linux-kernel - Re: [PATCH RFC 1/8] Introduce dynamic clock devices

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20101204145343.GA8390@riccoc20.at.omicron.at>
Date:	Sat, 4 Dec 2010 15:55:22 +0100
From:	Richard Cochran <richardcochran@...il.com>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	linux-kernel@...r.kernel.org, linux-api@...r.kernel.org,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Christoph Lameter <cl@...ux.com>,
	John Stultz <johnstul@...ibm.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH RFC 1/8] Introduce dynamic clock devices

On Mon, Nov 08, 2010 at 07:38:41AM +0100, Arnd Bergmann wrote:
> On Thursday 04 November 2010, Richard Cochran wrote:
> > +struct clock_device {
> > +	struct file_operations fops;
> > +	struct file_operations *driver_fops;
> > +	struct clock_device_operations *ops;
> > +	struct cdev cdev;
> > +	struct kref kref;
> > +	struct mutex mux;
> > +	void *priv;
> > +	int index;
> > +	bool zombie;
> > +};
> 
> You should really not need the file_operations here, neither the
> struct nor the pointer. Just define a static file_operations
> structure containing clock_device_open and clock_device_release,
> and whatever else you might need, then add the driver's operations
> to clock_device_operations, and pass the clock_device pointer
> directly to them, instead of passing the file/inode pointers.

Arnd, I'm working a revision of this series, and I am not sure I
understand your comment.

The intent here was to allow clock drivers to register a character
device through the clock_device API, since some clocks (hpet, rtc)
already offer a chardev interface.

The same FD from the open character device will also be usable as a
clockid for the generic posix clock_get/settime calls. Thus, the
clock_device layer needs to hook into the file open/release functions.

Are you suggesting that I simply offer all of the functions from a
'struct file_operations' (sans file/inode) in the 'struct
clock_device_operations' too?

I wanted to avoid duplicating the file_operations functions, so that
future changes in those functions would automatically trickle down to
the clock drivers.

Thanks,
Richard

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/