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
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This archive was generated by hypermail 2b29 : Fri Nov 30 2001 - 21:00:33 EST