[PATCH] x86: kernel irq balance doesn't work
[linux-2.6.git] / kernel / irq / proc.c
1 /*
2  * linux/kernel/irq/proc.c
3  *
4  * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
5  *
6  * This file contains the /proc/irq/ handling code.
7  */
8
9 #include <linux/irq.h>
10 #include <linux/proc_fs.h>
11 #include <linux/interrupt.h>
12
13 #include "internals.h"
14
15 static struct proc_dir_entry *root_irq_dir, *irq_dir[NR_IRQS];
16
17 #ifdef CONFIG_SMP
18
19 /*
20  * The /proc/irq/<irq>/smp_affinity values:
21  */
22 static struct proc_dir_entry *smp_affinity_entry[NR_IRQS];
23
24 #ifdef CONFIG_GENERIC_PENDING_IRQ
25 void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
26 {
27         set_balance_irq_affinity(irq, mask_val);
28
29         /*
30          * Save these away for later use. Re-progam when the
31          * interrupt is pending
32          */
33         set_pending_irq(irq, mask_val);
34 }
35 #else
36 void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
37 {
38         set_balance_irq_affinity(irq, mask_val);
39         irq_affinity[irq] = mask_val;
40         irq_desc[irq].handler->set_affinity(irq, mask_val);
41 }
42 #endif
43
44 static int irq_affinity_read_proc(char *page, char **start, off_t off,
45                                   int count, int *eof, void *data)
46 {
47         int len = cpumask_scnprintf(page, count, irq_affinity[(long)data]);
48
49         if (count - len < 2)
50                 return -EINVAL;
51         len += sprintf(page + len, "\n");
52         return len;
53 }
54
55 int no_irq_affinity;
56 static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
57                                    unsigned long count, void *data)
58 {
59         unsigned int irq = (int)(long)data, full_count = count, err;
60         cpumask_t new_value, tmp;
61
62         if (!irq_desc[irq].handler->set_affinity || no_irq_affinity)
63                 return -EIO;
64
65         err = cpumask_parse(buffer, count, new_value);
66         if (err)
67                 return err;
68
69         /*
70          * Do not allow disabling IRQs completely - it's a too easy
71          * way to make the system unusable accidentally :-) At least
72          * one online CPU still has to be targeted.
73          */
74         cpus_and(tmp, new_value, cpu_online_map);
75         if (cpus_empty(tmp))
76                 /* Special case for empty set - allow the architecture
77                    code to set default SMP affinity. */
78                 return select_smp_affinity(irq) ? -EINVAL : full_count;
79
80         proc_set_irq_affinity(irq, new_value);
81
82         return full_count;
83 }
84
85 #endif
86
87 #define MAX_NAMELEN 128
88
89 static int name_unique(unsigned int irq, struct irqaction *new_action)
90 {
91         struct irq_desc *desc = irq_desc + irq;
92         struct irqaction *action;
93
94         for (action = desc->action ; action; action = action->next)
95                 if ((action != new_action) && action->name &&
96                                 !strcmp(new_action->name, action->name))
97                         return 0;
98         return 1;
99 }
100
101 void register_handler_proc(unsigned int irq, struct irqaction *action)
102 {
103         char name [MAX_NAMELEN];
104
105         if (!irq_dir[irq] || action->dir || !action->name ||
106                                         !name_unique(irq, action))
107                 return;
108
109         memset(name, 0, MAX_NAMELEN);
110         snprintf(name, MAX_NAMELEN, "%s", action->name);
111
112         /* create /proc/irq/1234/handler/ */
113         action->dir = proc_mkdir(name, irq_dir[irq]);
114 }
115
116 #undef MAX_NAMELEN
117
118 #define MAX_NAMELEN 10
119
120 void register_irq_proc(unsigned int irq)
121 {
122         char name [MAX_NAMELEN];
123
124         if (!root_irq_dir ||
125                 (irq_desc[irq].handler == &no_irq_type) ||
126                         irq_dir[irq])
127                 return;
128
129         memset(name, 0, MAX_NAMELEN);
130         sprintf(name, "%d", irq);
131
132         /* create /proc/irq/1234 */
133         irq_dir[irq] = proc_mkdir(name, root_irq_dir);
134
135 #ifdef CONFIG_SMP
136         {
137                 struct proc_dir_entry *entry;
138
139                 /* create /proc/irq/<irq>/smp_affinity */
140                 entry = create_proc_entry("smp_affinity", 0600, irq_dir[irq]);
141
142                 if (entry) {
143                         entry->nlink = 1;
144                         entry->data = (void *)(long)irq;
145                         entry->read_proc = irq_affinity_read_proc;
146                         entry->write_proc = irq_affinity_write_proc;
147                 }
148                 smp_affinity_entry[irq] = entry;
149         }
150 #endif
151 }
152
153 #undef MAX_NAMELEN
154
155 void unregister_handler_proc(unsigned int irq, struct irqaction *action)
156 {
157         if (action->dir)
158                 remove_proc_entry(action->dir->name, irq_dir[irq]);
159 }
160
161 void init_irq_proc(void)
162 {
163         int i;
164
165         /* create /proc/irq */
166         root_irq_dir = proc_mkdir("irq", NULL);
167         if (!root_irq_dir)
168                 return;
169
170         /*
171          * Create entries for all existing IRQs.
172          */
173         for (i = 0; i < NR_IRQS; i++)
174                 register_irq_proc(i);
175 }
176