From patchwork Tue Jun 27 18:36:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nitesh Shetty X-Patchwork-Id: 113693 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:994d:0:b0:3d9:f83d:47d9 with SMTP id k13csp8762712vqr; Wed, 28 Jun 2023 01:33:29 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ5P3c7JRO2YIMO2R144/Y4DwQYCiVH5jFhuUyT6974HcY26/e91aXLGYTpKCZ4ZI7JHmuBU X-Received: by 2002:a17:90a:318b:b0:262:c2a1:c01f with SMTP id j11-20020a17090a318b00b00262c2a1c01fmr3924478pjb.3.1687941209370; Wed, 28 Jun 2023 01:33:29 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1687941209; cv=none; d=google.com; s=arc-20160816; b=oQDmoZkPH+eCCT8jkmXBGyduRewV8JZtILKmUnwHTna+TcchoZb18/jZf8BbwIxqlD J6bMFAvTUNJ0jptMkgEZyp5CmogIakB6KlY8Z9uwfVKcK+Pj/OPk771xrWpfk1SYW0gV z3bUo+gk5oV2s3BR4VcoG6YmmxonquFO4tG7AMvkpi2ANeKJI5zU113Kydw6+6HBCgzV e552r2XtAxTrTIcHMUKZypkS9Xy5yVuKdHEfD2urjBZ6YsyuICQeR9F/VFgCHv7VLPf8 YEZ+WqSw/omUnZ2GEASe71xTt53Zemi4WJzXuaDksmc9+Yzo1NJNH49JuJaBlEKgbQRP hzjw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:references:dlp-filter:cms-type :content-transfer-encoding:mime-version:in-reply-to:message-id:date :subject:cc:to:from:dkim-signature:dkim-filter; bh=kSunFsCYmbL+fZnS1g1aUFPpWAVuxrnXDZ3DH0imMyQ=; fh=ceNER2F1QklcPlsyU5QlHqgEyIaXbMxBTH6lwYWnttI=; b=e5XHoVtMjtI5+XfTO/9qvrmgkJ71eEPLw/WtpWpZ3pdATHVoumnvlEFu+MF0dacge/ ueXIkjBRs92J91Bg6lpjUWWs9nvx5K3h8eqaKlgDrcmX/pBF9s7cOMF4DJBqgSZCbMJz gmWYLZO5heqvwxgQVMr5+N46tdcmMwg7X75qrbeWjcB+5c/sZ9lN9RAerLW3OOnfNA2U 6Yk0Lt6U4aRacco3vX/mo+RGqbDs+bZL+tr7jc/CWyIuabSL57GFWrMQ/6NpFlHQ3Dgf kR+znmtCr8iFn086sKy/1yJ8b/HwXH5IoTkyTb+SCST9hSsEcaubS5cLapb2LSLk6/b0 abUA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@samsung.com header.s=mail20170921 header.b=WYsHuHMK; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=samsung.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id lp14-20020a17090b4a8e00b0025bae7f2b10si12089717pjb.13.2023.06.28.01.33.13; Wed, 28 Jun 2023 01:33:29 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@samsung.com header.s=mail20170921 header.b=WYsHuHMK; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=samsung.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232324AbjF1IIf (ORCPT + 99 others); Wed, 28 Jun 2023 04:08:35 -0400 Received: from mailout2.samsung.com ([203.254.224.25]:15413 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232898AbjF1IDM (ORCPT ); Wed, 28 Jun 2023 04:03:12 -0400 Received: from epcas5p1.samsung.com (unknown [182.195.41.39]) by mailout2.samsung.com (KnoxPortal) with ESMTP id 20230628064459epoutp02e03c43f68a71156c3d209ced0e79a28b~sv6qCbuAt2756127561epoutp02j for ; Wed, 28 Jun 2023 06:44:59 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout2.samsung.com 20230628064459epoutp02e03c43f68a71156c3d209ced0e79a28b~sv6qCbuAt2756127561epoutp02j DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1687934699; bh=kSunFsCYmbL+fZnS1g1aUFPpWAVuxrnXDZ3DH0imMyQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WYsHuHMKKI5Ul3vxnw1SDQnMI8JEJrPwoEm4Gme9vEJXHPClwt3fhYZVtaZU28Lhs hd+319CR3o2p+puav3/Tcn7Wq05acJLoJnCES4mAMkRqxJDdmY2fRiNZ2EIPQBg9yZ pwGrDf+Il9eZ2s89e9Eb+ViNvoRWRlbgfgSBoOV4= Received: from epsnrtp3.localdomain (unknown [182.195.42.164]) by epcas5p4.samsung.com (KnoxPortal) with ESMTP id 20230628064458epcas5p4dfb71fabb7e845688f0d0544b68a650b~sv6pV6pjj2985329853epcas5p4d; Wed, 28 Jun 2023 06:44:58 +0000 (GMT) Received: from epsmges5p2new.samsung.com (unknown [182.195.38.174]) by epsnrtp3.localdomain (Postfix) with ESMTP id 4QrXBd0qW5z4x9QG; Wed, 28 Jun 2023 06:44:57 +0000 (GMT) Received: from epcas5p3.samsung.com ( [182.195.41.41]) by epsmges5p2new.samsung.com (Symantec Messaging Gateway) with SMTP id F5.36.44250.8E6DB946; Wed, 28 Jun 2023 15:44:56 +0900 (KST) Received: from epsmtrp2.samsung.com (unknown [182.195.40.14]) by epcas5p3.samsung.com (KnoxPortal) with ESMTPA id 20230627184117epcas5p3a9102988870743b20127422928f072bd~smCx4nFGU0780707807epcas5p3z; Tue, 27 Jun 2023 18:41:17 +0000 (GMT) Received: from epsmgmcp1.samsung.com (unknown [182.195.42.82]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20230627184117epsmtrp2812d3ec232f11f2b039cfc76bf06bdf1~smCx3iv1i2845228452epsmtrp22; Tue, 27 Jun 2023 18:41:17 +0000 (GMT) X-AuditID: b6c32a4a-ec1fd7000000acda-1a-649bd6e8b64d Received: from epsmtip2.samsung.com ( [182.195.34.31]) by epsmgmcp1.samsung.com (Symantec Messaging Gateway) with SMTP id 60.0D.64355.C4D2B946; Wed, 28 Jun 2023 03:41:16 +0900 (KST) Received: from green245.sa.corp.samsungelectronics.net (unknown [107.99.41.245]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20230627184112epsmtip21d03faeb240fce47dbdf754dc4660d97~smCt8YCRz0383003830epsmtip2k; Tue, 27 Jun 2023 18:41:12 +0000 (GMT) From: Nitesh Shetty To: Jens Axboe , Jonathan Corbet , Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com, Keith Busch , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , Alexander Viro , Christian Brauner Cc: martin.petersen@oracle.com, linux-scsi@vger.kernel.org, willy@infradead.org, hare@suse.de, djwong@kernel.org, bvanassche@acm.org, ming.lei@redhat.com, dlemoal@kernel.org, nitheshshetty@gmail.com, gost.dev@samsung.com, Nitesh Shetty , Damien Le Moal , Anuj Gupta , Vincent Fu , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v13 