From 34f8fe501f0624de115d087680c84000b5d9abc9 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 26 Aug 2019 09:06:53 -0700 Subject: bdi: Add bdi->id There currently is no way to universally identify and lookup a bdi without holding a reference and pointer to it. This patch adds an non-recycling bdi->id and implements bdi_get_by_id() which looks up bdis by their ids. This will be used by memcg foreign inode flushing. I left bdi_list alone for simplicity and because while rb_tree does support rcu assignment it doesn't seem to guarantee lossless walk when walk is racing aginst tree rebalance operations. Reviewed-by: Jan Kara Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- include/linux/backing-dev-defs.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/backing-dev-defs.h') diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index 8fb740178d5d..1075f2552cfc 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -185,6 +185,8 @@ struct bdi_writeback { }; struct backing_dev_info { + u64 id; + struct rb_node rb_node; /* keyed by ->id */ struct list_head bdi_list; unsigned long ra_pages; /* max readahead in PAGE_SIZE units */ unsigned long io_pages; /* max allowed IO size */ -- cgit v1.2.3