linux-toradex.git/include/linux/pid.h, branch v2.6.26-rc5

pidns: make pid->level and pid_ns->level unsigned

2008-04-30T15:29:49+00:00

These values represent the nesting level of a namespace and pids living in it,
and it's always non-negative.

Turning this from int to unsigned int saves some space in pid.c (11 bytes on
x86 and 64 on ia64) by letting the compiler optimize the pid_nr_ns a bit.
E.g.  on ia64 this removes the sign extension calls, which compiler adds to
optimize access to pid->nubers[ns->level].

Signed-off-by: Pavel Emelyanov 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pids: introduce change_pid() helper

2008-04-30T15:29:48+00:00

Based on Eric W. Biederman's idea.

Without tasklist_lock held task_session()/task_pgrp() can return NULL if the
caller races with setprgp()/setsid() which does detach_pid() + attach_pid().
This can happen even if task == current.

Intoduce the new helper, change_pid(), which should be used instead.  This way
the caller always sees the special pid != NULL, either old or new.

Also change the prototype of attach_pid(), it always returns 0 and nobody
check the returned value.

Signed-off-by: Oleg Nesterov 
Cc:  "Eric W. Biederman" 
Cc: Pavel Emelyanov 
Cc: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

include/linux: Remove all users of FASTCALL() macro

2008-02-14T00:21:18+00:00

FASTCALL() is always expanded to empty, remove it.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Harvey Harrison 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

uglify while_each_pid_task() to make sure we don't count the execing pricess twice

2008-02-08T17:22:28+00:00

There is a window when de_thread() switches the leader and drops
tasklist_lock.  In that window do_each_pid_task(PIDTYPE_PID) finds both new
and old leaders.

The problem is pretty much theoretical and probably can be ignored.  Currently
the only users of do_each_pid_task(PIDTYPE_PID) are send_sigio/send_sigurg, so
they can send the signal to the same process twice.

Signed-off-by: Oleg Nesterov 
Cc: "Eric W. Biederman" 
Cc: Davide Libenzi 
Cc: Pavel Emelyanov 
Cc: Roland McGrath 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

pid: Extend/Fix pid_vnr

2008-02-08T17:22:27+00:00

pid_vnr returns the user space pid with respect to the pid namespace the
struct pid was allocated in.  What we want before we return a pid to user
space is the user space pid with respect to the pid namespace of current.

pid_vnr is a very nice optimization but because it isn't quite what we want
it is easy to use pid_vnr at times when we aren't certain the struct pid
was allocated in our pid namespace.

Currently this describes at least tiocgpgrp and tiocgsid in ttyio.c the
parent process reported in the core dumps and the parent process in
get_signal_to_deliver.

So unless the performance impact is huge having an interface that does what
we want instead of always what we want should be much more reliable and
much less error prone.

Signed-off-by: Eric W. Biederman 
Cc: Oleg Nesterov 
Acked-by: Pavel Emelyanov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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

Uninline find_pid etc set of functions

2007-10-19T18:53:41+00:00

The find_pid/_vpid/_pid_ns functions are used to find the struct pid by its
id, depending on whic id - global or virtual - is used.

The find_vpid() is a macro that pushes the current->nsproxy->pid_ns on the
stack to call another function - find_pid_ns().  It turned out, that this
dereference together with the push itself cause the kernel text size to
grow too much.

Move all these out-of-line.  Together with the previous patch this saves a
bit less that 400 bytes from .text section.

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

pid namespaces: remove the struct pid unneeded fields

2007-10-19T18:53:40+00:00

Since we've switched from using pid->nr to pid->upids->nr some
fields on struct pid are no longer needed

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: destroy pid namespace on init's death

2007-10-19T18:53:40+00:00

Terminate all processes in a namespace when the reaper of the namespace is
exiting.  We do this by walking the pidmap of the namespace and sending
SIGKILL to all processes.

Signed-off-by: Sukadev Bhattiprolu 
Acked-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: helpers to find the task by its numerical ids

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

When searching the task by numerical id on may need to find it using global
pid (as it is done now in kernel) or by its virtual id, e.g.  when sending a
signal to a task from one namespace the sender will specify the task's virtual
id and we should find the task by this value.

[akpm@linux-foundation.org: fix gfs2 linkage]
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