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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Generic pidhash and scalable, time-bounded PID allocator | |
3 | * | |
4 | * (C) 2002-2003 William Irwin, IBM | |
5 | * (C) 2004 William Irwin, Oracle | |
6 | * (C) 2002-2004 Ingo Molnar, Red Hat | |
7 | * | |
8 | * pid-structures are backing objects for tasks sharing a given ID to chain | |
9 | * against. There is very little to them aside from hashing them and | |
10 | * parking tasks using given ID's on a list. | |
11 | * | |
12 | * The hash is always changed with the tasklist_lock write-acquired, | |
13 | * and the hash is only accessed with the tasklist_lock at least | |
14 | * read-acquired, so there's no additional SMP locking needed here. | |
15 | * | |
16 | * We have a list of bitmap pages, which bitmaps represent the PID space. | |
17 | * Allocating and freeing PIDs is completely lockless. The worst-case | |
18 | * allocation scenario when all but one out of 1 million PIDs possible are | |
19 | * allocated already: the scanning of 32 list entries and at most PAGE_SIZE | |
20 | * bytes. The typical fastpath is a single successful setbit. Freeing is O(1). | |
21 | */ | |
22 | ||
23 | #include <linux/mm.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/slab.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/bootmem.h> | |
28 | #include <linux/hash.h> | |
61a58c6c | 29 | #include <linux/pid_namespace.h> |
820e45db | 30 | #include <linux/init_task.h> |
1da177e4 | 31 | |
8ef047aa PE |
32 | #define pid_hashfn(nr, ns) \ |
33 | hash_long((unsigned long)nr + (unsigned long)ns, pidhash_shift) | |
92476d7f | 34 | static struct hlist_head *pid_hash; |
1da177e4 | 35 | static int pidhash_shift; |
820e45db | 36 | struct pid init_struct_pid = INIT_STRUCT_PID; |
1da177e4 LT |
37 | |
38 | int pid_max = PID_MAX_DEFAULT; | |
1da177e4 LT |
39 | |
40 | #define RESERVED_PIDS 300 | |
41 | ||
42 | int pid_max_min = RESERVED_PIDS + 1; | |
43 | int pid_max_max = PID_MAX_LIMIT; | |
44 | ||
1da177e4 LT |
45 | #define BITS_PER_PAGE (PAGE_SIZE*8) |
46 | #define BITS_PER_PAGE_MASK (BITS_PER_PAGE-1) | |
3fbc9648 | 47 | |
61a58c6c SB |
48 | static inline int mk_pid(struct pid_namespace *pid_ns, |
49 | struct pidmap *map, int off) | |
3fbc9648 | 50 | { |
61a58c6c | 51 | return (map - pid_ns->pidmap)*BITS_PER_PAGE + off; |
3fbc9648 SB |
52 | } |
53 | ||
1da177e4 LT |
54 | #define find_next_offset(map, off) \ |
55 | find_next_zero_bit((map)->page, BITS_PER_PAGE, off) | |
56 | ||
57 | /* | |
58 | * PID-map pages start out as NULL, they get allocated upon | |
59 | * first use and are never deallocated. This way a low pid_max | |
60 | * value does not cause lots of bitmaps to be allocated, but | |
61 | * the scheme scales to up to 4 million PIDs, runtime. | |
62 | */ | |
61a58c6c | 63 | struct pid_namespace init_pid_ns = { |
9a575a92 CLG |
64 | .kref = { |
65 | .refcount = ATOMIC_INIT(2), | |
66 | }, | |
3fbc9648 SB |
67 | .pidmap = { |
68 | [ 0 ... PIDMAP_ENTRIES-1] = { ATOMIC_INIT(BITS_PER_PAGE), NULL } | |
69 | }, | |
84d73786 | 70 | .last_pid = 0, |
faacbfd3 PE |
71 | .level = 0, |
72 | .child_reaper = &init_task, | |
3fbc9648 | 73 | }; |
198fe21b | 74 | EXPORT_SYMBOL_GPL(init_pid_ns); |
1da177e4 | 75 | |
