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From: Logan Gunthorpe <logang@deltatee.com>
To: Dan Williams <dan.j.williams@intel.com>, gregkh@linuxfoundation.org
Cc: 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@intel.com, linux-kernel@vger.kernel.org,
	linux-nvdimm@lists.01.org
Subject: Re: [PATCH 1/3] cdev: Finish the cdev api with queued mode support
Date: Wed, 20 Jan 2021 12:50:43 -0700	[thread overview]
Message-ID: <809823fb-6eb6-8ce9-c49a-d85b03897fc7@deltatee.com> (raw)
In-Reply-To: <161117153776.2853729.6944617921517514510.stgit@dwillia2-desk3.amr.corp.intel.com>




On 2021-01-20 12:38 p.m., Dan Williams wrote:
> ...common reference count handling scenarios were addressed, but the
> shutdown-synchronization problem was only mentioned as something driver
> developers need to be aware in the following note:
> 
>     NOTE: This guarantees that associated sysfs callbacks are not running
>     or runnable, however any cdevs already open will remain and their fops
>     will still be callable even after this function returns.
> 
> Remove that responsibility from driver developers with the concept of a
> 'queued' mode for cdevs.

I find the queued name confusing. What's being queued?

> +static const struct file_operations cdev_queued_fops = {
> +	.owner = THIS_MODULE,
> +	.open = cdev_queued_open,
> +	.unlocked_ioctl = cdev_queued_ioctl,
> +	.compat_ioctl = compat_ptr_ioctl,
> +	.llseek = noop_llseek,
> +};

Why do we only protect these fops? I'd find it a bit confusing to have
ioctl protected from use after del, but not write/read/etc.

Logan

  parent reply	other threads:[~2021-01-20 20:08 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 [this message]
2021-01-20 20:38     ` Dan Williams
2021-01-21  8:13   ` Greg KH
2021-01-21 17:50     ` Dan Williams
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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