Keep reference count on transport and file ops modules

[lttng-modules.git] / ltt-debugfs-abi.c

diff --git a/ltt-debugfs-abi.c b/ltt-debugfs-abi.c
index aa8dc0f4a0d973af21f4739aa373170cfb63a9d6..cfc364a844635f1476a17e7e7c794b73478f6017 100644 (file)
--- a/ltt-debugfs-abi.c
+++ b/ltt-debugfs-abi.c
@@ -49,6 +49,11 @@ static const struct file_operations lttng_channel_fops;
 static const struct file_operations lttng_metadata_fops;
 static const struct file_operations lttng_event_fops;
 
+/*
+ * Teardown management: opened file descriptors keep a refcount on the module,
+ * so it can only exit when all file descriptors are closed.
+ */
+
 enum channel_type {
        PER_CPU_CHANNEL,
        METADATA_CHANNEL,
@@ -196,6 +201,8 @@ long lttng_abi_add_context(struct file *file,
  *             Returns the LTTng kernel tracer version
  *     LTTNG_KERNEL_TRACEPOINT_LIST
  *             Returns a file descriptor listing available tracepoints
+ *     LTTNG_KERNEL_WAIT_QUIESCENT
+ *             Returns after all previously running probes have completed
  *
  * The returned session will be deleted when its file descriptor is closed.
  */
@@ -210,12 +217,16 @@ long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
                                (struct lttng_kernel_tracer_version __user *) arg);
        case LTTNG_KERNEL_TRACEPOINT_LIST:
                return lttng_abi_tracepoint_list();
+       case LTTNG_KERNEL_WAIT_QUIESCENT:
+               synchronize_trace();
+               return 0;
        default:
                return -ENOIOCTLCMD;
        }
 }
 
 static const struct file_operations lttng_fops = {
+       .owner = THIS_MODULE,
        .unlocked_ioctl = lttng_ioctl,
 #ifdef CONFIG_COMPAT
        .compat_ioctl = lttng_ioctl,
@@ -284,12 +295,24 @@ int lttng_abi_create_channel(struct file *session_file,
        }
        switch (channel_type) {
        case PER_CPU_CHANNEL:
-               transport_name = chan_param.overwrite ?
-                       "relay-overwrite" : "relay-discard";
+               if (chan_param.output == LTTNG_KERNEL_SPLICE) {
+                       transport_name = chan_param.overwrite ?
+                               "relay-overwrite" : "relay-discard";
+               } else if (chan_param.output == LTTNG_KERNEL_MMAP) {
+                       transport_name = chan_param.overwrite ?
+                               "relay-overwrite-mmap" : "relay-discard-mmap";
+               } else {
+                       return -EINVAL;
+               }
                fops = &lttng_channel_fops;
                break;
        case METADATA_CHANNEL:
-               transport_name = "relay-metadata";
+               if (chan_param.output == LTTNG_KERNEL_SPLICE)
+                       transport_name = "relay-metadata";
+               else if (chan_param.output == LTTNG_KERNEL_MMAP)
+                       transport_name = "relay-metadata-mmap";
+               else
+                       return -EINVAL;
                fops = &lttng_metadata_fops;
                break;
        default:
@@ -393,6 +416,7 @@ int lttng_session_release(struct inode *inode, struct file *file)
 }
 
 static const struct file_operations lttng_session_fops = {
+       .owner = THIS_MODULE,
        .release = lttng_session_release,
        .unlocked_ioctl = lttng_session_ioctl,
 #ifdef CONFIG_COMPAT
@@ -592,8 +616,9 @@ unsigned int lttng_channel_poll(struct file *file, poll_table *wait)
                        return POLLERR;
                if (channel->ops->is_finalized(channel->chan))
                        return POLLHUP;
-               else
+               if (channel->ops->buffer_has_read_closed_stream(channel->chan))
                        return POLLIN | POLLRDNORM;
+               return 0;
        }
        return mask;
 
@@ -610,6 +635,7 @@ int lttng_channel_release(struct inode *inode, struct file *file)
 }
 
 static const struct file_operations lttng_channel_fops = {
+       .owner = THIS_MODULE,
        .release = lttng_channel_release,
        .poll = lttng_channel_poll,
        .unlocked_ioctl = lttng_channel_ioctl,
@@ -619,6 +645,7 @@ static const struct file_operations lttng_channel_fops = {
 };
 
 static const struct file_operations lttng_metadata_fops = {
+       .owner = THIS_MODULE,
        .release = lttng_channel_release,
        .unlocked_ioctl = lttng_metadata_ioctl,
 #ifdef CONFIG_COMPAT
@@ -672,6 +699,7 @@ int lttng_event_release(struct inode *inode, struct file *file)
 
 /* TODO: filter control ioctl */
 static const struct file_operations lttng_event_fops = {
+       .owner = THIS_MODULE,
        .release = lttng_event_release,
        .unlocked_ioctl = lttng_event_ioctl,
 #ifdef CONFIG_COMPAT