b461cc03 | 76 | int is_container_init(struct task_struct *tsk) |
b460cbc5 | 77 | { |
b461cc03 PE |
78 | int ret = 0; |
79 | struct pid *pid; | |
80 | ||
81 | rcu_read_lock(); | |
82 | pid = task_pid(tsk); | |
83 | if (pid != NULL && pid->numbers[pid->level].nr == 1) | |
84 | ret = 1; | |
85 | rcu_read_unlock(); | |
86 | ||
87 | return ret; | |
b460cbc5 | 88 | } |
b461cc03 | 89 | EXPORT_SYMBOL(is_container_init); |
b460cbc5 | 90 | |
92476d7f EB |
91 | /* |
92 | * Note: disable interrupts while the pidmap_lock is held as an | |
93 | * interrupt might come in and do read_lock(&tasklist_lock). | |
94 | * | |
95 | * If we don't disable interrupts there is a nasty deadlock between | |
96 | * detach_pid()->free_pid() and another cpu that does | |
97 | * spin_lock(&pidmap_lock) followed by an interrupt routine that does | |
98 | * read_lock(&tasklist_lock); | |
99 | * | |
100 | * After we clean up the tasklist_lock and know there are no | |
101 | * irq handlers that take it we can leave the interrupts enabled. | |
102 | * For now it is easier to be safe than to prove it can't happen. | |
103 | */ | |
3fbc9648 | 104 | |
1da177e4 LT |
105 | static __cacheline_aligned_in_smp DEFINE_SPINLOCK(pidmap_lock); |
106 | ||
61a58c6c | 107 | static fastcall void free_pidmap(struct pid_namespace *pid_ns, int pid) |
1da177e4 | 108 | { |
61a58c6c | 109 | struct pidmap *map = pid_ns->pidmap + pid / BITS_PER_PAGE; |
1da177e4 LT |
110 | int offset = pid & BITS_PER_PAGE_MASK; |
111 | ||
112 | clear_bit(offset, map->page); | |
113 | atomic_inc(&map->nr_free); | |
114 | } | |
115 | ||
61a58c6c | 116 | static int alloc_pidmap(struct pid_namespace *pid_ns) |
1da177e4 | 117 | { |
61a58c6c | 118 | int i, offset, max_scan, pid, last = pid_ns->last_pid; |
6a1f3b84 | 119 | struct pidmap *map; |
1da177e4 LT |
120 | |
121 | pid = last + 1; | |
122 | if (pid >= pid_max) | |
123 | pid = RESERVED_PIDS; | |
124 | offset = pid & BITS_PER_PAGE_MASK; | |
61a58c6c | 125 | map = &pid_ns->pidmap[pid/BITS_PER_PAGE]; |
1da177e4 LT |
126 | max_scan = (pid_max + BITS_PER_PAGE - 1)/BITS_PER_PAGE - !offset; |
127 | for (i = 0; i <= max_scan; ++i) { | |
128 | if (unlikely(!map->page)) { | |
3fbc9648 | 129 | void *page = kzalloc(PAGE_SIZE, GFP_KERNEL); |
1da177e4 LT |
130 | /* |
131 | * Free the page if someone raced with us | |
132 | * installing it: | |
133 | */ | |
92476d7f | 134 | spin_lock_irq(&pidmap_lock); |
1da177e4 | 135 | if (map->page) |
3fbc9648 | 136 | kfree(page); |
1da177e4 | 137 | else |
3fbc9648 | 138 | map->page = page; |
92476d7f | 139 | spin_unlock_irq(&pidmap_lock); |
1da177e4 LT |
140 | if (unlikely(!map->page)) |
141 | break; | |
142 | } | |
143 | if (likely(atomic_read(&map->nr_free))) { | |
144 | do { | |
145 | if (!test_and_set_bit(offset, map->page)) { | |
146 | atomic_dec(&map->nr_free); | |
61a58c6c | 147 | pid_ns->last_pid = pid; |
1da177e4 LT |
148 | return pid; |
149 | } | |
150 | offset = find_next_offset(map, offset); | |
61a58c6c | 151 | pid = mk_pid(pid_ns, map, offset); |
1da177e4 LT |
152 | /* |
153 | * find_next_offset() found a bit, the pid from it | |
154 | * is in-bounds, and if we fell back to the last | |
155 | * bitmap block and the final block was the same | |
