From: Christoph Hellwig <hch@lst.de>
Date: Wed, 1 Feb 2017 13:41:42 +0000 (+0100)
Subject: PCI/MSI: Check that we have a legacy interrupt line before using it
X-Git-Tag: v4.11-rc1~92^2~21^2~4
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=862290f9e23c39051e59bf12ce65707a8ec8b911;p=linux.git

PCI/MSI: Check that we have a legacy interrupt line before using it

It seems like there are some devices (e.g. the PCIe root port driver) that
may not always have a INTx interrupt.  Check for dev->irq before returning
a legacy interrupt in pci_irq_alloc_vectors to properly handle this case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index b44ad7c21b29..52ac675f0bd7 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -1198,9 +1198,11 @@ int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
 	}
 
 	/* use legacy irq if allowed */
-	if ((flags & PCI_IRQ_LEGACY) && min_vecs == 1) {
-		pci_intx(dev, 1);
-		return 1;
+	if (flags & PCI_IRQ_LEGACY) {
+		if (min_vecs == 1 && dev->irq) {
+			pci_intx(dev, 1);
+			return 1;
+		}
 	}
 
 	return vecs;