Re: Use of double pointer in linux kernel Hash list implementation

On Wed, Jun 16, 2010 at 11:32 PM, Namhyung Kim <[email protected]> wrote:

> 2010-06-16 (수), 22:50 -0400, Balachandar:
> > Hi,
> >   I am trying to understand Linux Kernel implementation of linked list
> > and hash table. A link to the implementation is here. I understood the
> > linked list implementation. But i am little confused of why double
> > pointers is being used in hlist (**pprev). Link for hlist is here. I
> > understand that hlist is used in implementation of hash table since
> > head of the list requires only one pointer and it saves space. Why
> > cant it be done using single pointer (just *prev like the linked
> > list)? Please help me.
> >
> >
> > Thanks,
> > Bala
>
>
> IMHO **pprev is only needed for fast deletion and/or insertion.
>
>
>
>
My doubt is why not use *prev as it is used in list_head implementation
rather than **pprev.