PCI/MSI: Remove pci_enable_msi_block_auto()

The new pci_msi_vec_count() interface makes pci_enable_msi_block_auto()
superfluous.

Drivers can use pci_msi_vec_count() to learn the maximum number of MSIs
supported by the device, and then call pci_enable_msi_block().

pci_enable_msi_block_auto() was introduced recently, and its only user is
the AHCI driver, which is also updated by this change.

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, 35 insertions, 21 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index e2903d03180e..8516f4d47893 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -1095,26 +1095,40 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
 {}
 #endif
 
-int ahci_init_interrupts(struct pci_dev *pdev, struct ahci_host_priv *hpriv)
+int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
+                         struct ahci_host_priv *hpriv)
 {
-        int rc;
-        unsigned int maxvec;
+        int rc, nvec;
 
-        if (!(hpriv->flags & AHCI_HFLAG_NO_MSI)) {
-                rc = pci_enable_msi_block_auto(pdev, &maxvec);
-                if (rc > 0) {
-                        if ((rc == maxvec) || (rc == 1))
-                                return rc;
-                        /*
-                         * Assume that advantage of multipe MSIs is negated,
-                         * so fallback to single MSI mode to save resources
-                         */
-                        pci_disable_msi(pdev);
-                        if (!pci_enable_msi(pdev))
-                                return 1;
-                }
-        }
+        if (hpriv->flags & AHCI_HFLAG_NO_MSI)
+                goto intx;
+
+        rc = pci_msi_vec_count(pdev);
+        if (rc < 0)
+                goto intx;
+
+        /*
+         * If number of MSIs is less than number of ports then Sharing Last
+         * Message mode could be enforced. In this case assume that advantage
+         * of multipe MSIs is negated and use single MSI mode instead.
+         */
+        if (rc < n_ports)
+                goto single_msi;
+
+        nvec = rc;
+        rc = pci_enable_msi_block(pdev, nvec);
+        if (rc)
+                goto intx;
 
+        return nvec;
+
+single_msi:
+        rc = pci_enable_msi(pdev);
+        if (rc)
+                goto intx;
+        return 1;
+
+intx:
         pci_intx(pdev, 1);
         return 0;
 }
@@ -1281,10 +1295,6 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
         hpriv->mmio = pcim_iomap_table(pdev)[ahci_pci_bar];
 
-        n_msis = ahci_init_interrupts(pdev, hpriv);
-        if (n_msis > 1)
-                hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
-
         /* save initial config */
         ahci_pci_save_initial_config(pdev, hpriv);
 
@@ -1339,6 +1349,10 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
          */
         n_ports = max(ahci_nr_ports(hpriv->cap), fls(hpriv->port_map));
 
+        n_msis = ahci_init_interrupts(pdev, n_ports, hpriv);
+        if (n_msis > 1)
+                hpriv->flags |= AHCI_HFLAG_MULTI_MSI;
+
         host = ata_host_alloc_pinfo(&pdev->dev, ppi, n_ports);
         if (!host)
                 return -ENOMEM;