5 files changed, 62 insertions, 28 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index b36762246265..c8a7c2eb6490 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -106,6 +106,3 @@ config HAVE_CLK
 config HAVE_DYN_ARRAY
         def_bool n
 
-config HAVE_SPARSE_IRQ
-        def_bool n
-
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b157e94637bf..600584b7a497 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -34,7 +34,6 @@ config X86
         select HAVE_GENERIC_DMA_COHERENT if X86_32
         select HAVE_EFFICIENT_UNALIGNED_ACCESS
         select HAVE_DYN_ARRAY
-        select HAVE_SPARSE_IRQ
 
 config ARCH_DEFCONFIG
         string
@@ -238,6 +237,17 @@ config SMP
 
           If you don't know what to do here, say N.
 
+config HAVE_SPARSE_IRQ
+        bool "Support sparse irq numbering"
+        depends on PCI_MSI || HT_IRQ
+        default y
+        help
+          This enables support for sparse irq, esp for msi/msi-x. the irq
+          number will be bus/dev/fn + 12bit. You may need if you have lots of
+          cards supports msi-x installed.
+
+          If you don't know what to do here, say Y.
+
 config X86_FIND_SMP_CONFIG
         def_bool y
         depends on X86_MPPARSE || X86_VOYAGER
diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index bf0e66d73030..f853b667fa5c 100644
--- a/arch/x86/kernel/io_apic.c
+++ b/arch/x86/kernel/io_apic.c
@@ -107,7 +107,9 @@ struct irq_cfg;
 struct irq_pin_list;
 struct irq_cfg {
         unsigned int irq;
+#ifdef CONFIG_HAVE_SPARSE_IRQ
         struct irq_cfg *next;
+#endif
         struct irq_pin_list *irq_2_pin;
         cpumask_t domain;
         cpumask_t old_domain;
@@ -137,20 +139,6 @@ static struct irq_cfg irq_cfg_legacy[] __initdata = {
 };
 
 static struct irq_cfg irq_cfg_init = { .irq =  -1U, };
-/* need to be biger than size of irq_cfg_legacy */
-static int nr_irq_cfg = 32;
-
-static int __init parse_nr_irq_cfg(char *arg)
-{
-        if (arg) {
-                nr_irq_cfg = simple_strtoul(arg, NULL, 0);
-                if (nr_irq_cfg < 32)
-                        nr_irq_cfg = 32;
-        }
-        return 0;
-}
-
-early_param("nr_irq_cfg", parse_nr_irq_cfg);
 
 static void init_one_irq_cfg(struct irq_cfg *cfg)
 {
@@ -158,7 +146,9 @@ static void init_one_irq_cfg(struct irq_cfg *cfg)
 }
 
 static struct irq_cfg *irq_cfgx;
+#ifdef CONFIG_HAVE_SPARSE_IRQ
 static struct irq_cfg *irq_cfgx_free;
+#endif
 static void __init init_work(void *data)
 {
         struct dyn_array *da = data;
@@ -174,15 +164,34 @@ static void __init init_work(void *data)
         for (i = legacy_count; i < *da->nr; i++)
                 init_one_irq_cfg(&cfg[i]);
 
+#ifdef CONFIG_HAVE_SPARSE_IRQ
         for (i = 1; i < *da->nr; i++)
                 cfg[i-1].next = &cfg[i];
 
         irq_cfgx_free = &irq_cfgx[legacy_count];
         irq_cfgx[legacy_count - 1].next = NULL;
+#endif
+}
+
+#ifdef CONFIG_HAVE_SPARSE_IRQ
+/* need to be biger than size of irq_cfg_legacy */
+static int nr_irq_cfg = 32;
+
+static int __init parse_nr_irq_cfg(char *arg)
+{
+        if (arg) {
+                nr_irq_cfg = simple_strtoul(arg, NULL, 0);
+                if (nr_irq_cfg < 32)
+                        nr_irq_cfg = 32;
+        }
+        return 0;
 }
 
