1// SPDX-License-Identifier: GPL-2.0
 2#define CREATE_TRACE_POINTS
 3#include <trace/events/mmap_lock.h>
 4
 5#include <linux/mm.h>
 6#include <linux/cgroup.h>
 7#include <linux/memcontrol.h>
 8#include <linux/mmap_lock.h>
 9#include <linux/mutex.h>
10#include <linux/percpu.h>
11#include <linux/rcupdate.h>
12#include <linux/smp.h>
13#include <linux/trace_events.h>
14#include <linux/local_lock.h>
15
16EXPORT_TRACEPOINT_SYMBOL(mmap_lock_start_locking);
17EXPORT_TRACEPOINT_SYMBOL(mmap_lock_acquire_returned);
18EXPORT_TRACEPOINT_SYMBOL(mmap_lock_released);
19
20#ifdef CONFIG_MEMCG
21
22/*
23 * Size of the buffer for memcg path names. Ignoring stack trace support,
24 * trace_events_hist.c uses MAX_FILTER_STR_VAL for this, so we also use it.
25 */
26#define MEMCG_PATH_BUF_SIZE MAX_FILTER_STR_VAL
27
28#define TRACE_MMAP_LOCK_EVENT(type, mm, ...)				\
29	do {								\
30		if (trace_mmap_lock_##type##_enabled()) {		\
31			char buf[MEMCG_PATH_BUF_SIZE];                  \
32			get_mm_memcg_path(mm, buf, sizeof(buf));        \
33			trace_mmap_lock_##type(mm, buf, ##__VA_ARGS__); \
34		}							\
35	} while (0)
36
37#else /* !CONFIG_MEMCG */
38
39#define TRACE_MMAP_LOCK_EVENT(type, mm, ...)                                   \
40	trace_mmap_lock_##type(mm, "", ##__VA_ARGS__)
41
42#endif /* CONFIG_MEMCG */
43
44#ifdef CONFIG_TRACING
45#ifdef CONFIG_MEMCG
46/*
47 * Write the given mm_struct's memcg path to a buffer. If the path cannot be
48 * determined, empty string is written.
49 */
50static void get_mm_memcg_path(struct mm_struct *mm, char *buf, size_t buflen)
51{
52	struct mem_cgroup *memcg;
53
54	buf[0] = '\0';
55	memcg = get_mem_cgroup_from_mm(mm);
56	if (memcg == NULL)
57		return;
58	if (memcg->css.cgroup)
59		cgroup_path(memcg->css.cgroup, buf, buflen);
60	css_put(&memcg->css);
61}
62
63#endif /* CONFIG_MEMCG */
64
65/*
66 * Trace calls must be in a separate file, as otherwise there's a circular
67 * dependency between linux/mmap_lock.h and trace/events/mmap_lock.h.
68 */
69
70void __mmap_lock_do_trace_start_locking(struct mm_struct *mm, bool write)
71{
72	TRACE_MMAP_LOCK_EVENT(start_locking, mm, write);
73}
74EXPORT_SYMBOL(__mmap_lock_do_trace_start_locking);
75
76void __mmap_lock_do_trace_acquire_returned(struct mm_struct *mm, bool write,
77					   bool success)
78{
79	TRACE_MMAP_LOCK_EVENT(acquire_returned, mm, write, success);
80}
81EXPORT_SYMBOL(__mmap_lock_do_trace_acquire_returned);
82
83void __mmap_lock_do_trace_released(struct mm_struct *mm, bool write)
84{
85	TRACE_MMAP_LOCK_EVENT(released, mm, write);
86}
87EXPORT_SYMBOL(__mmap_lock_do_trace_released);
88#endif /* CONFIG_TRACING */