linux-kernel - [PATCH 3/4] iommu/amd: Fix device

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Date:	Wed, 30 Jul 2014 16:04:39 +0200
From:	Joerg Roedel <joro@...tes.org>
To:	iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Cc:	Joerg Roedel <jroedel@...e.de>
Subject: [PATCH 3/4] iommu/amd: Fix device_state reference counting

From: Joerg Roedel <jroedel@...e.de>

The references to the device state are not dropped
everywhere. This might cause a dead-lock in
amd_iommu_free_device(). Fix it.

Signed-off-by: Joerg Roedel <jroedel@...e.de>
Tested-by: Oded Gabbay <oded.gabbay@....com>
---
 drivers/iommu/amd_iommu_v2.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/iommu/amd_iommu_v2.c b/drivers/iommu/amd_iommu_v2.c
index 524fd67..2de13be 100644
--- a/drivers/iommu/amd_iommu_v2.c
+++ b/drivers/iommu/amd_iommu_v2.c
@@ -368,6 +368,9 @@ static void free_pasid_states(struct device_state *dev_state)
 
 		put_pasid_state_wait(pasid_state); /* Reference taken in
 						      amd_iommu_pasid_bind */
+
+		/* Drop reference taken in amd_iommu_bind_pasid */
+		put_device_state(dev_state);
 	}
 
 	if (dev_state->pasid_levels == 2)
@@ -748,6 +751,10 @@ void amd_iommu_unbind_pasid(struct pci_dev *pdev, int pasid)
 	put_pasid_state_wait(pasid_state); /* Reference taken in
 					      amd_iommu_pasid_bind */
 out:
+	/* Drop reference taken in this function */
+	put_device_state(dev_state);
+
+	/* Drop reference taken in amd_iommu_bind_pasid */
 	put_device_state(dev_state);
 }
 EXPORT_SYMBOL(amd_iommu_unbind_pasid);
-- 
1.9.1

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