linux-toradex.git/include/linux/pid_namespace.h, branch v2.6.25-rc2

namespaces: cleanup the code managed with PID_NS option

2008-02-08T17:22:23+00:00

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"

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Pavel Emelyanov 
Acked-by: Serge Hallyn 
Cc: Cedric Le Goater 
Cc: "Eric W. Biederman" 
Cc: Herbert Poetzl 
Cc: Kirill Korotaev 
Cc: Sukadev Bhattiprolu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pidns: Place under CONFIG_EXPERIMENTAL

2007-11-15T02:45:43+00:00

This is my trivial patch to swat innumerable little bugs with a single
blow.

After some intensive review (my apologies for not having gotten to this
sooner) what we have looks like a good base to build on with the current
pid namespace code but it is not complete, and it is still much to simple
to find issues where the kernel does the wrong thing outside of the initial
pid namespace.

Until the dust settles and we are certain we have the ABI and the
implementation is as correct as humanly possible let's keep process ID
namespaces behind CONFIG_EXPERIMENTAL.

Allowing us the option of fixing any ABI or other bugs we find as long as
they are minor.

Allowing users of the kernel to avoid those bugs simply by ensuring their
kernel does not have support for multiple pid namespaces.

[akpm@linux-foundation.org: coding-style cleanups]
Signed-off-by: Eric W. Biederman 
Cc: Cedric Le Goater 
Cc: Adrian Bunk 
Cc: Jeremy Fitzhardinge 
Cc: Kir Kolyshkin 
Cc: Kirill Korotaev 
Cc: Pavel Emelyanov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: miscellaneous preparations for pid namespaces

2007-10-19T18:53:39+00:00

* remove pid.h from pid_namespaces.h;
* rework is_(cgroup|global)_init;
* optimize (get|put)_pid_ns for init_pid_ns;
* declare task_child_reaper to return actual reaper.

Signed-off-by: Pavel Emelyanov 
Cc: Oleg Nesterov 
Cc: Sukadev Bhattiprolu 
Cc: Paul Menage 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: make proc have multiple superblocks - one for each namespace

2007-10-19T18:53:39+00:00

Each pid namespace have to be visible through its own proc mount.  Thus we
need to have per-namespace proc trees with their own superblocks.

We cannot easily show different pid namespace via one global proc tree, since
each pid refers to different tasks in different namespaces.  E.g.  pid 1
refers to the init task in the initial namespace and to some other task when
seeing from another namespace.  Moreover - pid, exisintg in one namespace may
not exist in the other.

This approach has one move advantage is that the tasks from the init namespace
can see what tasks live in another namespace by reading entries from another
proc tree.

Signed-off-by: Pavel Emelyanov 
Cc: Oleg Nesterov 
Cc: Sukadev Bhattiprolu 
Cc: Paul Menage 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: add support for pid namespaces hierarchy

2007-10-19T18:53:38+00:00

Each namespace has a parent and is characterized by its "level".  Level is the
number of the namespace generation.  E.g.  init namespace has level 0, after
cloning new one it will have level 1, the next one - 2 and so on and so forth.
 This level is not explicitly limited.

True hierarchy must have some way to find each namespace's children, but it is
not used in the patches, so this ability is not added (yet).

Signed-off-by: Pavel Emelyanov 
Cc: Oleg Nesterov 
Cc: Sukadev Bhattiprolu 
Cc: Paul Menage 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: rename child_reaper() function

2007-10-19T18:53:37+00:00

Rename the child_reaper() function to task_child_reaper() to be similar to
other task_* functions and to distinguish the function from 'struct
pid_namspace.child_reaper'.

Signed-off-by: Sukadev Bhattiprolu 
Cc: Pavel Emelianov 
Cc: Eric W. Biederman 
Cc: Cedric Le Goater 
Cc: Dave Hansen 
Cc: Serge Hallyn 
Cc: Herbert Poetzel 
Cc: Kirill Korotaev 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: define and use task_active_pid_ns() wrapper

2007-10-19T18:53:37+00:00

With multiple pid namespaces, a process is known by some pid_t in every
ancestor pid namespace.  Every time the process forks, the child process also
gets a pid_t in every ancestor pid namespace.

While a process is visible in >=1 pid namespaces, it can see pid_t's in only
one pid namespace.  We call this pid namespace it's "active pid namespace",
and it is always the youngest pid namespace in which the process is known.

This patch defines and uses a wrapper to find the active pid namespace of a
process.  The implementation of the wrapper will be changed in when support
for multiple pid namespaces are added.

Changelog:
	2.6.22-rc4-mm2-pidns1:
	- [Pavel Emelianov, Alexey Dobriyan] Back out the change to use
	  task_active_pid_ns() in child_reaper() since task->nsproxy
	  can be NULL during task exit (so child_reaper() continues to
	  use init_pid_ns).

	  to implement child_reaper() since init_pid_ns.child_reaper to
	  implement child_reaper() since tsk->nsproxy can be NULL during exit.

	2.6.21-rc6-mm1:
	- Rename task_pid_ns() to task_active_pid_ns() to reflect that a
	  process can have multiple pid namespaces.

Signed-off-by: Sukadev Bhattiprolu 
Acked-by: Pavel Emelianov 
Cc: Eric W. Biederman 
Cc: Cedric Le Goater 
Cc: Dave Hansen 
Cc: Serge Hallyn 
Cc: Herbert Poetzel 
Cc: Kirill Korotaev 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: dynamic kmem cache allocator for pid namespaces

2007-10-19T18:53:37+00:00

Add kmem_cache to pid_namespace to allocate pids from.

Since both implementations expand the struct pid to carry more numerical
values each namespace should have separate cache to store pids of different
sizes.

Each kmem cache is name "pid_", where  is the number of numerical ids
on the pid.  Different namespaces with same level of nesting will have same
caches.

This patch has two FIXMEs that are to be fixed after we reach the consensus
about the struct pid itself.

The first one is that the namespace to free the pid from in free_pid() must be
taken from pid.  Now the init_pid_ns is used.

The second FIXME is about the cache allocation.  When we do know how long the
object will be then we'll have to calculate this size in create_pid_cachep.
Right now the sizeof(struct pid) value is used.

[akpm@linux-foundation.org: coding-style repair]
Signed-off-by: Pavel Emelianov 
Acked-by: Cedric Le Goater 
Acked-by: Sukadev Bhattiprolu 
Cc: Kirill Korotaev 
Cc: "Eric W. Biederman" 
Cc: Herbert Poetzl 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid namespaces: make get_pid_ns() return the namespace itself

2007-10-19T18:53:37+00:00

Make get_pid_ns() return the namespace itself to look like the other getters
and make the code using it look nicer.

Signed-off-by: Pavel Emelianov 
Acked-by: Cedric Le Goater 
Cc: Kirill Korotaev 
Cc: "Eric W. Biederman" 
Cc: Herbert Poetzl 
Cc: Sukadev Bhattiprolu 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

namespace: ensure clone_flags are always stored in an unsigned long

2007-07-16T16:05:48+00:00

While working on unshare support for the network namespace I noticed we
were putting clone flags in an int.  Which is weird because the syscall
uses unsigned long and we at least need an unsigned to properly hold all of
the unshare flags.

So to make the code consistent, this patch updates the code to use
unsigned long instead of int for the clone flags in those places
where we get it wrong today.

Signed-off-by: Eric W. Biederman 
Acked-by: Cedric Le Goater 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds