pid: reduce code size by using a pointer to iterate over array

[safe/jmp/linux-2.6] / kernel / pid.c

diff --git a/kernel/pid.c b/kernel/pid.c
index 064e76a..2e17c9c 100644 (file)
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -40,7 +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;
@@ -141,11 +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;
                }
@@ -268,12 +269,11 @@ 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:
@@ -378,31 +378,22 @@ 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_ns(int type, int nr,
-               struct pid_namespace *ns)
+struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns)
 {
-       return pid_task(find_pid_ns(nr, ns), type);
+       return pid_task(find_pid_ns(nr, ns), PIDTYPE_PID);
 }
 
-EXPORT_SYMBOL(find_task_by_pid_type_ns);
-
 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;
@@ -450,11 +441,24 @@ 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)
 {
@@ -462,20 +466,14 @@ 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_ns.
  */
@@ -501,19 +499,12 @@ struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
 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]);
 }