From: Russell King <rmk@arm.linux.org.uk>
To: "David C. Hansen" <haveblue@us.ibm.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] remove BKL from drivers' release functions
Date: Thu, 29 Nov 2001 00:41:13 +0000 [thread overview]
Message-ID: <20011129004113.D2561@flint.arm.linux.org.uk> (raw)
In-Reply-To: <E169EFX-0006TA-00@the-village.bc.nu> <3C057410.3090201@us.ibm.com> <20011128234505.C2561@flint.arm.linux.org.uk> <3C0580A8.5030706@us.ibm.com>
In-Reply-To: <3C0580A8.5030706@us.ibm.com>; from haveblue@us.ibm.com on Wed, Nov 28, 2001 at 04:26:16PM -0800
On Wed, Nov 28, 2001 at 04:26:16PM -0800, David C. Hansen wrote:
> I wrote a quick and dirty char device driver to see if this happened.
> If I run two tasks doing a bunch of opens and closes, the -EBUSY
> condition in the open function does happen. Is my driver doing
> something wrong?
What's happening is:
task 1 task 2
-> sys_open
-> lock_kernel
-> testdev_open
-> test_and_set_bit
return success
unlock kernel
-> sys_open
-> lock_kernel (blocks on it)
-> testdev_open
-> test_and_set_bit
return -EBUSY
unlock kernel
return
return
The BKL is only held for the duration of the open, not until you close the
device.
--
Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux
http://www.arm.linux.org.uk/personal/aboutme.html
next prev parent reply other threads:[~2001-11-29 0:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-11-28 23:05 [PATCH] remove BKL from drivers' release functions David C. Hansen
2001-11-28 23:29 ` Andrew Morton
2001-11-28 23:42 ` David C. Hansen
2001-11-28 23:50 ` Robert Love
2001-11-28 23:36 ` Alan Cox
2001-11-28 23:32 ` David C. Hansen
2001-11-28 23:45 ` Russell King
2001-11-29 0:26 ` David C. Hansen
2001-11-29 0:37 ` Jeff Garzik
2001-11-29 0:41 ` Russell King [this message]
2001-11-29 1:33 ` David C. Hansen
2001-11-29 1:42 ` Jeff Garzik
2001-11-29 7:17 ` Oliver Neukum
2001-11-29 1:47 ` Alan Cox
2001-11-29 9:15 ` Russell King
2001-11-29 13:55 ` BALBIR SINGH
2001-11-30 19:30 ` Rick Lindsley
2001-11-30 9:57 ` Alexander Viro
2001-11-30 12:41 ` Victor Yodaiken
2001-11-30 20:02 ` Rick Lindsley
2001-11-30 19:38 ` David C. Hansen
2001-11-30 23:12 ` Alexander Viro
2001-12-01 0:47 ` Rick Lindsley
2001-12-01 9:52 ` Alan Cox
2001-12-01 10:06 ` Rick Lindsley
2001-11-30 20:11 ` Rick Lindsley
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