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-rw-r--r--arch/powerpc/platforms/cell/spufs/sched.c2
-rw-r--r--fs/proc/loadavg.c2
-rw-r--r--include/linux/pid_namespace.h14
-rw-r--r--init/main.c2
-rw-r--r--kernel/pid.c201
-rw-r--r--kernel/pid_namespace.c53
6 files changed, 65 insertions, 209 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 1fbb5da..e47761c 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -1093,7 +1093,7 @@ static int show_spu_loadavg(struct seq_file *s, void *private)
LOAD_INT(c), LOAD_FRAC(c),
count_active_contexts(),
atomic_read(&nr_spu_contexts),
- task_active_pid_ns(current)->last_pid);
+ idr_get_cursor(&task_active_pid_ns(current)->idr));
return 0;
}
diff --git a/fs/proc/loadavg.c b/fs/proc/loadavg.c
index 9bc5c58..a000d75 100644
--- a/fs/proc/loadavg.c
+++ b/fs/proc/loadavg.c
@@ -24,7 +24,7 @@ static int loadavg_proc_show(struct seq_file *m, void *v)
LOAD_INT(avnrun[1]), LOAD_FRAC(avnrun[1]),
LOAD_INT(avnrun[2]), LOAD_FRAC(avnrun[2]),
nr_running(), nr_threads,
- task_active_pid_ns(current)->last_pid);
+ idr_get_cursor(&task_active_pid_ns(current)->idr));
return 0;
}
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index c78af60..92c6aa5 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -10,15 +10,8 @@
#include <linux/nsproxy.h>
#include <linux/kref.h>
#include <linux/ns_common.h>
+#include <linux/idr.h>
-struct pidmap {
- atomic_t nr_free;
- void *page;
-};
-
-#define BITS_PER_PAGE (PAGE_SIZE * 8)
-#define BITS_PER_PAGE_MASK (BITS_PER_PAGE-1)
-#define PIDMAP_ENTRIES ((PID_MAX_LIMIT+BITS_PER_PAGE-1)/BITS_PER_PAGE)
struct fs_pin;
@@ -30,9 +23,8 @@ enum { /* definitions for pid_namespace's hide_pid field */
struct pid_namespace {
struct kref kref;
- struct pidmap pidmap[PIDMAP_ENTRIES];
+ struct idr idr;
struct rcu_head rcu;
- int last_pid;
unsigned int nr_hashed;
struct task_struct *child_reaper;
struct kmem_cache *pid_cachep;
@@ -106,6 +98,6 @@ static inline int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk);
void pidhash_init(void);
-void pidmap_init(void);
+void pid_idr_init(void);
#endif /* _LINUX_PID_NS_H */
diff --git a/init/main.c b/init/main.c
index 859a786..d0cbcfc 100644
--- a/init/main.c
+++ b/init/main.c
@@ -669,7 +669,7 @@ asmlinkage __visible void __init start_kernel(void)
if (late_time_init)
late_time_init();
calibrate_delay();
- pidmap_init();
+ pid_idr_init();
anon_vma_init();
#ifdef CONFIG_X86
if (efi_enabled(EFI_RUNTIME_SERVICES))
diff --git a/kernel/pid.c b/kernel/pid.c
index 020dedb..0ce5936 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -39,6 +39,7 @@
#include <linux/proc_ns.h>
#include <linux/proc_fs.h>
#include <linux/sched/task.h>
+#include <linux/idr.h>
#define pid_hashfn(nr, ns) \
hash_long((unsigned long)nr + (unsigned long)ns, pidhash_shift)
@@ -53,14 +54,6 @@ int pid_max = PID_MAX_DEFAULT;
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
@@ -70,10 +63,7 @@ static inline int mk_pid(struct pid_namespace *pid_ns,
*/
struct pid_namespace init_pid_ns = {
.kref = KREF_INIT(2),
- .pidmap = {
- [ 0 ... PIDMAP_ENTRIES-1] = { ATOMIC_INIT(BITS_PER_PAGE), NULL }
- },