156 | * as the starting point, pid is before last_pid. | |
157 | */ | |
158 | } while (offset < BITS_PER_PAGE && pid < pid_max && | |
159 | (i != max_scan || pid < last || | |
160 | !((last+1) & BITS_PER_PAGE_MASK))); | |
161 | } | |
61a58c6c | 162 | if (map < &pid_ns->pidmap[(pid_max-1)/BITS_PER_PAGE]) { |
1da177e4 LT |
163 | ++map; |
164 | offset = 0; | |
165 | } else { | |
61a58c6c | 166 | map = &pid_ns->pidmap[0]; |
1da177e4 LT |
167 | offset = RESERVED_PIDS; |
168 | if (unlikely(last == offset)) | |
169 | break; | |
170 | } | |
61a58c6c | 171 | pid = mk_pid(pid_ns, map, offset); |
1da177e4 LT |
172 | } |
173 | return -1; | |
174 | } | |
175 | ||
61a58c6c | 176 | static int next_pidmap(struct pid_namespace *pid_ns, int last) |
0804ef4b EB |
177 | { |
178 | int offset; | |
f40f50d3 | 179 | struct pidmap *map, *end; |
0804ef4b EB |
180 | |
181 | offset = (last + 1) & BITS_PER_PAGE_MASK; | |
61a58c6c SB |
182 | map = &pid_ns->pidmap[(last + 1)/BITS_PER_PAGE]; |
183 | end = &pid_ns->pidmap[PIDMAP_ENTRIES]; | |
f40f50d3 | 184 | for (; map < end; map++, offset = 0) { |
0804ef4b EB |
185 | if (unlikely(!map->page)) |
186 | continue; | |
187 | offset = find_next_bit((map)->page, BITS_PER_PAGE, offset); | |
188 | if (offset < BITS_PER_PAGE) | |
61a58c6c | 189 | return mk_pid(pid_ns, map, offset); |
0804ef4b EB |
190 | } |
191 | return -1; | |
192 | } | |
193 | ||
92476d7f EB |
194 | fastcall void put_pid(struct pid *pid) |
195 | { | |
baf8f0f8 PE |
196 | struct pid_namespace *ns; |
197 | ||
92476d7f EB |
198 | if (!pid) |
199 | return; | |
baf8f0f8 | 200 | |
8ef047aa | 201 | ns = pid->numbers[pid->level].ns; |
92476d7f | 202 | if ((atomic_read(&pid->count) == 1) || |
8ef047aa | 203 | atomic_dec_and_test(&pid->count)) { |
baf8f0f8 | 204 | kmem_cache_free(ns->pid_cachep, pid); |
b461cc03 | 205 | put_pid_ns(ns); |
8ef047aa | 206 | } |
92476d7f | 207 | } |
bbf73147 | 208 | EXPORT_SYMBOL_GPL(put_pid); |
92476d7f EB |
209 | |
210 | static void delayed_put_pid(struct rcu_head *rhp) | |
211 | { | |
212 | struct pid *pid = container_of(rhp, struct pid, rcu); | |
213 | put_pid(pid); | |
214 | } | |
215 | ||
216 | fastcall void free_pid(struct pid *pid) | |
217 | { | |
218 | /* We can be called with write_lock_irq(&tasklist_lock) held */ | |
8ef047aa | 219 | int i; |
92476d7f EB |
220 | unsigned long flags; |
221 | ||
222 | spin_lock_irqsave(&pidmap_lock, flags); | |
198fe21b PE |
223 | for (i = 0; i <= pid->level; i++) |
224 | hlist_del_rcu(&pid->numbers[i].pid_chain); | |
92476d7f EB |
225 | spin_unlock_irqrestore(&pidmap_lock, flags); |
226 | ||
8ef047aa PE |
227 | for (i = 0; i <= pid->level; i++) |
228 | free_pidmap(pid->numbers[i].ns, pid->numbers[i].nr); | |
229 | ||
92476d7f EB |
230 | call_rcu(&pid->rcu, delayed_put_pid); |
231 | } | |
232 | ||
8ef047aa | 233 | struct pid *alloc_pid(struct pid_namespace *ns) |
92476d7f EB |
234 | { |
235 | struct pid *pid; | |
236 | enum pid_type type; | |
8ef047aa PE |
237 | int i, nr; |
238 | struct pid_namespace *tmp; | |
198fe21b | 239 | struct upid *upid; |
92476d7f | 240 | |
baf8f0f8 | 241 | pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL); |
92476d7f EB |
242 | if (!pid) |
243 | goto out; | |
244 | ||
8ef047aa PE |
245 | tmp = ns; |
246 | for (i = ns->level; i >= 0; i--) { | |
