linux/kernel/pid.c, branch v2.6.24

pidns: Place under CONFIG_EXPERIMENTAL

2007-11-15T02:45:43Z

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

Uninline the task_xid_nr_ns() calls

2007-10-19T18:53:41Z

Since these are expanded into call to pid_nr_ns() anyway, it's OK to move the whole routine out-of-line. This is a cheap way to save ~100 bytes from vmlinux. Together with the previous two patches, it saves half-a-kilo from the vmlinux. Un-inline other (currently inlined) functions must be done with additional performance testing. 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

Uninline find_pid etc set of functions

2007-10-19T18:53:41Z

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

2007-10-19T18:53:40Z

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

Uninline find_task_by_xxx set of functions

2007-10-19T18:53:40Z

The find_task_by_something is a set of macros are used to find task by pid depending on what kind of pid is proposed - global or virtual one. All of them are wrappers above the most generic one - find_task_by_pid_type_ns() - and just substitute some args for it. It turned out, that dereferencing the current->nsproxy->pid_ns construction and pushing one more argument on the stack inline cause kernel text size to grow. This patch moves all this stuff out-of-line into kernel/pid.c. Together with the next patch it saves a bit less than 400 bytes from the .text section. Signed-off-by: Pavel Emelyanov Cc: Sukadev Bhattiprolu Cc: Oleg Nesterov Cc: Paul Menage Cc: "Eric W. Biederman" Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pid namespaces: destroy pid namespace on init's death

2007-10-19T18:53:40Z

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: create a slab-cache for 'struct pid_namespace'

2007-10-19T18:53:40Z

This will help fixing memory leaks due to bad reference counting. Signed-off-by: Sukadev Bhattiprolu 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: allow cloning of new namespace

2007-10-19T18:53:39Z

When clone() is invoked with CLONE_NEWPID, create a new pid namespace and then create a new struct pid for the new process. Allocate pid_t's for the new process in the new pid namespace and all ancestor pid namespaces. Make the newly cloned process the session and process group leader. Since the active pid namespace is special and expected to be the first entry in pid->upid_list, preserve the order of pid namespaces. The size of 'struct pid' is dependent on the the number of pid namespaces the process exists in, so we use multiple pid-caches'. Only one pid cache is created during system startup and this used by processes that exist only in init_pid_ns. When a process clones its pid namespace, we create additional pid caches as necessary and use the pid cache to allocate 'struct pids' for that depth. Note, that with this patch the newly created namespace won't work, since the rest of the kernel still uses global pids, but this is to be fixed soon. Init pid namespace still works. [oleg@tv-sign.ru: merge fix] Signed-off-by: Pavel Emelyanov Signed-off-by: Sukadev Bhattiprolu Cc: Paul Menage Cc: "Eric W. Biederman" Cc: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pid namespaces: miscellaneous preparations for pid namespaces

2007-10-19T18:53:39Z

* 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: helpers to find the task by its numerical ids

2007-10-19T18:53:39Z

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