-#define for_each_irq_cfg(cfg)           \
-        for (cfg = irq_cfgx; cfg; cfg = cfg->next)
+early_param("nr_irq_cfg", parse_nr_irq_cfg);
+
+#define for_each_irq_cfg(irqX, cfg)           \
+        for (cfg = irq_cfgx, irqX = cfg->irq; cfg; cfg = cfg->next, irqX = cfg ? cfg->irq : -1U)
+
 
 DEFINE_DYN_ARRAY(irq_cfgx, sizeof(struct irq_cfg), nr_irq_cfg, PAGE_SIZE, init_work);
 
@@ -273,7 +282,26 @@ static struct irq_cfg *irq_cfg_alloc(unsigned int irq)
 #endif
         return cfg;
 }
+#else
+
+#define for_each_irq_cfg(irq, cfg)              \
+        for (irq = 0, cfg = &irq_cfgx[irq]; irq < nr_irqs; irq++, cfg = &irq_cfgx[irq])
+
+DEFINE_DYN_ARRAY(irq_cfgx, sizeof(struct irq_cfg), nr_irqs, PAGE_SIZE, init_work);
 
+struct irq_cfg *irq_cfg(unsigned int irq)
+{
+        if (irq < nr_irqs)
+                return &irq_cfgx[irq];
+
+        return NULL;
+}
+struct irq_cfg *irq_cfg_alloc(unsigned int irq)
+{
+        return irq_cfg(irq);
+}
+
+#endif
 /*
  * This is performance-critical, we want to do it O(1)
  *
@@ -1282,11 +1310,10 @@ void __setup_vector_irq(int cpu)
         struct irq_cfg *cfg;
 
         /* Mark the inuse vectors */
-        for_each_irq_cfg(cfg) {
+        for_each_irq_cfg(irq, cfg) {
                 if (!cpu_isset(cpu, cfg->domain))
                         continue;
                 vector = cfg->vector;
-                irq = cfg->irq;
                 per_cpu(vector_irq, cpu)[vector] = irq;
         }
         /* Mark the free vectors */
@@ -1563,6 +1590,7 @@ __apicdebuginit(void) print_IO_APIC(void)
         union IO_APIC_reg_03 reg_03;
         unsigned long flags;
         struct irq_cfg *cfg;
+        unsigned int irq;
 
         if (apic_verbosity == APIC_QUIET)
                 return;
@@ -1651,11 +1679,11 @@ __apicdebuginit(void) print_IO_APIC(void)
         }
         }
         printk(KERN_DEBUG "IRQ to pin mappings:\n");
-        for_each_irq_cfg(cfg) {
+        for_each_irq_cfg(irq, cfg) {
                 struct irq_pin_list *entry = cfg->irq_2_pin;
                 if (!entry)
                         continue;
-                printk(KERN_DEBUG "IRQ%d ", cfg->irq);
+                printk(KERN_DEBUG "IRQ%d ", irq);
                 for (;;) {
                         printk("-> %d:%d", entry->apic, entry->pin);
                         if (!entry->next)
@@ -2535,8 +2563,7 @@ static inline void init_IO_APIC_traps(void)
          * Also, we've got to be careful not to trash gate
          * 0x80, because int 0x80 is hm, kind of importantish. ;)
          */
-        for_each_irq_cfg(cfg) {
-                irq = cfg->irq;
+        for_each_irq_cfg(irq, cfg) {
                 if (IO_APIC_IRQ(irq) && !cfg->vector) {
                         /*
                          * Hmm.. We don't have an entry for this,
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index cc929f2f84f1..b2e1082cf5ad 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -269,7 +269,7 @@ int show_interrupts(struct seq_file *p, void *v)
         struct irqaction * action;
         unsigned long flags;
         unsigned int entries;
-        struct irq_desc *desc;
+        struct irq_desc *desc = NULL;
         int tail = 0;
 
 #ifdef CONFIG_HAVE_SPARSE_IRQ
diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 348a11168c2b..c2fca89a3f7e 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -74,7 +74,7 @@ int show_interrupts(struct seq_file *p, void *v)
         struct irqaction * action;
         unsigned long flags;
         unsigned int entries;
-        struct irq_desc *desc;
+        struct irq_desc *desc = NULL;
         int tail = 0;
 
 #ifdef CONFIG_HAVE_SPARSE_IRQ