1 // SPDX-License-Identifier: GPL-2.0
5 #include <internal/rc_check.h>
6 #include <linux/refcount.h>
7 #include <linux/zalloc.h>
10 DECLARE_RC_STRUCT(comm_str) {
15 static struct comm_strs {
16 struct rw_semaphore lock;
17 struct comm_str **strs;
22 static void comm_strs__remove_if_last(struct comm_str *cs);
24 static void comm_strs__init(void)
26 init_rwsem(&_comm_strs.lock);
27 _comm_strs.capacity = 16;
28 _comm_strs.num_strs = 0;
29 _comm_strs.strs = calloc(16, sizeof(*_comm_strs.strs));
32 static struct comm_strs *comm_strs__get(void)
34 static pthread_once_t comm_strs_type_once = PTHREAD_ONCE_INIT;
36 pthread_once(&comm_strs_type_once, comm_strs__init);
41 static refcount_t *comm_str__refcnt(struct comm_str *cs)
43 return &RC_CHK_ACCESS(cs)->refcnt;
46 static const char *comm_str__str(const struct comm_str *cs)
48 return &RC_CHK_ACCESS(cs)->str[0];
51 static struct comm_str *comm_str__get(struct comm_str *cs)
53 struct comm_str *result;
55 if (RC_CHK_GET(result, cs))
56 refcount_inc_not_zero(comm_str__refcnt(cs));
61 static void comm_str__put(struct comm_str *cs)
66 if (refcount_dec_and_test(comm_str__refcnt(cs))) {
69 if (refcount_read(comm_str__refcnt(cs)) == 1)
70 comm_strs__remove_if_last(cs);
76 static struct comm_str *comm_str__new(const char *str)
78 struct comm_str *result = NULL;
79 RC_STRUCT(comm_str) *cs;
81 cs = malloc(sizeof(*cs) + strlen(str) + 1);
82 if (ADD_RC_CHK(result, cs)) {
83 refcount_set(comm_str__refcnt(result), 1);
84 strcpy(&cs->str[0], str);
89 static int comm_str__search(const void *_key, const void *_member)
91 const char *key = _key;
92 const struct comm_str *member = *(const struct comm_str * const *)_member;
94 return strcmp(key, comm_str__str(member));
97 static void comm_strs__remove_if_last(struct comm_str *cs)
99 struct comm_strs *comm_strs = comm_strs__get();
101 down_write(&comm_strs->lock);
103 * Are there only references from the array, if so remove the array
104 * reference under the write lock so that we don't race with findnew.
106 if (refcount_read(comm_str__refcnt(cs)) == 1) {
107 struct comm_str **entry;
109 entry = bsearch(comm_str__str(cs), comm_strs->strs, comm_strs->num_strs,
110 sizeof(struct comm_str *), comm_str__search);
111 comm_str__put(*entry);
112 for (int i = entry - comm_strs->strs; i < comm_strs->num_strs - 1; i++)
113 comm_strs->strs[i] = comm_strs->strs[i + 1];
114 comm_strs->num_strs--;
116 up_write(&comm_strs->lock);
119 static struct comm_str *__comm_strs__find(struct comm_strs *comm_strs, const char *str)
121 struct comm_str **result;
123 result = bsearch(str, comm_strs->strs, comm_strs->num_strs, sizeof(struct comm_str *),
129 return comm_str__get(*result);
132 static struct comm_str *comm_strs__findnew(const char *str)
134 struct comm_strs *comm_strs = comm_strs__get();
135 struct comm_str *result;
140 down_read(&comm_strs->lock);
141 result = __comm_strs__find(comm_strs, str);
142 up_read(&comm_strs->lock);
146 down_write(&comm_strs->lock);
147 result = __comm_strs__find(comm_strs, str);
149 if (comm_strs->num_strs == comm_strs->capacity) {
150 struct comm_str **tmp;
152 tmp = reallocarray(comm_strs->strs,
153 comm_strs->capacity + 16,
154 sizeof(*comm_strs->strs));
156 up_write(&comm_strs->lock);
159 comm_strs->strs = tmp;
160 comm_strs->capacity += 16;
162 result = comm_str__new(str);
164 int low = 0, high = comm_strs->num_strs - 1;
165 int insert = comm_strs->num_strs; /* Default to inserting at the end. */
167 while (low <= high) {
168 int mid = low + (high - low) / 2;
169 int cmp = strcmp(comm_str__str(comm_strs->strs[mid]), str);
178 memmove(&comm_strs->strs[insert + 1], &comm_strs->strs[insert],
179 (comm_strs->num_strs - insert) * sizeof(struct comm_str *));
180 comm_strs->num_strs++;
181 comm_strs->strs[insert] = result;
184 up_write(&comm_strs->lock);
185 return comm_str__get(result);
188 struct comm *comm__new(const char *str, u64 timestamp, bool exec)
190 struct comm *comm = zalloc(sizeof(*comm));
195 comm->start = timestamp;
198 comm->comm_str = comm_strs__findnew(str);
199 if (!comm->comm_str) {
207 int comm__override(struct comm *comm, const char *str, u64 timestamp, bool exec)
209 struct comm_str *new, *old = comm->comm_str;
211 new = comm_strs__findnew(str);
216 comm->comm_str = new;
217 comm->start = timestamp;
224 void comm__free(struct comm *comm)
226 comm_str__put(comm->comm_str);
230 const char *comm__str(const struct comm *comm)
232 return comm_str__str(comm->comm_str);