Merge: PCI: switchtec: Fix stdev_release() crash after surprise hot remove

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/3881

```
JIRA: https://issues.redhat.com/browse/RHEL-29481
CVE: CVE-2023-52617

Signed-off-by: Myron Stowe <mstowe@redhat.com>
```

Approved-by: Charles Mirabile <cmirabil@redhat.com>
Approved-by: John W. Linville <linville@redhat.com>
Approved-by: Andrew Halaney <ahalaney@redhat.com>
Approved-by: David Arcari <darcari@redhat.com>
Approved-by: Steve Best <sbest@redhat.com>
Approved-by: Lenny Szubowicz <lszubowi@redhat.com>
Approved-by: Prarit Bhargava <prarit@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Lucas Zampieri <lzampier@redhat.com>

Author: zampierilucas

drivers/pci/switch/switchtec.c

@@ -1308,13 +1308,6 @@ static void stdev_release(struct device *dev)
 {
 	struct switchtec_dev *stdev = to_stdev(dev);
 
-	if (stdev->dma_mrpc) {
-		iowrite32(0, &stdev->mmio_mrpc->dma_en);
-		flush_wc_buf(stdev);
-		writeq(0, &stdev->mmio_mrpc->dma_addr);
-		dma_free_coherent(&stdev->pdev->dev, sizeof(*stdev->dma_mrpc),
-				stdev->dma_mrpc, stdev->dma_mrpc_dma_addr);
-	}
 	kfree(stdev);
 }
 
@@ -1358,7 +1351,7 @@ static struct switchtec_dev *stdev_create(struct pci_dev *pdev)
 		return ERR_PTR(-ENOMEM);
 
 	stdev->alive = true;
-	stdev->pdev = pdev;
+	stdev->pdev = pci_dev_get(pdev);
 	INIT_LIST_HEAD(&stdev->mrpc_queue);
 	mutex_init(&stdev->mrpc_mutex);
 	stdev->mrpc_busy = 0;
@@ -1391,6 +1384,7 @@ static struct switchtec_dev *stdev_create(struct pci_dev *pdev)
 	return stdev;
 
 err_put:
+	pci_dev_put(stdev->pdev);
 	put_device(&stdev->dev);
 	return ERR_PTR(rc);
 }
@@ -1644,6 +1638,18 @@ static int switchtec_init_pci(struct switchtec_dev *stdev,
 	return 0;
 }
 
+static void switchtec_exit_pci(struct switchtec_dev *stdev)
+{
+	if (stdev->dma_mrpc) {
+		iowrite32(0, &stdev->mmio_mrpc->dma_en);
+		flush_wc_buf(stdev);
+		writeq(0, &stdev->mmio_mrpc->dma_addr);
+		dma_free_coherent(&stdev->pdev->dev, sizeof(*stdev->dma_mrpc),
+				  stdev->dma_mrpc, stdev->dma_mrpc_dma_addr);
+		stdev->dma_mrpc = NULL;
+	}
+}
+
 static int switchtec_pci_probe(struct pci_dev *pdev,
 			       const struct pci_device_id *id)
 {
@@ -1705,6 +1711,9 @@ static void switchtec_pci_remove(struct pci_dev *pdev)
 	ida_free(&switchtec_minor_ida, MINOR(stdev->dev.devt));
 	dev_info(&stdev->dev, "unregistered.\n");
 	stdev_kill(stdev);
+	switchtec_exit_pci(stdev);
+	pci_dev_put(stdev->pdev);
+	stdev->pdev = NULL;
 	put_device(&stdev->dev);
 }