From: David Goulet <dgoulet@efficios.com>
Date: Mon, 14 Jan 2013 19:41:38 +0000 (-0500)
Subject: Add internal kernel channel destroy function
X-Git-Tag: v2.2.0-rc1~116
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=fb5f35b688fa31b21b25f9a6a831df3e5aa243ed;p=lttng-tools.git

Add internal kernel channel destroy function

The internal representation of a kernel channel in the session daemon
now has a session pointer that points to the associated session. This is
needed so when we destroy a channel, we can update the channel count of
the session if available.

Signed-off-by: David Goulet <dgoulet@efficios.com>
---

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index 3471fd940..b417cb077 100644
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -148,6 +148,7 @@ int kernel_create_channel(struct ltt_kernel_session *session,
 	/* Add channel to session */
 	cds_list_add(&lkc->list, &session->channel_list.head);
 	session->channel_count++;
+	lkc->session = session;
 
 	DBG("Kernel channel %s created (fd: %d)", lkc->channel->name, lkc->fd);
 
@@ -708,3 +709,33 @@ void kernel_destroy_session(struct ltt_kernel_session *ksess)
 
 	trace_kernel_destroy_session(ksess);
 }
+
+/*
+ * Destroy a kernel channel object. It does not do anything on the tracer side.
+ */
+void kernel_destroy_channel(struct ltt_kernel_channel *kchan)
+{
+	struct ltt_kernel_session *ksess = NULL;
+
+	assert(kchan);
+	assert(kchan->channel);
+
+	DBG3("Kernel destroy channel %s", kchan->channel->name);
+
+	/* Update channel count of associated session. */
+	if (kchan->session) {
+		/* Keep pointer reference so we can update it after the destroy. */
+		ksess = kchan->session;
+	}
+
+	trace_kernel_destroy_channel(kchan);
+
+	/*
+	 * At this point the kernel channel is not visible anymore. This is safe
+	 * since in order to work on a visible kernel session, the tracing session
+	 * lock (ltt_session.lock) MUST be acquired.
+	 */
+	if (ksess) {
+		ksess->channel_count--;
+	}
+}
diff --git a/src/bin/lttng-sessiond/kernel.h b/src/bin/lttng-sessiond/kernel.h
index 86ae00371..4813c931d 100644
--- a/src/bin/lttng-sessiond/kernel.h
+++ b/src/bin/lttng-sessiond/kernel.h
@@ -52,6 +52,7 @@ void kernel_wait_quiescent(int fd);
 int kernel_calibrate(int fd, struct lttng_kernel_calibrate *calibrate);
 int kernel_validate_version(int tracer_fd);
 void kernel_destroy_session(struct ltt_kernel_session *ksess);
+void kernel_destroy_channel(struct ltt_kernel_channel *kchan);
 
 int init_kernel_workarounds(void);
 
diff --git a/src/bin/lttng-sessiond/trace-kernel.h b/src/bin/lttng-sessiond/trace-kernel.h
index 27baa6d39..8bd1ffe32 100644
--- a/src/bin/lttng-sessiond/trace-kernel.h
+++ b/src/bin/lttng-sessiond/trace-kernel.h
@@ -65,6 +65,8 @@ struct ltt_kernel_channel {
 	struct ltt_kernel_event_list events_list;
 	struct ltt_kernel_stream_list stream_list;
 	struct cds_list_head list;
+	/* Session pointer which has a reference to this object. */
+	struct ltt_kernel_session *session;
 };
 
 /* Metadata */