[tip: irq/core] PCI/MSI: Check for MSI enabled in __pci_msix_enable()

[tip-bot2 for Thomas Gleixner]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     fe97f59a78fefda6c4a8c8ee6a070b1f769fc801
Gitweb:        https://git.kernel.org/tip/fe97f59a78fefda6c4a8c8ee6a070b1f769fc801
Author:        Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate:    Fri, 11 Nov 2022 14:54:15 +01:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Thu, 17 Nov 2022 15:15:18 +01:00

PCI/MSI: Check for MSI enabled in __pci_msix_enable()

PCI/MSI and PCI/MSI-X are mutually exclusive, but the MSI-X enable code
lacks a check for already enabled MSI.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Ashok Raj <ashok.raj@xxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221111122013.653556720@xxxxxxxxxxxxx

---
 drivers/pci/msi/msi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index fdd2ec0..160af9f 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -935,6 +935,11 @@ static int __pci_enable_msix_range(struct pci_dev *dev,
 	if (maxvec < minvec)
 		return -ERANGE;
 
+	if (dev->msi_enabled) {
+		pci_info(dev, "can't enable MSI-X (MSI already enabled)\n");
+		return -EINVAL;
+	}
+
 	if (WARN_ON_ONCE(dev->msix_enabled))
 		return -EINVAL;