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namespaces: cleanup the code managed with PID_NS option
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Just like with the user namespaces, move the namespace management code into
the separate .c file and mark the (already existing) PID_NS option as "depend
on NAMESPACES"

[[email protected]: coding-style fixes]
Signed-off-by: Pavel Emelyanov <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Cc: Cedric Le Goater <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Herbert Poetzl <[email protected]>
Cc: Kirill Korotaev <[email protected]>
Cc: Sukadev Bhattiprolu <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@xemul
xemul authored and Linus Torvalds committed Feb 8, 2008
1 parent aee16ce commit 74bd59b
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Showing 6 changed files with 220 additions and 194 deletions.
2 changes: 1 addition & 1 deletion include/linux/pid.h
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Original file line number Diff line number Diff line change
Expand Up @@ -118,10 +118,10 @@ extern struct pid *find_pid(int nr);
*/
extern struct pid *find_get_pid(int nr);
extern struct pid *find_ge_pid(int nr, struct pid_namespace *);
int next_pidmap(struct pid_namespace *pid_ns, int last);

extern struct pid *alloc_pid(struct pid_namespace *ns);
extern void FASTCALL(free_pid(struct pid *pid));
extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);

/*
* the helpers to get the pid's id seen from different namespaces
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6 changes: 6 additions & 0 deletions include/linux/pid_namespace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@ static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)

extern struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *ns);
extern void free_pid_ns(struct kref *kref);
extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);

static inline void put_pid_ns(struct pid_namespace *ns)
{
Expand Down Expand Up @@ -66,6 +67,11 @@ static inline void put_pid_ns(struct pid_namespace *ns)
{
}


static inline void zap_pid_ns_processes(struct pid_namespace *ns)
{
BUG();
}
#endif /* CONFIG_PID_NS */

static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
Expand Down
24 changes: 12 additions & 12 deletions init/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -214,18 +214,6 @@ config TASK_IO_ACCOUNTING

Say N if unsure.

config PID_NS
bool "PID Namespaces (EXPERIMENTAL)"
default n
depends on EXPERIMENTAL
help
Suport process id namespaces. This allows having multiple
process with the same pid as long as they are in different
pid namespaces. This is a building block of containers.

Unless you want to work with an experimental feature
say N here.

config AUDIT
bool "Auditing support"
depends on NET
Expand Down Expand Up @@ -442,6 +430,18 @@ config USER_NS
to provide different user info for different servers.
If unsure, say N.

config PID_NS
bool "PID Namespaces (EXPERIMENTAL)"
default n
depends on NAMESPACES && EXPERIMENTAL
help
Suport process id namespaces. This allows having multiple
process with the same pid as long as they are in different
pid namespaces. This is a building block of containers.

Unless you want to work with an experimental feature
say N here.

config BLK_DEV_INITRD
bool "Initial RAM filesystem and RAM disk (initramfs/initrd) support"
depends on BROKEN || !FRV
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1 change: 1 addition & 0 deletions kernel/Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@ obj-$(CONFIG_CPUSETS) += cpuset.o
obj-$(CONFIG_CGROUP_NS) += ns_cgroup.o
obj-$(CONFIG_UTS_NS) += utsname.o
obj-$(CONFIG_USER_NS) += user_namespace.o
obj-$(CONFIG_PID_NS) += pid_namespace.o
obj-$(CONFIG_IKCONFIG) += configs.o
obj-$(CONFIG_RESOURCE_COUNTERS) += res_counter.o
obj-$(CONFIG_STOP_MACHINE) += stop_machine.o
Expand Down
184 changes: 3 additions & 181 deletions kernel/pid.c
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,6 @@
static struct hlist_head *pid_hash;
static int pidhash_shift;
struct pid init_struct_pid = INIT_STRUCT_PID;
static struct kmem_cache *pid_ns_cachep;

int pid_max = PID_MAX_DEFAULT;

Expand Down Expand Up @@ -181,7 +180,7 @@ static int alloc_pidmap(struct pid_namespace *pid_ns)
return -1;
}

static int next_pidmap(struct pid_namespace *pid_ns, int last)
int next_pidmap(struct pid_namespace *pid_ns, int last)
{
int offset;
struct pidmap *map, *end;
Expand Down Expand Up @@ -488,180 +487,6 @@ struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
}
EXPORT_SYMBOL_GPL(find_get_pid);

struct pid_cache {
int nr_ids;
char name[16];
struct kmem_cache *cachep;
struct list_head list;
};

static LIST_HEAD(pid_caches_lh);
static DEFINE_MUTEX(pid_caches_mutex);