- .last_pid = 0,
+ .idr = IDR_INIT,
.nr_hashed = PIDNS_HASH_ADDING,
.level = 0,
.child_reaper = &init_task,
@@ -101,138 +91,6 @@ EXPORT_SYMBOL_GPL(init_pid_ns);
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))
- return -ENOMEM;
- }
- 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 -EAGAIN;
-}
-
-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;
@@ -266,7 +124,7 @@ void free_pid(struct pid *pid)
struct upid *upid = pid->numbers + i;
struct pid_namespace *ns = upid->ns;
hlist_del_rcu(&upid->pid_chain);
- switch(--ns->nr_hashed) {
+ switch (--ns->nr_hashed) {
case 2:
case 1:
/* When all that is left in the pid namespace
@@ -284,12 +142,11 @@ void free_pid(struct pid *pid)
schedule_work(&ns->proc_work);
break;
}
+
+ idr_remove(&ns->idr, upid->nr);
}
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);
}
@@ -308,8 +165,29 @@ struct pid *alloc_pid(struct pid_namespace *ns)
tmp = ns;
pid->level = ns->level;
+
for (i = ns->level; i >= 0; i--) {
- nr = alloc_pidmap(tmp);
+ int pid_min = 1;
+
+ idr_preload(GFP_KERNEL);
+ spin_lock_irq(&pidmap_lock);
+
+ /*
+ * init really needs pid 1, but after reaching the maximum
+ * wrap back to RESERVED_PIDS
+ */
+ if (idr_get_cursor(&tmp->idr) > RESERVED_PIDS)
+ pid_min = RESERVED_PIDS;
+
+ /*
+ * Store a null pointer so find_pid_ns does not find
+ * a partially initialized PID (see below).
+ */
+ nr = idr_alloc_cyclic(&tmp->idr, NULL, pid_min,
+ pid_max, GFP_ATOMIC);
+ spin_unlock_irq(&pidmap_lock);
+ idr_preload_end();
+
if (nr < 0) {
retval = nr;
goto out_free;
@@ -339,6 +217,8 @@ struct pid *alloc_pid(struct pid_namespace *ns)
for ( ; upid >= pid->numbers; --upid) {
hlist_add_head_rcu(&upid->pid_chain,
&pid_hash[pid_hashfn(upid->nr, upid->ns)]);
+ /* Make the PID visible to find_pid_ns. */
+ idr_replace(&upid->ns->idr, pid, upid->nr);
upid->ns->nr_hashed++;
}
spin_unlock_irq(&pidmap_lock);
@@ -350,8 +230,11 @@ out_unlock:
put_pid_ns(ns);
out_free:
+ spin_lock_irq(&pidmap_lock);
while (++i <= ns->level)
- free_pidmap(pid->numbers + i);
+ idr_remove(&ns->idr, (pid->numbers + i)->nr);
+
+ spin_unlock_irq(&pidmap_lock);
kmem_cache_free(ns->pid_cachep, pid);
return ERR_PTR(retval);
@@ -553,16 +436,7 @@ EXPORT_SYMBOL_GPL(task_active_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;
+ return idr_get_next(&ns->idr, &nr);
}
/*
@@ -578,7 +452,7 @@ void __init pidhash_init(void)
0, 4096);
}
-void __init pidmap_init(void)
+void __init pid_idr_init(void)
{
/* Verify no one has done anything silly: */
BUILD_BUG_ON(PID_MAX_LIMIT >= PIDNS_HASH_ADDING);
@@ -590,10 +464,7 @@ void __init pidmap_init(void)
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);
+ idr_init(&init_pid_ns.idr);
init_pid_ns.pid_cachep = KMEM_CACHE(pid,
SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT);
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index 4918314..ca7c8a8 100644
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -21,6 +21,7 @@
#include <linux/export.h>
#include <linux/sched/task.h>
#include <linux/sched/signal.h>
+#include <linux/idr.h>
struct pid_cache {
int nr_ids;
@@ -98,7 +99,6 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
