Eric Lee / linux-smarc-t335x-v3.2

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Commit 9795302acf2817d0842e56d23df6008e43df0970

Authored by Mathieu Desnoyers
Committed by Ingo Molnar
1 parent 611b159768
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

tracepoints: use TABLE_SIZE macro 

Steven Rostedt suggested:

| Wouldn't it look nicer to have: (TRACEPOINT_TABLE_SIZE - 1) ?

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Showing 1 changed file with 3 additions and 3 deletions Inline Diff

1 /* 1 /*
2 * Copyright (C) 2008 Mathieu Desnoyers 2 * Copyright (C) 2008 Mathieu Desnoyers
3 * 3 *
4 * This program is free software; you can redistribute it and/or modify 4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by 5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or 6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version. 7 * (at your option) any later version.
8 * 8 *
9 * This program is distributed in the hope that it will be useful, 9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details. 12 * GNU General Public License for more details.
13 * 13 *
14 * You should have received a copy of the GNU General Public License 14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software 15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 */ 17 */
18 #include <linux/module.h> 18 #include <linux/module.h>
19 #include <linux/mutex.h> 19 #include <linux/mutex.h>
20 #include <linux/types.h> 20 #include <linux/types.h>
21 #include <linux/jhash.h> 21 #include <linux/jhash.h>
22 #include <linux/list.h> 22 #include <linux/list.h>
23 #include <linux/rcupdate.h> 23 #include <linux/rcupdate.h>
24 #include <linux/tracepoint.h> 24 #include <linux/tracepoint.h>
25 #include <linux/err.h> 25 #include <linux/err.h>
26 #include <linux/slab.h> 26 #include <linux/slab.h>
27 27
28 extern struct tracepoint __start___tracepoints[]; 28 extern struct tracepoint __start___tracepoints[];
29 extern struct tracepoint __stop___tracepoints[]; 29 extern struct tracepoint __stop___tracepoints[];
30 30
31 /* Set to 1 to enable tracepoint debug output */ 31 /* Set to 1 to enable tracepoint debug output */
32 static const int tracepoint_debug; 32 static const int tracepoint_debug;
33 33
34 /* 34 /*
35 * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the 35 * tracepoints_mutex nests inside module_mutex. Tracepoints mutex protects the
36 * builtin and module tracepoints and the hash table. 36 * builtin and module tracepoints and the hash table.
37 */ 37 */
38 static DEFINE_MUTEX(tracepoints_mutex); 38 static DEFINE_MUTEX(tracepoints_mutex);
39 39
40 /* 40 /*
41 * Tracepoint hash table, containing the active tracepoints. 41 * Tracepoint hash table, containing the active tracepoints.
42 * Protected by tracepoints_mutex. 42 * Protected by tracepoints_mutex.
43 */ 43 */
44 #define TRACEPOINT_HASH_BITS 6 44 #define TRACEPOINT_HASH_BITS 6
45 #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS) 45 #define TRACEPOINT_TABLE_SIZE (1 << TRACEPOINT_HASH_BITS)
46 46
47 /* 47 /*
48 * Note about RCU : 48 * Note about RCU :
49 * It is used to to delay the free of multiple probes array until a quiescent 49 * It is used to to delay the free of multiple probes array until a quiescent
50 * state is reached. 50 * state is reached.
51 * Tracepoint entries modifications are protected by the tracepoints_mutex. 51 * Tracepoint entries modifications are protected by the tracepoints_mutex.