247 | nr = alloc_pidmap(tmp); | |
248 | if (nr < 0) | |
249 | goto out_free; | |
92476d7f | 250 | |
8ef047aa PE |
251 | pid->numbers[i].nr = nr; |
252 | pid->numbers[i].ns = tmp; | |
253 | tmp = tmp->parent; | |
254 | } | |
255 | ||
b461cc03 | 256 | get_pid_ns(ns); |
8ef047aa PE |
257 | pid->level = ns->level; |
258 | pid->nr = pid->numbers[0].nr; | |
92476d7f | 259 | atomic_set(&pid->count, 1); |
92476d7f EB |
260 | for (type = 0; type < PIDTYPE_MAX; ++type) |
261 | INIT_HLIST_HEAD(&pid->tasks[type]); | |
262 | ||
263 | spin_lock_irq(&pidmap_lock); | |
198fe21b PE |
264 | for (i = ns->level; i >= 0; i--) { |
265 | upid = &pid->numbers[i]; | |
266 | hlist_add_head_rcu(&upid->pid_chain, | |
267 | &pid_hash[pid_hashfn(upid->nr, upid->ns)]); | |
268 | } | |
92476d7f EB |
269 | spin_unlock_irq(&pidmap_lock); |
270 | ||
271 | out: | |
272 | return pid; | |
273 | ||
274 | out_free: | |
8ef047aa PE |
275 | for (i++; i <= ns->level; i++) |
276 | free_pidmap(pid->numbers[i].ns, pid->numbers[i].nr); | |
277 | ||
baf8f0f8 | 278 | kmem_cache_free(ns->pid_cachep, pid); |
92476d7f EB |
279 | pid = NULL; |
280 | goto out; | |
281 | } | |
282 | ||
198fe21b | 283 | struct pid * fastcall find_pid_ns(int nr, struct pid_namespace *ns) |
1da177e4 LT |
284 | { |
285 | struct hlist_node *elem; | |
198fe21b PE |
286 | struct upid *pnr; |
287 | ||
288 | hlist_for_each_entry_rcu(pnr, elem, | |
289 | &pid_hash[pid_hashfn(nr, ns)], pid_chain) | |
290 | if (pnr->nr == nr && pnr->ns == ns) | |
291 | return container_of(pnr, struct pid, | |
292 | numbers[ns->level]); | |
1da177e4 | 293 | |
1da177e4 LT |
294 | return NULL; |
295 | } | |
198fe21b | 296 | EXPORT_SYMBOL_GPL(find_pid_ns); |
1da177e4 | 297 | |
e713d0da SB |
298 | /* |
299 | * attach_pid() must be called with the tasklist_lock write-held. | |
300 | */ | |
301 | int fastcall attach_pid(struct task_struct *task, enum pid_type type, | |
302 | struct pid *pid) | |
1da177e4 | 303 | { |
92476d7f | 304 | struct pid_link *link; |
92476d7f | 305 | |
92476d7f | 306 | link = &task->pids[type]; |
e713d0da | 307 | link->pid = pid; |
92476d7f | 308 | hlist_add_head_rcu(&link->node, &pid->tasks[type]); |
1da177e4 LT |
309 | |
310 | return 0; | |
311 | } | |
312 | ||
36c8b586 | 313 | void fastcall detach_pid(struct task_struct *task, enum pid_type type) |
1da177e4 | 314 | { |
92476d7f EB |
315 | struct pid_link *link; |
316 | struct pid *pid; | |
317 | int tmp; | |
1da177e4 | 318 | |
92476d7f EB |
319 | link = &task->pids[type]; |
320 | pid = link->pid; | |
1da177e4 | 321 | |
92476d7f EB |
322 | hlist_del_rcu(&link->node); |
323 | link->pid = NULL; | |
1da177e4 | 324 | |
92476d7f EB |
325 | for (tmp = PIDTYPE_MAX; --tmp >= 0; ) |
326 | if (!hlist_empty(&pid->tasks[tmp])) | |
327 | return; | |
1da177e4 | 328 | |
92476d7f | 329 | free_pid(pid); |
1da177e4 LT |
330 | } |
331 | ||
c18258c6 EB |
332 | /* transfer_pid is an optimization of attach_pid(new), detach_pid(old) */ |
333 | void fastcall transfer_pid(struct task_struct *old, struct task_struct *new, | |
334 | enum pid_type type) | |
335 | { | |
336 | new->pids[type].pid = old->pids[type].pid; | |
337 | hlist_replace_rcu(&old->pids[type].node, &new->pids[type].node); | |
338 | old->pids[type].pid = NULL; | |
