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authorLinus Torvalds <torvalds@linux-foundation.org>2010-02-27 19:18:30 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2010-02-27 19:18:30 -0500
commit8d37a371b6869920e6c40c495c68eabba1ef3909 (patch)
treedad784512b13832f4f5494cfe0791965c6a2b0f6 /Documentation
parentef1a8de8ea004a689b2aa9f5cefcba2b1a0262f2 (diff)
parent7b4884ca8853a638df0eb5d251d80d67777b8b1a (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6: (49 commits) pcmcia: validate late-added resources pcmcia: allow for extension of resource interval pcmcia: remove useless msleep in ds.c pcmcia: use read_cis_mem return value pcmcia: handle error in serial_cs config calls pcmcia: add locking to pcmcia_{read,write}_cis_mem pcmcia: avoid prod_id memleak pcmcia: avoid sysfs-related lockup for cardbus pcmcia: use state machine for extended requery pcmcia: delay re-scanning and re-querying of PCMCIA bus pcmcia: use pccardd to handle eject, insert, suspend and resume requests pcmcia: use ops_mutex for rsrc_{mgr,nonstatic} locking pcmcia: use mutex for dynid lock pcmcia: assert locking to struct pcmcia_device pcmcia: add locking documentation pcmcia: simplify locking pcmcia: add locking to struct pcmcia_socket->pcmcia_state() pcmcia: protect s->device_count pcmcia: properly lock skt->irq, skt->irq_mask pcmcia: lock ops->set_socket ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/pcmcia/locking.txt118
1 files changed, 118 insertions, 0 deletions
diff --git a/Documentation/pcmcia/locking.txt b/Documentation/pcmcia/locking.txt
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1This file explains the locking and exclusion scheme used in the PCCARD
2and PCMCIA subsystems.
3
4
5A) Overview, Locking Hierarchy:
6===============================
7
8pcmcia_socket_list_rwsem - protects only the list of sockets
9- skt_mutex - serializes card insert / ejection
10 - ops_mutex - serializes socket operation
11
12
13B) Exclusion
14============
15
16The following functions and callbacks to struct pcmcia_socket must
17be called with "skt_mutex" held:
18
19 socket_detect_change()
20 send_event()
21 socket_reset()
22 socket_shutdown()
23 socket_setup()
24 socket_remove()
25 socket_insert()
26 socket_early_resume()
27 socket_late_resume()
28 socket_resume()
29 socket_suspend()
30
31 struct pcmcia_callback *callback
32
33The following functions and callbacks to struct pcmcia_socket must
34be called with "ops_mutex" held:
35
36 socket_reset()
37 socket_setup()
38
39 struct pccard_operations *ops
40 struct pccard_resource_ops *resource_ops;
41
42Note that send_event() and struct pcmcia_callback *callback must not be
43called with "ops_mutex" held.
44
45
46C) Protection
47=============
48
491. Global Data:
50---------------
51struct list_head pcmcia_socket_list;
52
53protected by pcmcia_socket_list_rwsem;
54
55
562. Per-Socket Data:
57-------------------
58The resource_ops and their data are protected by ops_mutex.
59
60The "main" struct pcmcia_socket is protected as follows (read-only fields
61or single-use fields not mentioned):
62
63- by pcmcia_socket_list_rwsem:
64 struct list_head socket_list;
65
66- by thread_lock:
67 unsigned int thread_events;
68
69- by skt_mutex:
70 u_int suspended_state;
71 void (*tune_bridge);
72 struct pcmcia_callback *callback;
73 int resume_status;
74
75- by ops_mutex:
76 socket_state_t socket;
77 u_int state;
78 u_short lock_count;
79 pccard_mem_map cis_mem;
80 void __iomem *cis_virt;
81 struct { } irq;
82 io_window_t io[];
83 pccard_mem_map win[];
84 struct list_head cis_cache;
85 size_t fake_cis_len;
86 u8 *fake_cis;
87 u_int irq_mask;
88 void (*zoom_video);
89 int (*power_hook);
90 u8 resource...;
91 struct list_head devices_list;
92 u8 device_count;
93 struct pcmcia_state;
94
95
963. Per PCMCIA-device Data:
97--------------------------
98
99The "main" struct pcmcia_devie is protected as follows (read-only fields
100or single-use fields not mentioned):
101
102
103- by pcmcia_socket->ops_mutex:
104 struct list_head socket_device_list;
105 struct config_t *function_config;
106 u16 _irq:1;
107 u16 _io:1;
108 u16 _win:4;
109 u16 _locked:1;
110 u16 allow_func_id_match:1;
111 u16 suspended:1;
112 u16 _removed:1;
113
114- by the PCMCIA driver:
115 io_req_t io;
116 irq_req_t irq;
117 config_req_t conf;
118 window_handle_t win;