Messages in this thread | | | Date | Tue, 14 Jul 2009 14:15:42 +0200 (CEST) | From | Julia Lawall <> | Subject | Re: [PATCH 1/2] fs/xfs: Drop unnecessary NULL test |
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On Tue, 14 Jul 2009, Olaf Weber wrote:
> Julia Lawall writes: > > > From: Julia Lawall <julia@diku.dk> > > The result of container_of should not be NULL. In particular, in this case > > the argument to the enclosing function has passed though INIT_DELAYED_WORK, > > which dereferences it, implying that its container cannot be NULL. > > Given the defn of container_of() it seems clear that neither its input > pointer nor its result should ever be NULL.
container_of just does pointer arithmetic. The result of that arithmetic can be NULL, ie if the argument was obtained from an expression of the form &x->f where x was NULL. But in principle, values should be checked for NULL beforehand.
julia
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