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Commit e66c33d579ea566d10e8c8695a7168aae3e02992

Authored by Steven Rostedt (Red Hat)
Committed by Steven Rostedt
1 parent 102c9323c3
Exists in smarc-imx_3.14.28_1.0.0_ga and in 1 other branch imx_3.14.28_1.0.0_ga

rcu: Add const annotation to char * for RCU tracepoints and functions 

All the RCU tracepoints and functions that reference char pointers do
so with just 'char *' even though they do not modify the contents of
the string itself. This will cause warnings if a const char * is used
in one of these functions.

The RCU tracepoints store the pointer to the string to refer back to them
when the trace output is displayed. As this can be minutes, hours or
even days later, those strings had better be constant.

This change also opens the door to allow the RCU tracepoint strings and
their addresses to be exported so that userspace tracing tools can
translate the contents of the pointers of the RCU tracepoints.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Showing 9 changed files with 54 additions and 54 deletions Side-by-side Diff

include/linux/rcupdate.h
Diff comments   View file @ e66c33d
... ... @@ -52,7 +52,7 @@
52 52 #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
53 53 extern void rcutorture_record_test_transition(void);
54 54 extern void rcutorture_record_progress(unsigned long vernum);
55   -extern void do_trace_rcu_torture_read(char *rcutorturename,
  55 +extern void do_trace_rcu_torture_read(const char *rcutorturename,
56 56 struct rcu_head *rhp,
57 57 unsigned long secs,
58 58 unsigned long c_old,
... ... @@ -65,7 +65,7 @@
65 65 {
66 66 }
67 67 #ifdef CONFIG_RCU_TRACE
68   -extern void do_trace_rcu_torture_read(char *rcutorturename,
  68 +extern void do_trace_rcu_torture_read(const char *rcutorturename,
69 69 struct rcu_head *rhp,
70 70 unsigned long secs,
71 71 unsigned long c_old,
include/trace/events/rcu.h
Diff comments   View file @ e66c33d
... ... @@ -19,12 +19,12 @@
19 19 */
20 20 TRACE_EVENT(rcu_utilization,
21 21  
22   - TP_PROTO(char *s),
  22 + TP_PROTO(const char *s),
23 23  
24 24 TP_ARGS(s),
25 25  
26 26 TP_STRUCT__entry(
27   - __field(char *, s)
  27 + __field(const char *, s)
28 28 ),
29 29  
30 30 TP_fast_assign(
31 31  
32 32  
... ... @@ -51,14 +51,14 @@
51 51 */
52 52 TRACE_EVENT(rcu_grace_period,
53 53  
54   - TP_PROTO(char *rcuname, unsigned long gpnum, char *gpevent),
  54 + TP_PROTO(const char *rcuname, unsigned long gpnum, const char *gpevent),
55 55  
56 56 TP_ARGS(rcuname, gpnum, gpevent),
57 57  
58 58 TP_STRUCT__entry(
59   - __field(char *, rcuname)
  59 + __field(const char *, rcuname)
60 60 __field(unsigned long, gpnum)
61   - __field(char *, gpevent)
  61 + __field(const char *, gpevent)
62 62 ),
63 63  
64 64 TP_fast_assign(
65 65  
66 66  
67 67  
... ... @@ -89,21 +89,21 @@
89 89 */
90 90 TRACE_EVENT(rcu_future_grace_period,
91 91  
92   - TP_PROTO(char *rcuname, unsigned long gpnum, unsigned long completed,
  92 + TP_PROTO(const char *rcuname, unsigned long gpnum, unsigned long completed,
93 93 unsigned long c, u8 level, int grplo, int grphi,
94   - char *gpevent),
  94 + const char *gpevent),
95 95  
96 96 TP_ARGS(rcuname, gpnum, completed, c, level, grplo, grphi, gpevent),
97 97  
98 98 TP_STRUCT__entry(
99   - __field(char *, rcuname)
