Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[linux-2.6] / 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/module.h>
10 #include <linux/random.h>
11 #include <linux/interrupt.h>
12 #include <linux/kernel_stat.h>
13
14 #include "internals.h"
15
16 static void init_copy_kstat_irqs(struct irq_desc *old_desc,
17                                  struct irq_desc *desc,
18                                  int cpu, int nr)
19 {
20         unsigned long bytes;
21
22         init_kstat_irqs(desc, cpu, nr);
23
24         if (desc->kstat_irqs != old_desc->kstat_irqs) {
25                 /* Compute how many bytes we need per irq and allocate them */
26                 bytes = nr * sizeof(unsigned int);
27
28                 memcpy(desc->kstat_irqs, old_desc->kstat_irqs, bytes);
29         }
30 }
31
32 static void free_kstat_irqs(struct irq_desc *old_desc, struct irq_desc *desc)
33 {
34         if (old_desc->kstat_irqs == desc->kstat_irqs)
35                 return;
36
37         kfree(old_desc->kstat_irqs);
38         old_desc->kstat_irqs = NULL;
39 }
40
41 static void init_copy_one_irq_desc(int irq, struct irq_desc *old_desc,
42                  struct irq_desc *desc, int cpu)
43 {
44         memcpy(desc, old_desc, sizeof(struct irq_desc));
45         spin_lock_init(&desc->lock);
46         desc->cpu = cpu;
47         lockdep_set_class(&desc->lock, &irq_desc_lock_class);
48         init_copy_kstat_irqs(old_desc, desc, cpu, nr_cpu_ids);
49         arch_init_copy_chip_data(old_desc, desc, cpu);
50 }
51
52 static void free_one_irq_desc(struct irq_desc *old_desc, struct irq_desc *desc)
53 {
54         free_kstat_irqs(old_desc, desc);
55         arch_free_chip_data(old_desc, desc);
56 }
57
58 static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
59                                                 int cpu)
60 {
61         struct irq_desc *desc;
62         unsigned int irq;
63         unsigned long flags;
64         int node;
65
66         irq = old_desc->irq;
67
68         spin_lock_irqsave(&sparse_irq_lock, flags);
69
70         /* We have to check it to avoid races with another CPU */
71         desc = irq_desc_ptrs[irq];
72
73         if (desc && old_desc != desc)
74                 goto out_unlock;
75
76         node = cpu_to_node(cpu);
77         desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
78         if (!desc) {
79                 printk(KERN_ERR "irq %d: can not get new irq_desc for migration.\n", irq);
80                 /* still use old one */
81                 desc = old_desc;
82                 goto out_unlock;
83         }
84         init_copy_one_irq_desc(irq, old_desc, desc, cpu);
85
86         irq_desc_ptrs[irq] = desc;
87         spin_unlock_irqrestore(&sparse_irq_lock, flags);
88
89         /* free the old one */
90         free_one_irq_desc(old_desc, desc);
91         spin_unlock(&old_desc->lock);
92         kfree(old_desc);
93         spin_lock(&desc->lock);
94
95         return desc;
96
97 out_unlock:
98         spin_unlock_irqrestore(&sparse_irq_lock, flags);
99
100         return desc;
101 }
102
103 struct irq_desc *move_irq_desc(struct irq_desc *desc, int cpu)
104 {
105         int old_cpu;
106         int node, old_node;
107
108         /* those all static, do move them */
109         if (desc->irq < NR_IRQS_LEGACY)
110                 return desc;
111
112         old_cpu = desc->cpu;
113         if (old_cpu != cpu) {
114                 node = cpu_to_node(cpu);
115                 old_node = cpu_to_node(old_cpu);
116                 if (old_node != node)
117                         desc = __real_move_irq_desc(desc, cpu);
118                 else
119                         desc->cpu = cpu;
120         }
121
122         return desc;
123 }
124