339 | } | |
340 | ||
92476d7f | 341 | struct task_struct * fastcall pid_task(struct pid *pid, enum pid_type type) |
1da177e4 | 342 | { |
92476d7f EB |
343 | struct task_struct *result = NULL; |
344 | if (pid) { | |
345 | struct hlist_node *first; | |
346 | first = rcu_dereference(pid->tasks[type].first); | |
347 | if (first) | |
348 | result = hlist_entry(first, struct task_struct, pids[(type)].node); | |
349 | } | |
350 | return result; | |
351 | } | |
1da177e4 | 352 | |
92476d7f EB |
353 | /* |
354 | * Must be called under rcu_read_lock() or with tasklist_lock read-held. | |
355 | */ | |
198fe21b PE |
356 | struct task_struct *find_task_by_pid_type_ns(int type, int nr, |
357 | struct pid_namespace *ns) | |
92476d7f | 358 | { |
198fe21b | 359 | return pid_task(find_pid_ns(nr, ns), type); |
92476d7f | 360 | } |
1da177e4 | 361 | |
198fe21b | 362 | EXPORT_SYMBOL(find_task_by_pid_type_ns); |
1da177e4 | 363 | |
1a657f78 ON |
364 | struct pid *get_task_pid(struct task_struct *task, enum pid_type type) |
365 | { | |
366 | struct pid *pid; | |
367 | rcu_read_lock(); | |
368 | pid = get_pid(task->pids[type].pid); | |
369 | rcu_read_unlock(); | |
370 | return pid; | |
371 | } | |
372 | ||
92476d7f EB |
373 | struct task_struct *fastcall get_pid_task(struct pid *pid, enum pid_type type) |
374 | { | |
375 | struct task_struct *result; | |
376 | rcu_read_lock(); | |
377 | result = pid_task(pid, type); | |
378 | if (result) | |
379 | get_task_struct(result); | |
380 | rcu_read_unlock(); | |
381 | return result; | |
1da177e4 LT |
382 | } |
383 | ||
92476d7f | 384 | struct pid *find_get_pid(pid_t nr) |
1da177e4 LT |
385 | { |
386 | struct pid *pid; | |
387 | ||
92476d7f | 388 | rcu_read_lock(); |
198fe21b | 389 | pid = get_pid(find_vpid(nr)); |
92476d7f | 390 | rcu_read_unlock(); |
1da177e4 | 391 | |
92476d7f | 392 | return pid; |
1da177e4 LT |
393 | } |
394 | ||
7af57294 PE |
395 | pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns) |
396 | { | |
397 | struct upid *upid; | |
398 | pid_t nr = 0; | |
399 | ||
400 | if (pid && ns->level <= pid->level) { | |
401 | upid = &pid->numbers[ns->level]; | |
402 | if (upid->ns == ns) | |
403 | nr = upid->nr; | |
404 | } | |
405 | return nr; | |
406 | } | |
407 | ||
0804ef4b EB |
408 | /* |
409 | * Used by proc to find the first pid that is greater then or equal to nr. | |
410 | * | |
411 | * If there is a pid at nr this function is exactly the same as find_pid. | |
412 | */ | |
198fe21b | 413 | struct pid *find_ge_pid(int nr, struct pid_namespace *ns) |
0804ef4b EB |
414 | { |
415 | struct pid *pid; | |
416 | ||
417 | do { | |
198fe21b | 418 | pid = find_pid_ns(nr, ns); |
0804ef4b EB |
419 | if (pid) |
420 | break; | |
198fe21b | 421 | nr = next_pidmap(ns, nr); |
0804ef4b EB |
422 | } while (nr > 0); |
423 | ||
424 | return pid; | |
425 | } | |
bbf73147 | 426 | EXPORT_SYMBOL_GPL(find_get_pid); |
0804ef4b | 427 | |
baf8f0f8 PE |
428 | struct pid_cache { |
429 | int nr_ids; | |
430 | char name[16]; | |
431 | struct kmem_cache *cachep; | |
432 | struct list_head list; | |
433 | }; | |
434 | ||
435 | static LIST_HEAD(pid_caches_lh); | |
436 | static DEFINE_MUTEX(pid_caches_mutex); | |
437 | ||
438 | /* | |
439 | * creates the kmem cache to allocate pids from. | |
