cxl: Clean up adapter MMIO unmap path.

- MMIO pointer unmapping is guarded by a null pointer check.
   However, iounmap doesn't null the pointer, just invalidate it.
   Therefore, explicitly null the pointer after unmapping.

 - afu_desc_mmio also needs to be unmapped.

 - PCI regions are allocated in cxl_map_adapter_regs.
   Therefore they should be released in unmap, not elsewhere.

Acked-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

drivers/misc/cxl/pci.c

@@ -539,10 +539,18 @@ err:
 
 static void cxl_unmap_slice_regs(struct cxl_afu *afu)
 {
-	if (afu->p2n_mmio)
+	if (afu->p2n_mmio) {
 		iounmap(afu->p2n_mmio);
-	if (afu->p1n_mmio)
+		afu->p2n_mmio = NULL;
+	}
+	if (afu->p1n_mmio) {
 		iounmap(afu->p1n_mmio);
+		afu->p1n_mmio = NULL;
+	}
+	if (afu->afu_desc_mmio) {
+		iounmap(afu->afu_desc_mmio);
+		afu->afu_desc_mmio = NULL;
+	}
 }
 
 static void cxl_release_afu(struct device *dev)
@@ -920,10 +928,16 @@ err1:
 
 static void cxl_unmap_adapter_regs(struct cxl *adapter)
 {
-	if (adapter->p1_mmio)
+	if (adapter->p1_mmio) {
 		iounmap(adapter->p1_mmio);
-	if (adapter->p2_mmio)
+		adapter->p1_mmio = NULL;
+		pci_release_region(to_pci_dev(adapter->dev.parent), 2);
+	}
+	if (adapter->p2_mmio) {
 		iounmap(adapter->p2_mmio);
+		adapter->p2_mmio = NULL;
+		pci_release_region(to_pci_dev(adapter->dev.parent), 0);
+	}
 }
 
 static int cxl_read_vsec(struct cxl *adapter, struct pci_dev *dev)
@@ -1132,8 +1146,6 @@ static void cxl_remove_adapter(struct cxl *adapter)
 
 	device_unregister(&adapter->dev);
 
-	pci_release_region(pdev, 0);
-	pci_release_region(pdev, 2);
 	pci_disable_device(pdev);
 }