summaryrefslogblamecommitdiff
path: root/Documentation/pcmcia/locking.txt
blob: b2c9b478906b4b517338d902505263c474dbe918 (plain) (tree) 
3d068261854b ^






































cfe5d809518e ^


3d068261854b ^

















cfe5d809518e ^

3d068261854b ^



































94a819f80297 ^





831527b7304d ^

94a819f80297 ^



















1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38

39
40

41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57

58

59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93

94
95
96
97
98

99

100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118






































                                                                      

                                                      
















                                                                       
                                                           


































                                                                         




                          
                                                                         


















                                                      
This file explains the locking and exclusion scheme used in the PCCARD
and PCMCIA subsystems.


A) Overview, Locking Hierarchy:
===============================

pcmcia_socket_list_rwsem	- protects only the list of sockets
- skt_mutex			- serializes card insert / ejection
  - ops_mutex			- serializes socket operation


B) Exclusion
============

The following functions and callbacks to struct pcmcia_socket must
be called with "skt_mutex" held:

	socket_detect_change()
	send_event()
	socket_reset()
	socket_shutdown()
	socket_setup()
	socket_remove()
	socket_insert()
	socket_early_resume()
	socket_late_resume()
	socket_resume()
	socket_suspend()

	struct pcmcia_callback	*callback

The following functions and callbacks to struct pcmcia_socket must
be called with "ops_mutex" held:

	socket_reset()
	socket_setup()

	struct pccard_operations	*ops
	struct pccard_resource_ops	*resource_ops;

Note that send_event() and struct pcmcia_callback *callback must not be
called with "ops_mutex" held.


C) Protection
=============

1. Global Data:
---------------
struct list_head	pcmcia_socket_list;

protected by pcmcia_socket_list_rwsem;


2. Per-Socket Data:
-------------------
The resource_ops and their data are protected by ops_mutex.

The "main" struct pcmcia_socket is protected as follows (read-only fields
or single-use fields not mentioned):

- by pcmcia_socket_list_rwsem:
	struct list_head	socket_list;

- by thread_lock:
	unsigned int		thread_events;

- by skt_mutex:
	u_int			suspended_state;
	void			(*tune_bridge);
	struct pcmcia_callback	*callback;
	int			resume_status;

- by ops_mutex:
	socket_state_t		socket;
	u_int			state;
	u_short			lock_count;
	pccard_mem_map		cis_mem;
	void __iomem 		*cis_virt;
	struct { }		irq;
	io_window_t		io[];
	pccard_mem_map		win[];
	struct list_head	cis_cache;
	size_t			fake_cis_len;
	u8			*fake_cis;
	u_int			irq_mask;
	void 			(*zoom_video);
	int 			(*power_hook);
	u8			resource...;
	struct list_head	devices_list;
	u8			device_count;
	struct 			pcmcia_state;


3. Per PCMCIA-device Data:
--------------------------

The "main" struct pcmcia_device is protected as follows (read-only fields
or single-use fields not mentioned):


- by pcmcia_socket->ops_mutex:
	struct list_head	socket_device_list;
	struct config_t		*function_config;
	u16			_irq:1;
	u16			_io:1;
	u16			_win:4;
	u16			_locked:1;
	u16			allow_func_id_match:1;
	u16			suspended:1;
	u16			_removed:1;

- by the PCMCIA driver:
	io_req_t		io;
	irq_req_t		irq;
	config_req_t		conf;
	window_handle_t		win;