  99 + __field(const char *, rcuname)
100 100 __field(unsigned long, gpnum)
101 101 __field(unsigned long, completed)
102 102 __field(unsigned long, c)
103 103 __field(u8, level)
104 104 __field(int, grplo)
105 105 __field(int, grphi)
106   - __field(char *, gpevent)
  106 + __field(const char *, gpevent)
107 107 ),
108 108  
109 109 TP_fast_assign(
110 110  
... ... @@ -132,13 +132,13 @@
132 132 */
133 133 TRACE_EVENT(rcu_grace_period_init,
134 134  
135   - TP_PROTO(char *rcuname, unsigned long gpnum, u8 level,
  135 + TP_PROTO(const char *rcuname, unsigned long gpnum, u8 level,
136 136 int grplo, int grphi, unsigned long qsmask),
137 137  
138 138 TP_ARGS(rcuname, gpnum, level, grplo, grphi, qsmask),
139 139  
140 140 TP_STRUCT__entry(
141   - __field(char *, rcuname)
  141 + __field(const char *, rcuname)
142 142 __field(unsigned long, gpnum)
143 143 __field(u8, level)
144 144 __field(int, grplo)
145 145  
... ... @@ -168,12 +168,12 @@
168 168 */
169 169 TRACE_EVENT(rcu_preempt_task,
170 170  
171   - TP_PROTO(char *rcuname, int pid, unsigned long gpnum),
  171 + TP_PROTO(const char *rcuname, int pid, unsigned long gpnum),
172 172  
173 173 TP_ARGS(rcuname, pid, gpnum),
174 174  
175 175 TP_STRUCT__entry(
176   - __field(char *, rcuname)
  176 + __field(const char *, rcuname)
177 177 __field(unsigned long, gpnum)
178 178 __field(int, pid)
179 179 ),
180 180  
... ... @@ -195,12 +195,12 @@
195 195 */
196 196 TRACE_EVENT(rcu_unlock_preempted_task,
197 197  
198   - TP_PROTO(char *rcuname, unsigned long gpnum, int pid),
  198 + TP_PROTO(const char *rcuname, unsigned long gpnum, int pid),
199 199  
200 200 TP_ARGS(rcuname, gpnum, pid),
201 201  
202 202 TP_STRUCT__entry(
203   - __field(char *, rcuname)
  203 + __field(const char *, rcuname)
204 204 __field(unsigned long, gpnum)
205 205 __field(int, pid)
206 206 ),
207 207  
... ... @@ -224,14 +224,14 @@
224 224 */
225 225 TRACE_EVENT(rcu_quiescent_state_report,
226 226  
227   - TP_PROTO(char *rcuname, unsigned long gpnum,
  227 + TP_PROTO(const char *rcuname, unsigned long gpnum,
228 228 unsigned long mask, unsigned long qsmask,
229 229 u8 level, int grplo, int grphi, int gp_tasks),
230 230  
231 231 TP_ARGS(rcuname, gpnum, mask, qsmask, level, grplo, grphi, gp_tasks),
232 232  
233 233 TP_STRUCT__entry(
234   - __field(char *, rcuname)
  234 + __field(const char *, rcuname)
235 235 __field(unsigned long, gpnum)
236 236 __field(unsigned long, mask)
237 237 __field(unsigned long, qsmask)
238 238  
239 239  
... ... @@ -268,15 +268,15 @@
268 268 */
269 269 TRACE_EVENT(rcu_fqs,
270 270  
271   - TP_PROTO(char *rcuname, unsigned long gpnum, int cpu, char *qsevent),
  271 + TP_PROTO(const char *rcuname, unsigned long gpnum, int cpu, const char *qsevent),
272 272  
273 273 TP_ARGS(rcuname, gpnum, cpu, qsevent),
274 274  
275 275 TP_STRUCT__entry(
276   - __field(char *, rcuname)
  276 + __field(const char *, rcuname)
277 277 __field(unsigned long, gpnum)
278 278 __field(int, cpu)
279   - __field(char *, qsevent)
  279 + __field(const char *, qsevent)
280 280 ),
281 281  
282 282 TP_fast_assign(
283 283  
... ... @@ -308,12 +308,12 @@
308 308 */
309 309 TRACE_EVENT(rcu_dyntick,
310 310  
311   - TP_PROTO(char *polarity, long long oldnesting, long long newnesting),
