[PATCH] x86: fix broken flushing in GART nofullflush path

[Joerg Roedel]

In the non-default nofullflush case the GART is only flushed when
next_bit wraps around. But it can happen that an unmap operation unmaps
memory which is behind the current next_bit location. If these addresses
are reused it may result in stale GART IO/TLB entries. Fix this by
setting the GART next_bit always behind an unmapped location.

Signed-off-by: Joerg Roedel <joerg.roedel@xxxxxxx>
---
 arch/x86/kernel/pci-gart_64.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/pci-gart_64.c b/arch/x86/kernel/pci-gart_64.c
index a42b02b..ba7ad83 100644
--- a/arch/x86/kernel/pci-gart_64.c
+++ b/arch/x86/kernel/pci-gart_64.c
@@ -123,6 +123,8 @@ static void free_iommu(unsigned long offset, int size)
 
 	spin_lock_irqsave(&iommu_bitmap_lock, flags);
 	iommu_area_free(iommu_gart_bitmap, offset, size);
+	if (offset >= next_bit)
+		next_bit = offset + size;
 	spin_unlock_irqrestore(&iommu_bitmap_lock, flags);
 }
 
-- 
1.5.6.4


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