• Tejun Heo's avatar
    blkcg: replace blkcg_policy->cpd_size with ->cpd_alloc/free_fn() methods · e4a9bde9
    Tejun Heo authored
    Each active policy has a cpd (blkcg_policy_data) on each blkcg.  The
    cpd's were allocated by blkcg core and each policy could request to
    allocate extra space at the end by setting blkcg_policy->cpd_size
    larger than the size of cpd.
    This is a bit unusual but blkg (blkcg_gq) policy data used to be
    handled this way too so it made sense to be consistent; however, blkg
    policy data switched to alloc/free callbacks.
    This patch makes similar changes to cpd handling.
    blkcg_policy->cpd_alloc/free_fn() are added to replace ->cpd_size.  As
    cpd allocation is now done from policy side, it can simply allocate a
    larger area which embeds cpd at the beginning.
    As ->cpd_alloc_fn() may be able to perform all necessary
    initializations, this patch makes ->cpd_init_fn() optional.
    Signed-off-by: default avatarTejun Heo <tj@kernel.org>
    Cc: Vivek Goyal <vgoyal@redhat.com>
    Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
    Signed-off-by: default avatarJens Axboe <axboe@fb.com>
blk-cgroup.h 18.1 KB