52 */ 52 */
53 struct tracepoint_entry { 53 struct tracepoint_entry {
54 struct hlist_node hlist; 54 struct hlist_node hlist;
55 void **funcs; 55 void **funcs;
56 int refcount; /* Number of times armed. 0 if disarmed. */ 56 int refcount; /* Number of times armed. 0 if disarmed. */
57 struct rcu_head rcu; 57 struct rcu_head rcu;
58 void *oldptr; 58 void *oldptr;
59 unsigned char rcu_pending:1; 59 unsigned char rcu_pending:1;
60 char name[0]; 60 char name[0];
61 }; 61 };
62 62
63 static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE]; 63 static struct hlist_head tracepoint_table[TRACEPOINT_TABLE_SIZE];
64 64
65 static void free_old_closure(struct rcu_head *head) 65 static void free_old_closure(struct rcu_head *head)
66 { 66 {
67 struct tracepoint_entry *entry = container_of(head, 67 struct tracepoint_entry *entry = container_of(head,
68 struct tracepoint_entry, rcu); 68 struct tracepoint_entry, rcu);
69 kfree(entry->oldptr); 69 kfree(entry->oldptr);
70 /* Make sure we free the data before setting the pending flag to 0 */ 70 /* Make sure we free the data before setting the pending flag to 0 */
71 smp_wmb(); 71 smp_wmb();
72 entry->rcu_pending = 0; 72 entry->rcu_pending = 0;
73 } 73 }
74 74
75 static void tracepoint_entry_free_old(struct tracepoint_entry *entry, void *old) 75 static void tracepoint_entry_free_old(struct tracepoint_entry *entry, void *old)
76 { 76 {
77 if (!old) 77 if (!old)
78 return; 78 return;
79 entry->oldptr = old; 79 entry->oldptr = old;
80 entry->rcu_pending = 1; 80 entry->rcu_pending = 1;
81 /* write rcu_pending before calling the RCU callback */ 81 /* write rcu_pending before calling the RCU callback */
82 smp_wmb(); 82 smp_wmb();
83 #ifdef CONFIG_PREEMPT_RCU 83 #ifdef CONFIG_PREEMPT_RCU
84 synchronize_sched(); /* Until we have the call_rcu_sched() */ 84 synchronize_sched(); /* Until we have the call_rcu_sched() */
85 #endif 85 #endif
86 call_rcu(&entry->rcu, free_old_closure); 86 call_rcu(&entry->rcu, free_old_closure);
87 } 87 }
88 88
89 static void debug_print_probes(struct tracepoint_entry *entry) 89 static void debug_print_probes(struct tracepoint_entry *entry)
90 { 90 {
91 int i; 91 int i;
92 92
93 if (!tracepoint_debug) 93 if (!tracepoint_debug)
94 return; 94 return;
95 95
96 for (i = 0; entry->funcs[i]; i++) 96 for (i = 0; entry->funcs[i]; i++)
97 printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]); 97 printk(KERN_DEBUG "Probe %d : %p\n", i, entry->funcs[i]);
98 } 98 }
99 99
100 static void * 100 static void *
101 tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe) 101 tracepoint_entry_add_probe(struct tracepoint_entry *entry, void *probe)
102 { 102 {
103 int nr_probes = 0; 103 int nr_probes = 0;
104 void **old, **new; 104 void **old, **new;
105 105
106 WARN_ON(!probe); 106 WARN_ON(!probe);
107 107
108 debug_print_probes(entry); 108 debug_print_probes(entry);
109 old = entry->funcs; 109 old = entry->funcs;
110 if (old) { 110 if (old) {
111 /* (N -> N+1), (N != 0, 1) probes */ 111 /* (N -> N+1), (N != 0, 1) probes */
112 for (nr_probes = 0; old[nr_probes]; nr_probes++) 112 for (nr_probes = 0; old[nr_probes]; nr_probes++)
113 if (old[nr_probes] == probe) 113 if (old[nr_probes] == probe)
114 return ERR_PTR(-EEXIST); 114 return ERR_PTR(-EEXIST);
115 } 115 }
116 /* + 2 : one for new probe, one for NULL func */ 116 /* + 2 : one for new probe, one for NULL func */
117 new = kzalloc((nr_probes + 2) * sizeof(void *), GFP_KERNEL); 117 new = kzalloc((nr_probes + 2) * sizeof(void *), GFP_KERNEL);
118 if (new == NULL) 118 if (new == NULL)
119 return ERR_PTR(-ENOMEM); 119 return ERR_PTR(-ENOMEM);
120 if (old) 120 if (old)
121 memcpy(new, old, nr_probes * sizeof(void *)); 121 memcpy(new, old, nr_probes * sizeof(void *));
