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=unavailable 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 91314C433DF for ; Tue, 23 Jun 2020 20:56:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 66D2520702 for ; Tue, 23 Jun 2020 20:56:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592945762; bh=Ue0UmwVWigaMg1k0SBFBFVuMmyzebbHag0LR1QUwES8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jq3fziC4zqUiX0GtOhB9qwz7pdVekVyK2lpgq9Bs0IYRBMEItwo92q4egl+JjAHFR HnK9z1p+9rxe20XnPo3kHcCWiFDGy+LTIuKs5xDEW+DGf2oA4o6hPNaK+5czVrbQAj buZYfBgDVW4FAMK2DqJ/9SNF0KAcWVC4eOuVz28w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390315AbgFWUoH (ORCPT ); Tue, 23 Jun 2020 16:44:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:41166 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403965AbgFWUoH (ORCPT ); Tue, 23 Jun 2020 16:44:07 -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 A4A002070E; Tue, 23 Jun 2020 20:44:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592945047; bh=Ue0UmwVWigaMg1k0SBFBFVuMmyzebbHag0LR1QUwES8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OzTq1cJ5edBoCgcPX1dILDazTEfiIyBbeCzBuDUVyJcLpgSgQAz1Z32IQkg3QR7uK fX3sZFEABEbobWpDFT+57zCcHcuKI4EpSCYJTJISp+r6kOvmYAHrmm9lgYp3Gfw8wR 7bA94joBpywwV7cTt3Ew+xBKkl2CzFkBK/IC2JMo= 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 4.14 019/136] dm mpath: switch paths in dm_blk_ioctl() code path Date: Tue, 23 Jun 2020 21:57:55 +0200 Message-Id: <20200623195304.580822821@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623195303.601828702@linuxfoundation.org> References: <20200623195303.601828702@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 8b7328666eaaf..7c60aace8d25d 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -1815,7 +1815,7 @@ 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