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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B0E6BEDE9AB for ; Tue, 10 Sep 2024 17:19:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=ixrlv3tZtoXEaPzIH7qeYoEDfnmLzucZfZkOQExt82o=; b=iEgMb63Z+Zb/AGiee1M7YO7pOX lHs76vVNKkONDhAk73KCPAP1ea25qtjpOTXBs5kP1YXVn0Cmj8C86zRsP2+MMRoGKedKPh1XWbttz XXMWeoc25vMjL4/wGf/cN3v5xyU+P+4cedyOXavkntKZAM/OWtFIh3jnR872/87187V8HyOFmiOq/ oMEYKmUC9+hN3BUgl4+oXr76mjgipSl0IIP2uIOaDbPFjpI2uJ0B4OzI+KOJkRd8OseP8sh3zkdz2 hX+/RvYbls+nfGeVlZAY4PPRLCmg4IFFtroaGJ8uzjW8RKF8RbmKVjOi7K2vyDHUi/eAy09h2FCgt D9gF1+ig==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1so4Wg-00000006W35-0Ijn; Tue, 10 Sep 2024 17:19:38 +0000 Received: from nyc.source.kernel.org ([2604:1380:45d1:ec00::3]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1so4Wc-00000006W2H-2ZBM for linux-nvme@lists.infradead.org; Tue, 10 Sep 2024 17:19:35 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 5364FA44718; Tue, 10 Sep 2024 17:19:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5B28C4CEC3; Tue, 10 Sep 2024 17:19:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725988773; bh=Jc2puORiYOo6/PGjGJmiUGrpWVJCAW6zaHCUDlRoGBY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YranuHzJ9O+PkhMM3y3l1AnOorUXlqQcyQwRVZS/I2MXrKLTxkSEksGcflLatAMsC 4/kt+ZrS9ugZZ9yVCSCvuhUSfP0poZrCz3oE97PAhK2UkTim4klKquEY+Kx01d9X9P MvCOFl3/enrM4UlnoDdDOSM9NgREXE+5+P7lrmPf/5NK5SLZsdp+OL80v9z7QjeYgd M85c3CEG05kKH67y3PR4hAuE1wgiEMe8n3A2InyDWc/2cno2zny4TBHcSFAzSp+RPw qv2w+atYYdvYmpvf4/NkCptgGCEREaftSw2v9ngdba8BKIEDs4cwpRrqe0+7h6BlnY ghHs1MsCCVZVQ== Date: Tue, 10 Sep 2024 11:19:30 -0600 From: Keith Busch To: Christoph Hellwig Cc: Keith Busch , axboe@kernel.dk, martin.petersen@oracle.com, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, sagi@grimberg.me Subject: Re: [PATCHv3 09/10] blk-integrity: consider entire bio list for merging Message-ID: References: <20240904152605.4055570-1-kbusch@meta.com> <20240904152605.4055570-10-kbusch@meta.com> <20240910154843.GI23805@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240910154843.GI23805@lst.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240910_101934_732171_33EFEAB6 X-CRM114-Status: GOOD ( 15.55 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Tue, Sep 10, 2024 at 05:48:43PM +0200, Christoph Hellwig wrote: > On Wed, Sep 04, 2024 at 08:26:04AM -0700, Keith Busch wrote: > > From: Keith Busch > > > > If a bio is merged to a req, the entire bio list is merged, so don't > > temporarily unchain it when counting segments for consideration. > > As far as I can tell we never do merge decisions on bio lists. If > bi_next is non-NULL here it probably is due to scheduler lists or > something like it. I think bi_next is always NULL, so the unlinking should be a no-op. But just in case it isn't, the current unlinking will get the wrong segment count from the resulting merge.