cfq-iosched: fix rcu freeing of cfq io contexts
[deliverable/linux.git] / include / linux / init.h
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1da177e4
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1#ifndef _LINUX_INIT_H
2#define _LINUX_INIT_H
3
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4#include <linux/compiler.h>
5
6/* These macros are used to mark some functions or
7 * initialized data (doesn't apply to uninitialized data)
8 * as `initialization' functions. The kernel can take this
9 * as hint that the function is used only during the initialization
10 * phase and free up used memory resources after
11 *
12 * Usage:
13 * For functions:
14 *
15 * You should add __init immediately before the function name, like:
16 *
17 * static void __init initme(int x, int y)
18 * {
19 * extern int z; z = x * y;
20 * }
21 *
22 * If the function has a prototype somewhere, you can also add
23 * __init between closing brace of the prototype and semicolon:
24 *
25 * extern int initialize_foobar_device(int, int, int) __init;
26 *
27 * For initialized data:
28 * You should insert __initdata between the variable name and equal
29 * sign followed by value, e.g.:
30 *
31 * static int init_variable __initdata = 0;
32 * static char linux_logo[] __initdata = { 0x32, 0x36, ... };
33 *
34 * Don't forget to initialize data not at file scope, i.e. within a function,
35 * as gcc otherwise puts the data into the bss section and not into the init
36 * section.
37 *
38 * Also note, that this data cannot be "const".
39 */
40
41/* These are for everybody (although not all archs will actually
42 discard it in modules) */
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43#define __init __section(.init.text) __cold
44#define __initdata __section(.init.data)
37c514e3 45#define __initconst __section(.init.rodata)
f3fe866d 46#define __exitdata __section(.exit.data)
3ff6eecc 47#define __exit_call __used __section(.exitcall.exit)
1da177e4 48
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49/* modpost check for section mismatches during the kernel build.
50 * A section mismatch happens when there are references from a
51 * code or data section to an init section (both code or data).
52 * The init sections are (for most archs) discarded by the kernel
53 * when early init has completed so all such references are potential bugs.
54 * For exit sections the same issue exists.
55 * The following markers are used for the cases where the reference to
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56 * the *init / *exit section (code or data) is valid and will teach
57 * modpost not to issue a warning.
0e0d314e 58 * The markers follow same syntax rules as __init / __initdata. */
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59#define __ref __section(.ref.text) noinline
60#define __refdata __section(.ref.data)
61#define __refconst __section(.ref.rodata)
62
63/* backward compatibility note
64 * A few places hardcode the old section names:
65 * .text.init.refok
66 * .data.init.refok
67 * .exit.text.refok
68 * They should be converted to use the defines from this file
69 */
70
71/* compatibility defines */
72#define __init_refok __ref
73#define __initdata_refok __refdata
74#define __exit_refok __ref
75
0e0d314e 76
1da177e4 77#ifdef MODULE
eb8f6890 78#define __exitused
1da177e4 79#else
eb8f6890 80#define __exitused __used
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81#endif
82
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83#define __exit __section(.exit.text) __exitused __cold
84
85/* Used for HOTPLUG */
86#define __devinit __section(.devinit.text) __cold
87#define __devinitdata __section(.devinit.data)
88#define __devinitconst __section(.devinit.rodata)
89#define __devexit __section(.devexit.text) __exitused __cold
90#define __devexitdata __section(.devexit.data)
91#define __devexitconst __section(.devexit.rodata)
92
93/* Used for HOTPLUG_CPU */
94#define __cpuinit __section(.cpuinit.text) __cold
95#define __cpuinitdata __section(.cpuinit.data)
96#define __cpuinitconst __section(.cpuinit.rodata)
97#define __cpuexit __section(.cpuexit.text) __exitused __cold
98#define __cpuexitdata __section(.cpuexit.data)
99#define __cpuexitconst __section(.cpuexit.rodata)
100
101/* Used for MEMORY_HOTPLUG */
102#define __meminit __section(.meminit.text) __cold
103#define __meminitdata __section(.meminit.data)
104#define __meminitconst __section(.meminit.rodata)
105#define __memexit __section(.memexit.text) __exitused __cold
106#define __memexitdata __section(.memexit.data)
107#define __memexitconst __section(.memexit.rodata)
108
1da177e4 109/* For assembly routines */
37c514e3 110#define __HEAD .section ".head.text","ax"
1da177e4 111#define __INIT .section ".init.text","ax"
86c0baf1 112#define __FINIT .previous
eb8f6890 113
838c4118 114#define __INITDATA .section ".init.data","aw"
9f9975a5 115#define __FINITDATA .previous
1da177e4 116
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117#define __DEVINIT .section ".devinit.text", "ax"
118#define __DEVINITDATA .section ".devinit.data", "aw"
119
120#define __CPUINIT .section ".cpuinit.text", "ax"
121#define __CPUINITDATA .section ".cpuinit.data", "aw"
122
123#define __MEMINIT .section ".meminit.text", "ax"
124#define __MEMINITDATA .section ".meminit.data", "aw"
125
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126/* silence warnings when references are OK */
127#define __REF .section ".ref.text", "ax"
128#define __REFDATA .section ".ref.data", "aw"
129#define __REFCONST .section ".ref.rodata", "aw"
312b1485 130
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131#ifndef __ASSEMBLY__
132/*
133 * Used for initialization calls..
