Each struct upid element of struct pid has to be initialized properly,
i.e. its nr mst be allocated from appropriate pidmap and ns set to
appropriate namespace.
When allocating a new pid, we need to know the namespace this pid will
live in, so the additional argument is added to alloc_pid().
On the other hand, the rest of the kernel still uses the pid->nr and
pid->pid_chain fields, so these ones are still initialized, but this
will be removed soon.
Signed-off-by: Pavel Emelyanov <[email protected]>
Cc: Oleg Nesterov <[email protected]>
---
include/linux/pid.h | 2 +-
kernel/fork.c | 2 +-
kernel/pid.c | 49 ++++++++++++++++++++++++++++++++++---------------
3 files changed, 36 insertions(+), 17 deletions(-)
--- ./include/linux/pid.h.ve8 2007-08-06 15:39:05.000000000 +0400
+++ ./include/linux/pid.h 2007-08-06 15:39:05.000000000 +0400
@@ -111,7 +111,7 @@ extern struct pid *FASTCALL(find_pid(int
extern struct pid *find_get_pid(int nr);
extern struct pid *find_ge_pid(int nr);
-extern struct pid *alloc_pid(void);
+extern struct pid *alloc_pid(struct pid_namespace *ns);
extern void FASTCALL(free_pid(struct pid *pid));
static inline pid_t pid_nr(struct pid *pid)
--- ./kernel/fork.c.ve8 2007-08-06 15:39:02.000000000 +0400
+++ ./kernel/fork.c 2007-08-06 15:39:05.000000000 +0400
@@ -1029,7 +1029,7 @@ static struct task_struct *copy_process(
goto bad_fork_cleanup_put_domain;
if (pid != &init_struct_pid) {
- pid = alloc_pid();
+ pid = alloc_pid(task_active_pid_ns(p));
if (!pid)
goto bad_fork_put_binfmt_module;
}
--- ./kernel/pid.c.ve8 2007-08-06 15:39:05.000000000 +0400
+++ ./kernel/pid.c 2007-08-06 15:41:34.000000000 +0400
@@ -29,7 +29,8 @@
#include <linux/pid_namespace.h>
#include <linux/init_task.h>
-#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;
struct pid init_struct_pid = INIT_STRUCT_PID;
@@ -188,11 +189,13 @@ fastcall void put_pid(struct pid *pid)
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);
+ if (ns != &init_pid_ns)
+ put_pid_ns(ns);
+ }
}
EXPORT_SYMBOL_GPL(put_pid);
@@ -205,45 +208,61 @@ 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 */
+ int i;
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);
+ for (i = 0; i <= pid->level; i++)
+ free_pidmap(pid->numbers[i].ns, pid->numbers[i].nr);
+
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;
- 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;
+ }
+
+ if (ns != &init_pid_ns)
+ get_pid_ns(ns);
+ pid->level = ns->level;
+ pid->nr = pid->numbers[0].nr;
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)]);
+ hlist_add_head_rcu(&pid->pid_chain, &pid_hash[pid_hashfn(pid->nr, 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);
+
kmem_cache_free(ns->pid_cachep, pid);
pid = NULL;
goto out;
@@ -255,7 +274,7 @@ struct pid * fastcall find_pid(int nr)
struct pid *pid;
hlist_for_each_entry_rcu(pid, elem,
- &pid_hash[pid_hashfn(nr)], pid_chain) {
+ &pid_hash[pid_hashfn(nr, &init_pid_ns)], pid_chain) {
if (pid->nr == nr)
return pid;
}
-
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