perf maps: Use a pointer for kmaps

struct maps is reference counted, using a pointer is more idiomatic.

Committer notes:

Delay:

   maps = machine__kernel_maps(&vmlinux);

To after:

  machine__init(&vmlinux, "", HOST_KERNEL_ID);

To avoid this on f34:

  In file included from /var/home/acme/git/perf/tools/perf/util/build-id.h:10,
                   from /var/home/acme/git/perf/tools/perf/util/dso.h:13,
                   from tests/vmlinux-kallsyms.c:8:
  In function ‘machine__kernel_maps’,
      inlined from ‘test__vmlinux_matches_kallsyms’ at tests/vmlinux-kallsyms.c:122:22:
  /var/home/acme/git/perf/tools/perf/util/machine.h:86:23: error: ‘vmlinux.kmaps’ is used uninitialized [-Werror=uninitialized]
     86 |         return machine->kmaps;
        |                ~~~~~~~^~~~~~~
  tests/vmlinux-kallsyms.c: In function ‘test__vmlinux_matches_kallsyms’:
  tests/vmlinux-kallsyms.c:121:34: note: ‘vmlinux’ declared here
    121 |         struct machine kallsyms, vmlinux;
        |                                  ^~~~~~~
  cc1: all warnings being treated as errors

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: André Almeida <andrealmeid@collabora.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Hao Luo <haoluo@google.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Miaoqian Lin <linmq006@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Cc: Song Liu <song@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Yury Norov <yury.norov@gmail.com>
Link: http://lore.kernel.org/lkml/20220211103415.2737789-6-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/arch/x86/util/event.c

@@ -18,7 +18,7 @@ int perf_event__synthesize_extra_kmaps(struct perf_tool *tool,
 {
 	int rc = 0;
 	struct map *pos;
-	struct maps *kmaps = &machine->kmaps;
+	struct maps *kmaps = machine__kernel_maps(machine);
 	union perf_event *event = zalloc(sizeof(event->mmap) +
 					 machine->id_hdr_size);
 

tools/perf/tests/vmlinux-kallsyms.c

@@ -119,7 +119,7 @@ static int test__vmlinux_matches_kallsyms(struct test_suite *test __maybe_unused
 	struct symbol *sym;
 	struct map *kallsyms_map, *vmlinux_map, *map;
 	struct machine kallsyms, vmlinux;
-	struct maps *maps = machine__kernel_maps(&vmlinux);
+	struct maps *maps;
 	u64 mem_start, mem_end;
 	bool header_printed;
 
@@ -132,6 +132,8 @@ static int test__vmlinux_matches_kallsyms(struct test_suite *test __maybe_unused
 	machine__init(&kallsyms, "", HOST_KERNEL_ID);
 	machine__init(&vmlinux, "", HOST_KERNEL_ID);
 
+	maps = machine__kernel_maps(&vmlinux);
+
 	/*
 	 * Step 2:
 	 *
@@ -293,7 +295,7 @@ next_pair:
 		 * so use the short name, less descriptive but the same ("[kernel]" in
 		 * both cases.
 		 */
-		pair = maps__find_by_name(&kallsyms.kmaps, (map->dso->kernel ?
+		pair = maps__find_by_name(kallsyms.kmaps, (map->dso->kernel ?
 								map->dso->short_name :
 								map->dso->name));
 		if (pair) {
@@ -315,7 +317,7 @@ next_pair:
 		mem_start = vmlinux_map->unmap_ip(vmlinux_map, map->start);
 		mem_end = vmlinux_map->unmap_ip(vmlinux_map, map->end);
 
-		pair = maps__find(&kallsyms.kmaps, mem_start);
+		pair = maps__find(kallsyms.kmaps, mem_start);
 		if (pair == NULL || pair->priv)
 			continue;
 

tools/perf/util/bpf-event.c

@@ -105,7 +105,7 @@ static int machine__process_bpf_event_load(struct machine *machine,
 	for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
 		u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
 		u64 addr = addrs[i];
-		struct map *map = maps__find(&machine->kmaps, addr);
+		struct map *map = maps__find(machine__kernel_maps(machine), addr);
 
 		if (map) {
 			map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;

tools/perf/util/callchain.c

@@ -1119,7 +1119,7 @@ int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *
 			goto out;
 	}
 
-	if (al->maps == &al->maps->machine->kmaps) {
+	if (al->maps == machine__kernel_maps(al->maps->machine)) {
 		if (machine__is_host(al->maps->machine)) {
 			al->cpumode = PERF_RECORD_MISC_KERNEL;
 			al->level = 'k';

tools/perf/util/event.c

@@ -484,7 +484,7 @@ size_t perf_event__fprintf_text_poke(union perf_event *event, struct machine *ma
 	if (machine) {
 		struct addr_location al;
 
