The alloc_pid(), free_pid() and put_pid() are splitted into two parts
- the generic pid manipulation, like refcount and task hlist heads;
- manipulations with pids numerical values.
E.g. alloc pid allocates the struct pid and initializes its refcount etc and
calls the alloc_pid_nrs() to allocate the pid numerical ids and hash it into
the hash-tables.
Signed-off-by: Pavel Emelianov <[EMAIL PROTECTED]>
---
pid.c | 90 +++++++++++++++++++++++++++++++++++++++++-------------------------
1 files changed, 56 insertions(+), 34 deletions(-)
--- ./kernel/pid.c.pidsplit 2007-06-14 15:57:41.000000000 +0400
+++ ./kernel/pid.c 2007-06-14 16:34:28.000000000 +0400
@@ -174,13 +174,64 @@ static int next_pidmap(struct pid_namesp
return -1;
}
+#ifndef CONFIG_PID_NS
+static inline int alloc_pid_nrs(struct pid *pid)
+{
+ int nr;
+
+ nr = alloc_pidmap(&init_pid_ns);
+ if (nr < 0)
+ return nr;
+
+ pid->nr = nr;
+ spin_lock_irq(&pidmap_lock);
+ hlist_add_head_rcu(&pid->pid_chain, &pid_hash[pid_hashfn(nr)]);
+ spin_unlock_irq(&pidmap_lock);
+ return 0;
+}
+
+static inline void unhash_pid_nrs(struct pid *pid)
+{
+ /* We can be called with write_lock_irq(&tasklist_lock) held */
+ unsigned long flags;
+
+ spin_lock_irqsave(&pidmap_lock, flags);
+ hlist_del_rcu(&pid->pid_chain);
+ spin_unlock_irqrestore(&pidmap_lock, flags);
+
+ free_pidmap(&init_pid_ns, pid->nr);
+}
+
+static inline void free_pid_nrs(struct pid *pid)
+{
+}
+
+struct pid * fastcall find_pid_ns(int nr, struct pid_namespace *ns)
+{
+ struct hlist_node *elem;
+ struct pid *pid;
+
+ hlist_for_each_entry_rcu(pid, elem,
+ &pid_hash[pid_hashfn(nr)], pid_chain) {
+ if (pid->nr == nr)
+ return pid;
+ }
+ return NULL;
+}
+#else
+#endif
+
+EXPORT_SYMBOL_GPL(find_pid_ns);
+
fastcall void put_pid(struct pid *pid)
{
if (!pid)
return;
if ((atomic_read(&pid->count) == 1) ||
- atomic_dec_and_test(&pid->count))
+ atomic_dec_and_test(&pid->count)) {
+ free_pid_nrs(pid);
kmem_cache_free(pid_cachep, pid);
+ }
}
EXPORT_SYMBOL_GPL(put_pid);
@@ -192,14 +243,7 @@ static void delayed_put_pid(struct rcu_h
fastcall void free_pid(struct pid *pid)
{
- /* We can be called with write_lock_irq(&tasklist_lock) held */
- unsigned long flags;
-
- spin_lock_irqsave(&pidmap_lock, flags);
- hlist_del_rcu(&pid->pid_chain);
- spin_unlock_irqrestore(&pidmap_lock, flags);
-
- free_pidmap(&init_pid_ns, pid->nr);
+ unhash_pid_nrs(pid);
call_rcu(&pid->rcu, delayed_put_pid);
}
@@ -207,47 +251,25 @@ struct pid *alloc_pid(void)
{
struct pid *pid;
enum pid_type type;
- int nr = -1;
pid = kmem_cache_alloc(pid_cachep, GFP_KERNEL);
if (!pid)
goto out;
- nr = alloc_pidmap(current->nsproxy->pid_ns);
- if (nr < 0)
- goto out_free;
-
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)]);
- spin_unlock_irq(&pidmap_lock);
+ if (alloc_pid_nrs(pid))
+ goto out_free;
-out:
return pid;
out_free:
kmem_cache_free(pid_cachep, pid);
- pid = NULL;
- goto out;
-}
-
-struct pid * fastcall find_pid_ns(int nr, struct pid_namespace *ns)
-{
- struct hlist_node *elem;
- struct pid *pid;
-
- hlist_for_each_entry_rcu(pid, elem,
- &pid_hash[pid_hashfn(nr)], pid_chain) {
- if (pid->nr == nr)
- return pid;
- }
+out:
return NULL;
}
-EXPORT_SYMBOL_GPL(find_pid_ns);
/*
* attach_pid() must be called with the tasklist_lock write-held.
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