FAILED: patch "[PATCH] PCI/MSI: pci-xgene-msi: Fix CPU hotplug registration handling" failed to apply to 4.9-stable tree

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Marc Zyngier <[email protected]>
Date: Tue, 17 Jan 2017 14:21:56 +0000
Subject: [PATCH] PCI/MSI: pci-xgene-msi: Fix CPU hotplug registration handling

The conversion to the new hotplug state machine introduced a regression where a successful hotplug registration would be treated as an error, effectively disabling the MSI driver forever.

Fix it by doing the proper check on the return value.

index 1f38d0836751..f1b633bce525 100644
@@ -517,7 +517,7 @@ static int xgene_msi_probe(struct platform_device *pdev)
 
 	rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "pci/xgene:online",
 			       xgene_msi_hwirq_alloc, NULL);
-	if (rc)
+	if (rc < 0)
 		goto err_cpuhp;
 	pci_xgene_online = rc;
 	rc = cpuhp_setup_state(CPUHP_PCI_XGENE_DEAD, "pci/xgene:dead", NULL,