| Matthew Wilcox | f8d5d0c | 2017-11-07 16:30:10 -0500 | [diff] [blame^] | 1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | /* |
| 3 | * XArray implementation |
| 4 | * Copyright (c) 2017 Microsoft Corporation |
| 5 | * Author: Matthew Wilcox <willy@infradead.org> |
| 6 | */ |
| 7 | |
| 8 | #include <linux/export.h> |
| 9 | #include <linux/xarray.h> |
| 10 | |
| 11 | /* |
| 12 | * Coding conventions in this file: |
| 13 | * |
| 14 | * @xa is used to refer to the entire xarray. |
| 15 | * @xas is the 'xarray operation state'. It may be either a pointer to |
| 16 | * an xa_state, or an xa_state stored on the stack. This is an unfortunate |
| 17 | * ambiguity. |
| 18 | * @index is the index of the entry being operated on |
| 19 | * @mark is an xa_mark_t; a small number indicating one of the mark bits. |
| 20 | * @node refers to an xa_node; usually the primary one being operated on by |
| 21 | * this function. |
| 22 | * @offset is the index into the slots array inside an xa_node. |
| 23 | * @parent refers to the @xa_node closer to the head than @node. |
| 24 | * @entry refers to something stored in a slot in the xarray |
| 25 | */ |
| 26 | |
| 27 | /** |
| 28 | * xa_init_flags() - Initialise an empty XArray with flags. |
| 29 | * @xa: XArray. |
| 30 | * @flags: XA_FLAG values. |
| 31 | * |
| 32 | * If you need to initialise an XArray with special flags (eg you need |
| 33 | * to take the lock from interrupt context), use this function instead |
| 34 | * of xa_init(). |
| 35 | * |
| 36 | * Context: Any context. |
| 37 | */ |
| 38 | void xa_init_flags(struct xarray *xa, gfp_t flags) |
| 39 | { |
| 40 | spin_lock_init(&xa->xa_lock); |
| 41 | xa->xa_flags = flags; |
| 42 | xa->xa_head = NULL; |
| 43 | } |
| 44 | EXPORT_SYMBOL(xa_init_flags); |