1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2021 VMware Inc, Steven Rostedt <rostedt@goodmis.org>
*/
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include "trace.h"
/**
* trace_pid_list_is_set - test if the pid is set in the list
* @pid_list: The pid list to test
* @pid: The pid to to see if set in the list.
*
* Tests if @pid is is set in the @pid_list. This is usually called
* from the scheduler when a task is scheduled. Its pid is checked
* if it should be traced or not.
*
* Return true if the pid is in the list, false otherwise.
*/
bool trace_pid_list_is_set(struct trace_pid_list *pid_list, unsigned int pid)
{
/*
* If pid_max changed after filtered_pids was created, we
* by default ignore all pids greater than the previous pid_max.
*/
if (pid >= pid_list->pid_max)
return false;
return test_bit(pid, pid_list->pids);
}
/**
* trace_pid_list_set - add a pid to the list
* @pid_list: The pid list to add the @pid to.
* @pid: The pid to add.
*
* Adds @pid to @pid_list. This is usually done explicitly by a user
* adding a task to be traced, or indirectly by the fork function
* when children should be traced and a task's pid is in the list.
*
* Return 0 on success, negative otherwise.
*/
int trace_pid_list_set(struct trace_pid_list *pid_list, unsigned int pid)
{
/* Sorry, but we don't support pid_max changing after setting */
if (pid >= pid_list->pid_max)
return -EINVAL;
set_bit(pid, pid_list->pids);
return 0;
}
/**
* trace_pid_list_clear - remove a pid from the list
* @pid_list: The pid list to remove the @pid from.
* @pid: The pid to remove.
*
* Removes @pid from @pid_list. This is usually done explicitly by a user
* removing tasks from tracing, or indirectly by the exit function
* when a task that is set to be traced exits.
*
* Return 0 on success, negative otherwise.
*/
int trace_pid_list_clear(struct trace_pid_list *pid_list, unsigned int pid)
{
/* Sorry, but we don't support pid_max changing after setting */
if (pid >= pid_list->pid_max)
return -EINVAL;
clear_bit(pid, pid_list->pids);
return 0;
}
/**
* trace_pid_list_next - return the next pid in the list
* @pid_list: The pid list to examine.
* @pid: The pid to start from
* @next: The pointer to place the pid that is set starting from @pid.
*
* Looks for the next consecutive pid that is in @pid_list starting
* at the pid specified by @pid. If one is set (including @pid), then
* that pid is placed into @next.
*
* Return 0 when a pid is found, -1 if there are no more pids included.
*/
int trace_pid_list_next(struct trace_pid_list *pid_list, unsigned int pid,
unsigned int *next)
{
pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
if (pid < pid_list->pid_max) {
*next = pid;
return 0;
}
return -1;
}
/**
* trace_pid_list_first - return the first pid in the list
* @pid_list: The pid list to examine.
* @pid: The pointer to place the pid first found pid that is set.
*
* Looks for the first pid that is set in @pid_list, and places it
* into @pid if found.
*
* Return 0 when a pid is found, -1 if there are no pids set.
*/
int trace_pid_list_first(struct trace_pid_list *pid_list, unsigned int *pid)
{
unsigned int first;
first = find_first_bit(pid_list->pids, pid_list->pid_max);
if (first < pid_list->pid_max) {
*pid = first;
return 0;
}
return -1;
}
/**
* trace_pid_list_alloc - create a new pid_list
*
* Allocates a new pid_list to store pids into.
*
* Returns the pid_list on success, NULL otherwise.
*/
struct trace_pid_list *trace_pid_list_alloc(void)
{
struct trace_pid_list *pid_list;
pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
if (!pid_list)
return NULL;
pid_list->pid_max = READ_ONCE(pid_max);
pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
if (!pid_list->pids) {
kfree(pid_list);
return NULL;
}
return pid_list;
}
/**
* trace_pid_list_free - Frees an allocated pid_list.
*
* Frees the memory for a pid_list that was allocated.
*/
void trace_pid_list_free(struct trace_pid_list *pid_list)
{
if (!pid_list)
return;
vfree(pid_list->pids);
kfree(pid_list);
}
|