122 new[nr_probes] = probe; 122 new[nr_probes] = probe;
123 entry->refcount = nr_probes + 1; 123 entry->refcount = nr_probes + 1;
124 entry->funcs = new; 124 entry->funcs = new;
125 debug_print_probes(entry); 125 debug_print_probes(entry);
126 return old; 126 return old;
127 } 127 }
128 128
129 static void * 129 static void *
130 tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe) 130 tracepoint_entry_remove_probe(struct tracepoint_entry *entry, void *probe)
131 { 131 {
132 int nr_probes = 0, nr_del = 0, i; 132 int nr_probes = 0, nr_del = 0, i;
133 void **old, **new; 133 void **old, **new;
134 134
135 old = entry->funcs; 135 old = entry->funcs;
136 136
137 debug_print_probes(entry); 137 debug_print_probes(entry);
138 /* (N -> M), (N > 1, M >= 0) probes */ 138 /* (N -> M), (N > 1, M >= 0) probes */
139 for (nr_probes = 0; old[nr_probes]; nr_probes++) { 139 for (nr_probes = 0; old[nr_probes]; nr_probes++) {
140 if ((!probe || old[nr_probes] == probe)) 140 if ((!probe || old[nr_probes] == probe))
141 nr_del++; 141 nr_del++;
142 } 142 }
143 143
144 if (nr_probes - nr_del == 0) { 144 if (nr_probes - nr_del == 0) {
145 /* N -> 0, (N > 1) */ 145 /* N -> 0, (N > 1) */
146 entry->funcs = NULL; 146 entry->funcs = NULL;
147 entry->refcount = 0; 147 entry->refcount = 0;
148 debug_print_probes(entry); 148 debug_print_probes(entry);
149 return old; 149 return old;
150 } else { 150 } else {
151 int j = 0; 151 int j = 0;
152 /* N -> M, (N > 1, M > 0) */ 152 /* N -> M, (N > 1, M > 0) */
153 /* + 1 for NULL */ 153 /* + 1 for NULL */
154 new = kzalloc((nr_probes - nr_del + 1) 154 new = kzalloc((nr_probes - nr_del + 1)
155 * sizeof(void *), GFP_KERNEL); 155 * sizeof(void *), GFP_KERNEL);
156 if (new == NULL) 156 if (new == NULL)
157 return ERR_PTR(-ENOMEM); 157 return ERR_PTR(-ENOMEM);
158 for (i = 0; old[i]; i++) 158 for (i = 0; old[i]; i++)
159 if ((probe && old[i] != probe)) 159 if ((probe && old[i] != probe))
160 new[j++] = old[i]; 160 new[j++] = old[i];
161 entry->refcount = nr_probes - nr_del; 161 entry->refcount = nr_probes - nr_del;
162 entry->funcs = new; 162 entry->funcs = new;
163 } 163 }
164 debug_print_probes(entry); 164 debug_print_probes(entry);
165 return old; 165 return old;
166 } 166 }
167 167
168 /* 168 /*
169 * Get tracepoint if the tracepoint is present in the tracepoint hash table. 169 * Get tracepoint if the tracepoint is present in the tracepoint hash table.
170 * Must be called with tracepoints_mutex held. 170 * Must be called with tracepoints_mutex held.
171 * Returns NULL if not present. 171 * Returns NULL if not present.
172 */ 172 */
173 static struct tracepoint_entry *get_tracepoint(const char *name) 173 static struct tracepoint_entry *get_tracepoint(const char *name)
174 { 174 {
175 struct hlist_head *head; 175 struct hlist_head *head;
176 struct hlist_node *node; 176 struct hlist_node *node;
177 struct tracepoint_entry *e; 177 struct tracepoint_entry *e;
178 u32 hash = jhash(name, strlen(name), 0); 178 u32 hash = jhash(name, strlen(name), 0);
179 179
180 head = &tracepoint_table[hash & ((1 << TRACEPOINT_HASH_BITS)-1)]; 180 head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
181 hlist_for_each_entry(e, node, head, hlist) { 181 hlist_for_each_entry(e, node, head, hlist) {
182 if (!strcmp(name, e->name)) 182 if (!strcmp(name, e->name))
183 return e; 183 return e;
184 } 184 }
185 return NULL; 185 return NULL;
186 } 186 }
187 187
188 /* 188 /*
189 * Add the tracepoint to the tracepoint hash table. Must be called with 189 * Add the tracepoint to the tracepoint hash table. Must be called with
190 * tracepoints_mutex held. 190 * tracepoints_mutex held.