  311 + TP_PROTO(const char *polarity, long long oldnesting, long long newnesting),
312 312  
313 313 TP_ARGS(polarity, oldnesting, newnesting),
314 314  
315 315 TP_STRUCT__entry(
316   - __field(char *, polarity)
  316 + __field(const char *, polarity)
317 317 __field(long long, oldnesting)
318 318 __field(long long, newnesting)
319 319 ),
320 320  
... ... @@ -352,12 +352,12 @@
352 352 */
353 353 TRACE_EVENT(rcu_prep_idle,
354 354  
355   - TP_PROTO(char *reason),
  355 + TP_PROTO(const char *reason),
356 356  
357 357 TP_ARGS(reason),
358 358  
359 359 TP_STRUCT__entry(
360   - __field(char *, reason)
  360 + __field(const char *, reason)
361 361 ),
362 362  
363 363 TP_fast_assign(
364 364  
... ... @@ -376,13 +376,13 @@
376 376 */
377 377 TRACE_EVENT(rcu_callback,
378 378  
379   - TP_PROTO(char *rcuname, struct rcu_head *rhp, long qlen_lazy,
  379 + TP_PROTO(const char *rcuname, struct rcu_head *rhp, long qlen_lazy,
380 380 long qlen),
381 381  
382 382 TP_ARGS(rcuname, rhp, qlen_lazy, qlen),
383 383  
384 384 TP_STRUCT__entry(
385   - __field(char *, rcuname)
  385 + __field(const char *, rcuname)
386 386 __field(void *, rhp)
387 387 __field(void *, func)
388 388 __field(long, qlen_lazy)
389 389  
... ... @@ -412,13 +412,13 @@
412 412 */
413 413 TRACE_EVENT(rcu_kfree_callback,
414 414  
415   - TP_PROTO(char *rcuname, struct rcu_head *rhp, unsigned long offset,
  415 + TP_PROTO(const char *rcuname, struct rcu_head *rhp, unsigned long offset,
416 416 long qlen_lazy, long qlen),
417 417  
418 418 TP_ARGS(rcuname, rhp, offset, qlen_lazy, qlen),
419 419  
420 420 TP_STRUCT__entry(
421   - __field(char *, rcuname)
  421 + __field(const char *, rcuname)
422 422 __field(void *, rhp)
423 423 __field(unsigned long, offset)
424 424 __field(long, qlen_lazy)
425 425  
... ... @@ -447,12 +447,12 @@
447 447 */
448 448 TRACE_EVENT(rcu_batch_start,
449 449  
450   - TP_PROTO(char *rcuname, long qlen_lazy, long qlen, long blimit),
  450 + TP_PROTO(const char *rcuname, long qlen_lazy, long qlen, long blimit),
451 451  
452 452 TP_ARGS(rcuname, qlen_lazy, qlen, blimit),
453 453  
454 454 TP_STRUCT__entry(
455   - __field(char *, rcuname)
  455 + __field(const char *, rcuname)
456 456 __field(long, qlen_lazy)
457 457 __field(long, qlen)
458 458 __field(long, blimit)
459 459  
... ... @@ -477,12 +477,12 @@
477 477 */
478 478 TRACE_EVENT(rcu_invoke_callback,
479 479  
480   - TP_PROTO(char *rcuname, struct rcu_head *rhp),
  480 + TP_PROTO(const char *rcuname, struct rcu_head *rhp),
481 481  
482 482 TP_ARGS(rcuname, rhp),
483 483  
484 484 TP_STRUCT__entry(
485   - __field(char *, rcuname)
  485 + __field(const char *, rcuname)
486 486 __field(void *, rhp)
487 487 __field(void *, func)
488 488 ),
489 489  
... ... @@ -506,12 +506,12 @@
506 506 */
507 507 TRACE_EVENT(rcu_invoke_kfree_callback,
508 508  
509   - TP_PROTO(char *rcuname, struct rcu_head *rhp, unsigned long offset),
  509 + TP_PROTO(const char *rcuname, struct rcu_head *rhp, unsigned long offset),
510 510  
511 511 TP_ARGS(rcuname, rhp, offset),
512 512  
513 513 TP_STRUCT__entry(
514   - __field(char *, rcuname)
  514 + __field(const char *, rcuname)
515 515 __field(void *, rhp)
516 516 __field(unsigned long, offset)
517 517 ),
518 518  
... ... @@ -539,13 +539,13 @@
539 539 */
540 540 TRACE_EVENT(rcu_batch_end,
