X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fpid.c;h=d3f722d20f9c6e8d849693a1754b616d3ba74bea;hb=fbfecd3712f917ca210a55c157233d88b785896b;hp=bb0785109d39998c63ec881bb4f92fed69efaa87;hpb=b460cbc581a53cc088ceba80608021dd49c63c43;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/pid.c b/kernel/pid.c index bb07851..d3f722d 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -18,20 +18,29 @@ * allocation scenario when all but one out of 1 million PIDs possible are * allocated already: the scanning of 32 list entries and at most PAGE_SIZE * bytes. The typical fastpath is a single successful setbit. Freeing is O(1). + * + * Pid namespaces: + * (C) 2007 Pavel Emelyanov , OpenVZ, SWsoft Inc. + * (C) 2007 Sukadev Bhattiprolu , IBM + * Many thanks to Oleg Nesterov for comments and help + * */ #include #include #include #include +#include #include #include #include #include +#include -#define pid_hashfn(nr) hash_long((unsigned long)nr, pidhash_shift) +#define pid_hashfn(nr, ns) \ + hash_long((unsigned long)nr + (unsigned long)ns, pidhash_shift) static struct hlist_head *pid_hash; -static int pidhash_shift; +static unsigned int pidhash_shift = 4; struct pid init_struct_pid = INIT_STRUCT_PID; int pid_max = PID_MAX_DEFAULT; @@ -67,13 +76,25 @@ struct pid_namespace init_pid_ns = { [ 0 ... PIDMAP_ENTRIES-1] = { ATOMIC_INIT(BITS_PER_PAGE), NULL } }, .last_pid = 0, - .child_reaper = &init_task + .level = 0, + .child_reaper = &init_task, }; +EXPORT_SYMBOL_GPL(init_pid_ns); -int is_global_init(struct task_struct *tsk) +int is_container_init(struct task_struct *tsk) { - return tsk == init_pid_ns.child_reaper; + int ret = 0; + struct pid *pid; + + rcu_read_lock(); + pid = task_pid(tsk); + if (pid != NULL && pid->numbers[pid->level].nr == 1) + ret = 1; + rcu_read_unlock(); + + return ret; } +EXPORT_SYMBOL(is_container_init); /* * Note: disable interrupts while the pidmap_lock is held as an @@ -91,10 +112,11 @@ int is_global_init(struct task_struct *tsk) static __cacheline_aligned_in_smp DEFINE_SPINLOCK(pidmap_lock); -static fastcall void free_pidmap(struct pid_namespace *pid_ns, int pid) +static void free_pidmap(struct upid *upid) { - struct pidmap *map = pid_ns->pidmap + pid / BITS_PER_PAGE; - int offset = pid & BITS_PER_PAGE_MASK; + int nr = upid->nr; + struct pidmap *map = upid->ns->pidmap + nr / BITS_PER_PAGE; + int offset = nr & BITS_PER_PAGE_MASK; clear_bit(offset, map->page); atomic_inc(&map->nr_free); @@ -160,7 +182,7 @@ static int alloc_pidmap(struct pid_namespace *pid_ns) return -1; } -static int next_pidmap(struct pid_namespace *pid_ns, int last) +int next_pidmap(struct pid_namespace *pid_ns, int last) { int offset; struct pidmap *map, *end; @@ -178,18 +200,19 @@ static int next_pidmap(struct pid_namespace *pid_ns, int last) return -1; } -fastcall void put_pid(struct pid *pid) +void put_pid(struct pid *pid) { struct pid_namespace *ns; if (!pid) return; - /* FIXME - this must be the namespace this pid lives in */ - ns = &init_pid_ns; + ns = pid->numbers[pid->level].ns; if ((atomic_read(&pid->count) == 1) || - atomic_dec_and_test(&pid->count)) + atomic_dec_and_test(&pid->count)) { kmem_cache_free(ns->pid_cachep, pid); + put_pid_ns(ns); + } } EXPORT_SYMBOL_GPL(put_pid); @@ -199,71 +222,97 @@ static void