Subject: Re: Rationale for converting if list to TAILQ
To: None <email@example.com>
From: Charles M. Hannum <firstname.lastname@example.org>
Date: 07/01/1995 19:20:29
The reason I ask is that in the past couple of months, the method used to
link struct ifnets has changed from a simple pointer to a TAILQ. I found
this out the hard way trying to install my firewall code at 1 AM (must
ship tomorrow) and it broke due to the change.
I don't mind that the change was made, but I'm wondering what advantages
there are to changing something simple like a pointer into a more
complicated list structure. Adding a new interface is faster, but that's
not really worth the savings - it's only done once at configuration time.
The old code was pretty severely bogus. It shoehorned what should
have been a doubly linked list into a singly linked list. While the
performance of this particular code isn't very important, there has
been a general push toward fixing the data structures in the kernel,
and this was just a small part of it.