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From: "Yordan Karadzhov (VMware)" <y.karadz@gmail.com>
To: rostedt@goodmis.org
Cc: linux-trace-devel@vger.kernel.org, tz.stoyanov@gmail.com,
	"Yordan Karadzhov (VMware)" <y.karadz@gmail.com>
Subject: [PATCH v3 4/5] libtracefs: Option's bit masks to be owned by the instance
Date: Thu,  8 Apr 2021 17:00:23 +0300	[thread overview]
Message-ID: <20210408140024.13093-5-y.karadz@gmail.com> (raw)
In-Reply-To: <20210408140024.13093-1-y.karadz@gmail.com>

If the instance owns two mask objects, we no longer need to
dynamically allocate memory in tracefs_options_get_supported() and
tracefs_options_get_enabled(). This will simplify the code on the
caller side, since the user is no longer responsible for freeing
those masks.

Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
---
 Documentation/libtracefs-option-get.txt |  4 +---
 include/tracefs-local.h                 |  8 ++++++++
 include/tracefs.h                       |  2 +-
 src/tracefs-instance.c                  | 15 +++++++++++++++
 src/tracefs-tools.c                     | 24 ++++++++++++++----------
 5 files changed, 39 insertions(+), 14 deletions(-)

diff --git a/Documentation/libtracefs-option-get.txt b/Documentation/libtracefs-option-get.txt
index 9b3cb56..3290f24 100644
--- a/Documentation/libtracefs-option-get.txt
+++ b/Documentation/libtracefs-option-get.txt
@@ -52,14 +52,13 @@ EXAMPLE
 --
 #include <tracefs.h>
 ...
-struct tracefs_options_mask *options;
+const struct tracefs_options_mask *options;
 ...
 options = tracefs_options_get_supported(NULL);
 if (!options) {
 	/* Failed to get supported options */
 } else {
 	...
-	free(options);
 }
 ...
 options = tracefs_options_get_enabled(NULL);
@@ -67,7 +66,6 @@ if (!options) {
 	/* Failed to get options, enabled in the top instance */
 } else {
 	...
-	free(options);
 }
 ...
 
diff --git a/include/tracefs-local.h b/include/tracefs-local.h
index 076b013..eb8c81b 100644
--- a/include/tracefs-local.h
+++ b/include/tracefs-local.h
@@ -25,6 +25,8 @@ struct tracefs_instance {
 	int			flags;
 	int			ftrace_filter_fd;
 	int			ftrace_notrace_fd;
+	struct tracefs_options_mask	supported_opts;
+	struct tracefs_options_mask	enabled_opts;
 };
 
 extern pthread_mutex_t toplevel_lock;
@@ -48,4 +50,10 @@ char *trace_find_tracing_dir(void);
 #define DEFFILEMODE (S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH) /* 0666*/
 #endif
 
+struct tracefs_options_mask *
+supported_opts_mask(struct tracefs_instance *instance);
+
+struct tracefs_options_mask *
+enabled_opts_mask(struct tracefs_instance *instance);
+
 #endif /* _TRACE_FS_LOCAL_H */
diff --git a/include/tracefs.h b/include/tracefs.h
index e1fbef6..ea9dbd0 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -132,7 +132,7 @@ enum tracefs_option_id {
 #define TRACEFS_OPTION_MAX (TRACEFS_OPTION_VERBOSE + 1)
 
 struct tracefs_options_mask;
-bool tracefs_option_is_set(struct tracefs_options_mask *options,
+bool tracefs_option_is_set(const struct tracefs_options_mask *options,
 			   enum tracefs_option_id id);
 struct tracefs_options_mask *tracefs_options_get_supported(struct tracefs_instance *instance);
 bool tracefs_option_is_supported(struct tracefs_instance *instance, enum tracefs_option_id id);
diff --git a/src/tracefs-instance.c b/src/tracefs-instance.c
index 599c3a7..74122aa 100644
--- a/src/tracefs-instance.c
+++ b/src/tracefs-instance.c
@@ -21,6 +21,21 @@
 
 #define FLAG_INSTANCE_NEWLY_CREATED	(1 << 0)
 
+struct tracefs_options_mask	toplevel_supported_opts;
+struct tracefs_options_mask	toplevel_enabled_opts;
+
+__hidden inline struct tracefs_options_mask *
+supported_opts_mask(struct tracefs_instance *instance)
+{
+	return instance? &instance->supported_opts : &toplevel_supported_opts;
+}
+
+__hidden inline struct tracefs_options_mask *
+enabled_opts_mask(struct tracefs_instance *instance)
+{
+	return instance? &instance->enabled_opts : &toplevel_enabled_opts;
+}
+
 /**
  * instance_alloc - allocate a new ftrace instance
  * @trace_dir - Full path to the tracing directory, where the instance is
diff --git a/src/tracefs-tools.c b/src/tracefs-tools.c
index fc9644a..b6967db 100644
--- a/src/tracefs-tools.c
+++ b/src/tracefs-tools.c
@@ -211,6 +211,7 @@ enum tracefs_option_id tracefs_option_id(const char *name)
 static struct tracefs_options_mask *trace_get_options(struct tracefs_instance *instance,
 						      bool enabled)
 {
+	pthread_mutex_t *lock = instance ? &instance->lock : &toplevel_lock;
 	struct tracefs_options_mask *bitmask;
 	enum tracefs_option_id id;
 	char file[PATH_MAX];
@@ -219,9 +220,6 @@ static struct tracefs_options_mask *trace_get_options(struct tracefs_instance *i
 	DIR *dir = NULL;
 	long long val;
 