541 541  
542   - TP_PROTO(char *rcuname, int callbacks_invoked,
  542 + TP_PROTO(const char *rcuname, int callbacks_invoked,
543 543 bool cb, bool nr, bool iit, bool risk),
544 544  
545 545 TP_ARGS(rcuname, callbacks_invoked, cb, nr, iit, risk),
546 546  
547 547 TP_STRUCT__entry(
548   - __field(char *, rcuname)
  548 + __field(const char *, rcuname)
549 549 __field(int, callbacks_invoked)
550 550 __field(bool, cb)
551 551 __field(bool, nr)
552 552  
... ... @@ -577,13 +577,13 @@
577 577 */
578 578 TRACE_EVENT(rcu_torture_read,
579 579  
580   - TP_PROTO(char *rcutorturename, struct rcu_head *rhp,
  580 + TP_PROTO(const char *rcutorturename, struct rcu_head *rhp,
581 581 unsigned long secs, unsigned long c_old, unsigned long c),
582 582  
583 583 TP_ARGS(rcutorturename, rhp, secs, c_old, c),
584 584  
585 585 TP_STRUCT__entry(
586   - __field(char *, rcutorturename)
  586 + __field(const char *, rcutorturename)
587 587 __field(struct rcu_head *, rhp)
588 588 __field(unsigned long, secs)
589 589 __field(unsigned long, c_old)
590 590  
... ... @@ -623,13 +623,13 @@
623 623 */
624 624 TRACE_EVENT(rcu_barrier,
625 625  
626   - TP_PROTO(char *rcuname, char *s, int cpu, int cnt, unsigned long done),
  626 + TP_PROTO(const char *rcuname, const char *s, int cpu, int cnt, unsigned long done),
627 627  
628 628 TP_ARGS(rcuname, s, cpu, cnt, done),
629 629  
630 630 TP_STRUCT__entry(
631   - __field(char *, rcuname)
632   - __field(char *, s)
  631 + __field(const char *, rcuname)
  632 + __field(const char *, s)
633 633 __field(int, cpu)
634 634 __field(int, cnt)
635 635 __field(unsigned long, done)
... ... @@ -94,7 +94,7 @@
94 94  
95 95 extern void kfree(const void *);
96 96  
97   -static inline bool __rcu_reclaim(char *rn, struct rcu_head *head)
  97 +static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
98 98 {
99 99 unsigned long offset = (unsigned long)head->func;
100 100  
... ... @@ -377,7 +377,7 @@
377 377 #endif /* #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD */
378 378  
379 379 #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU) || defined(CONFIG_RCU_TRACE)
380   -void do_trace_rcu_torture_read(char *rcutorturename, struct rcu_head *rhp,
  380 +void do_trace_rcu_torture_read(const char *rcutorturename, struct rcu_head *rhp,
381 381 unsigned long secs,
382 382 unsigned long c_old, unsigned long c)
383 383 {
... ... @@ -264,7 +264,7 @@
264 264 */
265 265 static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
266 266 {
267   - char *rn = NULL;
  267 + const char *rn = NULL;
268 268 struct rcu_head *next, *list;
269 269 unsigned long flags;
270 270 RCU_TRACE(int cb_count = 0);
kernel/rcutiny_plugin.h
Diff comments   View file @ e66c33d
... ... @@ -36,7 +36,7 @@
36 36 RCU_TRACE(unsigned long gp_start); /* Start time for stalls. */
37 37 RCU_TRACE(unsigned long ticks_this_gp); /* Statistic for stalls. */
38 38 RCU_TRACE(unsigned long jiffies_stall); /* Jiffies at next stall. */
39   - RCU_TRACE(char *name); /* Name of RCU type. */
  39 + RCU_TRACE(const char *name); /* Name of RCU type. */
40 40 };
41 41  
42 42 /* Definition for rcupdate control block. */
... ... @@ -267,7 +267,7 @@
267 267 * Absorb kthreads into a kernel function that won't return, so that
268 268 * they won't ever access module text or data again.
