generic: sparse irqs: use irq_desc() together with dyn_array, instead of irq_desc[]

add CONFIG_HAVE_SPARSE_IRQ to for use condensed array.
Get rid of irq_desc[] array assumptions.

Preallocate 32 irq_desc, and irq_desc() will try to get more.

( No change in functionality is expected anywhere, except the odd build
  failure where we missed a code site or where a crossing commit itroduces
  new irq_desc[] usage. )

v2: according to Eric, change get_irq_desc() to irq_desc()

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 49 insertions, 26 deletions

diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
index 93a3ffabfe6a..cab5a25d81b1 100644
--- a/arch/x86/kernel/io_apic_64.c
+++ b/arch/x86/kernel/io_apic_64.c
@@ -345,6 +345,7 @@ static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t mask)
         unsigned long flags;
         unsigned int dest;
         cpumask_t tmp;
+        struct irq_desc *desc;
 
         cpus_and(tmp, mask, cpu_online_map);
         if (cpus_empty(tmp))
@@ -361,9 +362,10 @@ static void set_ioapic_affinity_irq(unsigned int irq, cpumask_t mask)
          */
         dest = SET_APIC_LOGICAL_ID(dest);
 
+        desc = irq_to_desc(irq);
         spin_lock_irqsave(&ioapic_lock, flags);
         __target_IO_APIC_irq(irq, dest, cfg->vector);
-        irq_desc[irq].affinity = mask;
+        desc->affinity = mask;
         spin_unlock_irqrestore(&ioapic_lock, flags);
 }
 #endif
@@ -933,14 +935,17 @@ static struct irq_chip ir_ioapic_chip;
 
 static void ioapic_register_intr(int irq, unsigned long trigger)
 {
+        struct irq_desc *desc;
+
+        desc = irq_to_desc(irq);
         if (trigger)
-                irq_desc[irq].status |= IRQ_LEVEL;
+                desc->status |= IRQ_LEVEL;
         else
-                irq_desc[irq].status &= ~IRQ_LEVEL;
+                desc->status &= ~IRQ_LEVEL;
 
 #ifdef CONFIG_INTR_REMAP
         if (irq_remapped(irq)) {
-                irq_desc[irq].status |= IRQ_MOVE_PCNTXT;
+                desc->status |= IRQ_MOVE_PCNTXT;
                 if (trigger)
                         set_irq_chip_and_handler_name(irq, &ir_ioapic_chip,
                                                       handle_fasteoi_irq,
@@ -1596,10 +1601,10 @@ static DECLARE_DELAYED_WORK(ir_migration_work, ir_irq_migration);
 static void migrate_ioapic_irq(int irq, cpumask_t mask)
 {
         struct irq_cfg *cfg = irq_cfg + irq;
-        struct irq_desc *desc = irq_desc + irq;
+        struct irq_desc *desc;
         cpumask_t tmp, cleanup_mask;
         struct irte irte;
-        int modify_ioapic_rte = desc->status & IRQ_LEVEL;
+        int modify_ioapic_rte;
         unsigned int dest;
         unsigned long flags;
 
@@ -1616,6 +1621,8 @@ static void migrate_ioapic_irq(int irq, cpumask_t mask)
         cpus_and(tmp, cfg->domain, mask);
         dest = cpu_mask_to_apicid(tmp);
 
+        desc = irq_to_desc(irq);
+        modify_ioapic_rte = desc->status & IRQ_LEVEL;
         if (modify_ioapic_rte) {
                 spin_lock_irqsave(&ioapic_lock, flags);
                 __target_IO_APIC_irq(irq, dest, cfg->vector);
@@ -1637,12 +1644,13 @@ static void migrate_ioapic_irq(int irq, cpumask_t mask)
                 cfg->move_in_progress = 0;
         }
 
-        irq_desc[irq].affinity = mask;
+        desc->affinity = mask;
 }
 
 static int migrate_irq_remapped_level(int irq)
 {
         int ret = -1;
+        struct irq_desc *desc = irq_to_desc(irq);
 
         mask_IO_APIC_irq(irq);
 
