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,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 102E6C433DF for ; Thu, 18 Jun 2020 02:50:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D6B5F2098B for ; Thu, 18 Jun 2020 02:50:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592448653; bh=aQ+s8ER3hoBSa3ufxybtu7BNUAdGWVj2UOglNEeqrkA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eqSUmLwEdFiA/FIRPSOjOHEaH/lI6L1Klka1hOx5FJDcWFEDw8n6Um9W9bXnGxfWI YlJjkMfCuY70A7CQdZQpG7sjUS3wxUS9EwLJVvLyMWVnDVYVD0D3bkpR9W4xPvhwsK 4MlXNgQW6JwsAkkJ2fL74H97sTB7LiAoHJjIEWdo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728055AbgFRBJK (ORCPT ); Wed, 17 Jun 2020 21:09:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:35264 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728049AbgFRBJJ (ORCPT ); Wed, 17 Jun 2020 21:09:09 -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 3D3F521D79; Thu, 18 Jun 2020 01:09:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592442549; bh=aQ+s8ER3hoBSa3ufxybtu7BNUAdGWVj2UOglNEeqrkA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Futf6twzzErxSNRzzl8puiYgpoZ0a3K2UBu7t8gjG6VHtOexbil5+Wj3YhBGwOdCV jwy84lLPURfYlcd+8C15GyUBZi9+v1vcx+ZcG0gvuHTSPlWxhF+0tQrammOSSgGblb tKlh8bL8MiC/8CMzHNAQS1NFGwIQcxDrklCVgtRI= 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 5.7 047/388] dm mpath: switch paths in dm_blk_ioctl() code path Date: Wed, 17 Jun 2020 21:02:24 -0400 Message-Id: <20200618010805.600873-47-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200618010805.600873-1-sashal@kernel.org> References: <20200618010805.600873-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 3e500098132f..e0c800cf87a9 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -1918,7 +1918,7 @@ 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