pidns: Use task_active_pid_ns where appropriate

ebiederm · ebiederm · commit 17cf22c33e1f · 2012-11-19T05:59:09.000-08:00
The expressions tsk-&gt;nsproxy-&gt;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 &lt;ebiederm@xmission.com&gt;
diff --git 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
@@ -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
@@ -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 @@ static int binder_thread_read(struct binder_proc *proc,
 		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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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
@@ -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))

Original file line number	Diff line number	Diff line change
`@@ -1094,7 +1094,7 @@ static int show_spu_loadavg(struct seq_file s, void private)`
`1094`	`1094`	`LOAD_INT(c), LOAD_FRAC(c),`
`1095`	`1095`	`count_active_contexts(),`
`1096`	`1096`	`atomic_read(&nr_spu_contexts),`
`1097`		`- current->nsproxy->pid_ns->last_pid);`
	`1097`	`+ task_active_pid_ns(current)->last_pid);`
`1098`	`1098`	`return 0;`
`1099`	`1099`	`}`
`1100`	`1100`
Original file line number	Diff line number	Diff line change
`@@ -123,7 +123,7 @@ void mconsole_log(struct mc_request *req)`
`123`	`123`
`124`	`124`	`void mconsole_proc(struct mc_request *req)`
`125`	`125`	`{`
`126`		`- struct vfsmount *mnt = current->nsproxy->pid_ns->proc_mnt;`
	`126`	`+ struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;`
`127`	`127`	`char *buf;`
`128`	`128`	`int len;`
`129`	`129`	`struct file *file;`
Original file line number	Diff line number	Diff line change
`@@ -106,7 +106,7 @@ static struct dentry proc_mount(struct file_system_type fs_type,`
`106`	`106`	`ns = (struct pid_namespace *)data;`
`107`	`107`	`options = NULL;`
`108`	`108`	`} else {`
`109`		`- ns = current->nsproxy->pid_ns;`
	`109`	`+ ns = task_active_pid_ns(current);`
`110`	`110`	`options = data;`
`111`	`111`	`}`
`112`	`112`
Original file line number	Diff line number	Diff line change
`@@ -3390,7 +3390,7 @@ static struct cgroup_pidlist cgroup_pidlist_find(struct cgroup cgrp,`
`3390`	`3390`	`{`
`3391`	`3391`	`struct cgroup_pidlist *l;`
`3392`	`3392`	`/* don't need task_nsproxy() if we're looking at ourself */`
`3393`		`- struct pid_namespace *ns = current->nsproxy->pid_ns;`
	`3393`	`+ struct pid_namespace *ns = task_active_pid_ns(current);`
`3394`	`3394`
`3395`	`3395`	`/*`
`3396`	`3396`	`* We can't drop the pidlist_mutex before taking the l->mutex in case`
Original file line number	Diff line number	Diff line change
`@@ -84,7 +84,7 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,`
`84`	`84`	`goto out_ipc;`
`85`	`85`	`}`
`86`	`86`
`87`		`- new_nsp->pid_ns = copy_pid_ns(flags, task_cred_xxx(tsk, user_ns), task_active_pid_ns(tsk));`
	`87`	`+ new_nsp->pid_ns = copy_pid_ns(flags, task_cred_xxx(tsk, user_ns), tsk->nsproxy->pid_ns);`
`88`	`88`	`if (IS_ERR(new_nsp->pid_ns)) {`
`89`	`89`	`err = PTR_ERR(new_nsp->pid_ns);`
`90`	`90`	`goto out_pid;`
Original file line number	Diff line number	Diff line change
`@@ -345,7 +345,7 @@ EXPORT_SYMBOL_GPL(find_pid_ns);`
`345`	`345`
`346`	`346`	`struct pid *find_vpid(int nr)`
`347`	`347`	`{`
`348`		`- return find_pid_ns(nr, current->nsproxy->pid_ns);`
	`348`	`+ return find_pid_ns(nr, task_active_pid_ns(current));`
`349`	`349`	`}`
`350`	`350`	`EXPORT_SYMBOL_GPL(find_vpid);`
`351`	`351`
`@@ -429,7 +429,7 @@ struct task_struct find_task_by_pid_ns(pid_t nr, struct pid_namespace ns)`
`429`	`429`
`430`	`430`	`struct task_struct *find_task_by_vpid(pid_t vnr)`
`431`	`431`	`{`
`432`		`- return find_task_by_pid_ns(vnr, current->nsproxy->pid_ns);`
	`432`	`+ return find_task_by_pid_ns(vnr, task_active_pid_ns(current));`
`433`	`433`	`}`
`434`	`434`
`435`	`435`	`struct pid get_task_pid(struct task_struct task, enum pid_type type)`
`@@ -484,7 +484,7 @@ EXPORT_SYMBOL_GPL(pid_nr_ns);`
`484`	`484`
`485`	`485`	`pid_t pid_vnr(struct pid *pid)`
`486`	`486`	`{`
`487`		`- return pid_nr_ns(pid, current->nsproxy->pid_ns);`
	`487`	`+ return pid_nr_ns(pid, task_active_pid_ns(current));`
`488`	`488`	`}`
`489`	`489`	`EXPORT_SYMBOL_GPL(pid_vnr);`
`490`	`490`
`@@ -495,7 +495,7 @@ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,`
`495`	`495`
`496`	`496`	`rcu_read_lock();`
`497`	`497`	`if (!ns)`
`498`		`- ns = current->nsproxy->pid_ns;`
	`498`	`+ ns = task_active_pid_ns(current);`
`499`	`499`	`if (likely(pid_alive(task))) {`
`500`	`500`	`if (type != PIDTYPE_PID)`
`501`	`501`	`task = task->group_leader;`