On Sat, Mar 8, 2014 at 10:52 AM, Christoph Hellwig <h...@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. Thanks, Mike -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/