android_kernel_samsung_msm8976/kernel/pid.c
Ian Maund f1b32d4e47 Merge upstream linux-stable v3.10.28 into msm-3.10
The following commits have been reverted from this merge, as they are
known to introduce new bugs and are currently incompatible with our
audio implementation. Investigation of these commits is ongoing, and
they are expected to be brought in at a later time:

86e6de7 ALSA: compress: fix drain calls blocking other compress functions (v6)
16442d4 ALSA: compress: fix drain calls blocking other compress functions

This merge commit also includes a change in block, necessary for
compilation. Upstream has modified elevator_init_fn to prevent race
conditions, requring updates to row_init_queue and test_init_queue.

* commit 'v3.10.28': (1964 commits)
  Linux 3.10.28
  ARM: 7938/1: OMAP4/highbank: Flush L2 cache before disabling
  drm/i915: Don't grab crtc mutexes in intel_modeset_gem_init()
  serial: amba-pl011: use port lock to guard control register access
  mm: Make {,set}page_address() static inline if WANT_PAGE_VIRTUAL
  md/raid5: Fix possible confusion when multiple write errors occur.
  md/raid10: fix two bugs in handling of known-bad-blocks.
  md/raid10: fix bug when raid10 recovery fails to recover a block.
  md: fix problem when adding device to read-only array with bitmap.
  drm/i915: fix DDI PLLs HW state readout code
  nilfs2: fix segctor bug that causes file system corruption
  thp: fix copy_page_rep GPF by testing is_huge_zero_pmd once only
  ftrace/x86: Load ftrace_ops in parameter not the variable holding it
  SELinux: Fix possible NULL pointer dereference in selinux_inode_permission()
  writeback: Fix data corruption on NFS
  hwmon: (coretemp) Fix truncated name of alarm attributes
  vfs: In d_path don't call d_dname on a mount point
  staging: comedi: adl_pci9111: fix incorrect irq passed to request_irq()
  staging: comedi: addi_apci_1032: fix subdevice type/flags bug
  mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully
  GFS2: Increase i_writecount during gfs2_setattr_chown
  perf/x86/amd/ibs: Fix waking up from S3 for AMD family 10h
  perf scripting perl: Fix build error on Fedora 12
  ARM: 7815/1: kexec: offline non panic CPUs on Kdump panic
  Linux 3.10.27
  sched: Guarantee new group-entities always have weight
  sched: Fix hrtimer_cancel()/rq->lock deadlock
  sched: Fix cfs_bandwidth misuse of hrtimer_expires_remaining
  sched: Fix race on toggling cfs_bandwidth_used
  x86, fpu, amd: Clear exceptions in AMD FXSAVE workaround
  netfilter: nf_nat: fix access to uninitialized buffer in IRC NAT helper
  SCSI: sd: Reduce buffer size for vpd request
  intel_pstate: Add X86_FEATURE_APERFMPERF to cpu match parameters.
  mac80211: move "bufferable MMPDU" check to fix AP mode scan
  ACPI / Battery: Add a _BIX quirk for NEC LZ750/LS
  ACPI / TPM: fix memory leak when walking ACPI namespace
  mfd: rtsx_pcr: Disable interrupts before cancelling delayed works
  clk: exynos5250: fix sysmmu_mfc{l,r} gate clocks
  clk: samsung: exynos5250: Add CLK_IGNORE_UNUSED flag for the sysreg clock
  clk: samsung: exynos4: Correct SRC_MFC register
  clk: clk-divider: fix divisor > 255 bug
  ahci: add PCI ID for Marvell 88SE9170 SATA controller
  parisc: Ensure full cache coherency for kmap/kunmap
  drm/nouveau/bios: make jump conditional
  ARM: shmobile: mackerel: Fix coherent DMA mask
  ARM: shmobile: armadillo: Fix coherent DMA mask
  ARM: shmobile: kzm9g: Fix coherent DMA mask
  ARM: dts: exynos5250: Fix MDMA0 clock number
  ARM: fix "bad mode in ... handler" message for undefined instructions
  ARM: fix footbridge clockevent device
  net: Loosen constraints for recalculating checksum in skb_segment()
  bridge: use spin_lock_bh() in br_multicast_set_hash_max
  netpoll: Fix missing TXQ unlock and and OOPS.
