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 31265CCD19A for ; Tue, 18 Nov 2025 05:03:29 +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=dwTNpuHcyu2RktZ01zd9bzaq9kCBEG3jtZnKCAFTvnw=; b=S6QTaDlkxtD1UINqFIVvkCquAe N8DCI1uoVlXAkDPslV6KoEk/VpLhGhRi39gh+N8awmMUB/U3et46fRxOFZZEJ7GCSAHT1bfbzYgnH x1ZkwB0lqPF50d40s5c4Ey9mfAA3XMp3qqKPuVi6tdTt+lYTthgcB0IP7lk5wRHLkw4h5y7+CoVP3 b2505NMTdq56K0gVsFJ18PvwyKsBFun9g45oEVPVBEwESSm1TDJZUhxH5YnlrvwSh0GvqhMwHfJjs A1pbQBW70modVY2m0JyDjrPjZCOWvb8xZIzpEN4jm7m/RCFPycnCNJtv2h0RDFHGhNuBfxAL+enB+ 5msa5B3A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLDsF-0000000HP0m-2ZY6; Tue, 18 Nov 2025 05:03:27 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vLDsD-0000000HOww-02lR for linux-nvme@lists.infradead.org; Tue, 18 Nov 2025 05:03:26 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id A1063227AAA; Tue, 18 Nov 2025 06:03:12 +0100 (CET) Date: Tue, 18 Nov 2025 06:03:11 +0100 From: Christoph Hellwig To: Leon Romanovsky Cc: Jens Axboe , Keith Busch , Christoph Hellwig , Sagi Grimberg , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Chaitanya Kulkarni Subject: Re: [PATCH v2 1/2] nvme-pci: Use size_t for length fields to handle larger sizes Message-ID: <20251118050311.GA21569@lst.de> References: <20251117-nvme-phys-types-v2-0-c75a60a2c468@nvidia.com> <20251117-nvme-phys-types-v2-1-c75a60a2c468@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251117-nvme-phys-types-v2-1-c75a60a2c468@nvidia.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251117_210325_192558_E0813241 X-CRM114-Status: GOOD ( 23.14 ) 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 Mon, Nov 17, 2025 at 09:22:43PM +0200, Leon Romanovsky wrote: > From: Leon Romanovsky > > This patch changes the length variables from unsigned int to size_t. > Using size_t ensures that we can handle larger sizes, as size_t is > always equal to or larger than the previously used u32 type. > > Originally, u32 was used because blk-mq-dma code evolved from > scatter-gather implementation, which uses unsigned int to describe length. > This change will also allow us to reuse the existing struct phys_vec in places > that don't need scatter-gather. > > Signed-off-by: Leon Romanovsky > Reviewed-by: Chaitanya Kulkarni > --- > block/blk-mq-dma.c | 8 ++++++-- > drivers/nvme/host/pci.c | 4 ++-- > 2 files changed, 8 insertions(+), 4 deletions(-) > > diff --git a/block/blk-mq-dma.c b/block/blk-mq-dma.c > index e9108ccaf4b0..e7d9b54c3eed 100644 > --- a/block/blk-mq-dma.c > +++ b/block/blk-mq-dma.c > @@ -8,7 +8,7 @@ > > struct phys_vec { > phys_addr_t paddr; > - u32 len; > + size_t len; > }; So we're now going to increase memory usage by 50% again after just reducing it by removing the scatterlist?