Re: SMP-CPU + IDE-HD + 2.2.13pre15

Alan Cox (alan@lxorguk.ukuu.org.uk)
Sun, 10 Oct 1999 23:46:27 +0100 (BST)

> I did try to follow the thread about this on this kernel list but I am
> not sure what kind of conclusion was taken. For one thing, 2.2.13pre14
> (and, in fact, none of previous kernels) never had this
> issue. Independent of the compiler and compiler flags I use. Also, my
> uniprocessor Laptop does not have this issue either. Even with an -O6
> optimised gcc-2.95.1 compiled 2.2.13pre15.

> So it looks like something generic between 2.2.13pre14 and 2.2.13pre15
> has given rise to this SMP-CPU + IDE-HD conflict. Should this change be undone?

It is trickier than that. The problem is that 2.2.13pre14 has a deadlock
condition in the IDE code for SMP. 2.2.13pre15 fixes the deadlock but opens
a race condition in the request handling. Trying to fix that looks like someone
will finally have to fix the locking in the ide driver and the request queue
handling instead of continually hacking up an existing bad job.

And it won't be me...

Alan

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