X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fpid.c;h=aebb30d9c233df40876afa35ef21cc5c306590a1;hb=595aac488b546c7185be7e29c8ae165a588b2a9f;hp=477691576b338b38caa173c386b3a70ce7351a72;hpb=7ad5b3a505e68cfdc342933d6e0fc0eaa5e0a4f7;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/pid.c b/kernel/pid.c index 4776915..aebb30d 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include #include @@ -39,7 +40,7 @@ #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; @@ -111,10 +112,11 @@ EXPORT_SYMBOL(is_container_init); static __cacheline_aligned_in_smp DEFINE_SPINLOCK(pidmap_lock); -static 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); @@ -139,11 +141,12 @@ static int alloc_pidmap(struct pid_namespace *pid_ns) * installing it: */ spin_lock_irq(&pidmap_lock); - if (map->page) - kfree(page); - else + if (!map->page) { map->page = page; + page = NULL; + } spin_unlock_irq(&pidmap_lock); + kfree(page); if (unlikely(!map->page)) break; } @@ -232,7 +235,7 @@ void free_pid(struct pid *pid) spin_unlock_irqrestore(&pidmap_lock, flags); for (i = 0; i <= pid->level; i++) - free_pidmap(pid->numbers[i].ns, pid->numbers[i].nr); + free_pidmap(pid->numbers + i); call_rcu(&pid->rcu, delayed_put_pid); } @@ -266,20 +269,19 @@ struct pid *alloc_pid(struct pid_namespace *ns) for (type = 0; type < PIDTYPE_MAX; ++type) INIT_HLIST_HEAD(&pid->tasks[type]); + upid = pid->numbers + ns->level; spin_lock_irq(&pidmap_lock); - for (i = ns->level; i >= 0; i--) { - upid = &pid->numbers[i]; + for ( ; upid >= pid->numbers; --upid) 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: - for (i++; i <= ns->level; i++) - free_pidmap(pid->numbers[i].ns, pid->numbers[i].nr); + while (++i <= ns->level) + free_pidmap(pid->numbers + i); kmem_cache_free(ns->pid_cachep, pid); pid = NULL; @@ -307,16 +309,10 @@ struct pid *find_vpid(int nr) } EXPORT_SYMBOL_GPL(find_vpid); -struct pid *find_pid(int nr) -{ - return find_pid_ns(nr, &init_pid_ns); -} -EXPORT_SYMBOL_GPL(find_pid); - /* * attach_pid() must be called with the tasklist_lock write-held. */ -int 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; @@ -324,11 +320,10 @@ int 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 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; @@ -338,7 +333,7 @@ void 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])) @@ -347,13 +342,24 @@ void 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 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 *pid_task(struct pid *pid, enum pid_type type) @@ -361,7 +367,9 @@ struct task_struct *pid_task(struct pid *pid, enum pid_type type) struct task_struct *result = NULL; if (pid) { struct hlist_node *first; - first = rcu_dereference(pid->tasks[type].first); + first = rcu_dereference_check(pid->tasks[type].first, + rcu_read_lock_held() || + lockdep_tasklist_lock_is_held()); if (first) result = hlist_entry(first, struct task_struct, pids[(type)].node); } @@ -370,39 +378,24 @@ struct task_struct *pid_task(struct pid *pid, enum pid_type type) EXPORT_SYMBOL(pid_task); /* - * Must be called under rcu_read_lock() or with tasklist_lock read-held. + * Must be called under rcu_read_lock(). */ -struct task_struct *find_task_by_pid_type_ns(int type, int nr, - struct pid_namespace *ns) -{ - return pid_task(find_pid_ns(nr, ns), type); -} - -EXPORT_SYMBOL(find_task_by_pid_type_ns); - -struct task_struct *find_task_by_pid(pid_t nr) +struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns) { - return find_task_by_pid_type_ns(PIDTYPE_PID, nr, &init_pid_ns); + return pid_task(find_pid_ns(nr, ns), PIDTYPE_PID); } -EXPORT_SYMBOL(find_task_by_pid); struct task_struct *find_task_by_vpid(pid_t vnr) { - return find_task_by_pid_type_ns(PIDTYPE_PID, vnr, - current->nsproxy->pid_ns); -} -EXPORT_SYMBOL(find_task_by_vpid); - -struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns) -{ - return find_task_by_pid_type_ns(PIDTYPE_PID, nr, ns); + return find_task_by_pid_ns(vnr, current->nsproxy->pid_ns); } -EXPORT_SYMBOL(find_task_by_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; @@ -429,6 +422,7 @@ struct pid *find_get_pid(pid_t nr) return pid; } +EXPORT_SYMBOL_GPL(find_get_pid); pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns) { @@ -449,11 +443,24 @@ pid_t pid_vnr(struct pid *pid) } EXPORT_SYMBOL_GPL(pid_vnr); -pid_t task_pid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) +pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type, + struct pid_namespace *ns) { - return pid_nr_ns(task_pid(tsk), ns); + pid_t nr = 0; + + 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(); + + return nr; } -EXPORT_SYMBOL(task_pid_nr_ns); +EXPORT_SYMBOL(__task_pid_nr_ns); pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) { @@ -461,22 +468,16 @@ pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) } EXPORT_SYMBOL(task_tgid_nr_ns); -pid_t task_pgrp_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) +struct pid_namespace *task_active_pid_ns(struct task_struct *tsk) { - return pid_nr_ns(task_pgrp(tsk), ns); + return ns_of_pid(task_pid(tsk)); } -EXPORT_SYMBOL(task_pgrp_nr_ns); - -pid_t task_session_nr_ns(struct task_struct *tsk, struct pid_namespace *ns) -{ - return pid_nr_ns(task_session(tsk), ns); -} -EXPORT_SYMBOL(task_session_nr_ns); +EXPORT_SYMBOL_GPL(task_active_pid_ns); /* - * Used by proc to find the first pid that is greater then or equal to nr. + * 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. + * 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) { @@ -491,7 +492,6 @@ struct pid *find_ge_pid(int nr, struct pid_namespace *ns) return pid; } -EXPORT_SYMBOL_GPL(find_get_pid); /* * The pid hash table is scaled according to the amount of memory in the @@ -501,19 +501,12 @@ EXPORT_SYMBOL_GPL(find_get_pid); 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]); }