Re: [Xen-devel] [PATCH v3 07/11] tmem: Make the uint64_t oid[3] a proper structure: tmem_oid

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Mon, Aug 31, 2015 at 12:14:16PM -0400, Konrad Rzeszutek Wilk wrote:
> > >And the 'container_of' macro looks to require only one level of
> > >nesting.
> > 
> > I'm pretty sure the macro can deal with both.
> 
> OK, let me experiement with it as at the first blush it does not work for me.

I can't get it to work.

My understanding (and the test case - see attached) seem to agree that
the 'container_of' is to be used when you have the pointer to the nested
member (oid) and want the pointer to the structure in which it is
embedded in (op). We have the opposite case - we have the pointer to the
structure in which it was embedded (op):

 struct tmem_op *op;
  
 oidp = (struct tmem_oid *)&op.u.gen.oid[0];

Hence using the container_of macro won't work.

Attachment: a.c
Description: Text document

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