Re: [PATCH] ahci: don't use MSI when PCI is disabled

From: Dan Williams
Date: Mon Nov 23 2015 - 12:25:45 EST


On Mon, Nov 23, 2015 at 1:47 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> 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 <arnd@xxxxxxxx>
> Fixes: d684a90d38e2 ("ahci: per-port msix support")
>
> diff --git a/drivers/ata/libahci.c b/drivers/ata/libahci.c
> index 1b6c7cc415bf..54fe01d8145b 100644
> --- a/drivers/ata/libahci.c
> +++ b/drivers/ata/libahci.c
> @@ -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;
>
> +#ifdef CONFIG_PCI_MSI
> if (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)
> + else
> +#endif
> + if (hpriv->flags & AHCI_HFLAG_EDGE_IRQ)
> rc = ata_host_activate(host, irq, ahci_single_edge_irq_intr,
> IRQF_SHARED, sht);
> else
>

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?
--
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