release/src-rt-6.x.4708/linux/linux-2.6.36/kernel/irq/numa_migrate.c

   1 /*
   2  * NUMA irq-desc migration code
   3  *
   4  * Migrate IRQ data structures (irq_desc, chip_data, etc.) over to
   5  * the new "home node" of the IRQ.
   6  */
   7
   8 #include <linux/irq.h>
   9 #include <linux/slab.h>
  10 #include <linux/module.h>
  11 #include <linux/random.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/kernel_stat.h>
  14
  15 #include "internals.h"
  16
  17 static void init_copy_kstat_irqs(struct irq_desc *old_desc,
  18                                  struct irq_desc *desc,
  19                                  int node, int nr)
  20 {
  21         init_kstat_irqs(desc, node, nr);
  22
  23         if (desc->kstat_irqs != old_desc->kstat_irqs)
  24                 memcpy(desc->kstat_irqs, old_desc->kstat_irqs,
  25                          nr * sizeof(*desc->kstat_irqs));
  26 }
  27
  28 static void free_kstat_irqs(struct irq_desc *old_desc, struct irq_desc *desc)
  29 {
  30         if (old_desc->kstat_irqs == desc->kstat_irqs)
  31                 return;
  32
  33         kfree(old_desc->kstat_irqs);
  34         old_desc->kstat_irqs = NULL;
  35 }
  36
  37 static bool init_copy_one_irq_desc(int irq, struct irq_desc *old_desc,
  38                  struct irq_desc *desc, int node)
  39 {
  40         memcpy(desc, old_desc, sizeof(struct irq_desc));
  41         if (!alloc_desc_masks(desc, node, false)) {
  42                 printk(KERN_ERR "irq %d: can not get new irq_desc cpumask "
  43                                 "for migration.\n", irq);
  44                 return false;
  45         }
  46         raw_spin_lock_init(&desc->lock);
  47         desc->node = node;
  48         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
  49         init_copy_kstat_irqs(old_desc, desc, node, nr_cpu_ids);
  50         init_copy_desc_masks(old_desc, desc);
  51         arch_init_copy_chip_data(old_desc, desc, node);
  52         return true;
  53 }
  54
  55 static void free_one_irq_desc(struct irq_desc *old_desc, struct irq_desc *desc)
  56 {
  57         free_kstat_irqs(old_desc, desc);
  58         free_desc_masks(old_desc, desc);
  59         arch_free_chip_data(old_desc, desc);
  60 }
  61
  62 static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
  63                                                 int node)
  64 {
  65         struct irq_desc *desc;
  66         unsigned int irq;
  67         unsigned long flags;
  68
  69         irq = old_desc->irq;
  70
  71         raw_spin_lock_irqsave(&sparse_irq_lock, flags);
  72
  73         /* We have to check it to avoid races with another CPU */
  74         desc = irq_to_desc(irq);
  75
  76         if (desc && old_desc != desc)
  77                 goto out_unlock;
  78
  79         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
  80         if (!desc) {
  81                 printk(KERN_ERR "irq %d: can not get new irq_desc "
  82                                 "for migration.\n", irq);
  83                 /* still use old one */
  84                 desc = old_desc;
  85                 goto out_unlock;
  86         }
  87         if (!init_copy_one_irq_desc(irq, old_desc, desc, node)) {
  88                 /* still use old one */
  89                 kfree(desc);
  90                 desc = old_desc;
  91                 goto out_unlock;
  92         }
  93
  94         replace_irq_desc(irq, desc);
  95         raw_spin_unlock_irqrestore(&sparse_irq_lock, flags);
  96
  97         /* free the old one */
  98         free_one_irq_desc(old_desc, desc);
  99         kfree(old_desc);
 100
 101         return desc;
 102
 103 out_unlock:
 104         raw_spin_unlock_irqrestore(&sparse_irq_lock, flags);
 105
 106         return desc;
 107 }
 108
 109 struct irq_desc *move_irq_desc(struct irq_desc *desc, int node)
 110 {
 111         /* those static or target node is -1, do not move them */
 112         if (desc->irq < NR_IRQS_LEGACY || node == -1)
 113                 return desc;
 114
 115         if (desc->node != node)
 116                 desc = __real_move_irq_desc(desc, node);
 117
 118         return desc;
 119 }