On Sun, Jan 15, 2017 at 06:54:31PM -0500, Tejun Heo wrote: > On Fri, Jan 13, 2017 at 11:17:12PM +0800, Geliang Tang wrote: > > To make the code clearer, use rb_entry() instead of container_of() to > > deal with rbtree. > > > > Signed-off-by: Geliang Tang <[email protected]> > > --- > > mm/backing-dev.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/mm/backing-dev.c b/mm/backing-dev.c > > index 3bfed5ab..ffb77a1 100644 > > --- a/mm/backing-dev.c > > +++ b/mm/backing-dev.c > > @@ -410,8 +410,8 @@ wb_congested_get_create(struct backing_dev_info *bdi, > > int blkcg_id, gfp_t gfp) > > > > while (*node != NULL) { > > parent = *node; > > - congested = container_of(parent, struct bdi_writeback_congested, > > - rb_node); > > + congested = rb_entry(parent, struct bdi_writeback_congested, > > + rb_node); > > I don't get the rb_entry() macro. It's just another name for > container_of(). I have no objection to the patch but this macro is a > bit silly. >
There are several *_entry macros which are defined in kernel data structures, like list_entry, hlist_entry, rb_entry, etc. Each of them is just another name for container_of. We use different *_entry so that we could identify the specific type of data structure that we are dealing with. -Geliang