-		al.map = maps__find(&machine->kmaps, tp->addr);
+		al.map = maps__find(machine__kernel_maps(machine), tp->addr);
 		if (al.map && map__load(al.map) >= 0) {
 			al.addr = al.map->map_ip(al.map, tp->addr);
 			al.sym = map__find_symbol(al.map, al.addr);
@@ -587,13 +587,13 @@ struct map *thread__find_map(struct thread *thread, u8 cpumode, u64 addr,
 
 	if (cpumode == PERF_RECORD_MISC_KERNEL && perf_host) {
 		al->level = 'k';
-		al->maps = maps = &machine->kmaps;
+		al->maps = maps = machine__kernel_maps(machine);
 		load_map = true;
 	} else if (cpumode == PERF_RECORD_MISC_USER && perf_host) {
 		al->level = '.';
 	} else if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL && perf_guest) {
 		al->level = 'g';
-		al->maps = maps = &machine->kmaps;
+		al->maps = maps = machine__kernel_maps(machine);
 		load_map = true;
 	} else if (cpumode == PERF_RECORD_MISC_GUEST_USER && perf_guest) {
 		al->level = 'u';

tools/perf/util/machine.c

@@ -89,7 +89,10 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
 	int err = -ENOMEM;
 
 	memset(machine, 0, sizeof(*machine));
-	maps__init(&machine->kmaps, machine);
+	machine->kmaps = maps__new(machine);
+	if (machine->kmaps == NULL)
+		return -ENOMEM;
+
 	RB_CLEAR_NODE(&machine->rb_node);
 	dsos__init(&machine->dsos);
 
@@ -108,7 +111,7 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
 
 	machine->root_dir = strdup(root_dir);
 	if (machine->root_dir == NULL)
-		return -ENOMEM;
+		goto out;
 
 	if (machine__set_mmap_name(machine))
 		goto out;
@@ -131,6 +134,7 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
 
 out:
 	if (err) {
+		zfree(&machine->kmaps);
 		zfree(&machine->root_dir);
 		zfree(&machine->mmap_name);
 	}
@@ -220,7 +224,7 @@ void machine__exit(struct machine *machine)
 		return;
 
 	machine__destroy_kernel_maps(machine);
-	maps__exit(&machine->kmaps);
+	maps__delete(machine->kmaps);
 	dsos__exit(&machine->dsos);
 	machine__exit_vdso(machine);
 	zfree(&machine->root_dir);
@@ -778,7 +782,7 @@ static int machine__process_ksymbol_register(struct machine *machine,
 					     struct perf_sample *sample __maybe_unused)
 {
 	struct symbol *sym;
-	struct map *map = maps__find(&machine->kmaps, event->ksymbol.addr);
+	struct map *map = maps__find(machine__kernel_maps(machine), event->ksymbol.addr);
 
 	if (!map) {
 		struct dso *dso = dso__new(event->ksymbol.name);
@@ -801,7 +805,7 @@ static int machine__process_ksymbol_register(struct machine *machine,
 
 		map->start = event->ksymbol.addr;
 		map->end = map->start + event->ksymbol.len;
-		maps__insert(&machine->kmaps, map);
+		maps__insert(machine__kernel_maps(machine), map);
 		map__put(map);
 		dso__set_loaded(dso);
 
@@ -827,12 +831,12 @@ static int machine__process_ksymbol_unregister(struct machine *machine,
 	struct symbol *sym;
 	struct map *map;
 
-	map = maps__find(&machine->kmaps, event->ksymbol.addr);
+	map = maps__find(machine__kernel_maps(machine), event->ksymbol.addr);
 	if (!map)
 		return 0;
 
 	if (map != machine->vmlinux_map)
-		maps__remove(&machine->kmaps, map);
+		maps__remove(machine__kernel_maps(machine), map);
 	else {
 		sym = dso__find_symbol(map->dso, map->map_ip(map, map->start));
 		if (sym)
@@ -858,7 +862,7 @@ int machine__process_ksymbol(struct machine *machine __maybe_unused,
 int machine__process_text_poke(struct machine *machine, union perf_event *event,
 			       struct perf_sample *sample __maybe_unused)
 {
-	struct map *map = maps__find(&machine->kmaps, event->text_poke.addr);
+	struct map *map = maps__find(machine__kernel_maps(machine), event->text_poke.addr);
 	u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
 
 	if (dump_trace)
@@ -914,7 +918,7 @@ static struct map *machine__addnew_module_map(struct machine *machine, u64 start
 	if (map == NULL)
 		goto out;
 
-	maps__insert(&machine->kmaps, map);
+	maps__insert(machine__kernel_maps(machine), map);
 
 	/* Put the map here because maps__insert already got it */
 	map__put(map);
@@ -1100,7 +1104,7 @@ int machine__create_extra_kernel_map(struct machine *machine,
 
 	strlcpy(kmap->name, xm->name, KMAP_NAME_LEN);
 
