[PATCH v13 17/21] perf config: Add __guarded_by and __must_hold annotations

[Ian Rogers <irogers@google.com>]

Add __guarded_by() and __must_hold() annotations to static parser and
config state in util/config.c.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/config.c | 47 +++++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index 287401f159e6..0e6b77a0a5e7 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -64,15 +64,29 @@ struct perf_stat_config stat_config = {
 
 char buildid_dir[MAXPATHLEN]; /* root dir for buildid, binary cache */
 
-static FILE *config_file;
-static const char *config_file_name;
-static int config_linenr;
-static int config_file_eof;
-static struct perf_config_set *config_set;
+/* Parsing and rewriting share the static parser state. */
+static DEFINE_MUTEX(config_mutex);
+
+/* Serializes whole perf_config__set_variable() updates. */
+static DEFINE_MUTEX(config_update_mutex);
+
+/*
+ * Protects the global config_set. Separate from config_mutex because
+ * initializing config_set parses the config files, which acquires
+ * config_mutex.
+ */
+static DEFINE_MUTEX(config_set_mutex);
+
+static FILE *config_file __guarded_by(&config_mutex);
+static const char *config_file_name __guarded_by(&config_mutex);
+static int config_linenr __guarded_by(&config_mutex);
+static int config_file_eof __guarded_by(&config_mutex);
+static struct perf_config_set *config_set __guarded_by(&config_set_mutex);
 
 const char *config_exclusive_filename;
 
 static int get_next_char(void)
+	__must_hold(&config_mutex)
 {
 	int c;
 	FILE *f;
@@ -99,8 +113,9 @@ static int get_next_char(void)
 }
 
 static char *parse_value(void)
+	__must_hold(&config_mutex)
 {
-	static char value[1024];
+	static char value[1024] __guarded_by(&config_mutex);
 	int quote = 0, comment = 0, space = 0;
 	size_t len = 0;
 
@@ -170,6 +185,7 @@ static inline int iskeychar(int c)
 }
 
 static int get_value(config_fn_t fn, void *data, char *name, unsigned int len)
+	__must_hold(&config_mutex)
 {
 	int c;
 	char *value;
@@ -201,6 +217,7 @@ static int get_value(config_fn_t fn, void *data, char *name, unsigned int len)
 }
 
 static int get_extended_base_var(char *name, int baselen, int c)
+	__must_hold(&config_mutex)
 {
 	do {
 		if (c == '\n')
@@ -237,6 +254,7 @@ static int get_extended_base_var(char *name, int baselen, int c)
 }
 
 static int get_base_var(char *name)
+	__must_hold(&config_mutex)
 {
 	int baselen = 0;
 
@@ -257,10 +275,11 @@ static int get_base_var(char *name)
 }
 
 static int perf_parse_file(config_fn_t fn, void *data)
+	__must_hold(&config_mutex)
 {
 	int comment = 0;
 	int baselen = 0;
-	static char var[MAXNAME];
+	static char var[MAXNAME] __guarded_by(&config_mutex);
 
 	/* U+FEFF Byte Order Mark in UTF8 */
 	static const unsigned char *utf8_bom = (unsigned char *) "\xef\xbb\xbf";
@@ -549,12 +568,6 @@ int perf_default_config(const char *var, const char *value,
 	return 0;
 }
 
-/* Parsing and rewriting share the static parser state. */
-static DEFINE_MUTEX(config_mutex);
-
-/* Serializes whole perf_config__set_variable() updates. */
-static DEFINE_MUTEX(config_update_mutex);
-
 static int perf_config_from_file(config_fn_t fn, const char *filename, void *data)
 {
 	int ret;
@@ -737,6 +750,7 @@ static int set_value(struct perf_config_item *item, const char *value)
 
 static int collect_config(const char *var, const char *value,
 			  void *perf_config_set)
+	__must_hold(&config_mutex)
 {
 	int ret = -1;
 	char *ptr, *key;
@@ -853,11 +867,8 @@ struct perf_config_set *perf_config_set__load_file(const char *file)
 	return set;
 }
 
-/* Not config_mutex: building the set parses the config files, which takes it. */
-static DEFINE_MUTEX(config_set_mutex);
-
-/* Called with config_set_mutex held. */
 static int perf_config__init(void)
+	__must_hold(&config_set_mutex)
 {
 	if (config_set == NULL)
 		config_set = perf_config_set__new();
@@ -975,7 +986,7 @@ int perf_config__set_variable(const char *var, const char *value)
 
 	/* Static: the parser publishes it as config_file_name. */
 	{
-		static char path[PATH_MAX];
+		static char path[PATH_MAX] __guarded_by(&config_update_mutex);
 		char *user_config = mkpath(path, sizeof(path), "%s/.perfconfig", getenv("HOME"));
 
 		config_filename = config_exclusive_filename ?: user_config;
-- 
2.56.1.703.gf848ed807c-goog