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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 89B06C433E0 for ; Thu, 18 Jun 2020 02:05:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5D3622220B for ; Thu, 18 Jun 2020 02:05:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592445910; bh=73WgdEFIZCa7hMRSJddpG2UJDaVIQocYkI0u7kpEY6U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Y5bFjxtPwOt1wXIH308G5D8Tn+k1cKE5JE56+LzYceHAybDWscyRD2rtQcpKwMyv1 llor9NDDmPkiscXJdQ6ST7D2q/T2GTCNrEDiShTIWds/Fkr39xMcOWlY4v+on2czl7 Wi1YzCP2vFX0ISz7Ydwmx76ARm2qxzZ74LPgL/QY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731098AbgFRCFG (ORCPT ); Wed, 17 Jun 2020 22:05:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:56084 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729612AbgFRBWw (ORCPT ); Wed, 17 Jun 2020 21:22:52 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0B1E1221E9; Thu, 18 Jun 2020 01:22:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592443371; bh=73WgdEFIZCa7hMRSJddpG2UJDaVIQocYkI0u7kpEY6U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eCiIqEQCTgFQiQjrQNU4mo9WL13+GOK6cOytdooJ6hQqTXHdrwPqOtjin4d07JlWB lRX8PfrK5327dG0HdcPbT2vJ+xlgQ6RB3M5ySPxUI1CLU+/UlZWhiNuox0Mx/7FOmA Px5+O0h/W4qB/HYwikmkyHe9UI69IbgZoeZqFn0M= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Martin Wilck , Hannes Reinecke , Mike Snitzer , Sasha Levin , dm-devel@redhat.com Subject: [PATCH AUTOSEL 4.19 025/172] dm mpath: switch paths in dm_blk_ioctl() code path Date: Wed, 17 Jun 2020 21:19:51 -0400 Message-Id: <20200618012218.607130-25-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200618012218.607130-1-sashal@kernel.org> References: <20200618012218.607130-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 207ca0ad0b59..c1ad84f3414c 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