191 */ 191 */
192 static struct tracepoint_entry *add_tracepoint(const char *name) 192 static struct tracepoint_entry *add_tracepoint(const char *name)
193 { 193 {
194 struct hlist_head *head; 194 struct hlist_head *head;
195 struct hlist_node *node; 195 struct hlist_node *node;
196 struct tracepoint_entry *e; 196 struct tracepoint_entry *e;
197 size_t name_len = strlen(name) + 1; 197 size_t name_len = strlen(name) + 1;
198 u32 hash = jhash(name, name_len-1, 0); 198 u32 hash = jhash(name, name_len-1, 0);
199 199
200 head = &tracepoint_table[hash & ((1 << TRACEPOINT_HASH_BITS)-1)]; 200 head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
201 hlist_for_each_entry(e, node, head, hlist) { 201 hlist_for_each_entry(e, node, head, hlist) {
202 if (!strcmp(name, e->name)) { 202 if (!strcmp(name, e->name)) {
203 printk(KERN_NOTICE 203 printk(KERN_NOTICE
204 "tracepoint %s busy\n", name); 204 "tracepoint %s busy\n", name);
205 return ERR_PTR(-EEXIST); /* Already there */ 205 return ERR_PTR(-EEXIST); /* Already there */
206 } 206 }
207 } 207 }
208 /* 208 /*
209 * Using kmalloc here to allocate a variable length element. Could 209 * Using kmalloc here to allocate a variable length element. Could
210 * cause some memory fragmentation if overused. 210 * cause some memory fragmentation if overused.
211 */ 211 */
212 e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL); 212 e = kmalloc(sizeof(struct tracepoint_entry) + name_len, GFP_KERNEL);
213 if (!e) 213 if (!e)
214 return ERR_PTR(-ENOMEM); 214 return ERR_PTR(-ENOMEM);
215 memcpy(&e->name[0], name, name_len); 215 memcpy(&e->name[0], name, name_len);
216 e->funcs = NULL; 216 e->funcs = NULL;
217 e->refcount = 0; 217 e->refcount = 0;
218 e->rcu_pending = 0; 218 e->rcu_pending = 0;
219 hlist_add_head(&e->hlist, head); 219 hlist_add_head(&e->hlist, head);
220 return e; 220 return e;
221 } 221 }
222 222
223 /* 223 /*
224 * Remove the tracepoint from the tracepoint hash table. Must be called with 224 * Remove the tracepoint from the tracepoint hash table. Must be called with
225 * mutex_lock held. 225 * mutex_lock held.
226 */ 226 */
227 static int remove_tracepoint(const char *name) 227 static int remove_tracepoint(const char *name)
228 { 228 {
229 struct hlist_head *head; 229 struct hlist_head *head;
230 struct hlist_node *node; 230 struct hlist_node *node;
231 struct tracepoint_entry *e; 231 struct tracepoint_entry *e;
232 int found = 0; 232 int found = 0;
233 size_t len = strlen(name) + 1; 233 size_t len = strlen(name) + 1;
234 u32 hash = jhash(name, len-1, 0); 234 u32 hash = jhash(name, len-1, 0);
235 235
236 head = &tracepoint_table[hash & ((1 << TRACEPOINT_HASH_BITS)-1)]; 236 head = &tracepoint_table[hash & (TRACEPOINT_TABLE_SIZE - 1)];
237 hlist_for_each_entry(e, node, head, hlist) { 237 hlist_for_each_entry(e, node, head, hlist) {
238 if (!strcmp(name, e->name)) { 238 if (!strcmp(name, e->name)) {
239 found = 1; 239 found = 1;
240 break; 240 break;
241 } 241 }
242 } 242 }
243 if (!found) 243 if (!found)
244 return -ENOENT; 244 return -ENOENT;
245 if (e->refcount) 245 if (e->refcount)
246 return -EBUSY; 246 return -EBUSY;
247 hlist_del(&e->hlist); 247 hlist_del(&e->hlist);
248 /* Make sure the call_rcu has been executed */ 248 /* Make sure the call_rcu has been executed */
249 if (e->rcu_pending) 249 if (e->rcu_pending)
250 rcu_barrier(); 250 rcu_barrier();
251 kfree(e); 251 kfree(e);
252 return 0; 252 return 0;
253 } 253 }
254 254
255 /* 255 /*
256 * Sets the probe callback corresponding to one tracepoint. 256 * Sets the probe callback corresponding to one tracepoint.
