[ 80/86] dca: check against empty dca_domains list before unregister provider

Greg Kroah-Hartman
2013-02-27T00:09:41Z

From: Maciej Sosnowski <maciej.sosnowski@intel.com>

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/dca/dca-core.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/dca/dca-core.c
+++ b/drivers/dca/dca-core.c
@@ -420,6 +420,11 @@ void unregister_dca_provider(struct dca_

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);