Re: [RFC PATCH 1/3] block: add rq->complete_io hook for request stacking

From: Grant Grundler
Date: Mon Mar 03 2008 - 12:40:34 EST


On Mon, Mar 3, 2008 at 8:24 AM, Hannes Reinecke <hare@xxxxxxx> wrote:

> I would rather have rq->complete_io() to be pointing to blk_end_io in the
> default case, this way rq->complete_io() would always be valid and we
> would be saving us the if() clause.

This is a good idea. But...

...
> So when using my proposal this would just become:
>
> {
> BUG_ON(!rq->complete_io);
>
> return rq->complete_io(rq, error, nr_bytes, 0, NULL);
> }

This "BUG_ON" is also an "if()" clause except
it will panic. The box will panic if the function
pointer is a null pointer and it won't be hard to
sort out why. I suggest omitting the BUG_ON.

thanks,
grant
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