From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 828C6C433DF for ; Tue, 23 Jun 2020 20:35:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5112B20836 for ; Tue, 23 Jun 2020 20:35:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592944524; bh=LpdBqfnHy9Us/Raz3M4gjLPdYu6w6ISBSDI2DIDW4Lc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ahx37ROfVfI+UvCu9PalCPO8pKCZBfpceREukbNO/9ygMhek0hBCKR7JB4jP8otyR nwOygQFJQwBY4hm/PjqdLwyFAOqHyLv+DwnUp7+X/pZCiJ/caUDx07L5EYSVcgPjx+ 2pLnw3rpPYL2XWq54REEcL8R3fWOZwHsRBiFylMg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391673AbgFWUfW (ORCPT ); Tue, 23 Jun 2020 16:35:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:57746 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391670AbgFWUfV (ORCPT ); Tue, 23 Jun 2020 16:35:21 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 63DA52080C; Tue, 23 Jun 2020 20:35:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592944521; bh=LpdBqfnHy9Us/Raz3M4gjLPdYu6w6ISBSDI2DIDW4Lc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RxyNKOVTSSfl77aArEx3FBprilnEL5PN9buHyFX0UEh8AC9q8jmTedOgSlXsAN80S /B78JclOgSwk3XQzRdmj1NsFHrlN8ps2zEHDgXooXPwNAwkglcGoWuc4a3Cpr44yo1 42meP75AP1xIM5GYwvgeFciQ2i9FgUOlPhhAqm7s= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Wilck , Hannes Reinecke , Mike Snitzer , Sasha Levin Subject: [PATCH 4.19 022/206] dm mpath: switch paths in dm_blk_ioctl() code path Date: Tue, 23 Jun 2020 21:55:50 +0200 Message-Id: <20200623195318.068661931@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623195316.864547658@linuxfoundation.org> References: <20200623195316.864547658@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Martin Wilck [ Upstream commit 2361ae595352dec015d14292f1b539242d8446d6 ] SCSI LUN passthrough code such as qemu's "scsi-block" device model pass every IO to the host via SG_IO ioctls. Currently, dm-multipath calls choose_pgpath() only in the block IO code path, not in the ioctl code path (unless current_pgpath is NULL). This has the effect that no path switching and thus no load balancing is done for SCSI-passthrough IO, unless the active path fails. Fix this by using the same logic in multipath_prepare_ioctl() as in multipath_clone_and_map(). Note: The allegedly best path selection algorithm, service-time, still wouldn't work perfectly, because the io size of the current request is always set to 0. Changing that for the IO passthrough case would require the ioctl cmd and arg to be passed to dm's prepare_ioctl() method. Signed-off-by: Martin Wilck Reviewed-by: Hannes Reinecke Signed-off-by: Mike Snitzer Signed-off-by: Sasha Levin --- drivers/md/dm-mpath.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index 207ca0ad0b59d..c1ad84f3414cd 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -1868,7 +1868,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti, int r; current_pgpath = READ_ONCE(m->current_pgpath); - if (!current_pgpath) + if (!current_pgpath || !test_bit(MPATHF_QUEUE_IO, &m->flags)) current_pgpath = choose_pgpath(m, 0); if (current_pgpath) { -- 2.25.1