From mboxrd@z Thu Jan  1 00:00:00 1970
From: Balachandar <bala1486@gmail.com>
Subject: Use of double pointer in linux kernel Hash list implementation
Date: Wed, 16 Jun 2010 22:50:17 -0400
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Hi,
  I am trying to understand Linux Kernel implementation of linked list and
hash table. A link to the implementation is
here<http://lxr.linux.no/linux+v2.6.34/include/linux/list.h>.
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<http://lxr.linux.no/linux+v2.6.34/include/linux/list.h#L554>.
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

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<div>Hi,</div><div>=A0=A0I am trying to understand Linux Kernel implementat=
ion of linked list and hash table. A link to the implementation is <a href=
=3D"http://lxr.linux.no/linux+v2.6.34/include/linux/list.h">here</a>. I und=
erstood the linked list implementation. But i am little confused of why dou=
ble pointers is being used in hlist (**pprev). Link for hlist is <a href=3D=
"http://lxr.linux.no/linux+v2.6.34/include/linux/list.h#L554">here</a>. I u=
nderstand 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.</di=
v>
<div><br></div><div>Thanks,</div><div>Bala</div>

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