audit: group task params

Group the audit parameters for each task into one structure. In particular, remove the loginuid and sessionid values and the audit context pointer from the task structure, replacing them with an audit task information structure to contain them. Use access functions to access audit values.

Use dynamic allocation of the audit task information structure employing kmem_cache. Static allocation has the limitation that future audit task information structure changes would cause a visible change to the rest of the kernel, whereas dynamic allocation would mostly hide any future changes.

Passes audit-testsuite.

Changelog:
v3
- drop patches 2, 3, 4 already merged.
- fix for previous v2 patch 3 (seccomp get audit_context)
- dynamic audit_task_info allocation from kmem_cache
- fix assignment in if statement v2 patch 1 (normalize loginuid read)
- fix a number of merge conflicts/checkpatch
v2
- p2/5: add audit header to init/init_task.c to quiet kbuildbot
- audit_signal_info(): fetch loginuid once
- remove task_struct from audit_context() param list
- remove extra task_struct local vars
- do nothing on request to set audit context when audit is disabled

Richard Guy Briggs (3):
audit: use new audit_context access funciton for
seccomp_actions_logged
audit: normalize loginuid read access
audit: collect audit task parameters

 include/linux/audit.h | 34 ++++++++++++++++-------
 include/linux/sched.h |  5 +---
 init/init_task.c      |  3 +-
 init/main.c           |  2 ++
 kernel/auditsc.c      | 77 ++++++++++++++++++++++++++++++++++++++-------------
 kernel/fork.c         |  2 +-
 6 files changed, 87 insertions(+), 36 deletions(-)

1.8.3.1