linux/init
Kirill Tkhai 9a56493f69
uts: Use generic ns_common::count
Switch over uts namespaces to use the newly introduced common lifetime
counter.

Currently every namespace type has its own lifetime counter which is stored
in the specific namespace struct. The lifetime counters are used
identically for all namespaces types. Namespaces may of course have
additional unrelated counters and these are not altered.

This introduces a common lifetime counter into struct ns_common. The
ns_common struct encompasses information that all namespaces share. That
should include the lifetime counter since its common for all of them.

It also allows us to unify the type of the counters across all namespaces.
Most of them use refcount_t but one uses atomic_t and at least one uses
kref. Especially the last one doesn't make much sense since it's just a
wrapper around refcount_t since 2016 and actually complicates cleanup
operations by having to use container_of() to cast the correct namespace
struct out of struct ns_common.

Having the lifetime counter for the namespaces in one place reduces
maintenance cost. Not just because after switching all namespaces over we
will have removed more code than we added but also because the logic is
more easily understandable and we indicate to the user that the basic
lifetime requirements for all namespaces are currently identical.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/159644978167.604812.1773586504374412107.stgit@localhost.localdomain
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2020-08-19 14:13:20 +02:00
..
calibrate.c
do_mounts_initrd.c Merge branch 'hch.init_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 09:40:34 -07:00
do_mounts_rd.c init: add an init_unlink helper 2020-07-31 08:17:52 +02:00
do_mounts.c init: add an init_chroot helper 2020-07-31 08:17:52 +02:00
do_mounts.h init: add an init_mknod helper 2020-07-31 08:17:54 +02:00
init_task.c OpenRISC updates for 5.9 2020-08-14 14:04:53 -07:00
initramfs.c init: add an init_utimes helper 2020-07-31 08:17:54 +02:00
Kconfig mm/slab: expand CONFIG_SLAB_FREELIST_HARDENED to include SLAB 2020-08-07 11:33:22 -07:00
main.c Tracing updates for 5.9 2020-08-07 18:29:15 -07:00
Makefile md: move the early init autodetect code to drivers/md/ 2020-07-16 15:34:47 +02:00
noinitramfs.c init: add an init_mknod helper 2020-07-31 08:17:54 +02:00
version.c uts: Use generic ns_common::count 2020-08-19 14:13:20 +02:00