Re: [PATCH] tpm: don't destroy chip device prematurely

From: Jason Gunthorpe
Date: Thu Oct 06 2016 - 12:23:03 EST

On Thu, Oct 06, 2016 at 02:23:57PM +0300, Jarkko Sakkinen wrote:

> I think that they should be fenced then for the sake of consistency.
> I do not see why sysfs code is privileged not to do fencing while other
> peers have to do it.

Certainly the locking could be changed, but it would be nice to have a
reason other than aesthetics.

sysfs is not unique, we also do not grab the rwlock lock during any
commands executed as part of probe. There are basically two locking
regimes - stuff that is proven to by synchronous with probe/remove
(sysfs, probe cmds) and everything else (kapi, cdev)

Further, the current sysfs implementation is nice and sane: the file
accesses cannot fail with ENODEV. That is a useful concrete property
and I don't think we should change it without a good reason.