Re: [PATCH 5/5 v2] nvme: LightNVM support

[Matias Bjorling]

Den 16-04-2015 kl. 16:55 skrev Keith Busch:
> On Wed, 15 Apr 2015, Matias BjÃrling wrote:
> > @@ -2316,7 +2686,9 @@ static int nvme_dev_add(struct nvme_dev *dev)
> >     struct nvme_id_ctrl *ctrl;
> >     void *mem;
> >     dma_addr_t dma_addr;
> > -    int shift = NVME_CAP_MPSMIN(readq(&dev->bar->cap)) + 12;
> > +    u64 cap = readq(&dev->bar->cap);
> > +    int shift = NVME_CAP_MPSMIN(cap) + 12;
> > +    int nvm_cmdset = NVME_CAP_NVM(cap);
>
> The controller capabilities' command sets supported used here is the
> right way to key off on support for this new command set, IMHO, but I do
> not see in this patch the command set being selected when the controller
> is enabled

I'll get that added. Wouldn't it just be that the command set always is 
selected? A NVMe controller can expose both normal and lightnvm 
namespaces. So we would always enable it, if CAP bit is set.

> Also if we're going this route, I think we need to define this reserved
> bit in the spec, but I'm not sure how to help with that.

Agree, we'll see how it can be proposed.

> > @@ -2332,6 +2704,7 @@ static int nvme_dev_add(struct nvme_dev *dev)
> >     ctrl = mem;
> >     nn = le32_to_cpup(&ctrl->nn);
> >     dev->oncs = le16_to_cpup(&ctrl->oncs);
> > +    dev->oacs = le16_to_cpup(&ctrl->oacs);
>
> I don't find OACS used anywhere in the rest of the patch. I think this
> must be left over from v1.

Oops, yes, that's just a left over.

> Otherwise it looks pretty good to me, but I think it would be cleaner if
> the lightnvm stuff is not mixed in the same file with the standard nvme
> command set. We might end up splitting nvme-core in the future anyway
> for command sets and transports.

Will do. Thanks.

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