  net: llc: fix use after free in llc_ui_recvmsg
  virtio-net: fix refill races during restore
  virtio_net: don't leak memory or block when too many frags
  virtio-net: make all RX paths handle errors consistently
  virtio_net: fix error handling for mergeable buffers
  vlan: Fix header ops passthru when doing TX VLAN offload.
  net: rose: restore old recvmsg behavior
  rds: prevent dereference of a NULL device
  ipv6: always set the new created dst's from in ip6_rt_copy
  net: fec: fix potential use after free
  hamradio/yam: fix info leak in ioctl
  drivers/net/hamradio: Integer overflow in hdlcdrv_ioctl()
  net: inet_diag: zero out uninitialized idiag_{src,dst} fields
  ip_gre: fix msg_name parsing for recvfrom/recvmsg
  net: unix: allow bind to fail on mutex lock
  ipv6: fix illegal mac_header comparison on 32bit
  netvsc: don't flush peers notifying work during setting mtu
  tg3: Initialize REG_BASE_ADDR at PCI config offset 120 to 0
  net: unix: allow set_peek_off to fail
  net: drop_monitor: fix the value of maxattr
  ipv6: don't count addrconf generated routes against gc limit
  packet: fix send path when running with proto == 0
  virtio: delete napi structures from netdev before releasing memory
  macvtap: signal truncated packets
  tun: update file current position
  macvtap: update file current position
  macvtap: Do not double-count received packets
  rds: prevent BUG_ON triggered on congestion update to loopback
  net: do not pretend FRAGLIST support
  IPv6: Fixed support for blackhole and prohibit routes
  HID: Revert "Revert "HID: Fix logitech-dj: missing Unifying device issue""
  gpio-rcar: R-Car GPIO IRQ share interrupt
  clocksource: em_sti: Set cpu_possible_mask to fix SMP broadcast
  irqchip: renesas-irqc: Fix irqc_probe error handling
  Linux 3.10.26
  sh: add EXPORT_SYMBOL(min_low_pfn) and EXPORT_SYMBOL(max_low_pfn) to sh_ksyms_32.c
  ext4: fix bigalloc regression
  arm64: Use Normal NonCacheable memory for writecombine
  arm64: Do not flush the D-cache for anonymous pages
  arm64: Avoid cache flushing in flush_dcache_page()
  ARM: KVM: arch_timers: zero CNTVOFF upon return to host
  ARM: hyp: initialize CNTVOFF to zero
  clocksource: arch_timer: use virtual counters
  arm64: Remove unused cpu_name ascii in arch/arm64/mm/proc.S
  arm64: dts: Reserve the memory used for secondary CPU release address
  arm64: check for number of arguments in syscall_get/set_arguments()
  arm64: fix possible invalid FPSIMD initialization state
  ...

Change-Id: Ia0e5d71b536ab49ec3a1179d59238c05bdd03106
Signed-off-by: Ian Maund <imaund@codeaurora.org>
2014-03-24 14:28:34 -07:00

603 lines
15 KiB
C

/*
* Generic pidhash and scalable, time-bounded PID allocator
*
* (C) 2002-2003 Nadia Yvette Chambers, IBM
* (C) 2004 Nadia Yvette Chambers, Oracle
* (C) 2002-2004 Ingo Molnar, Red Hat
*
* pid-structures are backing objects for tasks sharing a given ID to chain
* against. There is very little to them aside from hashing them and
* parking tasks using given ID's on a list.
*
* The hash is always changed with the tasklist_lock write-acquired,
* and the hash is only accessed with the tasklist_lock at least
* read-acquired, so there's no additional SMP locking needed here.
*
* We have a list of bitmap pages, which bitmaps represent the PID space.
* Allocating and freeing PIDs is completely lockless. The worst-case
* allocation scenario when all but one out of 1 million PIDs possible are
* allocated already: the scanning of 32 list entries and at most PAGE_SIZE
* bytes. The typical fastpath is a single successful setbit. Freeing is O(1).