257 */ 257 */
258 static void set_tracepoint(struct tracepoint_entry **entry, 258 static void set_tracepoint(struct tracepoint_entry **entry,
259 struct tracepoint *elem, int active) 259 struct tracepoint *elem, int active)
260 { 260 {
261 WARN_ON(strcmp((*entry)->name, elem->name) != 0); 261 WARN_ON(strcmp((*entry)->name, elem->name) != 0);
262 262
263 /* 263 /*
264 * rcu_assign_pointer has a smp_wmb() which makes sure that the new 264 * rcu_assign_pointer has a smp_wmb() which makes sure that the new
265 * probe callbacks array is consistent before setting a pointer to it. 265 * probe callbacks array is consistent before setting a pointer to it.
266 * This array is referenced by __DO_TRACE from 266 * This array is referenced by __DO_TRACE from
267 * include/linux/tracepoints.h. A matching smp_read_barrier_depends() 267 * include/linux/tracepoints.h. A matching smp_read_barrier_depends()
268 * is used. 268 * is used.
269 */ 269 */
270 rcu_assign_pointer(elem->funcs, (*entry)->funcs); 270 rcu_assign_pointer(elem->funcs, (*entry)->funcs);
271 elem->state = active; 271 elem->state = active;
272 } 272 }
273 273
274 /* 274 /*
275 * Disable a tracepoint and its probe callback. 275 * Disable a tracepoint and its probe callback.
276 * Note: only waiting an RCU period after setting elem->call to the empty 276 * Note: only waiting an RCU period after setting elem->call to the empty
277 * function insures that the original callback is not used anymore. This insured 277 * function insures that the original callback is not used anymore. This insured
278 * by preempt_disable around the call site. 278 * by preempt_disable around the call site.
279 */ 279 */
280 static void disable_tracepoint(struct tracepoint *elem) 280 static void disable_tracepoint(struct tracepoint *elem)
281 { 281 {
282 elem->state = 0; 282 elem->state = 0;
283 } 283 }
284 284
285 /** 285 /**
286 * tracepoint_update_probe_range - Update a probe range 286 * tracepoint_update_probe_range - Update a probe range
287 * @begin: beginning of the range 287 * @begin: beginning of the range
288 * @end: end of the range 288 * @end: end of the range
289 * 289 *
290 * Updates the probe callback corresponding to a range of tracepoints. 290 * Updates the probe callback corresponding to a range of tracepoints.