-	maps__insert(&machine->kmaps, map);
+	maps__insert(machine__kernel_maps(machine), map);
 
 	pr_debug2("Added extra kernel map %s %" PRIx64 "-%" PRIx64 "\n",
 		  kmap->name, map->start, map->end);
@@ -1145,7 +1149,7 @@ static u64 find_entry_trampoline(struct dso *dso)
 int machine__map_x86_64_entry_trampolines(struct machine *machine,
 					  struct dso *kernel)
 {
-	struct maps *kmaps = &machine->kmaps;
+	struct maps *kmaps = machine__kernel_maps(machine);
 	int nr_cpus_avail, cpu;
 	bool found = false;
 	struct map *map;
@@ -1215,7 +1219,7 @@ __machine__create_kernel_maps(struct machine *machine, struct dso *kernel)
 		return -1;
 
 	machine->vmlinux_map->map_ip = machine->vmlinux_map->unmap_ip = identity__map_ip;
-	maps__insert(&machine->kmaps, machine->vmlinux_map);
+	maps__insert(machine__kernel_maps(machine), machine->vmlinux_map);
 	return 0;
 }
 
@@ -1228,7 +1232,7 @@ void machine__destroy_kernel_maps(struct machine *machine)
 		return;
 
 	kmap = map__kmap(map);
-	maps__remove(&machine->kmaps, map);
+	maps__remove(machine__kernel_maps(machine), map);
 	if (kmap && kmap->ref_reloc_sym) {
 		zfree((char **)&kmap->ref_reloc_sym->name);
 		zfree(&kmap->ref_reloc_sym);
@@ -1323,7 +1327,7 @@ int machine__load_kallsyms(struct machine *machine, const char *filename)
 		 * kernel, with modules between them, fixup the end of all
 		 * sections.
 		 */
-		maps__fixup_end(&machine->kmaps);
+		maps__fixup_end(machine__kernel_maps(machine));
 	}
 
 	return ret;
@@ -1471,7 +1475,7 @@ static int machine__set_modules_path(struct machine *machine)
 		 machine->root_dir, version);
 	free(version);
 
-	return maps__set_modules_path_dir(&machine->kmaps, modules_path, 0);
+	return maps__set_modules_path_dir(machine__kernel_maps(machine), modules_path, 0);
 }
 int __weak arch__fix_module_text_start(u64 *start __maybe_unused,
 				u64 *size __maybe_unused,
@@ -1544,11 +1548,11 @@ static void machine__update_kernel_mmap(struct machine *machine,
 	struct map *map = machine__kernel_map(machine);
 
 	map__get(map);
-	maps__remove(&machine->kmaps, map);
+	maps__remove(machine__kernel_maps(machine), map);
 
 	machine__set_kernel_mmap(machine, start, end);
 
-	maps__insert(&machine->kmaps, map);
+	maps__insert(machine__kernel_maps(machine), map);
 	map__put(map);
 }
 

tools/perf/util/machine.h

@@ -51,7 +51,7 @@ struct machine {
 	struct vdso_info  *vdso_info;
 	struct perf_env   *env;
 	struct dsos	  dsos;
-	struct maps	  kmaps;
+	struct maps	  *kmaps;
 	struct map	  *vmlinux_map;
 	u64		  kernel_start;
 	pid_t		  *current_tid;
@@ -83,7 +83,7 @@ struct map *machine__kernel_map(struct machine *machine)
 static inline
 struct maps *machine__kernel_maps(struct machine *machine)
 {
-	return &machine->kmaps;
+	return machine->kmaps;
 }
 
 int machine__get_kernel_start(struct machine *machine);
@@ -223,7 +223,7 @@ static inline
 struct symbol *machine__find_kernel_symbol(struct machine *machine, u64 addr,
 					   struct map **mapp)
 {
-	return maps__find_symbol(&machine->kmaps, addr, mapp);
+	return maps__find_symbol(machine->kmaps, addr, mapp);
 }
 
 static inline
@@ -231,7 +231,7 @@ struct symbol *machine__find_kernel_symbol_by_name(struct machine *machine,
 						   const char *name,
 						   struct map **mapp)
 {
-	return maps__find_symbol_by_name(&machine->kmaps, name, mapp);
+	return maps__find_symbol_by_name(machine->kmaps, name, mapp);
 }
 
 int arch__fix_module_text_start(u64 *start, u64 *size, const char *name);

tools/perf/util/probe-event.c

@@ -332,7 +332,7 @@ static int kernel_get_module_dso(const char *module, struct dso **pdso)
 		char module_name[128];
 
 		snprintf(module_name, sizeof(module_name), "[%s]", module);
-		map = maps__find_by_name(&host_machine->kmaps, module_name);
+		map = maps__find_by_name(machine__kernel_maps(host_machine), module_name);
 		if (map) {
 			dso = map->dso;
 			goto found;