*
* Pid namespaces:
* (C) 2007 Pavel Emelyanov <xemul@openvz.org>, OpenVZ, SWsoft Inc.
* (C) 2007 Sukadev Bhattiprolu <sukadev@us.ibm.com>, IBM
* Many thanks to Oleg Nesterov for comments and help
*
*/
#include <linux/mm.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/rculist.h>
#include <linux/bootmem.h>
#include <linux/hash.h>
#include <linux/pid_namespace.h>
#include <linux/init_task.h>
#include <linux/syscalls.h>
#include <linux/proc_ns.h>
#include <linux/proc_fs.h>
#define pid_hashfn(nr, ns) \
hash_long((unsigned long)nr + (unsigned long)ns, pidhash_shift)
static struct hlist_head *pid_hash;
static unsigned int pidhash_shift = 4;
struct pid init_struct_pid = INIT_STRUCT_PID;
int pid_max = PID_MAX_DEFAULT;
#define RESERVED_PIDS 300
int pid_max_min = RESERVED_PIDS + 1;
int pid_max_max = PID_MAX_LIMIT;
static inline int mk_pid(struct pid_namespace *pid_ns,
struct pidmap *map, int off)
{
return (map - pid_ns->pidmap)*BITS_PER_PAGE + off;
}
#define find_next_offset(map, off) \
find_next_zero_bit((map)->page, BITS_PER_PAGE, off)
/*
* PID-map pages start out as NULL, they get allocated upon
* first use and are never deallocated. This way a low pid_max
* value does not cause lots of bitmaps to be allocated, but
* the scheme scales to up to 4 million PIDs, runtime.
*/
struct pid_namespace init_pid_ns = {
.kref = {
.refcount = ATOMIC_INIT(2),
},
.pidmap = {
[ 0 ... PIDMAP_ENTRIES-1] = { ATOMIC_INIT(BITS_PER_PAGE), NULL }
},
.last_pid = 0,
.level = 0,
.child_reaper = &init_task,
.user_ns = &init_user_ns,
.proc_inum = PROC_PID_INIT_INO,
};
EXPORT_SYMBOL_GPL(init_pid_ns);
/*
* Note: disable interrupts while the pidmap_lock is held as an
* interrupt might come in and do read_lock(&tasklist_lock).
*
* If we don't disable interrupts there is a nasty deadlock between
* detach_pid()->free_pid() and another cpu that does
* spin_lock(&pidmap_lock) followed by an interrupt routine that does
* read_lock(&tasklist_lock);
*
* After we clean up the tasklist_lock and know there are no
* irq handlers that take it we can leave the interrupts enabled.
* For now it is easier to be safe than to prove it can't happen.
*/
static __cacheline_aligned_in_smp DEFINE_SPINLOCK(pidmap_lock);
static void free_pidmap(struct upid *upid)
{
int nr = upid->nr;
struct pidmap *map = upid->ns->pidmap + nr / BITS_PER_PAGE;
int offset = nr & BITS_PER_PAGE_MASK;
clear_bit(offset, map->page);
atomic_inc(&map->nr_free);
}
/*
* If we started walking pids at 'base', is 'a' seen before 'b'?
*/
static int pid_before(int base, int a, int b)
{
/*
* This is the same as saying
*
* (a - base + MAXUINT) % MAXUINT < (b - base + MAXUINT) % MAXUINT
* and that mapping orders 'a' and 'b' with respect to 'base'.
*/
return (unsigned)(a - base) < (unsigned)(b - base);
}
/*
* We might be racing with someone else trying to set pid_ns->last_pid
* at the pid allocation time (there's also a sysctl for this, but racing
* with this one is OK, see comment in kernel/pid_namespace.c about it).
* We want the winner to have the "later" value, because if the
* "earlier" value prevails, then a pid may get reused immediately.
*
* Since pids rollover, it is not sufficient to just pick the bigger
* value. We have to consider where we started counting from.
*
* 'base' is the value of pid_ns->last_pid that we observed when
* we started looking for a pid.
*
* 'pid' is the pid that we eventually found.
