[PATCH 2/5] PCI: Use MSI/MSI-X cap cache in pci_msi_check_device()

[Gavin Shan <shangw@linux.vnet.ibm.com>]

The function pci_msi_check_device() is called while enabling MSI
or MSI-X interrupts to make sure the PCI device can support MSI
or MSI-X capability. The patch changes the function for a bit to
use the cached MSI or MSI-X capability in pci_dev instead of polling
them from config space.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 drivers/pci/msi.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 3459bdf..5f51e10 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -772,6 +772,11 @@ static int pci_msi_check_device(struct pci_dev *dev, int nvec, int type)
 	if (!pci_msi_enable || !dev || dev->no_msi)
 		return -EINVAL;
 
+	/* Check if the PCI device has MSI or MSI-X capability */
+	if ((type == PCI_CAP_ID_MSI && !dev->msi_cap) ||
+	    (type == PCI_CAP_ID_MSIX && !dev->msix_cap))
+		return -EINVAL;
+
 	/*
 	 * You can't ask to have 0 or less MSIs configured.
 	 *  a) it's stupid ..
@@ -795,9 +800,6 @@ static int pci_msi_check_device(struct pci_dev *dev, int nvec, int type)
 	if (ret)
 		return ret;
 
-	if (!pci_find_capability(dev, type))
-		return -EINVAL;
-
 	return 0;
 }
 
-- 
1.7.5.4