291 */ 291 */
292 void tracepoint_update_probe_range(struct tracepoint *begin, 292 void tracepoint_update_probe_range(struct tracepoint *begin,
293 struct tracepoint *end) 293 struct tracepoint *end)
294 { 294 {
295 struct tracepoint *iter; 295 struct tracepoint *iter;
296 struct tracepoint_entry *mark_entry; 296 struct tracepoint_entry *mark_entry;
297 297
298 mutex_lock(&tracepoints_mutex); 298 mutex_lock(&tracepoints_mutex);
299 for (iter = begin; iter < end; iter++) { 299 for (iter = begin; iter < end; iter++) {
300 mark_entry = get_tracepoint(iter->name); 300 mark_entry = get_tracepoint(iter->name);
301 if (mark_entry) { 301 if (mark_entry) {
302 set_tracepoint(&mark_entry, iter, 302 set_tracepoint(&mark_entry, iter,
303 !!mark_entry->refcount); 303 !!mark_entry->refcount);
304 } else { 304 } else {
305 disable_tracepoint(iter); 305 disable_tracepoint(iter);
306 } 306 }
307 } 307 }
308 mutex_unlock(&tracepoints_mutex); 308 mutex_unlock(&tracepoints_mutex);
309 } 309 }
310 310
311 /* 311 /*
312 * Update probes, removing the faulty probes. 312 * Update probes, removing the faulty probes.
313 */ 313 */
314 static void tracepoint_update_probes(void) 314 static void tracepoint_update_probes(void)
315 { 315 {
316 /* Core kernel tracepoints */ 316 /* Core kernel tracepoints */
317 tracepoint_update_probe_range(__start___tracepoints, 317 tracepoint_update_probe_range(__start___tracepoints,
318 __stop___tracepoints); 318 __stop___tracepoints);
319 /* tracepoints in modules. */ 319 /* tracepoints in modules. */
320 module_update_tracepoints(); 320 module_update_tracepoints();
321 } 321 }
322 322
323 /** 323 /**
324 * tracepoint_probe_register - Connect a probe to a tracepoint 324 * tracepoint_probe_register - Connect a probe to a tracepoint
325 * @name: tracepoint name 325 * @name: tracepoint name
326 * @probe: probe handler 326 * @probe: probe handler
327 * 327 *
328 * Returns 0 if ok, error value on error. 328 * Returns 0 if ok, error value on error.
329 * The probe address must at least be aligned on the architecture pointer size. 329 * The probe address must at least be aligned on the architecture pointer size.
330 */ 330 */
331 int tracepoint_probe_register(const char *name, void *probe) 331 int tracepoint_probe_register(const char *name, void *probe)
332 { 332 {
333 struct tracepoint_entry *entry; 333 struct tracepoint_entry *entry;
334 int ret = 0; 334 int ret = 0;
335 void *old; 335 void *old;
336 336
337 mutex_lock(&tracepoints_mutex); 337 mutex_lock(&tracepoints_mutex);
338 entry = get_tracepoint(name); 338 entry = get_tracepoint(name);
339 if (!entry) { 339 if (!entry) {
340 entry = add_tracepoint(name); 340 entry = add_tracepoint(name);
341 if (IS_ERR(entry)) { 341 if (IS_ERR(entry)) {
342 ret = PTR_ERR(entry); 342 ret = PTR_ERR(entry);
343 goto end; 343 goto end;
344 } 344 }
345 } 345 }
346 /* 346 /*
347 * If we detect that a call_rcu is pending for this tracepoint, 347 * If we detect that a call_rcu is pending for this tracepoint,
348 * make sure it's executed now. 348 * make sure it's executed now.