*/
static void set_last_pid(struct pid_namespace *pid_ns, int base, int pid)
{
int prev;
int last_write = base;
do {
prev = last_write;
last_write = cmpxchg(&pid_ns->last_pid, prev, pid);
} while ((prev != last_write) && (pid_before(base, last_write, pid)));
}
static int alloc_pidmap(struct pid_namespace *pid_ns)
{
int i, offset, max_scan, pid, last = pid_ns->last_pid;
struct pidmap *map;
pid = last + 1;
if (pid >= pid_max)
pid = RESERVED_PIDS;
offset = pid & BITS_PER_PAGE_MASK;
map = &pid_ns->pidmap[pid/BITS_PER_PAGE];
/*
* If last_pid points into the middle of the map->page we
* want to scan this bitmap block twice, the second time
* we start with offset == 0 (or RESERVED_PIDS).
*/
max_scan = DIV_ROUND_UP(pid_max, BITS_PER_PAGE) - !offset;
for (i = 0; i <= max_scan; ++i) {
if (unlikely(!map->page)) {
void *page = kzalloc(PAGE_SIZE, GFP_KERNEL);
/*
* Free the page if someone raced with us
* installing it:
*/
spin_lock_irq(&pidmap_lock);
if (!map->page) {
map->page = page;
page = NULL;
}
spin_unlock_irq(&pidmap_lock);
kfree(page);
if (unlikely(!map->page))
break;
}
if (likely(atomic_read(&map->nr_free))) {
for ( ; ; ) {
if (!test_and_set_bit(offset, map->page)) {
atomic_dec(&map->nr_free);
set_last_pid(pid_ns, last, pid);
return pid;
}
offset = find_next_offset(map, offset);
if (offset >= BITS_PER_PAGE)
break;
pid = mk_pid(pid_ns, map, offset);
if (pid >= pid_max)
break;
}
}
if (map < &pid_ns->pidmap[(pid_max-1)/BITS_PER_PAGE]) {
++map;
offset = 0;
} else {
map = &pid_ns->pidmap[0];
offset = RESERVED_PIDS;
if (unlikely(last == offset))
break;
}
pid = mk_pid(pid_ns, map, offset);
}
return -1;
}
int next_pidmap(struct pid_namespace *pid_ns, unsigned int last)
{
int offset;
struct pidmap *map, *end;
if (last >= PID_MAX_LIMIT)
return -1;
offset = (last + 1) & BITS_PER_PAGE_MASK;
map = &pid_ns->pidmap[(last + 1)/BITS_PER_PAGE];
end = &pid_ns->pidmap[PIDMAP_ENTRIES];
for (; map < end; map++, offset = 0) {
if (unlikely(!map->page))
continue;
offset = find_next_bit((map)->page, BITS_PER_PAGE, offset);
if (offset < BITS_PER_PAGE)
return mk_pid(pid_ns, map, offset);
}
return -1;
}
void put_pid(struct pid *pid)
{
struct pid_namespace *ns;
if (!pid)
return;
ns = pid->numbers[pid->level].ns;
if ((atomic_read(&pid->count) == 1) ||
atomic_dec_and_test(&pid->count)) {
kmem_cache_free(ns->pid_cachep, pid);
put_pid_ns(ns);
}
}
EXPORT_SYMBOL_GPL(put_pid);
static void delayed_put_pid(struct rcu_head *rhp)
{
struct pid *pid = container_of(rhp, struct pid, rcu);
put_pid(pid);
}
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);
for (i = 0; i <= pid->level; i++) {
struct upid *upid = pid->numbers + i;
struct pid_namespace *ns = upid->ns;
hlist_del_rcu(&upid->pid_chain);
switch(--ns->nr_hashed) {
case 2:
case 1:
/* When all that is left in the pid namespace
* is the reaper wake up the reaper. The reaper
* may be sleeping in zap_pid_ns_processes().
