perf lock: Rename fields in lock_type_table

`lock_type_table` contains `name` and `str` which can be confusing.
Rename them to `flags_name` and `lock_name` and add descriptions to
enhance understanding.
Tested by building perf for x86.

Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Chun-Tse Shao <ctshao@google.com>
Cc: nick.forrington@arm.com
Link: https://lore.kernel.org/r/20250116235838.2769691-3-ctshao@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

tools/perf/builtin-lock.c

@@ -1468,8 +1468,13 @@ static void sort_result(void)
 
 static const struct {
 	unsigned int flags;
-	const char *str;
-	const char *name;
+	/*
+	 * Name of the lock flags (access), with delimeter ':'.
+	 * For example, rwsem:R of rwsem:W.
+	 */
+	const char *flags_name;
+	/* Name of the lock (type), for example, rwlock or rwsem. */
+	const char *lock_name;
 } lock_type_table[] = {
 	{ 0,				"semaphore",	"semaphore" },
 	{ LCB_F_SPIN,			"spinlock",	"spinlock" },
@@ -1488,24 +1493,24 @@ static const struct {
 	{ LCB_F_MUTEX | LCB_F_SPIN,	"mutex:spin",	"mutex-spin" },
 };
 
-static const char *get_type_str(unsigned int flags)
+static const char *get_type_flags_name(unsigned int flags)
 {
 	flags &= LCB_F_TYPE_MASK;
 
 	for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
 		if (lock_type_table[i].flags == flags)
-			return lock_type_table[i].str;
+			return lock_type_table[i].flags_name;
 	}
 	return "unknown";
 }
 
-static const char *get_type_name(unsigned int flags)
+static const char *get_type_lock_name(unsigned int flags)
 {
 	flags &= LCB_F_TYPE_MASK;
 
 	for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
 		if (lock_type_table[i].flags == flags)
-			return lock_type_table[i].name;
+			return lock_type_table[i].lock_name;
 	}
 	return "unknown";
 }
@@ -1618,7 +1623,7 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
 
 	switch (aggr_mode) {
 	case LOCK_AGGR_CALLER:
-		fprintf(lock_output, "  %10s   %s\n", get_type_str(st->flags), st->name);
+		fprintf(lock_output, "  %10s   %s\n", get_type_flags_name(st->flags), st->name);
 		break;
 	case LOCK_AGGR_TASK:
 		pid = st->addr;
@@ -1628,7 +1633,7 @@ static void print_lock_stat_stdio(struct lock_contention *con, struct lock_stat
 		break;
 	case LOCK_AGGR_ADDR:
 		fprintf(lock_output, "  %016llx   %s (%s)\n", (unsigned long long)st->addr,
-			st->name, get_type_name(st->flags));
+			st->name, get_type_lock_name(st->flags));
 		break;
 	case LOCK_AGGR_CGROUP:
 		fprintf(lock_output, "  %s\n", st->name);
@@ -1669,7 +1674,7 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
 
 	switch (aggr_mode) {
 	case LOCK_AGGR_CALLER:
-		fprintf(lock_output, "%s%s %s", get_type_str(st->flags), sep, st->name);
+		fprintf(lock_output, "%s%s %s", get_type_flags_name(st->flags), sep, st->name);
 		if (verbose <= 0)
 			fprintf(lock_output, "\n");
 		break;
@@ -1681,7 +1686,7 @@ static void print_lock_stat_csv(struct lock_contention *con, struct lock_stat *s
 		break;
 	case LOCK_AGGR_ADDR:
 		fprintf(lock_output, "%llx%s %s%s %s\n", (unsigned long long)st->addr, sep,
-			st->name, sep, get_type_name(st->flags));
+			st->name, sep, get_type_lock_name(st->flags));
 		break;
 	case LOCK_AGGR_CGROUP:
 		fprintf(lock_output, "%s\n",st->name);
@@ -2249,10 +2254,10 @@ static int parse_lock_type(const struct option *opt __maybe_unused, const char *
 	for (tok = strtok_r(s, ", ", &tmp); tok; tok = strtok_r(NULL, ", ", &tmp)) {
 		bool found = false;
 
-		/* `tok` is `str` in `lock_type_table` if it contains ':'. */
+		/* `tok` is a flags name if it contains ':'. */
 		if (strchr(tok, ':')) {
 			for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
-				if (!strcmp(lock_type_table[i].str, tok) &&
+				if (!strcmp(lock_type_table[i].flags_name, tok) &&
 				    add_lock_type(lock_type_table[i].flags)) {
 					found = true;
 					break;
@@ -2269,14 +2274,14 @@ static int parse_lock_type(const struct option *opt __maybe_unused, const char *
 		}
 
 		/*
-		 * Otherwise `tok` is `name` in `lock_type_table`.
+		 * Otherwise `tok` is a lock name.
 		 * Single lock name could contain multiple flags.
 		 * Replace alias `pcpu-sem` with actual name `percpu-rwsem.
 		 */
 		if (!strcmp(tok, "pcpu-sem"))
 			tok = (char *)"percpu-rwsem";
 		for (unsigned int i = 0; i < ARRAY_SIZE(lock_type_table); i++) {
-			if (!strcmp(lock_type_table[i].name, tok)) {
+			if (!strcmp(lock_type_table[i].lock_name, tok)) {
 				if (add_lock_type(lock_type_table[i].flags)) {
 					found = true;
 				} else {