delayed_put_pid(struct rcu_head *rhp) put_pid(pid); } -fastcall void free_pid(struct pid *pid) +void free_pid(struct pid *pid) { /* We can be called with write_lock_irq(&tasklist_lock) held */ + int i; unsigned long flags; spin_lock_irqsave(&pidmap_lock, flags); - hlist_del_rcu(&pid->pid_chain); + for (i = 0; i <= pid->level; i++) + hlist_del_rcu(&pid->numbers[i].pid_chain); spin_unlock_irqrestore(&pidmap_lock, flags); - free_pidmap(&init_pid_ns, pid->nr); + for (i = 0; i <= pid->level; i++) + free_pidmap(pid->numbers + i); + call_rcu(&pid->rcu, delayed_put_pid); } -struct pid *alloc_pid(void) +struct pid *alloc_pid(struct pid_namespace *ns) { struct pid *pid; enum pid_type type; - int nr = -1; - struct pid_namespace *ns; + int i, nr; + struct pid_namespace *tmp; + struct upid *upid; - ns = task_active_pid_ns(current); pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL); if (!pid) goto out; - nr = alloc_pidmap(ns); - if (nr < 0) - goto out_free; + tmp = ns; + for (i = ns->level; i >= 0; i--) { + nr = alloc_pidmap(tmp); + if (nr < 0) + goto out_free; + + pid->numbers[i].nr = nr; + pid->numbers[i].ns = tmp; + tmp = tmp->parent; + } + get_pid_ns(ns); + pid->level = ns->level; atomic_set(&pid->count, 1); - pid->nr = nr; for (type = 0; type < PIDTYPE_MAX; ++type) INIT_HLIST_HEAD(&pid->tasks[type]); spin_lock_irq(&pidmap_lock); - hlist_add_head_rcu(&pid->pid_chain, &pid_hash[pid_hashfn(pid->nr)]); + for (i = ns->level; i >= 0; i--) { + upid = &pid->numbers[i]; + hlist_add_head_rcu(&upid->pid_chain, + &pid_hash[pid_hashfn(upid->nr, upid->ns)]); + } spin_unlock_irq(&pidmap_lock); out: return pid; out_free: + while (++i <= ns->level) + free_pidmap(pid->numbers + i); + kmem_cache_free(ns->pid_cachep, pid); pid = NULL; goto out; } -struct pid * fastcall find_pid(int nr) +struct pid *find_pid_ns(int nr, struct pid_namespace *ns) { struct hlist_node *elem; - struct pid *pid; + struct upid *pnr; + + hlist_for_each_entry_rcu(pnr, elem, + &pid_hash[pid_hashfn(nr, ns)], pid_chain) + if (pnr->nr == nr && pnr->ns == ns) + return container_of(pnr, struct pid, + numbers[ns->level]); - hlist_for_each_entry_rcu(pid, elem, - &pid_hash[pid_hashfn(nr)], pid_chain) { - if (pid->nr == nr) - return pid; - } return NULL; } -EXPORT_SYMBOL_GPL(find_pid); +EXPORT_SYMBOL_GPL(find_pid_ns); + +struct pid *find_vpid(int nr) +{ + return find_pid_ns(nr, current->nsproxy->pid_ns); +} +EXPORT_SYMBOL_GPL(find_vpid); /* * attach_pid() must be called with the tasklist_lock write-held. */ -int fastcall attach_pid(struct task_struct *task, enum pid_type type, +void attach_pid(struct task_struct *task, enum pid_type type, struct pid *pid) { struct pid_link *link; @@ -271,11 +320,10 @@ int fastcall attach_pid(struct task_struct *task, enum pid_type type, link = &task->pids[type]; link->pid = pid; hlist_add_head_rcu(&link->node, &pid->tasks[type]); - - return 0; } -void fastcall detach_pid(struct task_struct *task, enum pid_type type) +static void __change_pid(struct task_struct *task, enum pid_type type, + struct pid *new) { struct pid_link *link; struct pid *pid; @@ -285,7 +333,7 @@ void fastcall detach_pid(struct task_struct *task, enum pid_type type) pid = link->pid; hlist_del_rcu(&link->node); - link->pid = NULL; + link->pid = new; for (tmp = PIDTYPE_MAX; --tmp >= 0; ) if (!hlist_empty(&pid->tasks[tmp])) @@ -294,16 +342,27 @@ void fastcall detach_pid(struct task_struct *task, enum pid_type type) free_pid(pid); } +void detach_pid(struct task_struct *task, enum pid_type type) +{ + __change_pid(task, type, NULL); +} + +void change_pid(struct task_struct *task, enum pid_type type, + struct pid *pid) +{ + __change_pid(task, type, pid); + attach_pid(task, type, pid); +} + /* transfer_pid is an optimization of attach_pid(new), detach_pid(old) */ -void fastcall transfer_pid(struct task_struct *old, struct task_struct *new, +void transfer_pid(struct task_struct *old, struct task_struct *new, enum pid_type type) { new->pids[type].pid = old->pids[type].pid; hlist_replace_rcu(&old->pids[type].node, &new->pids[type].node); - old->pids[type].pid = NULL; } -struct task_struct * fastcall pid_task(struct pid *pid, enum pid_type type) +struct task_struct *pid_task(struct pid *pid, enum pid_type type) { struct task_struct *result = NULL; if (pid) { @@ -314,27 +373,33 @@ struct task_struct * fastcall pid_task(struct pid *pid, enum pid_type type) } return result; } +EXPORT_SYMBOL(pid_task); /* * Must be called under rcu_read_lock() or with tasklist_lock read-held. */ -struct task_struct *find_task_by_pid_type(int type, int nr) +struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns) { - return pid_task(find_pid(nr), type); + return pid_task(find_pid_ns(nr, ns), PIDTYPE_PID); } -EXPORT_SYMBOL(find_task_by_pid_type); +struct task_struct *find_task_by_vpid(pid_t vnr) +{ + return find_task_by_pid_ns(vnr, current->nsproxy->pid_ns); +} struct pid *get_task_pid(struct task_struct *task, enum pid_type type) { struct pid *pid; rcu_read_lock(); + if (type != PIDTYPE_PID) + task = task->group_leader; pid = get_pid(task->pids[type].pid); rcu_read_unlock(); return pid; } -struct task_struct *fastcall get_pid_task(struct pid *pid, enum pid_type type) +struct task_struct *get_pid_task(struct pid *pid, enum pid_type type) { struct task_struct *result; rcu_read_lock(); @@ -350,95 +415,80 @@ struct pid *find_get_pid(pid_t nr) struct pid *pid; rcu_read_lock(); - pid = get_pid(find_pid(nr)); + pid = get_pid(find_vpid(nr)); rcu_read_unlock(); return pid; } +EXPORT_SYMBOL_GPL(find_get_pid); -/* - * Used by proc to find the first pid that is greater then or equal to nr. - * - * If there is a pid at nr this function is exactly the same as find_pid. - */ -struct pid *find_ge_pid(int nr) +pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns) { - struct pid *pid; + struct upid *upid; + pid_t nr = 0; - do { - pid = find_pid(nr); - if (pid) - break; - nr = next_pidmap(task_active_pid_ns(current), nr); - } while (nr > 0); + if (pid && ns->level <= pid->level) { + upid = &pid->numbers[ns->level]; + if (upid->ns == ns) + nr = upid->nr; + } + return nr; +} - return pid; +pid_t pid_vnr(struct pid *pid) +{ + return pid_nr_ns(pid, current->nsproxy->pid_ns); } -EXPORT_SYMBOL_GPL(find_get_pid); +EXPORT_SYMBOL_GPL(pid_vnr); -struct pid_cache { - int nr_ids; - char name[16]; - struct kmem_cache *cachep; - struct list_head list; -}; +pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, + struct pid_namespace *ns) +{ + pid_t nr = 0; -static LIST_HEAD(pid_caches_lh); -static