2 files changed, 57 insertions, 15 deletions

diff --git a/drivers/hv/hv_utils_transport.c b/drivers/hv/hv_utils_transport.c
index 59c6f3d29f9a..31c2f8649271 100644
--- a/drivers/hv/hv_utils_transport.c
+++ b/drivers/hv/hv_utils_transport.c
@@ -27,11 +27,9 @@ static struct list_head hvt_list = LIST_HEAD_INIT(hvt_list);
 
 static void hvt_reset(struct hvutil_transport *hvt)
 {
-	mutex_lock(&hvt->lock);
 	kfree(hvt->outmsg);
 	hvt->outmsg = NULL;
 	hvt->outmsg_len = 0;
-	mutex_unlock(&hvt->lock);
 	if (hvt->on_reset)
 		hvt->on_reset();
 }
@@ -44,10 +42,17 @@ static ssize_t hvt_op_read(struct file *file, char __user *buf,
 
 	hvt = container_of(file->f_op, struct hvutil_transport, fops);
 
-	if (wait_event_interruptible(hvt->outmsg_q, hvt->outmsg_len > 0))
+	if (wait_event_interruptible(hvt->outmsg_q, hvt->outmsg_len > 0 ||
+				     hvt->mode != HVUTIL_TRANSPORT_CHARDEV))
 		return -EINTR;
 
 	mutex_lock(&hvt->lock);
+
+	if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
+		ret = -EBADF;
+		goto out_unlock;
+	}
+
 	if (!hvt->outmsg) {
 		ret = -EAGAIN;
 		goto out_unlock;
@@ -85,7 +90,10 @@ static ssize_t hvt_op_write(struct file *file, const char __user *buf,
 	if (IS_ERR(inmsg))
 		return PTR_ERR(inmsg);
 
-	ret = hvt->on_msg(inmsg, count);
+	if (hvt->mode == HVUTIL_TRANSPORT_DESTROY)
+		ret = -EBADF;
+	else
+		ret = hvt->on_msg(inmsg, count);
 
 	kfree(inmsg);
 
@@ -99,6 +107,10 @@ static unsigned int hvt_op_poll(struct file *file, poll_table *wait)
 	hvt = container_of(file->f_op, struct hvutil_transport, fops);
 
 	poll_wait(file, &hvt->outmsg_q, wait);
+
+	if (hvt->mode == HVUTIL_TRANSPORT_DESTROY)
+		return -EBADF;
+
 	if (hvt->outmsg_len > 0)
 		return POLLIN | POLLRDNORM;
 
@@ -108,26 +120,39 @@ static unsigned int hvt_op_poll(struct file *file, poll_table *wait)
 static int hvt_op_open(struct inode *inode, struct file *file)
 {
 	struct hvutil_transport *hvt;
+	int ret = 0;
+	bool issue_reset = false;
 
 	hvt = container_of(file->f_op, struct hvutil_transport, fops);
 
-	/*
-	 * Switching to CHARDEV mode. We switch bach to INIT when device
-	 * gets released.
-	 */
-	if (hvt->mode == HVUTIL_TRANSPORT_INIT)
+	mutex_lock(&hvt->lock);
+
+	if (hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
+		ret = -EBADF;
+	} else if (hvt->mode == HVUTIL_TRANSPORT_INIT) {
+		/*
+		 * Switching to CHARDEV mode. We switch bach to INIT when
+		 * device gets released.
+		 */
 		hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
+	}
 	else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
 		/*
 		 * We're switching from netlink communication to using char
 		 * device. Issue the reset first.
 		 */
-		hvt_reset(hvt);
+		issue_reset = true;
 		hvt->mode = HVUTIL_TRANSPORT_CHARDEV;
-	} else
-		return -EBUSY;
+	} else {
+		ret = -EBUSY;
+	}
 
-	return 0;
+	if (issue_reset)
+		hvt_reset(hvt);
+
+	mutex_unlock(&hvt->lock);
+
+	return ret;
 }
 
 static int hvt_op_release(struct inode *inode, struct file *file)
@@ -136,12 +161,15 @@ static int hvt_op_release(struct inode *inode, struct file *file)
 
 	hvt = container_of(file->f_op, struct hvutil_transport, fops);
 
-	hvt->mode = HVUTIL_TRANSPORT_INIT;
+	mutex_lock(&hvt->lock);
+	if (hvt->mode != HVUTIL_TRANSPORT_DESTROY)
+		hvt->mode = HVUTIL_TRANSPORT_INIT;
 	/*
 	 * Cleanup message buffers to avoid spurious messages when the daemon
 	 * connects back.
 	 */
 	hvt_reset(hvt);
+	mutex_unlock(&hvt->lock);
 
 	return 0;
 }
@@ -168,6 +196,7 @@ static void hvt_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 	 * Switching to NETLINK mode. Switching to CHARDEV happens when someone
 	 * opens the device.
 	 */
+	mutex_lock(&hvt->lock);
 	if (hvt->mode == HVUTIL_TRANSPORT_INIT)
 		hvt->mode = HVUTIL_TRANSPORT_NETLINK;
 
@@ -175,6 +204,7 @@ static void hvt_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 		hvt_found->on_msg(msg->data, msg->len);
 	else
 		pr_warn("hvt_cn_callback: unexpected netlink message!\n");
+	mutex_unlock(&hvt->lock);
 }
 
 int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len)
@@ -182,7 +212,8 @@ int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len)
 	struct cn_msg *cn_msg;
 	int ret = 0;
 
-	if (hvt->mode == HVUTIL_TRANSPORT_INIT) {
+	if (hvt->mode == HVUTIL_TRANSPORT_INIT ||
+	    hvt->mode == HVUTIL_TRANSPORT_DESTROY) {
 		return -EINVAL;
 	} else if (hvt->mode == HVUTIL_TRANSPORT_NETLINK) {
 		cn_msg = kzalloc(sizeof(*cn_msg) + len, GFP_ATOMIC);
@@ -198,6 +229,11 @@ int hvutil_transport_send(struct hvutil_transport *hvt, void *msg, int len)
 	}
 	/* HVUTIL_TRANSPORT_CHARDEV */
 	mutex_lock(&hvt->lock);
+	if (hvt->mode != HVUTIL_TRANSPORT_CHARDEV) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
 	if (hvt->outmsg) {
 		/* Previous message wasn't received */
 		ret = -EFAULT;
@@ -268,6 +304,11 @@ err_free_hvt:
 
 void hvutil_transport_destroy(struct hvutil_transport *hvt)
 {
+	mutex_lock(&hvt->lock);
+	hvt->mode = HVUTIL_TRANSPORT_DESTROY;
+	wake_up_interruptible(&hvt->outmsg_q);
+	mutex_unlock(&hvt->lock);
+
 	spin_lock(&hvt_list_lock);
 	list_del(&hvt->list);
 	spin_unlock(&hvt_list_lock);
diff --git a/drivers/hv/hv_utils_transport.h b/drivers/hv/hv_utils_transport.h
index bff4c921e817..06254a165a18 100644
--- a/drivers/hv/hv_utils_transport.h
+++ b/drivers/hv/hv_utils_transport.h
@@ -25,6 +25,7 @@ enum hvutil_transport_mode {
 	HVUTIL_TRANSPORT_INIT = 0,
 	HVUTIL_TRANSPORT_NETLINK,
 	HVUTIL_TRANSPORT_CHARDEV,
+	HVUTIL_TRANSPORT_DESTROY,
 };
 
 struct hvutil_transport {