[ 47/53] dca: check against empty dca_domains list before unregister provider

From: Greg Kroah-Hartman
Date: Tue Feb 26 2013 - 19:04:50 EST

3.0-stable review patch. If anyone has any objections, please let me know.


From: Maciej Sosnowski <maciej.sosnowski@xxxxxxxxx>

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@xxxxxxxxxx>
Tested-by: Gaohuai Han <hangaohuai@xxxxxxxxxx>
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@xxxxxxxxx>
Signed-off-by: Dan Williams <djbw@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

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

--- a/drivers/dca/dca-core.c
+++ b/drivers/dca/dca-core.c
@@ -409,6 +409,11 @@ void unregister_dca_provider(struct dca_

spin_lock_irqsave(&dca_lock, flags);

+ if (list_empty(&dca_domains)) {
+ raw_spin_unlock_irqrestore(&dca_lock, flags);
+ return;
+ }

pci_rc = dca_pci_rc_from_dev(dev);

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