Re: NET_NEEDS_GIANT removal

On Friday 01 June 2007 12:13, Robert Watson wrote:
> Dear all,
>
> Another of the things in flight for 7.0 is the removal of NET_NEEDS_GIANT.
> This is the compatibility code that allows non-MPSAFE network protocols to
> operate--when they are compiled into the kernel, Giant is forced over the
> entire network stack.  This allows them to run moderately safely, but
> eliminates use of more than one processor at a time in any part of the
> network stack, as well as increasing contention on Giant for any other
> non-MPSAFE components, requiring Giant be acquired in possible shared
> ithreads, etc. The components currently requiring Giant are:
>
> i4b		- ISDN implementation
> netatm		- One of three ATM implementations
> ng_h4		- tty line discipline for bluetooth serial (?)
> KAME IPSEC	- One of two IPSEC implementations
> IPX over IP	- IPX over IP tunnel support
>
> Of these, I have patches for IPX over IP (but no testers despite several
> e-mails to mailing lists), and George has patches that add IPv6 support to
> FAST_IPSEC and remove KAME IPSEC, currently in testing on the net_at_ mailing
> list.  Skip Ford has been working on locking for netatm, but I'm not sure
> what the current status is.  Bjoern has been starting to look at i4b but
> has let me know that it is unlikely this will be done before 7.1.  I have
> no information on the status of ng_h4, but it may well be that its
> involvement in the tty code puts it in a tricky situation, as the tty code
> is not MPSAFE. Right now the strategy for the next two weeks is as follows:
>
> - Locking for IPX over IP will go into CVS or, if I still can't find any
>    testers, IPX over IP support will be removed.  Note that normal IPX/SPX
>    support is unaffected, as that has been MPSAFE for some time.
>
> - IPv6 support for FAST_IPSEC will go into the tree, and KAME IPSEC will be
>    removed.
>
> - NET_NEEDS_GIANT shims will be removed from the tree.
>
> - i4b, netatm, and ng_h4 will be disconnected from the build, but not
> deleted.

Just a comment:

Aswell as there is a new USB stack, there is also new I4B stack done by me:

http://www.turbocat.net/~hselasky/isdn4bsd

--HPS