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authorTejun Heo <tj@kernel.org>2013-05-14 13:52:30 -0700
committerTejun Heo <tj@kernel.org>2013-05-14 13:52:30 -0700
commitdd4a4ffc0a4723cd0bef065af549803d256e1f7e (patch)
treea246b7307e85983c6633eadbd49f8c3b24dc1dd6 /block/blk-cgroup.h
parent2423c9c3f0ffffa8f87cbdafe9781273c5d1b6a2 (diff)
blkcg: move blkg_for_each_descendant_pre() to block/blk-cgroup.h
blk-throttle hierarchy support will make use of it. Move blkg_for_each_descendant_pre() from block/blk-cgroup.c to block/blk-cgroup.h. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
Diffstat (limited to 'block/blk-cgroup.h')
-rw-r--r--block/blk-cgroup.h20
1 files changed, 20 insertions, 0 deletions
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 4e595ee8c91..11f5b92d9a4 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -282,6 +282,26 @@ static inline void blkg_put(struct blkcg_gq *blkg)
__blkg_release(blkg);
}
+struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q,
+ bool update_hint);
+
+/**
+ * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
+ * @d_blkg: loop cursor pointing to the current descendant
+ * @pos_cgrp: used for iteration
+ * @p_blkg: target blkg to walk descendants of
+ *
+ * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
+ * read locked. If called under either blkcg or queue lock, the iteration
+ * is guaranteed to include all and only online blkgs. The caller may
+ * update @pos_cgrp by calling cgroup_rightmost_descendant() to skip
+ * subtree.
+ */
+#define blkg_for_each_descendant_pre(d_blkg, pos_cgrp, p_blkg) \
+ cgroup_for_each_descendant_pre((pos_cgrp), (p_blkg)->blkcg->css.cgroup) \
+ if (((d_blkg) = __blkg_lookup(cgroup_to_blkcg(pos_cgrp), \
+ (p_blkg)->q, false)))
+
/**
* blk_get_rl - get request_list to use
* @q: request_queue of interest