linux-kernel - [PATCH 1/1] vfio iommu type1: WARN_ON if notifier block is not unregistered

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Date:   Tue, 6 Dec 2016 02:38:20 +0530
From:   Kirti Wankhede <kwankhede@...dia.com>
To:     <alex.williamson@...hat.com>, <pbonzini@...hat.com>,
        <kraxel@...hat.com>, <cjia@...dia.com>
CC:     <qemu-devel@...gnu.org>, <kvm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Kirti Wankhede <kwankhede@...dia.com>
Subject: [PATCH 1/1] vfio iommu type1: WARN_ON if notifier block is not unregistered

mdev vendor driver should unregister the iommu notifier since the vfio
iommu can persist beyond the attachment of the mdev group. WARN_ON will
show warning if vendor driver doesn't unregister the notifier and is
forced to follow the implementations steps.

Signed-off-by: Kirti Wankhede <kwankhede@...dia.com>
Signed-off-by: Neo Jia <cjia@...dia.com>
Change-Id: I75fd0a40e582a144fe7a037c7140d3513e8ff030
---
 drivers/vfio/vfio_iommu_type1.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 023fba7b8d5a..37871ee0c0c5 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -1361,6 +1361,8 @@ static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu)
 		if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list)))
 			break;
 	}
+	/* mdev venfor driver must unregister notifier */
+	WARN_ON(iommu->notifier.head);
 }
 
 static void vfio_iommu_type1_detach_group(void *iommu_data,
-- 
2.7.0