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b7cdc182 | 1 | /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only) |
9f36eaed | 2 | * |
42d9070d AG |
3 | * wrapper/writeback.h |
4 | * | |
5 | * wrapper around global_dirty_limit read. Using KALLSYMS with KALLSYMS_ALL | |
6 | * to get its address when available, else we need to have a kernel that | |
7 | * exports this variable to GPL modules. | |
8 | * | |
9 | * Copyright (C) 2013 Mentor Graphics Corp. | |
42d9070d AG |
10 | */ |
11 | ||
9f36eaed MJ |
12 | #ifndef _LTTNG_WRAPPER_WRITEBACK_H |
13 | #define _LTTNG_WRAPPER_WRITEBACK_H | |
14 | ||
6284ae7c | 15 | #ifdef CONFIG_KALLSYMS_ALL |
9f881196 | 16 | |
42d9070d | 17 | #include <linux/kallsyms.h> |
5a2f5e92 | 18 | #include <wrapper/kallsyms.h> |
42d9070d | 19 | |
6284ae7c MJ |
20 | static struct wb_domain *global_wb_domain_sym; |
21 | ||
22 | static inline | |
23 | unsigned long wrapper_global_dirty_limit(void) | |
24 | { | |
25 | if (!global_wb_domain_sym) | |
26 | global_wb_domain_sym = | |
27 | (void *) kallsyms_lookup_dataptr("global_wb_domain"); | |
28 | if (global_wb_domain_sym) { | |
29 | return global_wb_domain_sym->dirty_limit; | |
30 | } else { | |
31 | printk_once(KERN_WARNING "LTTng: global_wb_domain symbol lookup failed.\n"); | |
32 | return 0; | |
33 | } | |
34 | } | |
3dfec228 MJ |
35 | |
36 | /* | |
37 | * Canary function to check for 'global_wb_domain' at compile time. | |
38 | * | |
39 | * From 'include/linux/writeback.h': | |
40 | * | |
41 | * extern struct wb_domain global_wb_domain; | |
42 | */ | |
43 | static inline | |
44 | unsigned long __canary__global_wb_domain(void) | |
45 | { | |
46 | return global_wb_domain.dirty_limit; | |
47 | } | |
48 | ||
6284ae7c | 49 | #else /* CONFIG_KALLSYMS_ALL */ |
42d9070d AG |
50 | |
51 | #include <linux/writeback.h> | |
52 | ||
53 | static inline | |
54 | unsigned long wrapper_global_dirty_limit(void) | |
55 | { | |
56 | return global_dirty_limit; | |
57 | } | |
58 | ||
9f881196 | 59 | #endif /* CONFIG_KALLSYMS_ALL */ |
42d9070d AG |
60 | |
61 | #endif /* _LTTNG_WRAPPER_WRITEBACK_H */ |