[DRAFT v3.4] - audit cmdline updates

Changes since last publish: * Ran all patches through checkpatch, some elluded me. * Changed cmdline copy/length API to reduce task_mm_get() mmput() calls Still need to know: * Any major objecttions to this still? * My public API changes are in proc, is this the best spot for those? As always, thanks. [PATCH 1/4] audit: Allow auditing of proc/self/cmdline value [PATCH 2/4] audit: Enable cacheing of cmdline in audit_context [PATCH 3/4] audit: dont allocate whole pages [PATCH 4/4] SQUASH audit: Change cmdline get API to reduce locking