Jason Wang
2020-Jul-15 09:42 UTC
[PATCH 3/7] vhost_vdpa: implement IRQ offloading functions in vhost_vdpa
On 2020/7/15 ??5:20, Zhu, Lingshan wrote:>>>> >>>> I meant something like: >>>> >>>> unregister(); >>>> vq->call_ctx.producer.token = ctx; >>>> register(); >>> This is what we are doing now, or I must missed somethig: >>> if (ctx && ctx != token) { >>> ????irq_bypass_unregister_producer(&vq->call_ctx.producer); >>> ????vq->call_ctx.producer.token = ctx; >>> ????irq_bypass_register_producer(&vq->call_ctx.producer); >>> >>> } >>> >>> It just unregister and register. >> >> >> I meant there's probably no need for the check and another check and >> unregister before. The whole function is as simple as I suggested above. >> >> Thanks > IMHO we still need the checks, this function handles three cases: > (1)if the ctx == token, we do nothing. For this unregister and register can work, but waste of time.But we have a more simple code and we don't care about the performance here since the operations is rare.> (2)if token exists but ctx is NULL, this means user space issued an unbind, so we need to only unregister the producer.Note that the register/unregister have a graceful check of whether or not there's a token.> (3)if ctx exists and ctx!=token, this means there is a new ctx, we need to update producer by unregister and register. > > I think we can not simply handle all these cases by "unregister and register".So it looks to me the functions are equivalent. Thanks> > Thanks, > BR > Zhu Lingshan