Re: [PATCH] nvme: make controller 'state' sysfs attribute pollable

[Johannes Thumshirn]

On Wed, Sep 20, 2017 at 04:59:31PM +0200, Christoph Hellwig wrote:
> On Wed, Sep 20, 2017 at 12:40:32PM +0200, Johannes Thumshirn wrote:
> > Notify sysfs about changes of a nvme controller so user-space can watch the
> > file via poll() or select() in order to react to a state change.
> 
> Userspace has no business polling for the state.

So why exposing it then in the first time? I know you don't want dm-mpath in
NVMe (neither do I) but we have to have something until your patchset and ANA
is merged. And with this patch it's trivial to build a path checker that just
looks at the state attribute in sysfs.

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