@@ -1658,11 +1666,11 @@ static int migrate_irq_remapped_level(int irq)
         }
 
         /* everthing is clear. we have right of way */
-        migrate_ioapic_irq(irq, irq_desc[irq].pending_mask);
+        migrate_ioapic_irq(irq, desc->pending_mask);
 
         ret = 0;
-        irq_desc[irq].status &= ~IRQ_MOVE_PENDING;
-        cpus_clear(irq_desc[irq].pending_mask);
+        desc->status &= ~IRQ_MOVE_PENDING;
+        cpus_clear(desc->pending_mask);
 
 unmask:
         unmask_IO_APIC_irq(irq);
@@ -1674,7 +1682,7 @@ static void ir_irq_migration(struct work_struct *work)
         int irq;
 
         for (irq = 0; irq < nr_irqs; irq++) {
-                struct irq_desc *desc = irq_desc + irq;
+                struct irq_desc *desc = irq_to_desc(irq);
                 if (desc->status & IRQ_MOVE_PENDING) {
                         unsigned long flags;
 
@@ -1686,8 +1694,7 @@ static void ir_irq_migration(struct work_struct *work)
                                 continue;
                         }
 
-                        desc->chip->set_affinity(irq,
-                                                 irq_desc[irq].pending_mask);
+                        desc->chip->set_affinity(irq, desc->pending_mask);
                         spin_unlock_irqrestore(&desc->lock, flags);
                 }
         }
@@ -1698,9 +1705,11 @@ static void ir_irq_migration(struct work_struct *work)
  */
 static void set_ir_ioapic_affinity_irq(unsigned int irq, cpumask_t mask)
 {
-        if (irq_desc[irq].status & IRQ_LEVEL) {
-                irq_desc[irq].status |= IRQ_MOVE_PENDING;
-                irq_desc[irq].pending_mask = mask;
+        struct irq_desc *desc = irq_to_desc(irq);
+
+        if (desc->status & IRQ_LEVEL) {
+                desc->status |= IRQ_MOVE_PENDING;
+                desc->pending_mask = mask;
                 migrate_irq_remapped_level(irq);
                 return;
         }
@@ -1725,7 +1734,7 @@ asmlinkage void smp_irq_move_cleanup_interrupt(void)
                 if (irq >= nr_irqs)
                         continue;
 
-                desc = irq_desc + irq;
+                desc = irq_to_desc(irq);
                 cfg = irq_cfg + irq;
                 spin_lock(&desc->lock);
                 if (!cfg->move_cleanup_count)
@@ -1791,7 +1800,7 @@ static void ack_apic_level(unsigned int irq)
         irq_complete_move(irq);
 #ifdef CONFIG_GENERIC_PENDING_IRQ
         /* If we are moving the irq we need to mask it */
-        if (unlikely(irq_desc[irq].status & IRQ_MOVE_PENDING)) {
+        if (unlikely(irq_to_desc(irq)->status & IRQ_MOVE_PENDING)) {
                 do_unmask_irq = 1;
                 mask_IO_APIC_irq(irq);
         }
@@ -1868,6 +1877,7 @@ static struct irq_chip ir_ioapic_chip __read_mostly = {
 static inline void init_IO_APIC_traps(void)
 {
         int irq;
+        struct irq_desc *desc;
 
