On Fri, Apr 21, 2017 at 01:29:34PM +0800, Herbert Xu wrote: > On Thu, Apr 20, 2017 at 12:50:29PM +0200, Steffen Klassert wrote: > > On Thu, Apr 20, 2017 at 05:52:35PM +0800, Herbert Xu wrote: > > > On Thu, Apr 20, 2017 at 11:17:52AM +0200, Steffen Klassert wrote: > > > > > > > > I tried to use async algorithms but it lead to serveral problems. > > > > The GSO layer can't handle async returns, we'd need callbacks > > > > for all the GSO handlers. Also we need something where we can > > > > requeue packets if the driver is busy etc. > > > > > > Why would we need to requeue? As it is if you get an EBUSY on > > > an IPsec packet it's simply dropped. > > > > Yes we could do this, but the GSO problem remain. > > > > We discussed this last year at netdevconf but could not come > > up with an acceptable solutuion. > > Why is it a problem exactly?
My solution for this added some extra code to the generic networking path, this was seen as too intrusive for this very special usecase. I still think we can get this to work, but it needs some extra care. > > > For now this is just a fallback to make hardware offloading > > possible at all, so this is slowpath anyway. Allowing async > > algorithms can (and should) be done in a second step once we > > found a not too intrusive solution. > > OK, as long as nobody gets silently switched from async to sync > then it's fine with me. The user has to explicitely ask for a offloaded state, so we don't hide anything here. In this case the user wants to use the crypto engine of the NIC, we just need a software fallback to catch some corner cases where the NIC can't do the crypto operation.
