diff --git a/fops.c b/fops.c
index 11eb6e4..340230a 100644
--- a/fops.c
+++ b/fops.c
@@ -240,7 +240,7 @@ static unsigned int mxdma_device_poll(struct file *file, poll_table *wait)
 	struct mx_pci_dev *mx_pdev;
 	struct mx_event *mx_event;
 	unsigned int mask = 0;
-	int flag;
+	int count;
 
 	mx_cdev = (struct mx_char_dev *)file->private_data;
 	if (!mx_cdev) {
@@ -271,11 +271,11 @@ static unsigned int mxdma_device_poll(struct file *file, poll_table *wait)
 
 	mx_event = &mx_pdev->event;
 	poll_wait(file, &mx_event->wq, wait);
-	flag = atomic_read(&mx_event->flag);
-	if (flag) {
+	count = atomic_read(&mx_event->count);
+	if (count > 0) {
+		atomic_dec(&mx_event->count);
 		mask = POLLIN | POLLRDNORM;
 	}
-	atomic_set(&mx_event->flag, 0);
 
 	return mask;
 }
diff --git a/init.c b/init.c
index fd62bd0..b203b7d 100644
--- a/init.c
+++ b/init.c
@@ -12,31 +12,31 @@ static void mx_event_init(struct mx_pci_dev *mx_pdev)
 	struct mx_event *mx_event = &mx_pdev->event;
 
 	init_waitqueue_head(&mx_event->wq);
-	atomic_set(&mx_event->flag, 0);
+	atomic_set(&mx_event->count, 0);
 }
 
 static irqreturn_t msi_irq_handler(int irq, void *data)
 {
-    struct mx_pci_dev *mx_pdev;
-    struct mx_event *mx_event;
+	struct mx_pci_dev *mx_pdev;
+	struct mx_event *mx_event;
 
-    mx_pdev = (struct mx_pci_dev *)data;
-    if (mx_pdev == NULL) {
-	pr_err("Invalid data\n");
-	goto out;
-    }
+	mx_pdev = (struct mx_pci_dev *)data;
+	if (mx_pdev == NULL) {
+		pr_err("Invalid data\n");
+		goto out;
+	}
 
-    mx_event = &(mx_pdev->event);
-    if (mx_event == NULL) {
-	pr_err("Invalid event\n");
-	goto out;
-    }
+	mx_event = &(mx_pdev->event);
+	if (mx_event == NULL) {
+		pr_err("Invalid event\n");
+		goto out;
+	}
 
-    atomic_set(&mx_event->flag, 1);
-    wake_up_interruptible(&mx_event->wq);
+	atomic_inc(&mx_event->count);
+	wake_up_interruptible(&mx_event->wq);
 
 out:
-    return IRQ_HANDLED;
+	return IRQ_HANDLED;
 }
 
 static void pci_device_exit(struct mx_pci_dev *mx_pdev, struct pci_dev *pdev)
@@ -390,7 +390,7 @@ int mxdma_driver_probe(struct pci_dev *pdev, const struct pci_device_id *id, int
 	}
 
 	pr_info("pci device is probed (vendor=%#x device=%#x bdf=%s cxl=mem%d)\n",
-		pdev->vendor, pdev->device, dev_name(&pdev->dev), cxl_memdev_id);
+			pdev->vendor, pdev->device, dev_name(&pdev->dev), cxl_memdev_id);
 
 	return 0;
 }
diff --git a/mx_dma.h b/mx_dma.h
index e38e643..ca9ba24 100644
--- a/mx_dma.h
+++ b/mx_dma.h
@@ -182,7 +182,7 @@ struct mx_char_dev {
 };
 
 struct mx_event {
-	atomic_t flag;
+	atomic_t count;
 	wait_queue_head_t wq;
 };
 
diff --git a/transfer.c b/transfer.c
index 5a24f8e..def6870 100644
--- a/transfer.c
+++ b/transfer.c
@@ -235,7 +235,7 @@ static int mx_command_init_common(struct mx_transfer *transfer, int opcode)
 
 	id = transfer_id_alloc(transfer);
 	if (id < 0) {
-		pr_warn("Failed to trasfer_id_alloc\n");
+		pr_warn("Failed to trasfer_id_alloc (err=%d)\n", id);
 		return -ENOMEM;
 	}
 
@@ -342,9 +342,12 @@ static int mx_transfer_init_ctrl(struct mx_transfer *transfer, int opcode)
 
 static int mx_transfer_destroy_ctrl(struct mx_transfer *transfer)
 {
+	struct mx_command *comm = &transfer->cmd;
 	uint64_t value;
 	int ret;
 
+	transfer_id_free(comm->id);
+
 	if (transfer->dir != DMA_FROM_DEVICE)
 		return 0;