-	bitmask = calloc(1, sizeof(struct tracefs_options_mask));
-	if (!bitmask)
-		return NULL;
 	dname = tracefs_instance_get_file(instance, "options");
 	if (!dname)
 		goto error;
@@ -229,6 +227,11 @@ static struct tracefs_options_mask *trace_get_options(struct tracefs_instance *i
 	if (!dir)
 		goto error;
 
+	bitmask = enabled? enabled_opts_mask(instance) :
+			   supported_opts_mask(instance);
+
+	pthread_mutex_lock(lock);
+	bitmask->mask = 0;
 	while ((dent = readdir(dir))) {
 		if (*dent->d_name == '.')
 			continue;
@@ -242,6 +245,8 @@ static struct tracefs_options_mask *trace_get_options(struct tracefs_instance *i
 		if (id > TRACEFS_OPTION_INVALID)
 			bitmask->mask |= (1ULL << (id - 1));
 	}
+	pthread_mutex_unlock(lock);
+
 	closedir(dir);
 	tracefs_put_tracing_file(dname);
 
@@ -251,7 +256,6 @@ error:
 	if (dir)
 		closedir(dir);
 	tracefs_put_tracing_file(dname);
-	free(bitmask);
 	return NULL;
 }
 
@@ -259,8 +263,8 @@ error:
  * tracefs_options_get_supported - Get all supported trace options in given instance
  * @instance: ftrace instance, can be NULL for the top instance
  *
- * Returns allocated bitmask structure with all trace options, supported in given
- * instance, or NULL in case of an error. The returned structure must be freed with free()
+ * Returns bitmask structure with all trace options, supported in given instance,
+ * or NULL in case of an error.
  */
 struct tracefs_options_mask *tracefs_options_get_supported(struct tracefs_instance *instance)
 {
@@ -271,8 +275,8 @@ struct tracefs_options_mask *tracefs_options_get_supported(struct tracefs_instan
  * tracefs_options_get_enabled - Get all currently enabled trace options in given instance
  * @instance: ftrace instance, can be NULL for the top instance
  *
- * Returns allocated bitmask structure with all trace options, enabled in given
- * instance, or NULL in case of an error. The returned structure must be freed with free()
+ * Returns bitmask structure with all trace options, enabled in given instance,
+ * or NULL in case of an error.
  */
 struct tracefs_options_mask *tracefs_options_get_enabled(struct tracefs_instance *instance)
 {
@@ -282,7 +286,7 @@ struct tracefs_options_mask *tracefs_options_get_enabled(struct tracefs_instance
 static int trace_config_option(struct tracefs_instance *instance,
 			       enum tracefs_option_id id, bool set)
 {
-	char *set_str = set ? "1" : "0";
+	const char *set_str = set ? "1" : "0";
 	char file[PATH_MAX];
 	const char *name;
 
@@ -370,7 +374,7 @@ bool tracefs_option_is_enabled(struct tracefs_instance *instance, enum tracefs_o
  * Returns true if an option with given id is set in the bitmask,
  * false if it is not set.
  */
-bool tracefs_option_is_set(struct tracefs_options_mask *options,
+bool tracefs_option_is_set(const struct tracefs_options_mask *options,
 			   enum tracefs_option_id id)
 {
 	if (id > TRACEFS_OPTION_INVALID)
-- 
2.27.0


  parent reply	other threads:[~2021-04-08 14:00 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-08 14:00 [PATCH v3 0/5] Refactor the APIs for tracing options Yordan Karadzhov (VMware)
2021-04-08 14:00 ` [PATCH v3 1/5] libtracefs: Fix issues with tracefs_option_id() Yordan Karadzhov (VMware)
2021-04-08 14:00 ` [PATCH v3 2/5] libtracefs: Modify the arguments of tracefs_option_is_set() Yordan Karadzhov (VMware)
2021-04-08 14:00 ` [PATCH v3 3/5] libtracefs: Encapsulate "struct tracefs_options_mask" Yordan Karadzhov (VMware)
2021-04-08 14:00 ` Yordan Karadzhov (VMware) [this message]
2021-04-09  4:36   ` [PATCH v3 4/5] libtracefs: Option's bit masks to be owned by the instance Tzvetomir Stoyanov
2021-04-08 14:00 ` [PATCH v3 5/5] libtracefs: Rename tracefs_option_is_set() Yordan Karadzhov (VMware)
2021-04-09  4:39 ` [PATCH v3 0/5] Refactor the APIs for tracing options Tzvetomir Stoyanov

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