/*
* creates the kmem cache to allocate pids from.
* @nr_ids: the number of numerical ids this pid will have to carry
*/

static struct kmem_cache *create_pid_cachep(int nr_ids)
{
struct pid_cache *pcache;
struct kmem_cache *cachep;

mutex_lock(&pid_caches_mutex);
list_for_each_entry (pcache, &pid_caches_lh, list)
if (pcache->nr_ids == nr_ids)
goto out;

pcache = kmalloc(sizeof(struct pid_cache), GFP_KERNEL);
if (pcache == NULL)
goto err_alloc;

snprintf(pcache->name, sizeof(pcache->name), "pid_%d", nr_ids);
cachep = kmem_cache_create(pcache->name,
sizeof(struct pid) + (nr_ids - 1) * sizeof(struct upid),
0, SLAB_HWCACHE_ALIGN, NULL);
if (cachep == NULL)
goto err_cachep;

pcache->nr_ids = nr_ids;
pcache->cachep = cachep;
list_add(&pcache->list, &pid_caches_lh);
out:
mutex_unlock(&pid_caches_mutex);
return pcache->cachep;

err_cachep:
kfree(pcache);
err_alloc:
mutex_unlock(&pid_caches_mutex);
return NULL;
}

#ifdef CONFIG_PID_NS
static struct pid_namespace *create_pid_namespace(int level)
{
struct pid_namespace *ns;
int i;

ns = kmem_cache_alloc(pid_ns_cachep, GFP_KERNEL);
if (ns == NULL)
goto out;

ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (!ns->pidmap[0].page)
goto out_free;

ns->pid_cachep = create_pid_cachep(level + 1);
if (ns->pid_cachep == NULL)
goto out_free_map;

kref_init(&ns->kref);
ns->last_pid = 0;
ns->child_reaper = NULL;
ns->level = level;

set_bit(0, ns->pidmap[0].page);
atomic_set(&ns->pidmap[0].nr_free, BITS_PER_PAGE - 1);

for (i = 1; i < PIDMAP_ENTRIES; i++) {
ns->pidmap[i].page = 0;
atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE);
}

return ns;

out_free_map:
kfree(ns->pidmap[0].page);
out_free:
kmem_cache_free(pid_ns_cachep, ns);
out:
return ERR_PTR(-ENOMEM);
}

static void destroy_pid_namespace(struct pid_namespace *ns)
{
int i;

for (i = 0; i < PIDMAP_ENTRIES; i++)
kfree(ns->pidmap[i].page);
kmem_cache_free(pid_ns_cachep, ns);
}

struct pid_namespace *copy_pid_ns(unsigned long flags, struct pid_namespace *old_ns)
{
struct pid_namespace *new_ns;

BUG_ON(!old_ns);
new_ns = get_pid_ns(old_ns);
if (!(flags & CLONE_NEWPID))
goto out;

new_ns = ERR_PTR(-EINVAL);
if (flags & CLONE_THREAD)
goto out_put;

new_ns = create_pid_namespace(old_ns->level + 1);
if (!IS_ERR(new_ns))
new_ns->parent = get_pid_ns(old_ns);

out_put:
put_pid_ns(old_ns);
out:
return new_ns;
}

void free_pid_ns(struct kref *kref)
{
struct pid_namespace *ns, *parent;

ns = container_of(kref, struct pid_namespace, kref);

parent = ns->parent;
destroy_pid_namespace(ns);

if (parent != NULL)
put_pid_ns(parent);
}
#endif /* CONFIG_PID_NS */

void zap_pid_ns_processes(struct pid_namespace *pid_ns)
{
int nr;
int rc;

/*
* The last thread in the cgroup-init thread group is terminating.
* Find remaining pid_ts in the namespace, signal and wait for them
* to exit.
*
* Note: This signals each threads in the namespace - even those that
* belong to the same thread group, To avoid this, we would have
* to walk the entire tasklist looking a processes in this
* namespace, but that could be unnecessarily expensive if the
* pid namespace has just a few processes. Or we need to
* maintain a tasklist for each pid namespace.
*
*/
read_lock(&tasklist_lock);
nr = next_pidmap(pid_ns, 1);
while (nr > 0) {
kill_proc_info(SIGKILL, SEND_SIG_PRIV, nr);
nr = next_pidmap(pid_ns, nr);
}
read_unlock(&tasklist_lock);

do {
clear_thread_flag(TIF_SIGPENDING);
rc = sys_wait4(-1, NULL, __WALL, NULL);
} while (rc != -ECHILD);


/* Child reaper for the pid namespace is going away */
pid_ns->child_reaper = NULL;
return;
}

/*
* The pid hash table is scaled according to the amount of memory in the
* machine. From a minimum of 16 slots up to 4096 slots at one gigabyte or
Expand Down Expand Up @@ -694,9 +519,6 @@ void __init pidmap_init(void)
set_bit(0, init_pid_ns.pidmap[0].page);
atomic_dec(&init_pid_ns.pidmap[0].nr_free);

init_pid_ns.pid_cachep = create_pid_cachep(1);
if (init_pid_ns.pid_cachep == NULL)
panic("Can't create pid_1 cachep\n");

pid_ns_cachep = KMEM_CACHE(pid_namespace, SLAB_PANIC);
init_pid_ns.pid_cachep = KMEM_CACHE(pid,
SLAB_HWCACHE_ALIGN | SLAB_PANIC);
}
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