Fix a race condition when quickly reconnecting during a disconnect.

git-svn-id: http://svn.digium.com/svn/zaptel/trunk@1377 5390a7c7-147a-4af0-8ec9-7488f05a26cb

1 files changed, 5 insertions, 0 deletions

diff --git a/xpp/xbus-core.c b/xpp/xbus-core.c
index 3b9d507..5e96147 100644
--- a/xpp/xbus-core.c
+++ b/xpp/xbus-core.c
@@ -313,6 +313,10 @@ static int xbus_poll(void *data)
 	int			xpd_num;
 	xbus_t			*xbus = data;
 
+	if(!down_read_trylock(&xbus->in_use)) {
+		ERR("%s is being removed...\n", xbus->busname);
+		return -EBUSY;
+	}
 	spin_lock_irqsave(&xbus->lock, flags);
 	DBG("%s\n", xbus->busname);
 
@@ -398,6 +402,7 @@ static int xbus_poll(void *data)
 		card_detected(card_desc);
 	}
 	complete_all(&xbus->xpds_initialized);
+	up_read(&xbus->in_use);
 	return 0;
 }