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 762C7C6FD1D for ; Thu, 30 Mar 2023 05:48:53 +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=hzc7anGXKRf1lpw82HRKJIg0dtUPw1vJDKZzq7QXFTk=; b=3RcDj5Lg6dy6NkQ4XbBDX+Wg0y TkfK16CwImzpam6UDytadkto0fwlxnxN+FZNIYaxuJRyIdckSvao7JtCHDXf6aqt1zUUrekLkb3KQ H0HQHuNzhGFGYsrpdrnRC8xArfvLQwLM1od8kK54GnOx4sPeOG3R4EWZ/r19Pu1ikjZLJAudehNBj 9tH3sNBqK6Vbs9Was9mAf70jWc2ETB4d6PlPcIx3FOPb3laaTmWNdW3tdIH7OZsKuyFQzsorAZNn2 pZcvgGZLO3ib+1H7x26NVSnKixa5FHWsJJ/hTgNdKtrSyFoyBqQdhBCjvlsdiQAMzE+lDZtq6bzod +zrP7IQg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1phl9V-002gBZ-0l; Thu, 30 Mar 2023 05:48:49 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1phl9S-002gAo-1h for linux-nvme@lists.infradead.org; Thu, 30 Mar 2023 05:48:48 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 04227B825AB; Thu, 30 Mar 2023 05:48:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6990DC433D2; Thu, 30 Mar 2023 05:48:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1680155323; bh=lQIWkG96HEOigO4uxjKwseyUJFpfgWSVR2DNobYfCEk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=S1y5ebevSlJFzuLM5GzkEyt/CYemxPmct+Tz3wAEbvbGVWEAXsQTkg1fmRCEliSsl LEdSb/Gl1dECvicoc6sJKNqlIVR8GONQ0rgtvlFJ5c3H6Z6sDmYypmKZ75MxFAr9B5 GgHX5jGLB8a5N5l8MPXcfkN4W21aGIiqZ0rlLl9QdEWkKDHyXn7suBHLJGk1UEUpEB MN7hrqBJmCCdC/nkPxaexkfrDkTCuQlHDWiZSSOWAr8DwpibCISqDB1MBgQjWpPF4D Tq5KlHh4/a4K2BJ4iqn5ohJOkYqItOrroYvLlO9xbruZlXLhNPVQzUdK0ppON3P1H7 WlJYooCLwgEgQ== Date: Thu, 30 Mar 2023 07:48:35 +0200 From: Christian Brauner To: Nitesh Shetty Cc: Anuj Gupta , Jens Axboe , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, Keith Busch , Christoph Hellwig , Sagi Grimberg , James Smart , Chaitanya Kulkarni , Alexander Viro , bvanassche@acm.org, hare@suse.de, ming.lei@redhat.com, damien.lemoal@opensource.wdc.com, joshi.k@samsung.com, nitheshshetty@gmail.com, gost.dev@samsung.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v8 4/9] fs, block: copy_file_range for def_blk_ops for direct block device. Message-ID: <20230330-strode-deforest-b65424417062@brauner> References: <20230327084103.21601-1-anuj20.g@samsung.com> <20230327084103.21601-5-anuj20.g@samsung.com> <20230329-glitter-drainpipe-bdf9d3876ac4@brauner> <20230329124236.GB3895@green5> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20230329124236.GB3895@green5> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230329_224846_870048_CCF7805F X-CRM114-Status: GOOD ( 29.22 ) 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 Wed, Mar 29, 2023 at 06:12:36PM +0530, Nitesh Shetty wrote: > On Wed, Mar 29, 2023 at 02:14:40PM +0200, Christian Brauner wrote: > > On Mon, Mar 27, 2023 at 02:10:52PM +0530, Anuj Gupta wrote: > > > From: Nitesh Shetty > > > > > > For direct block device opened with O_DIRECT, use copy_file_range to > > > issue device copy offload, and fallback to generic_copy_file_range incase > > > device copy offload capability is absent. > > > Modify checks to allow bdevs to use copy_file_range. > > > > > > Suggested-by: Ming Lei > > > Signed-off-by: Anuj Gupta > > > Signed-off-by: Nitesh Shetty > > > --- > > > block/blk-lib.c | 22 ++++++++++++++++++++++ > > > block/fops.c | 20 ++++++++++++++++++++ > > > fs/read_write.c | 11 +++++++++-- > > > include/linux/blkdev.h | 3 +++ > > > 4 files changed, 54 insertions(+), 2 deletions(-) > > > > > > diff --git a/block/blk-lib.c b/block/blk-lib.c > > > index a21819e59b29..c288573c7e77 100644 > > > --- a/block/blk-lib.c > > > +++ b/block/blk-lib.c > > > @@ -475,6 +475,28 @@ static inline bool blk_check_copy_offload(struct request_queue *q_in, > > > return blk_queue_copy(q_in) && blk_queue_copy(q_out); > > > } > > > > > > +int blkdev_copy_offload(struct block_device *bdev_in, loff_t pos_in, > > > + struct block_device *bdev_out, loff_t pos_out, size_t len, > > > + cio_iodone_t end_io, void *private, gfp_t gfp_mask) > > > +{ > > > + struct request_queue *in_q = bdev_get_queue(bdev_in); > > > + struct request_queue *out_q = bdev_get_queue(bdev_out); > > > + int ret = -EINVAL; > > > > Why initialize to -EINVAL if blk_copy_sanity_check() initializes it > > right away anyway? > > > > acked. > > > > + bool offload = false; > > > > Same thing with initializing offload. > > > acked > > > > + > > > + ret = blk_copy_sanity_check(bdev_in, pos_in, bdev_out, pos_out, len); > > > + if (ret) > > > + return ret; > > > + > > > + offload = blk_check_copy_offload(in_q, out_q); > > > + if (offload) > > > + ret = __blk_copy_offload(bdev_in, pos_in, bdev_out, pos_out, > > > + len, end_io, private, gfp_mask); > > > + > > > + return ret; > > > +} > > > +EXPORT_SYMBOL_GPL(blkdev_copy_offload); > > > + > > > /* > > > * @bdev_in: source block device > > > * @pos_in: source offset > > > diff --git a/block/fops.c b/block/fops.c > > > index d2e6be4e3d1c..3b7c05831d5c 100644 > > > --- a/block/fops.c > > > +++ b/block/fops.c > > > @@ -611,6 +611,25 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) > > > return ret; > > > } > > > > > > +static ssize_t blkdev_copy_file_range(struct file *file_in, loff_t pos_in, > > > + struct file *file_out, loff_t pos_out, > > > + size_t len, unsigned int flags) > > > +{ > > > + struct block_device *in_bdev = I_BDEV(bdev_file_inode(file_in)); > > > + struct block_device *out_bdev = I_BDEV(bdev_file_inode(file_out)); > > > + int comp_len = 0; > > > + > > > + if ((file_in->f_iocb_flags & IOCB_DIRECT) && > > > + (file_out->f_iocb_flags & IOCB_DIRECT)) > > > + comp_len = blkdev_copy_offload(in_bdev, pos_in, out_bdev, > > > + pos_out, len, NULL, NULL, GFP_KERNEL); > > > + if (comp_len != len) > > > + comp_len = generic_copy_file_range(file_in, pos_in + comp_len, > > > + file_out, pos_out + comp_len, len - comp_len, flags); > > > > I'm not deeply familiar with this code but this looks odd. It at least > > seems possible that comp_len could be -EINVAL and len 20 at which point > > you'd be doing len - comp_len aka 20 - 22 = -2 in generic_copy_file_range(). 20 - -22 = 44 ofc > > comp_len should be 0 incase of error. We do agree, some function I mean, not to hammer on this point too much but just to be clear blk_copy_sanity_check(), which is introduced in the second patch, can return both -EPERM and -EINVAL and is first called in blkdev_copy_offload() so it's definitely possible for comp_len to be negative.