9/9] null_blk: add support for copy offload Date: Wed, 28 Jun 2023 00:06:23 +0530 Message-Id: <20230627183629.26571-10-nj.shetty@samsung.com> X-Mailer: git-send-email 2.35.1.500.gb896f729e2 In-Reply-To: <20230627183629.26571-1-nj.shetty@samsung.com> MIME-Version: 1.0 X-Brightmail-Tracker: H4sIAAAAAAAAA02TeVBTVxTGe99LHsE29hGoXGhFDJUpe4IBLggFlTpvtNOhU9s67bTwSp6A CSGTBETUkUUsssuibUABpVQCI5VNIGApCsjWWDaHWIta6KCU1c5IB5EmRKz//c53v3vOPefO 4eC8ajNbTpRMxShktJRPbGA13nBycns0WiQW5G5GNb1dOErOXcFR1b0cAk3fWATo7Py/OJpo /xag5QEdjoYmNqL7PweittkiNhprb8ZQ68U8DFVWdWIor2MUoMkRNYba9C6o7FQ5C7W29bDQ UEsxgUoqJs1Qxp0mAv3Y/RxDHfkpGGqaSAKocbkER1em51jolv5t9GdGGkC6lW42Wl4qJoLs qKHhfVSz+p4ZpfvjKouqu+xMDQ3EUrWa0wRVV36C0o4lEtSl7Hw2lZUyS1DNqeNsamFSz6Lm ro8QVHa9BlB1fUepJ7V2IRZfSPwjGVrMKOwZWXiMOEoWEcDf90no7lAvb4HQTeiLfPj2Mjqa CeAHfxjitidKahgT3z6OlsYapBBaqeR7vO+viIlVMfaRMUpVAJ+Ri6VykdxdSUcrY2UR7jJG 5ScUCDy9DMYwSeTT0cdsuc43/uTwCEgENYJ0wOFAUgT704+mgw0cHqkFsDe9mEgH5oZgEcCp U/AlZ5QfWveXd1mb/M0AXuu9gpmCVAw+UOvMjCaCdIF9qxyjbkUm4vAn7SVgDHCyjAXv/pUJ jFktyUCo7ctnGZlFboOlqX1sI3PJHfB86TTLVM0D5oxbGGVzg6zV3XxhsYA930+sXcXJLTCl oQg3MiQHzeGZpGMmDobDLTqWiS3h4+56MxPbwiezbYSJD8PKgsuE8W2QPAmg+o4amA4CYWpv Dm58A046wZoWD5O8GRauNWysuxFmLU9gJp0Lmy6sswOsril9kd8Gjj5NIkytUPBqtp1pVtkA Pk9OA7nAXv1KO+pX2lH/X7kU4Bpgw8iV0RGM0kvuKWMOv/zh8JjoWrC2Ns57m8CD+/PuHQDj gA4AOTjfirtp6ZyYxxXTRxIYRUyoIlbKKDuAl2HcZ3Dbt8JjDHsnU4UKRb4Ckbe3t8h3u7eQ b82tGM4S88gIWsVIGEbOKNbvYRxz20TMZmAlIdnRtvzrhyqHLJ/b8cG835TvOClCz9qZaSpn +neWmPsJHN+onCo5UH087jvgVf7Dewf3q6475u6lfZqvjS5v5cWRQW86vWstGXC+23DAYiZv ML6963VPdSR2flPfjkK6DR7U4mHzZb9bb/2y87NGq2LKITPz2K3BOPfJv+cOLeSmwV+Dduur tj1znSm2XHXddbNClqaqF5WVfro9LOK0rHN/auuJfz7eIvXv/OWrWv/jq/23L5a6cL2O1NV4 FIzrNVPx+rQ9kmfTuyQlrQ/1TnYF6Vnc2EL7R83hwsUPXKdWNIvU590LvOKGnnm/1745J5Ur Fy98RNdFsyOsE8Y6lir5LGUkLXTGFUr6P2P8Gfm/BAAA X-Brightmail-Tracker: H4sIAAAAAAAAA02Sf0yMcRzHfZ/nuaen7OzpUn0LZXciNXFm9tW1ypr1XYyY3/l1c4+iK+eu LDKlJB2Ja5R+EE66jJuO6iR0+iGxY9exrnHhkmkrv2Pt/LiazX/vz+v9fn/2+ePDkII3lD+z MzWNU6ZK5ULag6p/IAycs2xOuWxeS40E6R+1kyjnpJNEV18W0WjwwWeAznz8SSLH/XyARp+Y SWRxTEJ996JQ81A5D/XcNxLozkUNgXRX2wikMT0HqN9aRqBmWyi6cERLoTvNnRSy3K6g0fnq fjd07EUjja50/CKQqTiXQI2OQwDVj54n0fXBYQo9tE1Bb48dBcjs7OCh0R8VdHQAtnQvxcay l27Y/OoGhQ01IdjyJB3X1RbQ2KDNwk092TS+dKKYhwtzh2hszLPz8Kd+G4WH71ppfOJmLcCG rkz8pS4g3nOjR4SMk+/cyynnRm7zSBp5/oGnMC/KONxtBdlAP08NGAayC6C23VcNPBgB2wBg fUMloQbuf7kfrHa2kuPaC+p+DbiNh3IJWHHcSbrKNBsKu34zLj6ZVZOwwDhEuQaSbaCgVn+Z 52p7sVGwqauYcmmKDYJVeV1jnM9KYGXVIDV+xVxYZPd0Yfe/uMncynNhARsOhzvix9OesPOs Y2wLyQbC3Fvl5EnAlv1nlf1nVQGiFnhzClVKYsp2hThMJU1Rpacmhm3fnVIHxt4gZFUjqNY7 w0yAYIAJQIYUTub7/CiRCfgy6b79nHL3VmW6nFOZwBSGEvryRfICmYBNlKZxyRyn4JT/XIJx 