Messages in this thread | | | Date | Wed, 10 Dec 2008 01:48:10 +0100 | From | Andreas Bombe <> | Subject | Re: [PATCH] amiflop: get rid of sleep_on calls |
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On Tue, Dec 09, 2008 at 09:26:08AM +0100, Joerg Dorchain wrote: > On Mon, Dec 08, 2008 at 04:59:38PM +0000, Andreas Bombe wrote: > > The replacement for the unconditional sleep_on() in fd_motor_on() is a > > complete_all() together with a INIT_COMPLETION() before the mod_timer() > > call. It appears to me that fd_motor_on() might be called concurrently > > and fd_select() does not guarantee mutual exclusivity in the case the > > same drive gets selected again. > > Selecting the same drive repeatly does not matter. The selected > drive is the one the next command or transfer applies to.
I think we're not talking about the same problem. If I were to use complete() together with wait_for_completion() there would be a problem if fd_motor_on() can get as far as wait_for_completion() while a previous completion is yet uncompleted. This can not happen for different drives, as the fd_select() would block. If it could happen for the same drive, the complete() would allow only one task to continue. The complete_all() takes care of that.
If requests are serialized for a drive so that there won't ever be two running at the same time for certain (thinking about it, it's probable), I could make it a simple complete(). It's hardly worth the risk, however.
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