Messages in this thread | | | Date | Tue, 22 May 2001 22:54:49 +0200 (MET DST) | From | Andries.Brouwer@cwi ... | Subject | Re: [PATCH] struct char_device |
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> They are entirely different. Too different sets of operations.
Maybe you didnt understand what I meant. both bdev and cdev take care of the correspondence device number <---> struct with operations.
The operations are different, but all bdev/cdev code is identical.
So the choice is between two uglies: (i) have some not entirely trivial amount of code twice in the kernel (ii) have a union at the point where the struct operations is assigned.
I preferred the union.
>> And a second remark: don't forget that presently the point where >> bdev is introduced is not quite right. We must only introduce it >> when we really have a device, not when there only is a device >> number (like on a mknod call).
> That's simply wrong. kdev_t is used for unopened objects quite often.
Yes, but that was my design mistake in 1995. I think you'll find if you continue on this way, as I found and already wrote in kdev_t.h that it is bad to carry pointers around for unopened and unknown devices.
So, I think that the setup must be changed a tiny little bit and distinguish meaningless numbers from devices.
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