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Date: Thu, 9 Apr 2015 10:17:07 -0700
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Subject: Re: [PATCH v4 6/9] rbtree: Implement generic latch_tree
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Peter Zijlstra <peterz@infradead.org>
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On Thu, Apr 9, 2015 at 10:12 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> It's just unusual, which I think makes it slightly harder to read for
> a *human* just because it breaks the normal pattern of those things.
> But there's nothing technically wrong with it.

You could have written it as

  static __always_inline struct latch_tree_node *
  __lt_from_rb(struct rb_node *node, int idx)
  {
         return (void *)(node-idx);
  }

which is actually shorter, but even if that container_of() use looks a
bit unusual, I think the container_of() shows more clearly what you
actually want. Plus it would be more reliable if you ever end up
adding any other fields to the struct latch_tree_node.

So I wouldn't actually suggest using that "(node-idx)" format. I think
it should result in the exact same code, though.

                         Linus