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24cedcfe MD |
1 | /* |
2 | * Copyright (C) 2011 Mathieu Desnoyers (mathieu.desnoyers@efficios.com) | |
3 | * | |
4 | * wrapper around poll __pollwait and poll_get_entry. Using KALLSYMS to get its | |
5 | * address when available, else we need to have a kernel that exports this | |
6 | * function to GPL modules. | |
7 | * | |
8 | * Dual LGPL v2.1/GPL v2 license. | |
9 | */ | |
10 | ||
11 | #ifdef CONFIG_KALLSYMS | |
12 | ||
13 | #include <linux/kallsyms.h> | |
14 | #include <linux/poll.h> | |
15 | ||
16 | struct poll_table_entry; | |
17 | struct splice_pipe_desc; | |
18 | ||
19 | static | |
20 | void (*__pollwait_sym)(struct file *filp, wait_queue_head_t *wait_address, | |
21 | poll_table *p); | |
22 | static | |
23 | struct poll_table_entry *(*poll_get_entry_sym)(struct poll_wqueues *p); | |
24 | ||
25 | void wrapper_pollwait_exclusive(struct file *filp, | |
26 | wait_queue_head_t *wait_address, | |
27 | poll_table *p) | |
28 | ||
29 | { | |
30 | struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt); | |
31 | struct poll_table_entry *entry; | |
32 | ||
33 | if (!poll_get_entry_sym) | |
34 | poll_get_entry_sym = (void *) kallsyms_lookup_name("poll_get_entry"); | |
35 | if (!poll_get_entry_sym) { | |
36 | printk(KERN_WARNING "LTTng: poll_get_entry_sym symbol lookup failed.\n"); | |
37 | return; | |
38 | } | |
39 | entry = poll_get_entry_sym(pwq); | |
40 | ||
41 | if (!__pollwait_sym) | |
42 | __pollwait_sym = (void *) kallsyms_lookup_name("__pollwait"); | |
43 | if (!__pollwait_sym) { | |
44 | printk(KERN_WARNING "LTTng: __pollwait symbol lookup failed.\n"); | |
45 | return; | |
46 | } | |
47 | return __pollwait_sym(filp, wait_address, p); | |
48 | } | |
49 | ||
50 | #else | |
51 | ||
52 | #include <linux/poll.h> | |
53 | ||
54 | ssize_t wrapper_pollwait_exclusive(struct file *filp, | |
55 | wait_queue_head_t *wait_address, | |
56 | poll_table *p) | |
57 | { | |
58 | return pollwait_exclusive(filp, wait_address, p); | |
59 | } | |
60 | ||
61 | #endif |