DEFINE_MUTEX(pid_caches_mutex); + rcu_read_lock(); + if (!ns) + ns = current->nsproxy->pid_ns; + if (likely(pid_alive(task))) { + if (type != PIDTYPE_PID) + task = task->group_leader; + nr = pid_nr_ns(task->pids[type].pid, ns); + } + rcu_read_unlock(); -/* - * creates the kmem cache to allocate pids from. - * @nr_ids: the number of numerical ids this pid will have to carry - */ + return nr; +} +EXPORT_SYMBOL(__task_pid_nr_ns); -static struct kmem_cache *create_pid_cachep(int nr_ids) +pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) { - struct pid_cache *pcache; - struct kmem_cache *cachep; - - mutex_lock(&pid_caches_mutex); - list_for_each_entry (pcache, &pid_caches_lh, list) - if (pcache->nr_ids == nr_ids) - goto out; - - pcache = kmalloc(sizeof(struct pid_cache), GFP_KERNEL); - if (pcache == NULL) - goto err_alloc; - - snprintf(pcache->name, sizeof(pcache->name), "pid_%d", nr_ids); - cachep = kmem_cache_create(pcache->name, - /* FIXME add numerical ids here */ - sizeof(struct pid), 0, SLAB_HWCACHE_ALIGN, NULL); - if (cachep == NULL) - goto err_cachep; - - pcache->nr_ids = nr_ids; - pcache->cachep = cachep; - list_add(&pcache->list, &pid_caches_lh); -out: - mutex_unlock(&pid_caches_mutex); - return pcache->cachep; - -err_cachep: - kfree(pcache); -err_alloc: - mutex_unlock(&pid_caches_mutex); - return NULL; + return pid_nr_ns(task_tgid(tsk), ns); } +EXPORT_SYMBOL(task_tgid_nr_ns); -struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns) +struct pid_namespace *task_active_pid_ns(struct task_struct *tsk) { - BUG_ON(!old_ns); - get_pid_ns(old_ns); - return old_ns; + return ns_of_pid(task_pid(tsk)); } +EXPORT_SYMBOL_GPL(task_active_pid_ns); -void free_pid_ns(struct kref *kref) +/* + * Used by proc to find the first pid that is greater than or equal to nr. + * + * If there is a pid at nr this function is exactly the same as find_pid_ns. + */ +struct pid *find_ge_pid(int nr, struct pid_namespace *ns) { - struct pid_namespace *ns; + struct pid *pid; + + do { + pid = find_pid_ns(nr, ns); + if (pid) + break; + nr = next_pidmap(ns, nr); + } while (nr > 0); - ns = container_of(kref, struct pid_namespace, kref); - kfree(ns); + return pid; } /* @@ -449,19 +499,12 @@ void free_pid_ns(struct kref *kref) void __init pidhash_init(void) { int i, pidhash_size; - unsigned long megabytes = nr_kernel_pages >> (20 - PAGE_SHIFT); - pidhash_shift = max(4, fls(megabytes * 4)); - pidhash_shift = min(12, pidhash_shift); + pid_hash = alloc_large_system_hash("PID", sizeof(*pid_hash), 0, 18, + HASH_EARLY | HASH_SMALL, + &pidhash_shift, NULL, 4096); pidhash_size = 1 << pidhash_shift; - printk("PID hash table entries: %d (order: %d, %Zd bytes)\n", - pidhash_size, pidhash_shift, - pidhash_size * sizeof(struct hlist_head)); - - pid_hash = alloc_bootmem(pidhash_size * sizeof(*(pid_hash))); - if (!pid_hash) - panic("Could not alloc pidhash!\n"); for (i = 0; i < pidhash_size; i++) INIT_HLIST_HEAD(&pid_hash[i]); } @@ -473,7 +516,6 @@ void __init pidmap_init(void) set_bit(0, init_pid_ns.pidmap[0].page); atomic_dec(&init_pid_ns.pidmap[0].nr_free); - init_pid_ns.pid_cachep = create_pid_cachep(1); - if (init_pid_ns.pid_cachep == NULL) - panic("Can't create pid_1 cachep\n"); + init_pid_ns.pid_cachep = KMEM_CACHE(pid, + SLAB_HWCACHE_ALIGN | SLAB_PANIC); }