From: Mark Gross Date: Tue, 4 Mar 2008 22:59:31 +0000 (-0800) Subject: PCI: iova: lockdep false alarm fix X-Git-Tag: v2.6.25-rc7~8 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8a443df40b35da89e32fcd499d7720c8c2cc2eee;p=linux-2.6 PCI: iova: lockdep false alarm fix lockdep goes off on the iova copy_reserved_iova() because it and a function it calls grabs locks in the from, and the to of the copy operation. The function grab locks of the same lock classes triggering the warning. The first lock grabbed is for the constant reserved areas that is never accessed after early boot. Technically you could do without grabbing the locks for the "from" structure its copying reserved areas from. But dropping the from locks to me looks wrong, even though it would be ok. The affected code only runs in early boot as its setting up the DMAR engines. This patch gives the reserved_ioval_list locks special lockdep classes. Signed-off-by: Mark Gross Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c index 977d29b322..4cb949f0eb 100644 --- a/drivers/pci/intel-iommu.c +++ b/drivers/pci/intel-iommu.c @@ -1097,6 +1097,8 @@ static void iommu_free_domain(struct dmar_domain *domain) } static struct iova_domain reserved_iova_list; +static struct lock_class_key reserved_alloc_key; +static struct lock_class_key reserved_rbtree_key; static void dmar_init_reserved_ranges(void) { @@ -1107,6 +1109,11 @@ static void dmar_init_reserved_ranges(void) init_iova_domain(&reserved_iova_list, DMA_32BIT_PFN); + lockdep_set_class(&reserved_iova_list.iova_alloc_lock, + &reserved_alloc_key); + lockdep_set_class(&reserved_iova_list.iova_rbtree_lock, + &reserved_rbtree_key); + /* IOAPIC ranges shouldn't be accessed by DMA */ iova = reserve_iova(&reserved_iova_list, IOVA_PFN(IOAPIC_RANGE_START), IOVA_PFN(IOAPIC_RANGE_END));