440 | * @nr_ids: the number of numerical ids this pid will have to carry | |
441 | */ | |
442 | ||
443 | static struct kmem_cache *create_pid_cachep(int nr_ids) | |
444 | { | |
445 | struct pid_cache *pcache; | |
446 | struct kmem_cache *cachep; | |
447 | ||
448 | mutex_lock(&pid_caches_mutex); | |
449 | list_for_each_entry (pcache, &pid_caches_lh, list) | |
450 | if (pcache->nr_ids == nr_ids) | |
451 | goto out; | |
452 | ||
453 | pcache = kmalloc(sizeof(struct pid_cache), GFP_KERNEL); | |
454 | if (pcache == NULL) | |
455 | goto err_alloc; | |
456 | ||
457 | snprintf(pcache->name, sizeof(pcache->name), "pid_%d", nr_ids); | |
458 | cachep = kmem_cache_create(pcache->name, | |
459 | /* FIXME add numerical ids here */ | |
460 | sizeof(struct pid), 0, SLAB_HWCACHE_ALIGN, NULL); | |
461 | if (cachep == NULL) | |
462 | goto err_cachep; | |
463 | ||
464 | pcache->nr_ids = nr_ids; | |
465 | pcache->cachep = cachep; | |
466 | list_add(&pcache->list, &pid_caches_lh); | |
467 | out: | |
468 | mutex_unlock(&pid_caches_mutex); | |
469 | return pcache->cachep; | |
470 | ||
471 | err_cachep: | |
472 | kfree(pcache); | |
473 | err_alloc: | |
474 | mutex_unlock(&pid_caches_mutex); | |
475 | return NULL; | |
476 | } | |
477 | ||
213dd266 | 478 | struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns) |
9a575a92 | 479 | { |
e3222c4e | 480 | BUG_ON(!old_ns); |
9a575a92 | 481 | get_pid_ns(old_ns); |
e3222c4e | 482 | return old_ns; |
9a575a92 CLG |
483 | } |
484 | ||
485 | void free_pid_ns(struct kref *kref) | |
486 | { | |
487 | struct pid_namespace *ns; | |
488 | ||
489 | ns = container_of(kref, struct pid_namespace, kref); | |
490 | kfree(ns); | |
491 | } | |
492 | ||
1da177e4 LT |
493 | /* |
494 | * The pid hash table is scaled according to the amount of memory in the | |
495 | * machine. From a minimum of 16 slots up to 4096 slots at one gigabyte or | |
496 | * more. | |
497 | */ | |
498 | void __init pidhash_init(void) | |
499 | { | |
92476d7f | 500 | int i, pidhash_size; |
1da177e4 LT |
501 | unsigned long megabytes = nr_kernel_pages >> (20 - PAGE_SHIFT); |
502 | ||
503 | pidhash_shift = max(4, fls(megabytes * 4)); | |
504 | pidhash_shift = min(12, pidhash_shift); | |
505 | pidhash_size = 1 << pidhash_shift; | |
506 | ||
507 | printk("PID hash table entries: %d (order: %d, %Zd bytes)\n", | |
508 | pidhash_size, pidhash_shift, | |
92476d7f EB |
509 | pidhash_size * sizeof(struct hlist_head)); |
510 | ||
511 | pid_hash = alloc_bootmem(pidhash_size * sizeof(*(pid_hash))); | |
512 | if (!pid_hash) | |
513 | panic("Could not alloc pidhash!\n"); | |
514 | for (i = 0; i < pidhash_size; i++) | |
515 | INIT_HLIST_HEAD(&pid_hash[i]); | |
1da177e4 LT |
516 | } |
517 | ||
518 | void __init pidmap_init(void) | |
519 | { | |
61a58c6c | 520 | init_pid_ns.pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL); |
73b9ebfe | 521 | /* Reserve PID 0. We never call free_pidmap(0) */ |
61a58c6c SB |
522 | set_bit(0, init_pid_ns.pidmap[0].page); |
523 | atomic_dec(&init_pid_ns.pidmap[0].nr_free); | |
92476d7f | 524 | |
baf8f0f8 PE |
525 | init_pid_ns.pid_cachep = create_pid_cachep(1); |
526 | if (init_pid_ns.pid_cachep == NULL) | |
527 | panic("Can't create pid_1 cachep\n"); | |
1da177e4 | 528 | } |