linux-kernel - [34-longterm 088/196] intel-iommu: Unlink domain from iommu

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Date:	Mon, 12 Mar 2012 20:20:01 -0400
From:	Paul Gortmaker <paul.gortmaker@...driver.com>
To:	stable@...nel.org, linux-kernel@...r.kernel.org
Cc:	stable-review@...nel.org,
	Alex Williamson <alex.williamson@...hat.com>,
	David Woodhouse <David.Woodhouse@...el.com>,
	Paul Gortmaker <paul.gortmaker@...driver.com>
Subject: [34-longterm 088/196] intel-iommu: Unlink domain from iommu

From: Alex Williamson <alex.williamson@...hat.com>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit a97590e56d0d58e1dd262353f7cbd84e81d8e600 upstream.

When we remove a device, we unlink the iommu from the domain, but
we never do the reverse unlinking of the domain from the iommu.
This means that we never clear iommu->domain_ids, eventually leading
to resource exhaustion if we repeatedly bind and unbind a device
to a driver.  Also free empty domains to avoid a resource leak.

Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
Acked-by: Donald Dutile <ddutile@...hat.com>
Signed-off-by: David Woodhouse <David.Woodhouse@...el.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
---
 drivers/pci/intel-iommu.c |   13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 3507692..62e92e5 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -3261,9 +3261,15 @@ static int device_notifier(struct notifier_block *nb,
 	if (!domain)
 		return 0;
 
-	if (action == BUS_NOTIFY_UNBOUND_DRIVER && !iommu_pass_through)
+	if (action == BUS_NOTIFY_UNBOUND_DRIVER && !iommu_pass_through) {
 		domain_remove_one_dev_info(domain, pdev);
 
+		if (!(domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE) &&
+		    !(domain->flags & DOMAIN_FLAG_STATIC_IDENTITY) &&
+		    list_empty(&domain->devices))
+			domain_exit(domain);
+	}
+
 	return 0;
 }
 
@@ -3412,6 +3418,11 @@ static void domain_remove_one_dev_info(struct dmar_domain *domain,
 		domain->iommu_count--;
 		domain_update_iommu_cap(domain);
 		spin_unlock_irqrestore(&domain->iommu_lock, tmp_flags);
+
+		spin_lock_irqsave(&iommu->lock, tmp_flags);
+		clear_bit(domain->id, iommu->domain_ids);
+		iommu->domains[domain->id] = NULL;
+		spin_unlock_irqrestore(&iommu->lock, tmp_flags);
 	}
 
 	spin_unlock_irqrestore(&device_domain_lock, flags);
-- 
1.7.9.3

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