Messages in this thread |  | | Date | Thu, 29 Nov 2001 00:41:13 +0000 | From | Russell King <> | Subject | Re: [PATCH] remove BKL from drivers' release functions |
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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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