269 269 */
270   -static void rcutorture_shutdown_absorb(char *title)
  270 +static void rcutorture_shutdown_absorb(const char *title)
271 271 {
272 272 if (ACCESS_ONCE(fullstop) == FULLSTOP_SHUTDOWN) {
273 273 pr_notice(
... ... @@ -337,7 +337,7 @@
337 337 }
338 338  
339 339 static void
340   -rcu_stutter_wait(char *title)
  340 +rcu_stutter_wait(const char *title)
341 341 {
342 342 while (stutter_pause_test || !rcutorture_runnable) {
343 343 if (rcutorture_runnable)
... ... @@ -366,7 +366,7 @@
366 366 int (*stats)(char *page);
367 367 int irq_capable;
368 368 int can_boost;
369   - char *name;
  369 + const char *name;
370 370 };
371 371  
372 372 static struct rcu_torture_ops *cur_ops;
... ... @@ -1364,7 +1364,7 @@
1364 1364 }
1365 1365  
1366 1366 static inline void
1367   -rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, char *tag)
  1367 +rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
1368 1368 {
1369 1369 pr_alert("%s" TORTURE_FLAG
1370 1370 "--- %s: nreaders=%d nfakewriters=%d "
... ... @@ -1032,7 +1032,7 @@
1032 1032 * rcu_nocb_wait_gp().
1033 1033 */
1034 1034 static void trace_rcu_future_gp(struct rcu_node *rnp, struct rcu_data *rdp,
1035   - unsigned long c, char *s)
  1035 + unsigned long c, const char *s)
1036 1036 {
1037 1037 trace_rcu_future_grace_period(rdp->rsp->name, rnp->gpnum,
1038 1038 rnp->completed, c, rnp->level,
... ... @@ -2720,7 +2720,7 @@
2720 2720 * Helper function for _rcu_barrier() tracing. If tracing is disabled,
2721 2721 * the compiler is expected to optimize this away.
2722 2722 */
2723   -static void _rcu_barrier_trace(struct rcu_state *rsp, char *s,
  2723 +static void _rcu_barrier_trace(struct rcu_state *rsp, const char *s,
2724 2724 int cpu, unsigned long done)
2725 2725 {
2726 2726 trace_rcu_barrier(rsp->name, s, cpu,
... ... @@ -445,7 +445,7 @@
445 445 /* for CPU stalls. */
446 446 unsigned long gp_max; /* Maximum GP duration in */
447 447 /* jiffies. */
448   - char *name; /* Name of structure. */
  448 + const char *name; /* Name of structure. */
449 449 char abbr; /* Abbreviated name. */
450 450 struct list_head flavors; /* List of RCU flavors. */
451 451 struct irq_work wakeup_work; /* Postponed wakeups */