![]() | |||||||||||||
Messages in this thread |
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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
| ||||||||||||
| Last update: 2005-03-22 13:13 [W:1.571 / U:0.140 seconds] ©2003-2008 Jasper Spaans | |||||||||||||