Messages in this thread | | | Date | Sat, 08 Mar 2014 20:51:18 +0100 | From | Hannes Reinecke <> | Subject | Re: [PATCH 1/1] block: rework flush sequencing for blk-mq |
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On 03/08/2014 06:33 PM, Mike Snitzer wrote: > On Sat, Mar 8, 2014 at 10:52 AM, Christoph Hellwig <hch@infradead.org> wrote: >> On Fri, Mar 07, 2014 at 03:45:09PM -0500, Jeff Moyer wrote: >>> Hi, Christoph, >>> >>> Did you mean to switch from list_add to list_add_tail? That seems like >>> a change that warrants mention. >> >> No, that wasn't intentional and should be fixed. Btw, there was another >> issue with that commit, in that dm-multipath also needs to allocate >> ->flush_rq. I saw a patch from Hannes fixing it in the SuSE tree, and >> would really love to see him submit that for mainline as well. > > Ugh, rq-based DM calls blk_init_allocated_queue.. (ah, looks like best > to move q->flush_rq allocation from blk_init_queue_node to > blk_alloc_queue_node?). Anyway, this all makes sense given the > crashes we've been dealing with.. we couldn't immediately understand > how the q->flush_rq would be NULL... grr. I guess I should've checked > with you sooner. I reverted commit 1874198 "blk-mq: rework flush > sequencing logic" from RHEL7 just yesterday because we were seeing > crashes on flush with dm-mpath. But can easily re-apply for RHEL7.1 > (since the request_queue's embedded flush_rq takes up so much space we > get ample kABI padding). > > Not overly proud of the revert, but I deemed easier to revert than > hunt down the fix given RHEL7 won't actually be providing any blk-mq > enabled drivers. That'll change for RHEL7.1. > >> Unfortunately SuSE seems to have lots of block and dm fixes and even >> features that they don't submit upstream. > > Yeah, it is certainly disturbing. No excuse for sitting on fixes like this. > > Hannes, _please_ get this dm-mpath flush_rq fix for 3.14 posted ASAP. > Jens or I will need to get it to Linus next week. > Hey, calm down. I've made the fix just two days ago. And was quite surprised that I've been the first hitting that; should've crashed for everybody using dm-multipath. And given the pushback I've gotten recently from patches I would have thought that it would work for most users; sure the author would've done due diligence on the original patchset ... Plus I've gotten the reports from S/390, so I put it down to mainframe weirdness.
BTW, it not _my_ decision to sit on tons of SUSE specific patches. I really try to get things upstream. But I cannot do more than sending patches upstream, answer patiently any questions, and redo the patchset. Which I did. Frequently, But, alas, it's up to the maintainer to apply them. And I can only ask and hope. The usual story...
I'll be sending the patch soon, Monday at latest.
Cheers,
Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.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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