Messages in this thread | | | Date | Fri, 19 Sep 2008 07:15:10 -0700 | From | Tejun Heo <> | Subject | Re: [PATCH 2/4 v2] libata: Implement disk shock protection support |
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Elias Oltmanns wrote: >> This should basically work but completion isn't really designed for >> this type of continuous events where single consumption should clear >> all pending events. INIT_COMPLETION comes close but it doesn't lock, >> so can't guarantee anything. What's necessary is the counterpart for >> complete_all() for the wait. > > You are right that it isn't designed for this use case and my approach > is somewhat hackish. Still, it really does exactly what we want. Please > note that ap->park_req_pending is protected by the host lock; the call > to complete() is atomic wrt the setting of ATA_EH_PARK for one of the > devices on the port and so is the call to INIT_COMPLETION() wrt clearing > ATA_EH_PARK requests for *all* devices on the port. > >> Well, anyways, I think the issue is slightly out of scope for this >> patch and the only side effect is possibly looping over the do {} >> while () block several times unnecessarily on certain cases, so I >> think just noting about it should be enough for now. >> >> Can you please add explanation above wait_for_complete_timeout() that >> all done counts should be cleared here but aren't and as a result the >> loop might repeat determinate number of times unnecessarily and resend >> as proper patch? > > Well, we don't really care about the done count after > wait_for_completion_timeout() has returned. All that matters is that the > done counter is cleared when all ATA_EH_PARK actions have been pulled in > which happens at the start of each cycle over the loop. > > Perhaps I should add comments to this effect before > wait_for_completion_timeout() as well as INIT_COMPLETION()?
Ah... I missed the pull_park_action part. Yes, in that case, it's correct now but I would really appreciate you explain amply what's going on inside the pull function and why it's needed.
Thanks.
-- tejun
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