From f8d5d0cc145cc21bfc56ef807dc28102aebbf228 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 7 Nov 2017 16:30:10 -0500 Subject: 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 Reviewed-by: Josef Bacik --- lib/xarray.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 lib/xarray.c (limited to 'lib/xarray.c') 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 + */ + +#include +#include + +/* + * 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); -- cgit v1.2.3-59-g8ed1b