On 2013/6/22 9:34, Tejun Heo wrote:
> There are quite a few places where all loaded [builtin] subsys are
> iterated. Implement for_each_[builtin_]subsys() and replace manual
> iterations with those to simplify those places a bit. The new
> iterators automatically skip NULL subsystems. This shouldn't cause
> any functional difference.
>
> Iteration loops which scan all subsystems and then skipping modular
> ones explicitly are converted to use for_each_builtin_subsys().
>
> While at it, reorder variable declarations and adjust whitespaces a
> bit in the affected functions.
>
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> ---
> kernel/cgroup.c | 143 ++++++++++++++++++++++++++------------------------------
> 1 file changed, 67 insertions(+), 76 deletions(-)
>
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index c4bbafb..a890b56 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -259,6 +259,27 @@ static int notify_on_release(const struct cgroup *cgrp)
> return test_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
> }
>
> +/**
> + * for_each_subsys - iterate all loaded cgroup subsystems
> + * @ss: the iteration cursor
> + * @i: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
> + */
> +#define for_each_subsys(ss, i) \
This should be called with cgroup_mutex held, so how about add a comment or
a lock assert for it?
> + for ((i) = 0; (i) < CGROUP_SUBSYS_COUNT; (i)++) \
> + if (!((ss) = cgroup_subsys[i])) { } \
> + else
> +
> +/**
> + * for_each_builtin_subsys - iterate all built-in cgroup subsystems
> + * @ss: the iteration cursor
> + * @i: the index of @ss, CGROUP_BUILTIN_SUBSYS_COUNT after reaching the end
> + *
> + * Bulit-in subsystems are always present.
> + */
> +#define for_each_builtin_subsys(ss, i) \
> + for ((i) = 0; (i) < CGROUP_BUILTIN_SUBSYS_COUNT && \
> + (((ss) = cgroup_subsys[i]) || true); (i)++)
Why "true" is needed here? given ss can't be NULL.
> +
> /* iterate each subsystem attached to a hierarchy */
> #define for_each_root_subsys(root, ss) \
> list_for_each_entry((ss), &(root)->subsys_list, sibling)
> @@ -356,10 +377,11 @@ static DEFINE_HASHTABLE(css_set_table, CSS_SET_HASH_BITS);
>
=
_______________________________________________
Containers mailing list
Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/containers