*/
wake_up_process(ns->child_reaper);
break;
case 0:
schedule_work(&ns->proc_work);
break;
}
}
spin_unlock_irqrestore(&pidmap_lock, flags);
for (i = 0; i <= pid->level; i++)
free_pidmap(pid->numbers + i);
call_rcu(&pid->rcu, delayed_put_pid);
}
struct pid *alloc_pid(struct pid_namespace *ns)
{
struct pid *pid;
enum pid_type type;
int i, nr;
struct pid_namespace *tmp;
struct upid *upid;
pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL);
if (!pid)
goto out;
tmp = ns;
pid->level = ns->level;
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 (unlikely(is_child_reaper(pid))) {
if (pid_ns_prepare_proc(ns))
goto out_free;
}
get_pid_ns(ns);
atomic_set(&pid->count, 1);
for (type = 0; type < PIDTYPE_MAX; ++type)
INIT_HLIST_HEAD(&pid->tasks[type]);
upid = pid->numbers + ns->level;
spin_lock_irq(&pidmap_lock);
if (!(ns->nr_hashed & PIDNS_HASH_ADDING))
goto out_unlock;
for ( ; upid >= pid->numbers; --upid) {
hlist_add_head_rcu(&upid->pid_chain,
&pid_hash[pid_hashfn(upid->nr, upid->ns)]);
upid->ns->nr_hashed++;
}
spin_unlock_irq(&pidmap_lock);
out:
return pid;
out_unlock:
spin_unlock_irq(&pidmap_lock);
out_free:
while (++i <= ns->level)
free_pidmap(pid->numbers + i);
kmem_cache_free(ns->pid_cachep, pid);
pid = NULL;
goto out;
}
void disable_pid_allocation(struct pid_namespace *ns)
{
spin_lock_irq(&pidmap_lock);
ns->nr_hashed &= ~PIDNS_HASH_ADDING;
spin_unlock_irq(&pidmap_lock);
}
struct pid *find_pid_ns(int nr, struct pid_namespace *ns)
{
struct upid *pnr;
hlist_for_each_entry_rcu(pnr,
&pid_hash[pid_hashfn(nr, ns)], pid_chain)
if (pnr->nr == nr && pnr->ns == ns)
return container_of(pnr, struct pid,
numbers[ns->level]);
return NULL;
}
EXPORT_SYMBOL_GPL(find_pid_ns);
struct pid *find_vpid(int nr)
{
return find_pid_ns(nr, task_active_pid_ns(current));
}
EXPORT_SYMBOL_GPL(find_vpid);
/*
* attach_pid() must be called with the tasklist_lock write-held.
*/
void attach_pid(struct task_struct *task, enum pid_type type,
struct pid *pid)
{
struct pid_link *link;
link = &task->pids[type];
link->pid = pid;
hlist_add_head_rcu(&link->node, &pid->tasks[type]);
}
static void __change_pid(struct task_struct *task, enum pid_type type,
struct pid *new)
{
struct pid_link *link;
struct pid *pid;
int tmp;
link = &task->pids[type];
pid = link->pid;
hlist_del_rcu(&link->node);
link->pid = new;
for (tmp = PIDTYPE_MAX; --tmp >= 0; )
if (!hlist_empty(&pid->tasks[tmp]))
return;
free_pid(pid);
}
void detach_pid(struct task_struct *task, enum pid_type type)
{
__change_pid(task, type, NULL);
}
void change_pid(struct task_struct *task, enum pid_type type,
struct pid *pid)
{
__change_pid(task, type, pid);
attach_pid(task, type, pid);
}
/* transfer_pid is an optimization of attach_pid(new), detach_pid(old) */
void transfer_pid(struct task_struct *old, struct task_struct *new,
enum pid_type type)
{
new->pids[type].pid = old->pids[type].pid;
hlist_replace_rcu(&old->pids[type].node, &new->pids[type].node);
}
struct task_struct *pid_task(struct pid *pid, enum pid_type type)
{
struct task_struct *result = NULL;
if (pid) {
struct hlist_node *first;
first = rcu_dereference_check(hlist_first_rcu(&pid->tasks[type]),
lockdep_tasklist_lock_is_held());
if (first)
result = hlist_entry(first, struct task_struct, pids[(type)].node);
}
return result;
}
EXPORT_SYMBOL(pid_task);
/*
* Must be called under rcu_read_lock().
