Drivers: hv: balloon: Do not post pressure status if interrupted

commit c5e2254f8d63a6654149aa32ac5f2b7dd66a976d upstream.

When we are posting pressure status, we may get interrupted and handle
the un-balloon operation. In this case just don't post the status as we
know the pressure status is stale.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 61b7351df1d4..deb5c25305af 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -975,6 +975,14 @@ static void post_status(struct hv_dynmem_device *dm)
                                 dm->num_pages_ballooned +
                                 compute_balloon_floor();
 
+        /*
+         * If our transaction ID is no longer current, just don't
+         * send the status. This can happen if we were interrupted
+         * after we picked our transaction ID.
+         */
+        if (status.hdr.trans_id != atomic_read(&trans_id))
+                return;
+
         vmbus_sendpacket(dm->dev->channel, &status,
                                 sizeof(struct dm_status),
                                 (unsigned long)NULL,