[GIT PULL 13/12 for v7.0] kernel misc

[Christian Brauner]

Hey Linus,

as announced in [1] this is one of pull requests that was delayed.

/* Summary */

- pid: introduce task_ppid_vnr() helper

- Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers"

- ipc: Add SPDX license id to mqueue.c

- pidfs: convert rb-tree to rhashtable

  Mateusz reported performance penalties during task creation because
  pidfs uses pidmap_lock to add elements into the rbtree. Switch to an
  rhashtable to have separate fine-grained locking and to decouple from
  pidmap_lock moving all heavy manipulations outside of it.

  Also move inode allocation outside of pidmap_lock. With this there's
  nothing happening for pidfs under pidmap_lock.

- pid: reorder fields in pid_namespace to reduce false sharing

Link: https://lore.kernel.org/20260206-vfs-v70-7df0b750d594@brauner [1]
/* Testing */

gcc (Debian 14.2.0-19) 14.2.0
Debian clang version 19.1.7 (3+b1)

No build failures or warnings were observed.

/* Conflicts */

Merge conflicts with mainline
=============================

No known conflicts.

Merge conflicts with other trees
================================

The following changes since commit 6cbfdf89470ef3c2110f376a507d135e7a7a7378:

  posix_acl: make posix_acl_to_xattr() alloc the buffer (2026-01-16 10:51:12 +0100)

are available in the Git repository at:

  git@xxxxxxxxxxxxxxxxxxx:pub/scm/linux/kernel/git/vfs/vfs tags/kernel-7.0-rc1.misc

for you to fetch changes up to 3673dd3c7dc1f37baf0448164d323d7c7a44d1da:

  Merge patch series "Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers"" (2026-02-10 11:39:31 +0100)

----------------------------------------------------------------
kernel-7.0-rc1.misc

Please consider pulling these changes from the signed kernel-7.0-rc1.misc tag.

Thanks!
Christian

----------------------------------------------------------------
Christian Brauner (2):
      pidfs: convert rb-tree to rhashtable
      Merge patch series "Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers""

Mateusz Guzik (2):
      pid: reorder fields in pid_namespace to reduce false sharing
      pidfs: implement ino allocation without the pidmap lock

Oleg Nesterov (2):
      Revert "pid: make __task_pid_nr_ns(ns => NULL) safe for zombie callers"
      pid: introduce task_ppid_vnr() helper

Tim Bird (1):
      ipc: Add SPDX license id to mqueue.c

 fs/pidfs.c                    | 174 +++++++++++++++++++++++-------------------
 include/linux/pid.h           |   9 ++-
 include/linux/pid_namespace.h |  14 ++--
 include/linux/pidfs.h         |   3 +-
 ipc/mqueue.c                  |   3 +-
 kernel/pid.c                  |  15 ++--
 6 files changed, 121 insertions(+), 97 deletions(-)