Am Dienstag, 11. Dezember 2001 21:53 schrieb Tom Rini:
> On Tue, Dec 11, 2001 at 09:42:02PM +0100, Oliver Neukum wrote:
> > > IMHO, since the only safe thing to do across all architectures is to
> > > kmalloc the devrequest structure, anything other than that is
> > > essentially micro optimization that's not worth it.
> >
> > On the other hand it makes using that function in the block IO path safe.
> > Thus, if there's really no risk in terms of dma in 2.4, I'd consider it
> > for 2.4.
>
> Er, but don't forget that people will be using 2.4 and adding in their
> non-pci and whatnot USB controllers to 2.4 for a while yet. So perhaps
> we shouldn't do anything to 2.4 and backport what 2.5 has when it's
> stable.
It's very likely that the type of the controller is not deciding the issue.
The question is rather how the architectures allocate the kernel stack.
Which architectures are hit ?
Completely fixing this bug requires a change to a lot of api functions.
Have a look at, eg. kaweth.c/kaweth_start_xmit(). It can deadlock on
smp.
There are a lot of drivers doing dma on the stack. I know it's bad,
but sometimes a compromise must be reached.
Regards
Oliver
_______________________________________________
[EMAIL PROTECTED]
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
