Messages in this thread | | | Date | Fri, 23 Jan 2009 08:59:10 -0800 | Subject | Re: [PATCH] cgroup: Fix root_count when mount fails due to busy subsystem | From | Paul Menage <> |
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On Fri, Jan 23, 2009 at 2:22 AM, Ingo Molnar <mingo@elte.hu> wrote: >> --- a/kernel/cgroup.c >> +++ b/kernel/cgroup.c >> @@ -1115,8 +1115,10 @@ static void cgroup_kill_sb(struct super_block *sb) { >> } >> write_unlock(&css_set_lock); >> >> - list_del(&root->root_list); >> - root_count--; >> + if (!list_empty(&root->root_list)) { >> + list_del(&root->root_list); >> + root_count--; >> + } > > That's ugly. It is _much_ cleaner to always keep the link head consistent > - i.e. initialize it with INIT_LIST_HEAD()
It is initialized with INIT_LIST_HEAD().
> and then remove from it via > list_del_init().
There's not much point doing list_del_init() rather than list_del() here since we're about to delete the root.
> > That way the error path will do the right thing automatically, and there's > no need for that ugly "if !list_empty" construct either.
The important part here is avoiding decrementing root_count.
So the code could equally be:
if (!list_empty(&root->root_list)) { root_count--; } list_del(&root->root_list);
but what I have in this patch seems more straightforward. It's actually how the code used to be before it was removed as a "redundant" check by a patch that I unfortunately didn't get a chance to read properly (or Ack) because I was too snowed under with other work.
Paul
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