From: Juergen Gross <jgross@suse.com>
Date: Mon, 8 Feb 2016 14:30:18 +0000 (+0100)
Subject: xen/scsiback: correct frontend counting
X-Git-Tag: firefly_0821_release~176^2~475^2~105
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=e32b123feea78479f8a60a9abf1a645f9c3ee728;p=firefly-linux-kernel-4.4.55.git

xen/scsiback: correct frontend counting

commit f285aa8db7cc4432c1a03f8b55ff34fe96317c11 upstream.

When adding a new frontend to xen-scsiback don't decrement the number
of active frontends in case of no error. Doing so results in a failure
when trying to remove the xen-pvscsi nexus even if no domain is using
it.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
index ad4eb1024d1f..51387d75c7bf 100644
--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -939,12 +939,12 @@ out:
 	spin_unlock_irqrestore(&info->v2p_lock, flags);
 
 out_free:
-	mutex_lock(&tpg->tv_tpg_mutex);
-	tpg->tv_tpg_fe_count--;
-	mutex_unlock(&tpg->tv_tpg_mutex);
-
-	if (err)
+	if (err) {
+		mutex_lock(&tpg->tv_tpg_mutex);
+		tpg->tv_tpg_fe_count--;
+		mutex_unlock(&tpg->tv_tpg_mutex);
 		kfree(new);
+	}
 
 	return err;
 }