349 */ 349 */
350 if (entry->rcu_pending) 350 if (entry->rcu_pending)
351 rcu_barrier(); 351 rcu_barrier();
352 old = tracepoint_entry_add_probe(entry, probe); 352 old = tracepoint_entry_add_probe(entry, probe);
353 if (IS_ERR(old)) { 353 if (IS_ERR(old)) {
354 ret = PTR_ERR(old); 354 ret = PTR_ERR(old);
355 goto end; 355 goto end;
356 } 356 }
357 mutex_unlock(&tracepoints_mutex); 357 mutex_unlock(&tracepoints_mutex);
358 tracepoint_update_probes(); /* may update entry */ 358 tracepoint_update_probes(); /* may update entry */
359 mutex_lock(&tracepoints_mutex); 359 mutex_lock(&tracepoints_mutex);
360 entry = get_tracepoint(name); 360 entry = get_tracepoint(name);
361 WARN_ON(!entry); 361 WARN_ON(!entry);
362 tracepoint_entry_free_old(entry, old); 362 tracepoint_entry_free_old(entry, old);
363 end: 363 end:
364 mutex_unlock(&tracepoints_mutex); 364 mutex_unlock(&tracepoints_mutex);
365 return ret; 365 return ret;
366 } 366 }
367 EXPORT_SYMBOL_GPL(tracepoint_probe_register); 367 EXPORT_SYMBOL_GPL(tracepoint_probe_register);
368 368
369 /** 369 /**
370 * tracepoint_probe_unregister - Disconnect a probe from a tracepoint 370 * tracepoint_probe_unregister - Disconnect a probe from a tracepoint
371 * @name: tracepoint name 371 * @name: tracepoint name
372 * @probe: probe function pointer 372 * @probe: probe function pointer
373 * 373 *
374 * We do not need to call a synchronize_sched to make sure the probes have 374 * We do not need to call a synchronize_sched to make sure the probes have
375 * finished running before doing a module unload, because the module unload 375 * finished running before doing a module unload, because the module unload
376 * itself uses stop_machine(), which insures that every preempt disabled section 376 * itself uses stop_machine(), which insures that every preempt disabled section
377 * have finished. 377 * have finished.
378 */ 378 */
379 int tracepoint_probe_unregister(const char *name, void *probe) 379 int tracepoint_probe_unregister(const char *name, void *probe)
380 { 380 {
381 struct tracepoint_entry *entry; 381 struct tracepoint_entry *entry;
382 void *old; 382 void *old;
383 int ret = -ENOENT; 383 int ret = -ENOENT;
384 384
385 mutex_lock(&tracepoints_mutex); 385 mutex_lock(&tracepoints_mutex);
386 entry = get_tracepoint(name); 386 entry = get_tracepoint(name);
387 if (!entry) 387 if (!entry)
388 goto end; 388 goto end;
389 if (entry->rcu_pending) 389 if (entry->rcu_pending)
390 rcu_barrier(); 390 rcu_barrier();
391 old = tracepoint_entry_remove_probe(entry, probe); 391 old = tracepoint_entry_remove_probe(entry, probe);
392 mutex_unlock(&tracepoints_mutex); 392 mutex_unlock(&tracepoints_mutex);
393 tracepoint_update_probes(); /* may update entry */ 393 tracepoint_update_probes(); /* may update entry */
394 mutex_lock(&tracepoints_mutex); 394 mutex_lock(&tracepoints_mutex);
395 entry = get_tracepoint(name); 395 entry = get_tracepoint(name);
396 if (!entry) 396 if (!entry)
397 goto end; 397 goto end;
398 tracepoint_entry_free_old(entry, old); 398 tracepoint_entry_free_old(entry, old);
399 remove_tracepoint(name); /* Ignore busy error message */ 399 remove_tracepoint(name); /* Ignore busy error message */
400 ret = 0; 400 ret = 0;
401 end: 401 end:
402 mutex_unlock(&tracepoints_mutex); 402 mutex_unlock(&tracepoints_mutex);
403 return ret; 403 return ret;
404 } 404 }
405 EXPORT_SYMBOL_GPL(tracepoint_probe_unregister); 405 EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
406 406
407 /** 407 /**
408 * tracepoint_get_iter_range - Get a next tracepoint iterator given a range. 408 * tracepoint_get_iter_range - Get a next tracepoint iterator given a range.
409 * @tracepoint: current tracepoints (in), next tracepoint (out) 409 * @tracepoint: current tracepoints (in), next tracepoint (out)
410 * @begin: beginning of the range 410 * @begin: beginning of the range
411 * @end: end of the range 411 * @end: end of the range
412 * 412 *
413 * Returns whether a next tracepoint has been found (1) or not (0). 413 * Returns whether a next tracepoint has been found (1) or not (0).
414 * Will return the first tracepoint in the range if the input tracepoint is 414 * Will return the first tracepoint in the range if the input tracepoint is
415 * NULL. 415 * NULL.
