From: Maciej Sosnowski <maciej.sosnowski@intel.com>
Date: Wed, 23 May 2012 15:27:07 +0000 (+0200)
Subject: dca: check against empty dca_domains list before unregister provider
X-Git-Tag: v3.2.40~146
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=10928eb067be9d946771fe1adcb22bbaad43830c;p=karo-tx-linux.git

dca: check against empty dca_domains list before unregister provider

commit c419fcfd071cf34ba00f9f65282583772d2655e7 upstream.

When providers get blocked unregister_dca_providers() is called ending up
with dca_providers and dca_domain lists emptied. Dca should be prevented from
trying to unregister any provider if dca_domain list is found empty.

Reported-by: Jiang Liu <jiang.liu@huawei.com>
Tested-by: Gaohuai Han <hangaohuai@huawei.com>
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <djbw@fb.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/drivers/dca/dca-core.c b/drivers/dca/dca-core.c
index bc6f5faa1e9e..819dfda88236 100644
--- a/drivers/dca/dca-core.c
+++ b/drivers/dca/dca-core.c
@@ -420,6 +420,11 @@ void unregister_dca_provider(struct dca_provider *dca, struct device *dev)
 
 	raw_spin_lock_irqsave(&dca_lock, flags);
 
+	if (list_empty(&dca_domains)) {
+		raw_spin_unlock_irqrestore(&dca_lock, flags);
+		return;
+	}
+
 	list_del(&dca->node);
 
 	pci_rc = dca_pci_rc_from_dev(dev);