134 */
135typedef int (*initcall_t)(void);
136typedef void (*exitcall_t)(void);
137
138extern initcall_t __con_initcall_start[], __con_initcall_end[];
139extern initcall_t __security_initcall_start[], __security_initcall_end[];
140
141/* Defined in init/main.c */
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142extern char __initdata boot_command_line[];
143extern char *saved_command_line;
7e96287d 144extern unsigned int reset_devices;
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145
146/* used by init/main.c */
46595390
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147void setup_arch(char **);
148void prepare_namespace(void);
77d47582 149
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150#endif
151
152#ifndef MODULE
153
154#ifndef __ASSEMBLY__
155
156/* initcalls are now grouped by functionality into separate
157 * subsections. Ordering inside the subsections is determined
158 * by link order.
159 * For backwards compatibility, initcall() puts the call in
160 * the device init subsection.
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161 *
162 * The `id' arg to __define_initcall() is needed so that multiple initcalls
163 * can point at the same handler without causing duplicate-symbol build errors.
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164 */
165
735a7ffb 166#define __define_initcall(level,fn,id) \
3ff6eecc 167 static initcall_t __initcall_##fn##id __used \
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168 __attribute__((__section__(".initcall" level ".init"))) = fn
169
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170/*
171 * A "pure" initcall has no dependencies on anything else, and purely
172 * initializes variables that couldn't be statically initialized.
173 *
174 * This only exists for built-in code, not for modules.
175 */
73dd1166 176#define pure_initcall(fn) __define_initcall("0",fn,0)
b3438f82 177
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178#define core_initcall(fn) __define_initcall("1",fn,1)
179#define core_initcall_sync(fn) __define_initcall("1s",fn,1s)
180#define postcore_initcall(fn) __define_initcall("2",fn,2)
181#define postcore_initcall_sync(fn) __define_initcall("2s",fn,2s)
182#define arch_initcall(fn) __define_initcall("3",fn,3)
183#define arch_initcall_sync(fn) __define_initcall("3s",fn,3s)
184#define subsys_initcall(fn) __define_initcall("4",fn,4)
185#define subsys_initcall_sync(fn) __define_initcall("4s",fn,4s)
186#define fs_initcall(fn) __define_initcall("5",fn,5)
187#define fs_initcall_sync(fn) __define_initcall("5s",fn,5s)
8d610dd5 188#define rootfs_initcall(fn) __define_initcall("rootfs",fn,rootfs)
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189#define device_initcall(fn) __define_initcall("6",fn,6)
190#define device_initcall_sync(fn) __define_initcall("6s",fn,6s)
191#define late_initcall(fn) __define_initcall("7",fn,7)
192#define late_initcall_sync(fn) __define_initcall("7s",fn,7s)
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193
194#define __initcall(fn) device_initcall(fn)
195
196#define __exitcall(fn) \
197 static exitcall_t __exitcall_##fn __exit_call = fn
198
199#define console_initcall(fn) \
200 static initcall_t __initcall_##fn \
3ff6eecc 201 __used __section(.con_initcall.init) = fn
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202
203#define security_initcall(fn) \
204 static initcall_t __initcall_##fn \
3ff6eecc 205 __used __section(.security_initcall.init) = fn
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206
207struct obs_kernel_param {
208 const char *str;
209 int (*setup_func)(char *);
210 int early;
211};
212
213/*
214 * Only for really core code. See moduleparam.h for the normal way.