struct pid_namespace *ns;
unsigned int level = parent_pid_ns->level + 1;
struct ucounts *ucounts;
- int i;
int err;
err = -EINVAL;
@@ -117,17 +117,15 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
if (ns == NULL)
goto out_dec;
- ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL);
- if (!ns->pidmap[0].page)
- goto out_free;
+ idr_init(&ns->idr);
ns->pid_cachep = create_pid_cachep(level + 1);
if (ns->pid_cachep == NULL)
- goto out_free_map;
+ goto out_free_idr;
err = ns_alloc_inum(&ns->ns);
if (err)
- goto out_free_map;
+ goto out_free_idr;
ns->ns.ops = &pidns_operations;
kref_init(&ns->kref);
@@ -138,17 +136,10 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
ns->nr_hashed = PIDNS_HASH_ADDING;
INIT_WORK(&ns->proc_work, proc_cleanup_work);
- 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++)
- atomic_set(&ns->pidmap[i].nr_free, BITS_PER_PAGE);
-
return ns;
-out_free_map:
- kfree(ns->pidmap[0].page);
-out_free:
+out_free_idr:
+ idr_destroy(&ns->idr);
kmem_cache_free(pid_ns_cachep, ns);
out_dec:
dec_pid_namespaces(ucounts);
@@ -168,11 +159,9 @@ static void delayed_free_pidns(struct rcu_head *p)
static void destroy_pid_namespace(struct pid_namespace *ns)
{
- int i;
-
ns_free_inum(&ns->ns);
- for (i = 0; i < PIDMAP_ENTRIES; i++)
- kfree(ns->pidmap[i].page);
+
+ idr_destroy(&ns->idr);
call_rcu(&ns->rcu, delayed_free_pidns);
}
@@ -213,6 +202,7 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
int rc;
struct task_struct *task, *me = current;
int init_pids = thread_group_leader(me) ? 1 : 2;
+ struct pid *pid;
/* Don't allow any more processes into the pid namespace */
disable_pid_allocation(pid_ns);
@@ -239,20 +229,16 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
* maintain a tasklist for each pid namespace.
*
*/
+ rcu_read_lock();
read_lock(&tasklist_lock);
- nr = next_pidmap(pid_ns, 1);
- while (nr > 0) {
- rcu_read_lock();
-
- task = pid_task(find_vpid(nr), PIDTYPE_PID);
+ nr = 2;
+ idr_for_each_entry_continue(&pid_ns->idr, pid, nr) {
+ task = pid_task(pid, PIDTYPE_PID);
if (task && !__fatal_signal_pending(task))
send_sig_info(SIGKILL, SEND_SIG_FORCED, task);
-
- rcu_read_unlock();
-
- nr = next_pidmap(pid_ns, nr);
}
read_unlock(&tasklist_lock);
+ rcu_read_unlock();
/*
* Reap the EXIT_ZOMBIE children we had before we ignored SIGCHLD.
@@ -301,6 +287,7 @@ static int pid_ns_ctl_handler(struct ctl_table *table, int write,
{
struct pid_namespace *pid_ns = task_active_pid_ns(current);
struct ctl_table tmp = *table;
+ int ret, next;
if (write && !ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
@@ -311,8 +298,14 @@ static int pid_ns_ctl_handler(struct ctl_table *table, int write,
* it should synchronize its usage with external means.
*/
- tmp.data = &pid_ns->last_pid;
- return proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+ next = idr_get_cursor(&pid_ns->idr) - 1;
+
+ tmp.data = &next;
+ ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
+ if (!ret && write)
+ idr_set_cursor(&pid_ns->idr, next + 1);
+
+ return ret;
}
extern int pid_max;
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