From: Bhavna Sarathy <bnagendr@redhat.com>
Date: Mon, 8 Jun 2009 15:37:40 -0400
Subject: [x86_64] amd iommu: fix spinlock imbalance
Message-id: 20090608193844.7837.79868.sendpatchset@localhost.localdomain
O-Subject: [RHEL5.4 PATCH 5/5] [KVM] Fix spinlock imbalance in AMD IOMMU driver
Bugzilla: 501571
RH-Acked-by: Rik van Riel <riel@redhat.com>
RH-Acked-by: Juan Quintela <quintela@redhat.com>
RH-Acked-by: Don Dutile <ddutile@redhat.com>

Resolves BZ 501571

In alloc_coherent there is an omitted unlock on the path where mapping
fails. Add the unlock.

diff --git a/arch/x86_64/kernel/amd_iommu.c b/arch/x86_64/kernel/amd_iommu.c
index 5379f85..75176eb 100644
--- a/arch/x86_64/kernel/amd_iommu.c
+++ b/arch/x86_64/kernel/amd_iommu.c
@@ -1536,8 +1536,10 @@ static void *alloc_coherent(struct device *dev, size_t size,
 	*dma_addr = __map_single(dev, iommu, domain->priv, paddr,
 				 size, DMA_BIDIRECTIONAL, true, dma_mask);
 
-	if (*dma_addr == bad_dma_address)
+	if (*dma_addr == bad_dma_address) {
+		spin_unlock_irqrestore(&domain->lock, flags);
 		goto out_free;
+	}
 
 	iommu_completion_wait(iommu);