         /*
          * NOTE! The local APIC isn't very good at handling
@@ -1889,9 +1899,11 @@ static inline void init_IO_APIC_traps(void)
                          */
                         if (irq < 16)
                                 make_8259A_irq(irq);
-                        else
+                        else {
+                                desc = irq_to_desc(irq);
                                 /* Strange. Oh, well.. */
-                                irq_desc[irq].chip = &no_irq_chip;
+                                desc->chip = &no_irq_chip;
+                        }
                 }
         }
 }
@@ -1926,7 +1938,10 @@ static struct irq_chip lapic_chip __read_mostly = {
 
 static void lapic_register_intr(int irq)
 {
-        irq_desc[irq].status &= ~IRQ_LEVEL;
+        struct irq_desc *desc;
+
+        desc = irq_to_desc(irq);
+        desc->status &= ~IRQ_LEVEL;
         set_irq_chip_and_handler_name(irq, &lapic_chip, handle_edge_irq,
                                       "edge");
 }
@@ -2402,6 +2417,7 @@ static void set_msi_irq_affinity(unsigned int irq, cpumask_t mask)
         struct msi_msg msg;
         unsigned int dest;
         cpumask_t tmp;
+        struct irq_desc *desc;
 
         cpus_and(tmp, mask, cpu_online_map);
         if (cpus_empty(tmp))
@@ -2421,7 +2437,8 @@ static void set_msi_irq_affinity(unsigned int irq, cpumask_t mask)
         msg.address_lo |= MSI_ADDR_DEST_ID(dest);
 
         write_msi_msg(irq, &msg);
-        irq_desc[irq].affinity = mask;
+        desc = irq_to_desc(irq);
+        desc->affinity = mask;
 }
 
 #ifdef CONFIG_INTR_REMAP
@@ -2435,6 +2452,7 @@ static void ir_set_msi_irq_affinity(unsigned int irq, cpumask_t mask)
         unsigned int dest;
         cpumask_t tmp, cleanup_mask;
         struct irte irte;
+        struct irq_desc *desc;
 
         cpus_and(tmp, mask, cpu_online_map);
         if (cpus_empty(tmp))
@@ -2469,7 +2487,8 @@ static void ir_set_msi_irq_affinity(unsigned int irq, cpumask_t mask)
                 cfg->move_in_progress = 0;
         }
 
-        irq_desc[irq].affinity = mask;
+        desc = irq_to_desc(irq);
+        desc->affinity = mask;
 }
 #endif
 #endif /* CONFIG_SMP */
@@ -2543,7 +2562,7 @@ static int setup_msi_irq(struct pci_dev *dev, struct msi_desc *desc, int irq)
 
 #ifdef CONFIG_INTR_REMAP
         if (irq_remapped(irq)) {
-                struct irq_desc *desc = irq_desc + irq;
+                struct irq_desc *desc = irq_to_desc(irq);
                 /*
                  * irq migration in process context
                  */
@@ -2655,6 +2674,7 @@ static void dmar_msi_set_affinity(unsigned int irq, cpumask_t mask)
         struct msi_msg msg;
         unsigned int dest;
         cpumask_t tmp;
+        struct irq_desc *desc;
 
         cpus_and(tmp, mask, cpu_online_map);
         if (cpus_empty(tmp))
@@ -2674,7 +2694,8 @@ static void dmar_msi_set_affinity(unsigned int irq, cpumask_t mask)
         msg.address_lo |= MSI_ADDR_DEST_ID(dest);
 
         dmar_msi_write(irq, &msg);
-        irq_desc[irq].affinity = mask;
+        desc = irq_to_desc(irq);
+        desc->affinity = mask;
 }
 #endif /* CONFIG_SMP */
 
@@ -2731,6 +2752,7 @@ static void set_ht_irq_affinity(unsigned int irq, cpumask_t mask)
         struct irq_cfg *cfg = irq_cfg + irq;
         unsigned int dest;
         cpumask_t tmp;
+        struct irq_desc *desc;
 
         cpus_and(tmp, mask, cpu_online_map);
         if (cpus_empty(tmp))
@@ -2743,7 +2765,8 @@ static void set_ht_irq_affinity(unsigned int irq, cpumask_t mask)
         dest = cpu_mask_to_apicid(tmp);
 
         target_ht_irq(irq, dest, cfg->vector);
-        irq_desc[irq].affinity = mask;
+        desc = irq_to_desc(irq);
+        desc->affinity = mask;
 }
 #endif