215 *
216 * Force the alignment so the compiler doesn't space elements of the
217 * obs_kernel_param "array" too far apart in .init.setup.
218 */
219#define __setup_param(str, unique_id, fn, early) \
d5aa0daf 220 static char __setup_str_##unique_id[] __initdata __aligned(1) = str; \
1da177e4 221 static struct obs_kernel_param __setup_##unique_id \
3ff6eecc 222 __used __section(.init.setup) \
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223 __attribute__((aligned((sizeof(long))))) \
224 = { __setup_str_##unique_id, fn, early }
225
226#define __setup_null_param(str, unique_id) \
227 __setup_param(str, unique_id, NULL, 0)
228
229#define __setup(str, fn) \
230 __setup_param(str, fn, fn, 0)
231
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232/* NOTE: fn is as per module_param, not __setup! Emits warning if fn
233 * returns non-zero. */
234#define early_param(str, fn) \
235 __setup_param(str, fn, fn, 1)
236
30d7e0d4 237/* Relies on boot_command_line being set */
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238void __init parse_early_param(void);
239#endif /* __ASSEMBLY__ */
240
241/**
242 * module_init() - driver initialization entry point
243 * @x: function to be run at kernel boot time or module insertion
244 *
72fd4a35 245 * module_init() will either be called during do_initcalls() (if
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246 * builtin) or at module insertion time (if a module). There can only
247 * be one per module.
248 */
249#define module_init(x) __initcall(x);
250
251/**
252 * module_exit() - driver exit entry point
253 * @x: function to be run when driver is removed
254 *
255 * module_exit() will wrap the driver clean-up code
256 * with cleanup_module() when used with rmmod when
257 * the driver is a module. If the driver is statically
258 * compiled into the kernel, module_exit() has no effect.
259 * There can only be one per module.
260 */
261#define module_exit(x) __exitcall(x);
262
263#else /* MODULE */
264
265/* Don't use these in modules, but some people do... */
266#define core_initcall(fn) module_init(fn)
267#define postcore_initcall(fn) module_init(fn)
268#define arch_initcall(fn) module_init(fn)
269#define subsys_initcall(fn) module_init(fn)
270#define fs_initcall(fn) module_init(fn)
271#define device_initcall(fn) module_init(fn)
272#define late_initcall(fn) module_init(fn)
273
274#define security_initcall(fn) module_init(fn)
275
276/* These macros create a dummy inline: gcc 2.9x does not count alias
277 as usage, hence the `unused function' warning when __init functions
278 are declared static. We use the dummy __*_module_inline functions
279 both to kill the warning and check the type of the init/cleanup
280 function. */
281
282/* Each module must use one module_init(), or one no_module_init */
283#define module_init(initfn) \
284 static inline initcall_t __inittest(void) \
285 { return initfn; } \
286 int init_module(void) __attribute__((alias(#initfn)));
287
288/* This is only required if you want to be unloadable. */
289#define module_exit(exitfn) \
290 static inline exitcall_t __exittest(void) \
291 { return exitfn; } \
292 void cleanup_module(void) __attribute__((alias(#exitfn)));
293
294#define __setup_param(str, unique_id, fn) /* nothing */
295#define __setup_null_param(str, unique_id) /* nothing */
296#define __setup(str, func) /* nothing */
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297#endif
298
ab3bfca7 299/* Data marked not to be saved by software suspend */
f3fe866d 300#define __nosavedata __section(.data.nosave)
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301
302/* This means "can be init if no module support, otherwise module load
303 may call it." */
304#ifdef CONFIG_MODULES
305#define __init_or_module
306#define __initdata_or_module
307#else
308#define __init_or_module __init
309#define __initdata_or_module __initdata
310#endif /*CONFIG_MODULES*/
311
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312/* Functions marked as __devexit may be discarded at kernel link time, depending
313 on config options. Newer versions of binutils detect references from
314 retained sections to discarded sections and flag an error. Pointers to
315 __devexit functions must use __devexit_p(function_name), the wrapper will
316 insert either the function_name or NULL, depending on the config options.
317 */
318#if defined(MODULE) || defined(CONFIG_HOTPLUG)
319#define __devexit_p(x) x
320#else
321#define __devexit_p(x) NULL
322#endif
323
324#ifdef MODULE
325#define __exit_p(x) x
326#else
327#define __exit_p(x) NULL
328#endif
329
330#endif /* _LINUX_INIT_H */
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