X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=lttng-abi.c;h=7cc4b5201f45a790d9cf842efd15d4f28def4248;hb=ed8d02d6a3d1dae8e7ecbda764202a0316b5ea6f;hp=26a456ece13f7ed0a62b5e3b3e92d2cff942c17c;hpb=d4d4b9c765362750b023ac23161573113189620d;p=lttng-modules.git

diff --git a/lttng-abi.c b/lttng-abi.c
index 26a456ec..7cc4b520 100644
--- a/lttng-abi.c
+++ b/lttng-abi.c
@@ -64,6 +64,7 @@ static const struct file_operations lttng_session_fops;
 static const struct file_operations lttng_channel_fops;
 static const struct file_operations lttng_metadata_fops;
 static const struct file_operations lttng_event_fops;
+static struct file_operations lttng_stream_ring_buffer_file_operations;
 
 /*
  * Teardown management: opened file descriptors keep a refcount on the module,
@@ -553,10 +554,9 @@ int lttng_metadata_ring_buffer_ioctl_get_next_subbuf(struct file *filp,
 	struct lttng_metadata_stream *stream = filp->private_data;
 	struct lib_ring_buffer *buf = stream->priv;
 	struct channel *chan = buf->backend.chan;
-	struct lttng_channel *lttng_chan = channel_get_private(chan);
 	int ret;
 
-	ret = lttng_metadata_output_channel(lttng_chan, stream);
+	ret = lttng_metadata_output_channel(stream, chan);
 	if (ret > 0) {
 		lib_ring_buffer_switch_slow(buf, SWITCH_ACTIVE);
 		ret = 0;
@@ -671,6 +671,10 @@ err:
 }
 #endif
 
+/*
+ * This is not used by anonymous file descriptors. This code is left
+ * there if we ever want to implement an inode with open() operation.
+ */
 static
 int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 {
@@ -678,6 +682,14 @@ int lttng_metadata_ring_buffer_open(struct inode *inode, struct file *file)
 	struct lib_ring_buffer *buf = stream->priv;
 
 	file->private_data = buf;
+	/*
+	 * Since life-time of metadata cache differs from that of
+	 * session, we need to keep our own reference on the transport.
+	 */
+	if (!try_module_get(stream->transport->owner)) {
+		printk(KERN_WARNING "LTT : Can't lock transport module.\n");
+		return -EBUSY;
+	}
 	return lib_ring_buffer_open(inode, file, buf);
 }
 
@@ -686,12 +698,9 @@ int lttng_metadata_ring_buffer_release(struct inode *inode, struct file *file)
 {
 	struct lttng_metadata_stream *stream = file->private_data;
 	struct lib_ring_buffer *buf = stream->priv;
-	struct channel *chan = buf->backend.chan;
-	struct lttng_channel *lttng_chan = channel_get_private(chan);
 
 	kref_put(&stream->metadata_cache->refcount, metadata_cache_destroy);
-	fput(lttng_chan->file);
-
+	module_put(stream->transport->owner);
 	return lib_ring_buffer_release(inode, file, buf);
 }
 
@@ -784,7 +793,7 @@ int lttng_abi_open_stream(struct file *channel_file)
 
 	stream_priv = buf;
 	ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
-			&lib_ring_buffer_file_operations);
+			&lttng_stream_ring_buffer_file_operations);
 	if (ret < 0)
 		goto fd_error;
 
@@ -811,24 +820,41 @@ int lttng_abi_open_metadata_stream(struct file *channel_file)
 
 	metadata_stream = kzalloc(sizeof(struct lttng_metadata_stream),
 			GFP_KERNEL);
-	if (!metadata_stream)
-		return -ENOMEM;
+	if (!metadata_stream) {
+		ret = -ENOMEM;
+		goto nomem;
+	}
 	metadata_stream->metadata_cache = session->metadata_cache;
 	init_waitqueue_head(&metadata_stream->read_wait);
 	metadata_stream->priv = buf;
 	stream_priv = metadata_stream;
+	metadata_stream->transport = channel->transport;
+
+	/*
+	 * Since life-time of metadata cache differs from that of
+	 * session, we need to keep our own reference on the transport.
+	 */
+	if (!try_module_get(metadata_stream->transport->owner)) {
+		printk(KERN_WARNING "LTT : Can't lock transport module.\n");
+		ret = -EINVAL;
+		goto notransport;
+	}
+
 	ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
 			&lttng_metadata_ring_buffer_file_operations);
 	if (ret < 0)
 		goto fd_error;
 
-	atomic_long_inc(&channel_file->f_count);
 	kref_get(&session->metadata_cache->refcount);
 	list_add(&metadata_stream->list,
 		&session->metadata_cache->metadata_stream);
 	return ret;
 
 fd_error:
+	module_put(metadata_stream->transport->owner);
+notransport:
+	kfree(metadata_stream);
+nomem:
 	channel->ops->buffer_read_close(buf);
 	return ret;
 }
@@ -1297,6 +1323,51 @@ static const struct file_operations lttng_event_fops = {
 #endif
 };
 
+static long lttng_stream_ring_buffer_ioctl(struct file *filp,
+		unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+		default:
+			return lib_ring_buffer_file_operations.unlocked_ioctl(filp,
+					cmd, arg);
+	}
+}
+
+#ifdef CONFIG_COMPAT
+static long lttng_stream_ring_buffer_compat_ioctl(struct file *filp,
+		unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+		default:
+			return lib_ring_buffer_file_operations.compat_ioctl(filp,
+					cmd, arg);
+	}
+}
+#endif /* CONFIG_COMPAT */
+
+static void lttng_stream_override_ring_buffer_fops(void)
+{
+	lttng_stream_ring_buffer_file_operations.owner = THIS_MODULE;
+	lttng_stream_ring_buffer_file_operations.open =
+		lib_ring_buffer_file_operations.open;
+	lttng_stream_ring_buffer_file_operations.release =
+		lib_ring_buffer_file_operations.release;
+	lttng_stream_ring_buffer_file_operations.poll =
+		lib_ring_buffer_file_operations.poll;
+	lttng_stream_ring_buffer_file_operations.splice_read =
+		lib_ring_buffer_file_operations.splice_read;
+	lttng_stream_ring_buffer_file_operations.mmap =
+		lib_ring_buffer_file_operations.mmap;
+	lttng_stream_ring_buffer_file_operations.unlocked_ioctl =
+		lttng_stream_ring_buffer_ioctl;
+	lttng_stream_ring_buffer_file_operations.llseek =
+		lib_ring_buffer_file_operations.llseek;
+#ifdef CONFIG_COMPAT
+	lttng_stream_ring_buffer_file_operations.compat_ioctl =
+		lttng_stream_ring_buffer_compat_ioctl;
+#endif
+}
+
 int __init lttng_abi_init(void)
 {
 	int ret = 0;
@@ -1310,6 +1381,8 @@ int __init lttng_abi_init(void)
 		ret = -ENOMEM;
 		goto error;
 	}
+	lttng_stream_override_ring_buffer_fops();
+
 error:
 	return ret;
 }