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: v4.1.12-92~158^2~11^2~2
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=49c97a3e1e4fa61d7ccd042a9a4eaf68fd0d270c;p=users%2Fjedix%2Flinux-maple.git

xen/scsiback: correct frontend counting

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>
Cc: stable@vger.kernel.org
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
(cherry picked from commit f285aa8db7cc4432c1a03f8b55ff34fe96317c11)
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
---

diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
index 5099fdfba55b9..24094882b98ce 100644
--- a/drivers/xen/xen-scsiback.c
+++ b/drivers/xen/xen-scsiback.c
@@ -941,12 +941,12 @@ 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;
 }