+ * @parent refers to the @xa_node closer to the head than @node.
+ * @entry refers to something stored in a slot in the xarray
+ */
+
+/**
+ * xa_init_flags() - Initialise an empty XArray with flags.
+ * @xa: XArray.
+ * @flags: XA_FLAG values.
+ *
+ * If you need to initialise an XArray with special flags (eg you need
+ * to take the lock from interrupt context), use this function instead
+ * of xa_init().
+ *
+ * Context: Any context.
+ */
+void xa_init_flags(struct xarray *xa, gfp_t flags)
+{
+ spin_lock_init(&xa->xa_lock);
+ xa->xa_flags = flags;
+ xa->xa_head = NULL;
+}
+EXPORT_SYMBOL(xa_init_flags);