Merge: Updates for powerpc EEH

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/4750

Description: Updates for powerpc EEH

JIRA: https://issues.redhat.com/browse/RHEL-45149

Build Info: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=62627363

Tested: Verified Brew build test kernel RPMs and confirmed issue is resovled

Signed-off-by: Mamatha Inamdar <minamdar@redhat.com>

commit a1216e6
Author: Ganesh Goudar <ganeshgr@linux.ibm.com>
Date:   Mon Jun 17 19:32:40 2024 +0530

    powerpc/eeh: avoid possible crash when edev->pdev changes

    If a PCI device is removed during eeh_pe_report_edev(), edev->pdev
    will change and can cause a crash, hold the PCI rescan/remove lock
    while taking a copy of edev->pdev->bus.

    Signed-off-by: Ganesh Goudar <ganeshgr@linux.ibm.com>
    Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
    Link: https://msgid.link/20240617140240.580453-1-ganeshgr@linux.ibm.com

Signed-off-by: Mamatha Inamdar <minamdar@redhat.com>

Approved-by: Steve Best <sbest@redhat.com>
Approved-by: Tony Camuso <tcamuso@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

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

Author: zampierilucas

arch/powerpc/kernel/eeh_pe.c

@@ -849,6 +849,7 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
 {
 	struct eeh_dev *edev;
 	struct pci_dev *pdev;
+	struct pci_bus *bus = NULL;
 
 	if (pe->type & EEH_PE_PHB)
 		return pe->phb->bus;
@@ -859,9 +860,11 @@ struct pci_bus *eeh_pe_bus_get(struct eeh_pe *pe)
 
 	/* Retrieve the parent PCI bus of first (top) PCI device */
 	edev = list_first_entry_or_null(&pe->edevs, struct eeh_dev, entry);
+	pci_lock_rescan_remove();
 	pdev = eeh_dev_to_pci_dev(edev);
 	if (pdev)
-		return pdev->bus;
+		bus = pdev->bus;
+	pci_unlock_rescan_remove();
 
-	return NULL;
+	return bus;
 }