libperf rc_check: Add RC_CHK_EQUAL

Comparing pointers with reference count checking is tricky to avoid a
SEGV. Add a convenience macro to simplify and use.

Signed-off-by: Ian Rogers <[e-mail]>
Cc: K Prateek Nayak <[e-mail]>
Cc: Ravi Bangoria <[e-mail]>
Cc: Sandipan Das <[e-mail]>
Cc: Anshuman Khandual <[e-mail]>
Cc: German Gomez <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Nick Terrell <[e-mail]>
Cc: Sean Christopherson <[e-mail]>
Cc: Changbin Du <[e-mail]>
Cc: liuwenyu <[e-mail]>
Cc: Yang Jihong <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Miguel Ojeda <[e-mail]>
Cc: Song Liu <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Athira Rajeev <[e-mail]>
Cc: Yanteng Si <[e-mail]>
Cc: Liam Howlett <[e-mail]>
Cc: Paolo Bonzini <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Namhyung Kim <[e-mail]>

tools/lib/perf/include/internal/rc_check.h

···
 /* A put operation removing the indirection layer. */
 #define RC_CHK_PUT(object) {}
 
+/* Pointer equality when the indirection may or may not be there. */
+#define RC_CHK_EQUAL(object1, object2) (object1 == object2)
+
 #else
 
 /* Replaces "struct foo" so that the pointer may be interposed. */
···
 			free(object);		\
 		}				\
 	} while(0)
+
+/* Pointer equality when the indirection may or may not be there. */
+#define RC_CHK_EQUAL(object1, object2) (object1 == object2 || \
+		(object1 && object2 && object1->orig == object2->orig))
 
 #endif
 

tools/perf/builtin-sched.c

···
 {
 	pid_t l_tid, r_tid;
 
-	if (RC_CHK_ACCESS(l->thread) == RC_CHK_ACCESS(r->thread))
+	if (RC_CHK_EQUAL(l->thread, r->thread))
 		return 0;
 	l_tid = thread__tid(l->thread);
 	r_tid = thread__tid(r->thread);

tools/perf/tests/hists_link.c

···
 		       struct thread *t, struct map *m, struct symbol *s)
 {
 	while (nr_samples--) {
-		if (RC_CHK_ACCESS(samples->thread) == RC_CHK_ACCESS(t) &&
-		    RC_CHK_ACCESS(samples->map) == RC_CHK_ACCESS(m) &&
+		if (RC_CHK_EQUAL(samples->thread, t) &&
+		    RC_CHK_EQUAL(samples->map, m) &&
 		    samples->sym == s)
 			return 1;
 		samples++;

tools/perf/tests/thread-maps-share.c

···
 	TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(maps)), 4);
 
 	/* test the maps pointer is shared */
-	TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(maps) == RC_CHK_ACCESS(thread__maps(t1)));
-	TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(maps) == RC_CHK_ACCESS(thread__maps(t2)));
-	TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(maps) == RC_CHK_ACCESS(thread__maps(t3)));
+	TEST_ASSERT_VAL("maps don't match", RC_CHK_EQUAL(maps, thread__maps(t1)));
+	TEST_ASSERT_VAL("maps don't match", RC_CHK_EQUAL(maps, thread__maps(t2)));
+	TEST_ASSERT_VAL("maps don't match", RC_CHK_EQUAL(maps, thread__maps(t3)));
 
 	/*
 	 * Verify the other leader was created by previous call.
···
 	other_maps = thread__maps(other);
 	TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(other_maps)), 2);
 
-	TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(other_maps) ==
-					    RC_CHK_ACCESS(thread__maps(other_leader)));
+	TEST_ASSERT_VAL("maps don't match", RC_CHK_EQUAL(other_maps, thread__maps(other_leader)));
 
 	/* release thread group */
 	thread__put(t3);

tools/perf/util/callchain.c

···
 		if (al->map == NULL)
 			goto out;
 	}
-	if (RC_CHK_ACCESS(al->maps) == RC_CHK_ACCESS(machine__kernel_maps(machine))) {
+	if (RC_CHK_EQUAL(al->maps, machine__kernel_maps(machine))) {
 		if (machine__is_host(machine)) {
 			al->cpumode = PERF_RECORD_MISC_KERNEL;
 			al->level = 'k';

tools/perf/util/hist.c

···
 					  struct hist_entry *he)
 {
 	if (hists->thread_filter != NULL &&
-	    RC_CHK_ACCESS(he->thread) != RC_CHK_ACCESS(hists->thread_filter)) {
+	    !RC_CHK_EQUAL(he->thread, hists->thread_filter)) {
 		he->filtered |= (1 << HIST_FILTER__THREAD);
 		return true;
 	}

tools/perf/util/machine.c

···
 	if (!map)
 		return 0;
 
-	if (RC_CHK_ACCESS(map) != RC_CHK_ACCESS(machine->vmlinux_map))
+	if (!RC_CHK_EQUAL(map, machine->vmlinux_map))
 		maps__remove(machine__kernel_maps(machine), map);
 	else {
 		struct dso *dso = map__dso(map);
···
 	if (!nd)
 		nd = thread_rb_node__find(th, &threads->entries.rb_root);
 
-	if (threads->last_match && RC_CHK_ACCESS(threads->last_match) == RC_CHK_ACCESS(th))
+	if (threads->last_match && RC_CHK_EQUAL(threads->last_match, th))
 		threads__set_last_match(threads, NULL);
 
 	if (lock)

tools/perf/util/sort.c

···
 	if (type != HIST_FILTER__THREAD)
 		return -1;
 
-	return th && RC_CHK_ACCESS(he->thread) != RC_CHK_ACCESS(th);
+	return th && !RC_CHK_EQUAL(he->thread, th);
 }
 
 struct sort_entry sort_thread = {

tools/perf/util/symbol.c

···
 			*module++ = '\0';
 			curr_map_dso = map__dso(curr_map);
 			if (strcmp(curr_map_dso->short_name, module)) {
-				if (RC_CHK_ACCESS(curr_map) != RC_CHK_ACCESS(initial_map) &&
+				if (!RC_CHK_EQUAL(curr_map, initial_map) &&
 				    dso->kernel == DSO_SPACE__KERNEL_GUEST &&
 				    machine__is_default_guest(machine)) {
 					/*
···
 
 		list_del_init(&new_node->node);
 
-		if (RC_CHK_ACCESS(new_map) == RC_CHK_ACCESS(replacement_map)) {
+		if (RC_CHK_EQUAL(new_map, replacement_map)) {
 			struct map *map_ref;
 
 			map__set_start(map, map__start(new_map));