From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH v4 04/10] tpm: Get rid of module locking Date: Mon, 29 Feb 2016 17:24:53 -0700 Message-ID: <20160301002453.GA12174@obsidianresearch.com> References: <1456766996-9300-1-git-send-email-stefanb@linux.vnet.ibm.com> <1456766996-9300-5-git-send-email-stefanb@linux.vnet.ibm.com> <20160229203550.GB26296@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20160229203550.GB26296-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tpmdd-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Jarkko Sakkinen Cc: tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: tpmdd-devel@lists.sourceforge.net On Mon, Feb 29, 2016 at 10:35:50PM +0200, Jarkko Sakkinen wrote: > On Mon, Feb 29, 2016 at 12:29:50PM -0500, Stefan Berger wrote: > > Now that the tpm core has strong locking around 'ops' it is possible > > to remove a TPM driver, module and all, even while user space still > > has things like /dev/tpmX open. For consistency and simplicity, drop > > the module locking entirely. > > I don't understand why the user visible behavior of /dev/tpmX should > be changed if there are no life and death reasons to do it. Do you > think that this patch is absolutely crucial for the feature > implemented? Stefan is addressing it here because once NULL is a legal parent for registration the chip->dev.parent->driver->owner expression becomes useless for module locking. If we want to keep module locking then Stefen has to add an 'owner' field to tpm_class_ops and update all drivers. The ops->owner would be used for the module locking instead of driver->owner Jason ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140