Resend with subject: No more non-MPSAFE network device drivers, please!

[Robert Watson]

On Mon, 22 May 2006, Sergey Matveychuk wrote:

>> We have also discussed requiring that all network device drivers in the 
>> system for 7.0 be able to operate MPSAFE.  This runs into some issues due 
>> to non-MPSAFEty of some key device driver subsystems, including Firewire, 
>> USB, and the TTY subsystem.  Poul-Henning is in the process of working on 
>> MPSAFE tty support, and I hope that people will step up to the plate to 
>> work on the remaining subsystems in the near future.  That way we will be 
>> able to remove the compatibility code, and continue cleanup and 
>> optimization work.
>
> Looks like there are no developers right now who could rewrite USB stack to 
> be MPSAFE. So all USB-Ethernet are broken.

Yes, hence this being something we are discussing, as opposed to implementing. 
In order for us to get to a world entirely without Giant-compatibility for 
network device drivers, we need to address the MPSAFEty of those major 
subsystems.  The goal of this message was to make sure we don't start growing 
new major subsystems and network device drivers -- i.e., that we're into the 
realm of monotonically decreasing numbers of non-MPSAFE network device 
drivers.  Specifically, I don't want to see any more PCI network device 
drivers that require Giant!

Per discussion at the developer summit, a significant rewrite of the USB code 
is needed to make it MPSAFE.  Volunteers welcome.

Robert N M Watson