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From: Dan Williams <dan.j.williams@intel.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Logan Gunthorpe <logang@deltatee.com>,
	Hans Verkuil <hans.verkuil@cisco.com>,
	Alexandre Belloni <alexandre.belloni@free-electrons.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Dave Jiang <dave.jiang@intel.com>,
	Vishal L Verma <vishal.l.verma@intel.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH 1/3] cdev: Finish the cdev api with queued mode support
Date: Thu, 21 Jan 2021 09:50:09 -0800	[thread overview]
Message-ID: <CAPcyv4hEpdh_aGcs_73w5KmYWdvR29KB2M2-NNXsaXwxf35Hwg@mail.gmail.com> (raw)
In-Reply-To: <YAk3lVeFqnv5vzA2@kroah.com>

On Thu, Jan 21, 2021 at 12:13 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Wed, Jan 20, 2021 at 11:38:57AM -0800, Dan Williams wrote:
> > -void cdev_del(struct cdev *p)
> > +void cdev_del(struct cdev *cdev)
> >  {
> > -     cdev_unmap(p->dev, p->count);
> > -     kobject_put(&p->kobj);
> > +     cdev_unmap(cdev->dev, cdev->count);
> > +     kobject_put(&cdev->kobj);
>
> After Christoph's patch series, the kobject in struct cdev does nothing,
> so I will be removing it.  So I don't think this patch set is going to
> do what you want :(

The proposal in this series has nothing to do with kobject lifetime.
Please take another look at the file_operations shutdown coordination
problem and the fact that it's not just cdev that has a use case to
manage file_operations this way. I believe Christoph's only objection,
correct me if I'm wrong, is that this proposal invents a new third way
to do this relative to procfs and debugfs. Perhaps there's a way to
generalize this for all three, and I'm going to put some thought
there, but at this point I think I'm failing to describe the problem
clearly.

  reply	other threads:[~2021-01-21 17:51 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-20 19:38 [PATCH 0/3] cdev: Generic shutdown handling Dan Williams
2021-01-20 19:38 ` [PATCH 1/3] cdev: Finish the cdev api with queued mode support Dan Williams
2021-01-20 19:46   ` Christoph Hellwig
2021-01-20 20:20     ` Dan Williams
2021-01-20 21:39       ` Dan Williams
2021-01-20 19:50   ` Logan Gunthorpe
2021-01-20 20:38     ` Dan Williams
2021-01-21  8:13   ` Greg KH
2021-01-21 17:50     ` Dan Williams [this message]
2021-01-20 19:39 ` [PATCH 2/3] libnvdimm/ida: Switch to non-deprecated ida helpers Dan Williams
2021-01-20 19:39 ` [PATCH 3/3] libnvdimm/ioctl: Switch to cdev_register_queued() Dan Williams
2021-01-21  8:15   ` Greg KH
2021-01-21 17:02     ` Dan Williams
2021-01-30  1:59 ` [PATCH 0/3] cdev: Generic shutdown handling Dan Williams

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