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Date: Thu, 9 Nov 2006 10:16:11 +0900 From: Tejun Heo <htejun@...il.com> To: zach.brown@...cle.com, pbadari@...ibm.com, suparna@...ibm.com, jmoyer@...hat.com, akpm@...l.org, cwyang@...tech.co.kr, linux-kernel@...r.kernel.org, htejun@...il.com Subject: [RESEND PATCHSET] direct-io: unify asyn/sync completion paths and fix completion bugs [forgot to include lkml, resending. sorry ppl.] Hello, Zach Brown, all. Chul-Woong Yang of Aratech reported kernel oops after failed aio (partially mapped request) on 2.6.19-rc4 and I spent three days chasing the bug and hacking direct-io only to find out that there are pending patches in -mm. Oh, well.. As my patches are almost ready now, I'm posting it, for cross-check if nothing else. The biggest difference between your fix and mine is that instead of merging waiting code, I just unified whole completion paths. ie. Sync requests are handled exactly the same as async requests. They are pre-dirtied, completed from bio completion callback and redirtied from bio_dirty_work if necessary. That simplified the code a lot and made it humanly readable. :-) The only concern is possible performance impact for sync DIOs due to the change in how dirtying is done. As it's done per-bio, the chance of being written back between pre-issue dirtying and post-completion checking should be pretty slim, so I don't think it would have any noticeable effect. Async DIOs have been handled that way after all. I reshuffled things a bit just before finding out your patch and didn't test it thoroughly after that, but it should be enough to get the idea. Arghh... The lesson here is... check -mm before starting hacking unfamiliar code. I'm back to libata now. Thanks. -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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