ipc: merge ipc_rcu and kern_ipc_perm
authorManfred Spraul <manfred@colorfullife.com>
Wed, 12 Jul 2017 21:34:41 +0000 (14:34 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 12 Jul 2017 23:26:01 +0000 (16:26 -0700)
commitdba4cdd39e698d8dcdad0656825423052ac90ccd
tree908f984f4652a42f603aac8f2db4edd059d11256
parent1a23395672658969a4035dcc518ea6cab835c579
ipc: merge ipc_rcu and kern_ipc_perm

ipc has two management structures that exist for every id:
 - struct kern_ipc_perm, it contains e.g. the permissions.
 - struct ipc_rcu, it contains the rcu head for rcu handling and the
   refcount.

The patch merges both structures.

As a bonus, we may save one cacheline, because both structures are
cacheline aligned.  In addition, it reduces the number of casts, instead
most codepaths can use container_of.

To simplify code, the ipc_rcu_alloc initializes the allocation to 0.

[manfred@colorfullife.com: really include the memset() into ipc_alloc_rcu()]
Link: http://lkml.kernel.org/r/564f8612-0601-b267-514f-a9f650ec9b32@colorfullife.com
Link: http://lkml.kernel.org/r/20170525185107.12869-3-manfred@colorfullife.com
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/ipc.h
ipc/msg.c
ipc/sem.c
ipc/shm.c
ipc/util.c
ipc/util.h