Linux內核中斷之中斷請求隊列的初始化

Linux內核中斷之中斷請求隊列的初始化：

1. /*
2. * Core internal functions to deal with irq descriptors
3. *
4. * This include will move to kernel/irq once we cleaned up the tree.
5. * For now it's included from <linux/irq.h>
6. */
8. struct irq_affinity_notify;
9. struct proc_dir_entry;
10. struct timer_rand_state;
11. /**
12. * struct irq_desc - interrupt descriptor
13. * @irq_data: per irq and chip data passed down to chip functions
14. * @timer_rand_state: pointer to timer rand state struct
15. * @kstat_irqs: irq stats per cpu
16. * @handle_irq: highlevel irq-events handler
17. * @preflow_handler: handler called before the flow handler (currently used by sparc)
18. * @action: the irq action chain
19. * @status: status information
20. * @core_internal_state__do_not_mess_with_it: core internal status information
21. * @depth: disable-depth, for nested irq_disable() calls
22. * @wake_depth: enable depth, for multiple irq_set_irq_wake() callers
23. * @irq_count: stats field to detect stalled irqs
24. * @last_unhandled: aging timer for unhandled count
25. * @irqs_unhandled: stats field for spurious unhandled interrupts
26. * @lock: locking for SMP
27. * @affinity_hint: hint to user space for preferred irq affinity
28. * @affinity_notify: context for notification of affinity changes
29. * @pending_mask: pending rebalanced interrupts
30. * @threads_oneshot: bitfield to handle shared oneshot threads
31. * @threads_active: number of irqaction threads currently running
32. * @wait_for_threads: wait queue for sync_irq to wait for threaded handlers
33. * @dir: /proc/irq/ procfs entry
34. * @name: flow handler name for /proc/interrupts output
35. */
36. struct irq_desc {
37. struct irq_data irq_data;
38. struct timer_rand_state *timer_rand_state;
39. unsigned int __percpu *kstat_irqs;
40. irq_flow_handler_t handle_irq;
41. #ifdef CONFIG_IRQ_PREFLOW_FASTEOI
42. irq_preflow_handler_t preflow_handler;
43. #endif
44. struct irqaction *action; /* IRQ action list 由中斷服務程序構成的單鏈表隊列*/
45. unsigned int status_use_accessors;
46. unsigned int core_internal_state__do_not_mess_with_it;
47. unsigned int depth; /* nested irq disables */
48. unsigned int wake_depth; /* nested wake enables */
49. unsigned int irq_count; /* For detecting broken IRQs */
50. unsigned long last_unhandled; /* Aging timer for unhandled count */
51. unsigned int irqs_unhandled;
52. raw_spinlock_t lock;
53. #ifdef CONFIG_SMP
54. const struct cpumask *affinity_hint;
55. struct irq_affinity_notify *affinity_notify;
56. #ifdef CONFIG_GENERIC_PENDING_IRQ
57. cpumask_var_t pending_mask;
58. #endif
59. #endif
60. unsigned long threads_oneshot;
61. atomic_t threads_active;
62. wait_queue_head_t wait_for_threads;
63. #ifdef CONFIG_PROC_FS
64. struct proc_dir_entry *dir;
65. #endif
66. const char *name;
67. } ____cacheline_internodealigned_in_smp;

這個數據結構中的第一字段需要給予特殊的關注，因為這想比於2.4有很大的區別：

1. struct msi_desc;
3. /**
4. * struct irq_data - per irq and irq chip data passed down to chip functions
5. * @irq: interrupt number
6. * @node: node index useful for balancing
7. * @state_use_accessors: status information for irq chip functions.
8. * Use accessor functions to deal with it
9. * @chip: low level interrupt hardware access
10. * @handler_data: per-IRQ data for the irq_chip methods
11. * @chip_data: platform-specific per-chip private data for the chip
12. * methods, to allow shared chip implementations
13. * @msi_desc: MSI descriptor
14. * @affinity: IRQ affinity on SMP
15. *
16. * The fields here need to overlay the ones in irq_desc until we
17. * cleaned up the direct references and switched everything over to
18. * irq_data.
19. */
20. struct irq_data {
21. unsigned int irq;
22. unsigned int node;
23. unsigned int state_use_accessors;
24. struct irq_chip *chip;
25. void *handler_data;
26. void *chip_data;
27. struct msi_desc *msi_desc;
28. #ifdef CONFIG_SMP
29. cpumask_var_t affinity;
30. #endif
31. };