416 */ 416 */
417 int tracepoint_get_iter_range(struct tracepoint **tracepoint, 417 int tracepoint_get_iter_range(struct tracepoint **tracepoint,
418 struct tracepoint *begin, struct tracepoint *end) 418 struct tracepoint *begin, struct tracepoint *end)
419 { 419 {
420 if (!*tracepoint && begin != end) { 420 if (!*tracepoint && begin != end) {
421 *tracepoint = begin; 421 *tracepoint = begin;
422 return 1; 422 return 1;
423 } 423 }
424 if (*tracepoint >= begin && *tracepoint < end) 424 if (*tracepoint >= begin && *tracepoint < end)
425 return 1; 425 return 1;
426 return 0; 426 return 0;
427 } 427 }
428 EXPORT_SYMBOL_GPL(tracepoint_get_iter_range); 428 EXPORT_SYMBOL_GPL(tracepoint_get_iter_range);
429 429
430 static void tracepoint_get_iter(struct tracepoint_iter *iter) 430 static void tracepoint_get_iter(struct tracepoint_iter *iter)
431 { 431 {
432 int found = 0; 432 int found = 0;
433 433
434 /* Core kernel tracepoints */ 434 /* Core kernel tracepoints */
435 if (!iter->module) { 435 if (!iter->module) {
436 found = tracepoint_get_iter_range(&iter->tracepoint, 436 found = tracepoint_get_iter_range(&iter->tracepoint,
437 __start___tracepoints, __stop___tracepoints); 437 __start___tracepoints, __stop___tracepoints);
438 if (found) 438 if (found)
439 goto end; 439 goto end;
440 } 440 }
441 /* tracepoints in modules. */ 441 /* tracepoints in modules. */
442 found = module_get_iter_tracepoints(iter); 442 found = module_get_iter_tracepoints(iter);
443 end: 443 end:
444 if (!found) 444 if (!found)
445 tracepoint_iter_reset(iter); 445 tracepoint_iter_reset(iter);
446 } 446 }
447 447
448 void tracepoint_iter_start(struct tracepoint_iter *iter) 448 void tracepoint_iter_start(struct tracepoint_iter *iter)
449 { 449 {
450 tracepoint_get_iter(iter); 450 tracepoint_get_iter(iter);
451 } 451 }
452 EXPORT_SYMBOL_GPL(tracepoint_iter_start); 452 EXPORT_SYMBOL_GPL(tracepoint_iter_start);
453 453
454 void tracepoint_iter_next(struct tracepoint_iter *iter) 454 void tracepoint_iter_next(struct tracepoint_iter *iter)
455 { 455 {
456 iter->tracepoint++; 456 iter->tracepoint++;
457 /* 457 /*
458 * iter->tracepoint may be invalid because we blindly incremented it. 458 * iter->tracepoint may be invalid because we blindly incremented it.
459 * Make sure it is valid by marshalling on the tracepoints, getting the 459 * Make sure it is valid by marshalling on the tracepoints, getting the
460 * tracepoints from following modules if necessary. 460 * tracepoints from following modules if necessary.
461 */ 461 */
462 tracepoint_get_iter(iter); 462 tracepoint_get_iter(iter);
463 } 463 }
464 EXPORT_SYMBOL_GPL(tracepoint_iter_next); 464 EXPORT_SYMBOL_GPL(tracepoint_iter_next);
465 465
466 void tracepoint_iter_stop(struct tracepoint_iter *iter) 466 void tracepoint_iter_stop(struct tracepoint_iter *iter)
467 { 467 {
468 } 468 }
469 EXPORT_SYMBOL_GPL(tracepoint_iter_stop); 469 EXPORT_SYMBOL_GPL(tracepoint_iter_stop);
470 470
471 void tracepoint_iter_reset(struct tracepoint_iter *iter) 471 void tracepoint_iter_reset(struct tracepoint_iter *iter)
472 { 472 {
473 iter->module = NULL; 473 iter->module = NULL;
474 iter->tracepoint = NULL; 474 iter->tracepoint = NULL;
475 } 475 }
476 EXPORT_SYMBOL_GPL(tracepoint_iter_reset); 476 EXPORT_SYMBOL_GPL(tracepoint_iter_reset);
477 477