Re: [PATCH 02/36] scsi,rcu: convert call_rcu(fc_rport_free_rcu) tokfree_rcu()

From: Matthew Wilcox
Date: Wed Mar 23 2011 - 19:19:56 EST


On Wed, Mar 23, 2011 at 09:05:51AM -0500, James Bottomley wrote:
> > #define kfree_rcu(ptr, rcu_head) \
> > __kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head))
>
> Isn't this one of those cases where the obvious use of the interface is
> definitely wrong?

But it's a compile time breakage if you use it wrong, not runtime.

> It's also another nasty pseudo C prototype. I know we do this sort of
> thing for container_of et al, but I don't really think we want to extend
> it.

We do it for list_entry, list_for_each_entry, etc. And those are very
widespread within the kernel.

--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
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