[PATCH kernel 2/2] powerpc/powernv/ioda2: Delay PE disposal

[Alexey Kardashevskiy <aik@ozlabs.ru>]

When SRIOV is disabled, the existing code presumes there is no
virtual function (VF) in use and destroys all associated PEs.
However it is possible to get into the situation when the user
activated SRIOV disabling while a VF is still in use via VFIO.
For example, unbinding a physical function (PF) while there is a guest
running with a VF passed throuhgh via VFIO will trigger the bug.

This defines an IODA2-specific IOMMU group release() callback.
This moves all the disposal code from pnv_ioda_release_vf_PE() to this
new callback so the cleanup happens when the last user of an IOMMU
group released the reference.

As pnv_pci_ioda2_release_dma_pe() was reduced to just calling
iommu_group_put(), this merges pnv_pci_ioda2_release_dma_pe()
into pnv_ioda_release_vf_PE().

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/platforms/powernv/pci-ioda.c | 33 +++++++++++++------------------
 1 file changed, 14 insertions(+), 19 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index ce9f2bf..8108c54 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1333,27 +1333,25 @@ static void pnv_pci_ioda2_set_bypass(struct pnv_ioda_pe *pe, bool enable);
 static void pnv_pci_ioda2_group_release(void *iommu_data)
 {
 	struct iommu_table_group *table_group = iommu_data;
+	struct pnv_ioda_pe *pe = container_of(table_group,
+			struct pnv_ioda_pe, table_group);
+	struct pci_controller *hose = pci_bus_to_host(pe->parent_dev->bus);
+	struct pnv_phb *phb = hose->private_data;
+	struct iommu_table *tbl = pe->table_group.tables[0];
+	int64_t rc;
 
-	table_group->group = NULL;
-}
-
-static void pnv_pci_ioda2_release_dma_pe(struct pci_dev *dev, struct pnv_ioda_pe *pe)
-{
-	struct iommu_table    *tbl;
-	int64_t               rc;
-
-	tbl = pe->table_group.tables[0];
 	rc = pnv_pci_ioda2_unset_window(&pe->table_group, 0);
 	if (rc)
 		pe_warn(pe, "OPAL error %ld release DMA window\n", rc);
 
 	pnv_pci_ioda2_set_bypass(pe, false);
-	if (pe->table_group.group) {
-		iommu_group_put(pe->table_group.group);
-		BUG_ON(pe->table_group.group);
-	}
+
+	BUG_ON(!tbl);
 	pnv_pci_ioda2_table_free_pages(tbl);
-	iommu_free_table(tbl, of_node_full_name(dev->dev.of_node));
+	iommu_free_table(tbl, of_node_full_name(pe->parent_dev->dev.of_node));
+
+	pnv_ioda_deconfigure_pe(phb, pe);
+	pnv_ioda_free_pe(phb, pe->pe_number);
 }
 
 static void pnv_ioda_release_vf_PE(struct pci_dev *pdev)
@@ -1376,16 +1374,13 @@ static void pnv_ioda_release_vf_PE(struct pci_dev *pdev)
 		if (pe->parent_dev != pdev)
 			continue;
 
-		pnv_pci_ioda2_release_dma_pe(pdev, pe);
-
 		/* Remove from list */
 		mutex_lock(&phb->ioda.pe_list_mutex);
 		list_del(&pe->list);
 		mutex_unlock(&phb->ioda.pe_list_mutex);
 
-		pnv_ioda_deconfigure_pe(phb, pe);
-
-		pnv_ioda_free_pe(phb, pe->pe_number);
+		if (pe->table_group.group)
+			iommu_group_put(pe->table_group.group);
 	}
 }
 
-- 
2.5.0.rc3