From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga07.intel.com ([134.134.136.100]:63294 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755451AbdCaVAc (ORCPT ); Fri, 31 Mar 2017 17:00:32 -0400 Date: Fri, 31 Mar 2017 17:09:00 -0400 From: Keith Busch To: Omar Sandoval Cc: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig , Josef Bacik , kernel-team@fb.com Subject: Re: [PATCH v3] blk-mq: remap queues when adding/removing hardware queues Message-ID: <20170331210900.GN20181@localhost.localdomain> References: <20170331204603.GB11462@vader> <9753ebd0c51a9d49f110a6d0d00888170905d97a.1490993257.git.osandov@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <9753ebd0c51a9d49f110a6d0d00888170905d97a.1490993257.git.osandov@fb.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Fri, Mar 31, 2017 at 01:48:35PM -0700, Omar Sandoval wrote: > From: Omar Sandoval > > blk_mq_update_nr_hw_queues() used to remap hardware queues, which is the > behavior that drivers expect. However, commit 4e68a011428a changed > blk_mq_queue_reinit() to not remap queues for the case of CPU > hotplugging, inadvertently making blk_mq_update_nr_hw_queues() not remap > queues as well. This breaks, for example, NBD's multi-connection mode, > leaving the added hardware queues unused. Fix it by making > blk_mq_update_nr_hw_queues() explicitly remap the queues. > > Fixes: 4e68a011428a ("blk-mq: don't redistribute hardware queues on a CPU hotplug event") > Signed-off-by: Omar Sandoval This looks good to me. Reviewed-by: Keith Busch