pidns: Use task_active_pid_ns where appropriate

The expressions tsk->nsproxy->pid_ns and task_active_pid_ns
aka ns_of_pid(task_pid(tsk)) should have the same number of
cache line misses with the practical difference that
ns_of_pid(task_pid(tsk)) is released later in a processes life.

Furthermore by using task_active_pid_ns it becomes trivial
to write an unshare implementation for the the pid namespace.

So I have used task_active_pid_ns everywhere I can.

In fork since the pid has not yet been attached to the
process I use ns_of_pid, to achieve the same effect.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 965d381..25db92a 100644 (file)
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -1094,7 +1094,7 @@ 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),
-               current->nsproxy->pid_ns->last_pid);
+               task_active_pid_ns(current)->last_pid);
        return 0;
 }
 

diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 79ccfe6..7fc71c6 100644 (file)
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -123,7 +123,7 @@ void mconsole_log(struct mc_request *req)
 
 void mconsole_proc(struct mc_request *req)
 {
-       struct vfsmount *mnt = current->nsproxy->pid_ns->proc_mnt;
+       struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
        char *buf;
        int len;
        struct file *file;

diff --git a/drivers/staging/android/binder.c b/drivers/staging/android/binder.c
index 5d4610b..a97bbcd 100644 (file)
--- a/drivers/staging/android/binder.c
+++ b/drivers/staging/android/binder.c
@@ -33,6 +33,7 @@
 #include <linux/uaccess.h>
 #include <linux/vmalloc.h>
 #include <linux/slab.h>
+#include <linux/pid_namespace.h>
 
 #include "binder.h"
 
@@ -2344,7 +2345,7 @@ retry:
                if (t->from) {
                        struct task_struct *sender = t->from->proc->tsk;
                        tr.sender_pid = task_tgid_nr_ns(sender,
-                                                       current->nsproxy->pid_ns);
+                                                       task_active_pid_ns(current));
                } else {
                        tr.sender_pid = 0;
                }

diff --git a/fs/hppfs/hppfs.c b/fs/hppfs/hppfs.c
index 78f21f8..43b315f 100644 (file)
--- a/fs/hppfs/hppfs.c
+++ b/fs/hppfs/hppfs.c
@@ -710,7 +710,7 @@ static int hppfs_fill_super(struct super_block *sb, void *d, int silent)
        struct vfsmount *proc_mnt;
        int err = -ENOENT;
 
-       proc_mnt = mntget(current->nsproxy->pid_ns->proc_mnt);
+       proc_mnt = mntget(task_active_pid_ns(current)->proc_mnt);
        if (IS_ERR(proc_mnt))
                goto out;
 

diff --git a/fs/proc/root.c b/fs/proc/root.c
index 13ef624..fc16093 100644 (file)
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -106,7 +106,7 @@ static struct dentry *proc_mount(struct file_system_type *fs_type,
                ns = (struct pid_namespace *)data;
                options = NULL;
        } else {
-               ns = current->nsproxy->pid_ns;
+               ns = task_active_pid_ns(current);
                options = data;
        }
 

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index f24f724..0dbfba2 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3390,7 +3390,7 @@ static struct cgroup_pidlist *cgroup_pidlist_find(struct cgroup *cgrp,
 {
        struct cgroup_pidlist *l;
        /* don't need task_nsproxy() if we're looking at ourself */
-       struct pid_namespace *ns = current->nsproxy->pid_ns;
+       struct pid_namespace *ns = task_active_pid_ns(current);
 
        /*
         * We can't drop the pidlist_mutex before taking the l->mutex in case

diff --git a/kernel/events/core.c b/kernel/events/core.c
index dbccf83..738f356 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6155,7 +6155,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 
        event->parent           = parent_event;
 
-       event->ns               = get_pid_ns(current->nsproxy->pid_ns);
+       event->ns               = get_pid_ns(task_active_pid_ns(current));
        event->id               = atomic64_inc_return(&perf_event_id);
 
        event->state            = PERF_EVENT_STATE_INACTIVE;

diff --git a/kernel/fork.c b/kernel/fork.c
index 8b20ab7..7798c24 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1442,7 +1442,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 
                if (thread_group_leader(p)) {
                        if (is_child_reaper(pid))
-                               p->nsproxy->pid_ns->child_reaper = p;
+                               ns_of_pid(pid)->child_reaper = p;
 
                        p->signal->leader_pid = pid;
                        p->signal->tty = tty_kref_get(current->signal->tty);

diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ca27d2c..acc9268 100644 (file)
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -84,7 +84,7 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
                goto out_ipc;
        }
 
-       new_nsp->pid_ns = copy_pid_ns(flags, task_cred_xxx(tsk, user_ns), task_active_pid_ns(tsk));
+       new_nsp->pid_ns = copy_pid_ns(flags, task_cred_xxx(tsk, user_ns), tsk->nsproxy->pid_ns);
        if (IS_ERR(new_nsp->pid_ns)) {
                err = PTR_ERR(new_nsp->pid_ns);
                goto out_pid;

diff --git a/kernel/pid.c b/kernel/pid.c
index 2a624f1..3a5f238 100644 (file)
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -345,7 +345,7 @@ EXPORT_SYMBOL_GPL(find_pid_ns);
 
 struct pid *find_vpid(int nr)
 {
-       return find_pid_ns(nr, current->nsproxy->pid_ns);
+       return find_pid_ns(nr, task_active_pid_ns(current));
 }
 EXPORT_SYMBOL_GPL(find_vpid);
 
@@ -429,7 +429,7 @@ struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns)
 
 struct task_struct *find_task_by_vpid(pid_t vnr)
 {
-       return find_task_by_pid_ns(vnr, current->nsproxy->pid_ns);
+       return find_task_by_pid_ns(vnr, task_active_pid_ns(current));
 }
 
 struct pid *get_task_pid(struct task_struct *task, enum pid_type type)
@@ -484,7 +484,7 @@ EXPORT_SYMBOL_GPL(pid_nr_ns);
 
 pid_t pid_vnr(struct pid *pid)
 {
-       return pid_nr_ns(pid, current->nsproxy->pid_ns);
+       return pid_nr_ns(pid, task_active_pid_ns(current));
 }
 EXPORT_SYMBOL_GPL(pid_vnr);
 
@@ -495,7 +495,7 @@ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
 
        rcu_read_lock();
        if (!ns)
-               ns = current->nsproxy->pid_ns;
+               ns = task_active_pid_ns(current);
        if (likely(pid_alive(task))) {
                if (type != PIDTYPE_PID)
                        task = task->group_leader;

diff --git a/kernel/signal.c b/kernel/signal.c
index 0af8868..b2445d8 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1752,7 +1752,7 @@ static void do_notify_parent_cldstop(struct task_struct *tsk,
         * see comment in do_notify_parent() about the following 4 lines
         */
        rcu_read_lock();
-       info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
+       info.si_pid = task_pid_nr_ns(tsk, task_active_pid_ns(parent));
        info.si_uid = from_kuid_munged(task_cred_xxx(parent, user_ns), task_uid(tsk));
        rcu_read_unlock();
 

diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index 65bdcf1..5a63844 100644 (file)
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -1344,7 +1344,7 @@ static ssize_t binary_sysctl(const int *name, int nlen,
                goto out_putname;
        }
 
-       mnt = current->nsproxy->pid_ns->proc_mnt;
+       mnt = task_active_pid_ns(current)->proc_mnt;
        file = file_open_root(mnt->mnt_root, mnt, pathname, flags);
        result = PTR_ERR(file);
        if (IS_ERR(file))