*/
struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns)
{
rcu_lockdep_assert(rcu_read_lock_held(),
"find_task_by_pid_ns() needs rcu_read_lock()"
" protection");
return pid_task(find_pid_ns(nr, ns), PIDTYPE_PID);
}
struct task_struct *find_task_by_vpid(pid_t vnr)
{
return find_task_by_pid_ns(vnr, task_active_pid_ns(current));
}
EXPORT_SYMBOL_GPL(find_task_by_vpid);
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;
}
EXPORT_SYMBOL_GPL(get_task_pid);
struct task_struct *get_pid_task(struct pid *pid, enum pid_type type)
{
struct task_struct *result;
rcu_read_lock();
result = pid_task(pid, type);
if (result)
get_task_struct(result);
rcu_read_unlock();
return result;
}
EXPORT_SYMBOL_GPL(get_pid_task);
struct pid *find_get_pid(pid_t nr)
{
struct pid *pid;
rcu_read_lock();
pid = get_pid(find_vpid(nr));
rcu_read_unlock();
return pid;
}
EXPORT_SYMBOL_GPL(find_get_pid);
pid_t pid_nr_ns(struct pid *pid, struct pid_namespace *ns)
{
struct upid *upid;
pid_t nr = 0;
if (pid && ns->level <= pid->level) {
upid = &pid->numbers[ns->level];
if (upid->ns == ns)
nr = upid->nr;
}
return nr;
}
EXPORT_SYMBOL_GPL(pid_nr_ns);
pid_t pid_vnr(struct pid *pid)
{
return pid_nr_ns(pid, task_active_pid_ns(current));
}
EXPORT_SYMBOL_GPL(pid_vnr);
pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
struct pid_namespace *ns)
{
pid_t nr = 0;
rcu_read_lock();
if (!ns)
ns = task_active_pid_ns(current);
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);
pid_t task_tgid_nr_ns(struct task_struct *tsk, struct pid_namespace *ns)
{
return pid_nr_ns(task_tgid(tsk), ns);
}
EXPORT_SYMBOL(task_tgid_nr_ns);
struct pid_namespace *task_active_pid_ns(struct task_struct *tsk)
{
return ns_of_pid(task_pid(tsk));
}
EXPORT_SYMBOL_GPL(task_active_pid_ns);
/*
* 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.
*/
struct pid *find_ge_pid(int nr, struct pid_namespace *ns)
{
struct pid *pid;
do {
pid = find_pid_ns(nr, ns);
if (pid)
break;
nr = next_pidmap(ns, nr);
} while (nr > 0);
return pid;
}
/*
* 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
* more.
*/
void __init pidhash_init(void)
{
unsigned int i, pidhash_size;
pid_hash = alloc_large_system_hash("PID", sizeof(*pid_hash), 0, 18,
HASH_EARLY | HASH_SMALL,
&pidhash_shift, NULL,
0, 4096);
pidhash_size = 1U << pidhash_shift;
for (i = 0; i < pidhash_size; i++)
INIT_HLIST_HEAD(&pid_hash[i]);
}
void __init pidmap_init(void)
{
/* Veryify no one has done anything silly */
BUILD_BUG_ON(PID_MAX_LIMIT >= PIDNS_HASH_ADDING);
/* bump default and minimum pid_max based on number of cpus */
pid_max = min(pid_max_max, max_t(int, pid_max,
PIDS_PER_CPU_DEFAULT * num_possible_cpus()));
pid_max_min = max_t(int, pid_max_min,
PIDS_PER_CPU_MIN * num_possible_cpus());
pr_info("pid_max: default: %u minimum: %u\n", pid_max, pid_max_min);
init_pid_ns.pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL);
/* Reserve PID 0. We never call free_pidmap(0) */
set_bit(0, init_pid_ns.pidmap[0].page);
atomic_dec(&init_pid_ns.pidmap[0].nr_free);
init_pid_ns.nr_hashed = PIDNS_HASH_ADDING;
init_pid_ns.pid_cachep = KMEM_CACHE(pid,
SLAB_HWCACHE_ALIGN | SLAB_PANIC);
}