ahci: Fix broken fallback to single MSI mode

Commit 7b92b4f61ec4 ("PCI/MSI: Remove pci_enable_msi_block_auto()")
introduced a regression: if multiple MSI initialization fails, the code
falls back to INTx rather than to single MSI.

Fixes: 7b92b4f61ec4 ("PCI/MSI: Remove pci_enable_msi_block_auto()")
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Tejun Heo <tj@kernel.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index dc2756fb6f33..3c5f35ef7e55 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1170,8 +1170,10 @@ static int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
 
         nvec = rc;
         rc = pci_enable_msi_block(pdev, nvec);
-        if (rc)
+        if (rc < 0)
                 goto intx;
+        else if (rc > 0)
+                goto single_msi;
 
         return nvec;