ahci: don't use MSI when PCI is disabled

The AHCI driver is used for some on-chip devices that do not use PCI for probing, and it can be built even when CONFIG_PCI is disabled, but that now results in a build failure:

ata/libahci.c: In function 'ahci_host_activate_multi_irqs':
ata/libahci.c:2475:4: error: invalid use of undefined type 'struct msix_entry' ata/libahci.c:2475:21: error: dereferencing pointer to incomplete type 'struct msix_entry'

This adds an #ifdef so we use that code only if actual PCI MSI is available.

Signed-off-by Arnd Bergmann <[email protected]>

Fixes d684a90d38e2 ("ahci: per-port msix support")

drivers/ata/libahci.c +4 -1

index 1b6c7cc415bf..54fe01d8145b 100644
@@ -1796,7 +1796,8 @@ static void ahci_port_intr(struct ata_port *ap)
        ahci_handle_port_interrupt(ap, port_mmio, status);
 }
 
-static irqreturn_t ahci_multi_irqs_intr_hard(int irq, void *dev_instance)
+static irqreturn_t __maybe_unused ahci_multi_irqs_intr_hard(int irq,
+                                                           void *dev_instance)
 {
        struct ata_port *ap = dev_instance;
        void __iomem *port_mmio = ahci_port_base(ap);

@@ -2454,6 +2455,7 @@ void ahci_set_em_messages(struct ahci_host_priv *hpriv,
 }
 EXPORT_SYMBOL_GPL(ahci_set_em_messages);
 
+#ifdef CONFIG_PCI_MSI
 static int ahci_host_activate_multi_irqs(struct ata_host *host,
                                         struct scsi_host_template *sht)
 {

@@ -2492,6 +2494,7 @@ static int ahci_host_activate_multi_irqs(struct ata_host *host,
 
        return ata_host_register(host, sht);
 }
+#endif
 
 /**
  *     ahci_host_activate - start AHCI host, request IRQs and register it

@@ -2510,9 +2513,12 @@ int ahci_host_activate(struct ata_host *host, struct scsi_host_template *sht)
        int irq = hpriv->irq;
        int rc;
 

If we had an "static inline ahci_irq_vector(int port)" helper to compile out the struct msix_entry de-reference would that be sufficient?

Quoted 4 lines · On Monday 23 November 2015 09:25:38 Dan Williams wrote:

If we had an "static inline ahci_irq_vector(int port)" helper to compile out the struct msix_entry de-reference would that be sufficient?

Yes, that is probably a nicer way to do it. We should then also do something like this:

drivers/ata/libahci.c +2 -1

@@ -2510,7 +2513,8 @@ int ahci_host_activate(struct ata_host *host, struct scsi_host_template *sht)
        int irq = hpriv->irq;
        int rc;
 
-       if (hpriv->flags & (AHCI_HFLAG_MULTI_MSI | AHCI_HFLAG_MULTI_MSIX))
+       if (IS_ENABLED(CONFIG_PCI_MSI) && \
+           hpriv->flags & (AHCI_HFLAG_MULTI_MSI | AHCI_HFLAG_MULTI_MSIX))
                rc = ahci_host_activate_multi_irqs(host, sht);
        else if (hpriv->flags & AHCI_HFLAG_EDGE_IRQ)
                rc = ata_host_activate(host, irq, ahci_single_edge_irq_intr,

which will let gcc leave out the entire ahci_host_activate_multi_irqs() function but still flag compile errors in it even if CONFIG_PCI is disabled.

Quoted 20 lines · On Monday 23 November 2015 20:34:30 Arnd Bergmann wrote:

Quoted 4 lines · On Monday 23 November 2015 09:25:38 Dan Williams wrote:

If we had an "static inline ahci_irq_vector(int port)" helper to compile out the struct msix_entry de-reference would that be sufficient?

Yes, that is probably a nicer way to do it. We should then also do something like this:

drivers/ata/libahci.c +2 -1

@@ -2510,7 +2513,8 @@ int ahci_host_activate(struct ata_host *host, struct scsi_host_template *sht)
        int irq = hpriv->irq;
        int rc;
 
-       if (hpriv->flags & (AHCI_HFLAG_MULTI_MSI | AHCI_HFLAG_MULTI_MSIX))
+       if (IS_ENABLED(CONFIG_PCI_MSI) && \
+           hpriv->flags & (AHCI_HFLAG_MULTI_MSI | AHCI_HFLAG_MULTI_MSIX))
                rc = ahci_host_activate_multi_irqs(host, sht);
        else if (hpriv->flags & AHCI_HFLAG_EDGE_IRQ)
                rc = ata_host_activate(host, irq, ahci_single_edge_irq_intr,

Quoted 4 lines

which will let gcc leave out the entire ahci_host_activate_multi_irqs() function but still flag compile errors in it even if CONFIG_PCI is disabled.

Dan, are you going to do the ahci_irq_vector patch, or should we use my original patch to fix up the build error?