The patch titled
pid namespaces: make alloc_pid(), free_pid() and put_pid() work with struct upid
has been added to the -mm tree. Its filename is
pid-namespaces-make-alloc_pid-free_pid-and-put_pid-work-with-struct-upid.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: pid namespaces: make alloc_pid(), free_pid() and put_pid() work with struct upid
From: Pavel Emelyanov <xemul@xxxxxxxxxx>
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 <xemul@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Sukadev Bhattiprolu <sukadev@xxxxxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pid.h | 2 -
kernel/fork.c | 2 -
kernel/pid.c | 49 +++++++++++++++++++++++++++++-------------
3 files changed, 36 insertions(+), 17 deletions(-)
diff -puN include/linux/pid.h~pid-namespaces-make-alloc_pid-free_pid-and-put_pid-work-with-struct-upid include/linux/pid.h
--- a/include/linux/pid.h~pid-namespaces-make-alloc_pid-free_pid-and-put_pid-work-with-struct-upid
+++ a/include/linux/pid.h
@@ -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)
diff -puN kernel/fork.c~pid-namespaces-make-alloc_pid-free_pid-and-put_pid-work-with-struct-upid kernel/fork.c
--- a/kernel/fork.c~pid-namespaces-make-alloc_pid-free_pid-and-put_pid-work-with-struct-upid
+++ a/kernel/fork.c
@@ -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;
}
diff -puN kernel/pid.c~pid-namespaces-make-alloc_pid-free_pid-and-put_pid-work-with-struct-upid kernel/pid.c
--- a/kernel/pid.c~pid-namespaces-make-alloc_pid-free_pid-and-put_pid-work-with-struct-upid
+++ a/kernel/pid.c
@@ -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;
@@ -186,11 +187,13 @@ 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);
@@ -203,45 +206,61 @@ 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;
@@ -253,7 +272,7 @@ 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;
}
_
Patches currently in -mm which might be from xemul@xxxxxxxxxx are
git-net.patch
pid-namespaces-round-up-the-api.patch
pid-namespaces-make-get_pid_ns-return-the-namespace-itself.patch
pid-namespaces-dynamic-kmem-cache-allocator-for-pid-namespaces.patch
pid-namespaces-dynamic-kmem-cache-allocator-for-pid-namespaces-fix.patch
pid-namespaces-define-and-use-task_active_pid_ns-wrapper.patch
pid-namespaces-rename-child_reaper-function.patch
pid-namespaces-use-task_pid-to-find-leaders-pid.patch
pid-namespaces-define-is_global_init-and-is_container_init.patch
pid-namespaces-move-alloc_pid-to-copy_process.patch
make-access-to-tasks-nsproxy-lighter.patch
pid-namespaces-rework-forget_original_parent.patch
pid-namespaces-move-exit_task_namespaces.patch
pid-namespaces-introduce-ms_kernmount-flag.patch
pid-namespaces-prepare-proc_flust_task-to-flush-entries-from-multiple-proc-trees.patch
pid-namespaces-introduce-struct-upid.patch
pid-namespaces-add-support-for-pid-namespaces-hierarchy.patch
pid-namespaces-make-alloc_pid-free_pid-and-put_pid-work-with-struct-upid.patch
pid-namespaces-helpers-to-obtain-pid-numbers.patch
pid-namespaces-helpers-to-find-the-task-by-its-numerical-ids.patch
pid-namespaces-move-alloc_pid-lower-in-copy_process.patch
pid-namespaces-make-proc-have-multiple-superblocks-one-for-each-namespace.patch
pid-namespaces-miscelaneous-preparations-for-pid-namespaces.patch
pid-namespaces-allow-cloning-of-new-namespace.patch
pid-namespaces-make-proc_flush_task-actually-from-entries-from-multiple-namespaces.patch
pid-namespaces-initialize-the-namespaces-proc_mnt.patch
pid-namespaces-allow-signalling-container-init.patch
pid-namespaces-destroy-pid-namespace-on-inits-death.patch
pid-namespaces-changes-to-show-virtual-ids-to-user.patch
pid-namespaces-remove-the-struct-pid-unneeded-fields.patch
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