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From: Arnd Bergmann <arnd@arndb.de>
To: Jean Delvare <khali@linux-fr.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	lm-sensors@lm-sensors.org, Hans de Goede <hdegoede@redhat.com>
Subject: Re: [lm-sensors] [patch 1/5] hwmon: Convert fschmd to unlocked_ioctl
Date: Fri, 6 Nov 2009 14:22:49 +0100	[thread overview]
Message-ID: <200911061422.49596.arnd@arndb.de> (raw)
In-Reply-To: <20091106141542.12404c5c@hyperion.delvare>

On Friday 06 November 2009, Jean Delvare wrote:
> I'm not sure why we need to hold the mutex here? My understanding is
> that watchdog_data_mutex protects watchdog_data_list and each
> watchdog's kref. And the above code doesn't touch either.
> 
> What I am more worried about is why ident is declared static. This
> looks like a bug to me. Instead of abusing watchdog_data_mutex to
> workaround this, I'd rather remove the "static". I guess that the
> current code happens to work because neither data->revision nor
> nowayout can change over time, but this looks needlessly fragile.
> 
> Hans, any comment?

The data copied into the watchdog_info data structure is completely
static. To make that clearer, I'd suggest moving it outside of
the ioctl function, and initializing it from fschmd_init.
Then it becomes obvious that the mutex is not needed to protect it.

	Arnd <><

  reply	other threads:[~2009-11-06 13:22 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-15 20:28 [patch 0/5] BKL another bunch Thomas Gleixner
2009-10-15 20:28 ` [patch 1/5] hwmon: Convert fschmd to unlocked_ioctl Thomas Gleixner
2009-11-06 13:15   ` [lm-sensors] " Jean Delvare
2009-11-06 13:22     ` Arnd Bergmann [this message]
2009-11-06 13:31       ` Jean Delvare
2009-11-06 13:36       ` Hans de Goede
2009-11-06 13:37         ` Arnd Bergmann
2009-11-06 13:35     ` Hans de Goede
2009-11-06 15:56     ` Thomas Gleixner
2009-12-17 13:12       ` Jean Delvare
2009-10-15 20:28 ` [patch 2/5] macintosh: Remove BKL from nvram driver Thomas Gleixner
2009-10-15 20:28 ` [patch 3/5] sunrpc: Convert to unlocked_ioctl and remove stray smp_lock.h Thomas Gleixner
2009-10-15 20:28 ` [patch 4/5] mtd: Remove BKL and convert to unlocked_ioctl Thomas Gleixner
2009-10-16  6:44   ` Artem Bityutskiy
2009-10-20  5:27     ` Thomas Gleixner
2009-10-15 20:28 ` [patch 5/5] bluetooth: Remove stub ioctl in hci_vhci Thomas Gleixner

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