[Patch Part3 v4 35/38] x86, irq: Refine the way to calculate NR_IRQS

From: Jiang Liu
Date: Tue Nov 25 2014 - 02:56:24 EST


Now we have made MSI independent of IOAPIC, so we need to refine the
way to calculate NR_IRQS to support configuration with MSI enabled but
IOAPIC disabled.

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
Tested-by: Joerg Roedel <jroedel@xxxxxxx>
---
arch/x86/include/asm/irq_vectors.h | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
index 666c89ec4bd7..b26cb124a4f1 100644
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -155,18 +155,22 @@ static inline int invalid_vm86_irq(int irq)
* static arrays.
*/

-#define NR_IRQS_LEGACY 16
+#define NR_IRQS_LEGACY 16

-#define IO_APIC_VECTOR_LIMIT ( 32 * MAX_IO_APICS )
+#define CPU_VECTOR_LIMIT (64 * NR_CPUS)
+#define IO_APIC_VECTOR_LIMIT (32 * MAX_IO_APICS)

-#ifdef CONFIG_X86_IO_APIC
-# define CPU_VECTOR_LIMIT (64 * NR_CPUS)
-# define NR_IRQS \
+#if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_PCI_MSI)
+#define NR_IRQS \
(CPU_VECTOR_LIMIT > IO_APIC_VECTOR_LIMIT ? \
(NR_VECTORS + CPU_VECTOR_LIMIT) : \
(NR_VECTORS + IO_APIC_VECTOR_LIMIT))
-#else /* !CONFIG_X86_IO_APIC: */
-# define NR_IRQS NR_IRQS_LEGACY
+#elif defined(CONFIG_X86_IO_APIC)
+#define NR_IRQS (NR_VECTORS + IO_APIC_VECTOR_LIMIT)
+#elif defined(CONFIG_PCI_MSI)
+#define NR_IRQS (NR_VECTORS + CPU_VECTOR_LIMIT)
+#else
+#define NR_IRQS NR_IRQS_LEGACY
#endif

#endif /* _ASM_X86_IRQ_VECTORS_H */
--
1.7.10.4

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