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=-8.5 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 9B4ACC43441 for ; Mon, 26 Nov 2018 22:13:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FD982082F for ; Mon, 26 Nov 2018 22:13:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=osandov-com.20150623.gappssmtp.com header.i=@osandov-com.20150623.gappssmtp.com header.b="f/7XFRkx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5FD982082F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=osandov.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-btrfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727066AbeK0JIe (ORCPT ); Tue, 27 Nov 2018 04:08:34 -0500 Received: from mail-pg1-f193.google.com ([209.85.215.193]:42367 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726315AbeK0JIe (ORCPT ); Tue, 27 Nov 2018 04:08:34 -0500 Received: by mail-pg1-f193.google.com with SMTP id d72so6805731pga.9 for ; Mon, 26 Nov 2018 14:12:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=osandov-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Z828Q1hGWN4xE0ZgmUT37ch1Jh+fPsJT+V+amprtHxs=; b=f/7XFRkxWkgNbPNPf+s6683DpOao683kKiPGfp+GDY1wWulUsqMdaALo9ICdTUmCxJ N9V3AYcRNie0T3XNvPm5DKhfUhniEaEw3zGp9Hse6oePD1pVUsqmvE2uC/mcg5+XIxnU LMKdFvP/+gdqw+WJ+0zz33dXh471ApwV+CszQ6S8iVabJDAyB8RgAw6VXGF1THvbn6Kj o9Flhc42RZGBCVbTQs5wtxHFWH2GcnA1vBPkvQefc+fi2XIgy8Vx9Q8wXXGWNEv5FBGD r3wuGSM48Ustfn1hUNS3X++TFN30nIeaTExPEOtWt+kYFe39c/YU7xDg2ixcbDV4lgxx K8zg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=Z828Q1hGWN4xE0ZgmUT37ch1Jh+fPsJT+V+amprtHxs=; b=YtdOZMhKGIxVcGCfYQUOrZWyncFUeBw3JP79mbUc4TriY9azFUyR82RrBx29wD3JtZ jaGICrncEnjvg7CGeNbLPrIl/iUFzk66anEZi+qGjOmA6yQLnuP+apeIojCIgWCXVr/x txbdmaNxGCC4PnUdc0gxWOIJLEjDYcWbyYhARaRBaT6cVs3w38DSm00mYt0+HuaNtQ9q kAhxll79+bY+jj4bs7M9zXDF14v+9mXF/+Eb1jiSHso7oxnc2AKEIiTSSmQwmLNy0V4Y xE6ayD/c3YZAkVn1r393g1F5YvilaI25uTlStvcI0mUZPa9VhHidNDzZ3sgyk9FiwxSr tMDQ== X-Gm-Message-State: AGRZ1gLgO6aj63StcS/FR/vm+SnLKr6MfCf2FN3WgQCy2LzFphtR3zeG LestDsNZE5GX35AppfjqTrNhWg== X-Google-Smtp-Source: AJdET5cTQuaqAg55SqlEDPYiv4+R2g4Vn4siqfxm4fzsHzoMq4v8KxsClX1F2y/iS6mNA81LmxEZAQ== X-Received: by 2002:a62:6d07:: with SMTP id i7-v6mr31099102pfc.146.1543270378421; Mon, 26 Nov 2018 14:12:58 -0800 (PST) Received: from vader ([2601:602:8b00:55d3:e6a7:a0ff:fe0b:c9a8]) by smtp.gmail.com with ESMTPSA id v184sm1780153pfb.182.2018.11.26.14.12.57 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 26 Nov 2018 14:12:57 -0800 (PST) Date: Mon, 26 Nov 2018 14:12:56 -0800 From: Omar Sandoval To: Ming Lei Cc: Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Theodore Ts'o , Omar Sandoval , Sagi Grimberg , Dave Chinner , Kent Overstreet , Mike Snitzer , dm-devel@redhat.com, Alexander Viro , linux-fsdevel@vger.kernel.org, Shaohua Li , linux-raid@vger.kernel.org, David Sterba , linux-btrfs@vger.kernel.org, "Darrick J . Wong" , linux-xfs@vger.kernel.org, Gao Xiang , Christoph Hellwig , linux-ext4@vger.kernel.org, Coly Li , linux-bcache@vger.kernel.org, Boaz Harrosh , Bob Peterson , cluster-devel@redhat.com Subject: Re: [PATCH V12 03/20] block: remove the "cluster" flag Message-ID: <20181126221256.GD30411@vader> References: <20181126021720.19471-1-ming.lei@redhat.com> <20181126021720.19471-4-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181126021720.19471-4-ming.lei@redhat.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Mon, Nov 26, 2018 at 10:17:03AM +0800, Ming Lei wrote: > From: Christoph Hellwig > > The cluster flag implements some very old SCSI behavior. As far as I > can tell the original intent was to enable or disable any kind of > segment merging. But the actually visible effect to the LLDD is that > it limits each segments to be inside a single page, which we can > also affect by setting the maximum segment size and the segment > boundary. Reviewed-by: Omar Sandoval One comment typo below. > Signed-off-by: Christoph Hellwig > > Replace virt boundary with segment boundary limit. > > Signed-off-by: Ming Lei > --- > block/blk-merge.c | 20 ++++++++------------ > block/blk-settings.c | 3 --- > block/blk-sysfs.c | 5 +---- > drivers/scsi/scsi_lib.c | 20 ++++++++++++++++---- > include/linux/blkdev.h | 6 ------ > 5 files changed, 25 insertions(+), 29 deletions(-) > [snip] > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > index 0df15cb738d2..78d6d05992b0 100644 > --- a/drivers/scsi/scsi_lib.c > +++ b/drivers/scsi/scsi_lib.c > @@ -1810,6 +1810,8 @@ static int scsi_map_queues(struct blk_mq_tag_set *set) > void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) > { > struct device *dev = shost->dma_dev; > + unsigned max_segment_size = dma_get_max_seg_size(dev); > + unsigned long segment_boundary = shost->dma_boundary; > > /* > * this limit is imposed by hardware restrictions > @@ -1828,13 +1830,23 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q) > blk_queue_max_hw_sectors(q, shost->max_sectors); > if (shost->unchecked_isa_dma) > blk_queue_bounce_limit(q, BLK_BOUNCE_ISA); > - blk_queue_segment_boundary(q, shost->dma_boundary); > dma_set_seg_boundary(dev, shost->dma_boundary); > > - blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); > + /* > + * Clustering is a really old concept from the stone age of Linux > + * SCSI support. But the basic idea is that we never give the > + * driver a segment that spans multiple pages. For that we need > + * to limit the segment size, and set the segment boundary so that > + * we never merge a second segment which is no page aligned. Typo, "which is not page aligned".