988m8t8XZmyIjD10esWE5OrhGkvpp3BNW6nAbmQEpX0Hgld2T024FrPrG92Z1mIKiCZFanFO 4bT3JT9n2D+sm1qrQoMiw5qv0QnxcRGyhIEgW9wLXar+S1aiKNYPPz1cuWAhaRhauUkyO1rT Lt8YK5lvzEyy5G1evIsvTBYZ3ozEBTHeTyfF0D49JTrv9e881+/JQeEXPvoEWi3FURnLpWEj 2PeW40aIFuolPAnM85odyxSdaytc9SzCP5iJC8p/7Readi1A+3hz72PrxArx/tffhTbxgH3Z loPS6Zn06h37NL26mTGP+j9HnlW0rGUCZ/W23vU5vY3tcxdkLQk+VaMXUqokqTiEVKqkfwCP aevHdQMAAA== X-CMS-MailID: 20230627184117epcas5p3a9102988870743b20127422928f072bd X-Msg-Generator: CA X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20230627184117epcas5p3a9102988870743b20127422928f072bd References: <20230627183629.26571-1-nj.shetty@samsung.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1769934641495344551?= X-GMAIL-MSGID: =?utf-8?q?1769934641495344551?= Implementaion is based on existing read and write infrastructure. copy_max_bytes: A new configfs and module parameter is introduced, which can be used to set hardware/driver supported maximum copy limit. Suggested-by: Damien Le Moal Signed-off-by: Anuj Gupta Signed-off-by: Nitesh Shetty Signed-off-by: Vincent Fu --- Documentation/block/null_blk.rst | 5 ++ drivers/block/null_blk/main.c | 85 +++++++++++++++++++++++++++++-- drivers/block/null_blk/null_blk.h | 1 + 3 files changed, 88 insertions(+), 3 deletions(-) diff --git a/Documentation/block/null_blk.rst b/Documentation/block/null_blk.rst index 4dd78f24d10a..6153e02fcf13 100644 --- a/Documentation/block/null_blk.rst +++ b/Documentation/block/null_blk.rst @@ -149,3 +149,8 @@ zone_size=[MB]: Default: 256 zone_nr_conv=[nr_conv]: Default: 0 The number of conventional zones to create when block device is zoned. If zone_nr_conv >= nr_zones, it will be reduced to nr_zones - 1. + +copy_max_bytes=[size in bytes]: Default: COPY_MAX_BYTES + A module and configfs parameter which can be used to set hardware/driver + supported maximum copy offload limit. + COPY_MAX_BYTES(=128MB at present) is defined in fs.h diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c index 864013019d6b..e9461bd4dc2c 100644 --- a/drivers/block/null_blk/main.c +++ b/drivers/block/null_blk/main.c @@ -157,6 +157,10 @@ static int g_max_sectors; module_param_named(max_sectors, g_max_sectors, int, 0444); MODULE_PARM_DESC(max_sectors, "Maximum size of a command (in 512B sectors)"); +static unsigned long g_copy_max_bytes = COPY_MAX_BYTES; +module_param_named(copy_max_bytes, g_copy_max_bytes, ulong, 0444); +MODULE_PARM_DESC(copy_max_bytes, "Maximum size of a copy command (in bytes)"); + static unsigned int nr_devices = 1; module_param(nr_devices, uint, 0444); MODULE_PARM_DESC(nr_devices, "Number of devices to register"); @@ -409,6 +413,7 @@ NULLB_DEVICE_ATTR(home_node, uint, NULL); NULLB_DEVICE_ATTR(queue_mode, uint, NULL); NULLB_DEVICE_ATTR(blocksize, uint, NULL); NULLB_DEVICE_ATTR(max_sectors, uint, NULL); +NULLB_DEVICE_ATTR(copy_max_bytes, uint, NULL); NULLB_DEVICE_ATTR(irqmode, uint, NULL); NULLB_DEVICE_ATTR(hw_queue_depth, uint, NULL); NULLB_DEVICE_ATTR(index, uint, NULL); @@ -550,6 +555,7 @@ static struct configfs_attribute *nullb_device_attrs[] = { &nullb_device_attr_queue_mode, &nullb_device_attr_blocksize, &nullb_device_attr_max_sectors, + &nullb_device_attr_copy_max_bytes, &nullb_device_attr_irqmode, &nullb_device_attr_hw_queue_depth, &nullb_device_attr_index, @@ -656,7 +662,8 @@ static ssize_t memb_group_features_show(struct config_item *item, char *page) "poll_queues,power,queue_mode,shared_tag_bitmap,size," "submit_queues,use_per_node_hctx,virt_boundary,zoned," "zone_capacity,zone_max_active,zone_max_open," - "zone_nr_conv,zone_offline,zone_readonly,zone_size\n"); + "zone_nr_conv,zone_offline,zone_readonly,zone_size," + "copy_max_bytes\n"); } CONFIGFS_ATTR_RO(memb_group_, features); @@ -722,6 +729,7 @@ static struct nullb_device *null_alloc_dev(void) dev->queue_mode = g_queue_mode; dev->blocksize = g_bs; dev->max_sectors = g_max_sectors; + dev->copy_max_bytes = g_copy_max_bytes; dev->irqmode = g_irqmode; dev->hw_queue_depth = g_hw_queue_depth; dev->blocking = g_blocking; @@ -1271,6 +1279,67 @@ static int null_transfer(struct nullb *nullb, struct page *page, return err; } +static inline int nullb_setup_copy_write(struct nullb *nullb, + struct request *req, bool is_fua) +{ + sector_t sector_in, sector_out; + void *in, *out; + size_t rem, temp; + struct bio *bio; + unsigned long offset_in, offset_out; + struct nullb_page *t_page_in, *t_page_out; + int ret = -EIO; + + sector_out = blk_rq_pos(req); + + __rq_for_each_bio(bio, req) { + sector_in = bio->bi_iter.bi_sector; + rem = bio->bi_iter.bi_size; + } + + if (WARN_ON(!rem)) + return BLK_STS_NOTSUPP; + + spin_lock_irq(&nullb->lock); + while (rem > 0) { + temp = min_t(size_t, nullb->dev->blocksize, rem); + offset_in = (sector_in & SECTOR_MASK) << SECTOR_SHIFT; + offset_out = (sector_out & SECTOR_MASK) << SECTOR_SHIFT; + + if (null_cache_active(nullb) && !is_fua) + null_make_cache_space(nullb, PAGE_SIZE); + + t_page_in = null_lookup_page(nullb, sector_in, false, + !null_cache_active(nullb)); + if (!t_page_in) + goto err; + t_page_out = null_insert_page(nullb, sector_out, + !null_cache_active(nullb) || is_fua); + if (!t_page_out) + goto err; + + in = kmap_local_page(t_page_in->page); + out = kmap_local_page(t_page_out->page); + + memcpy(out + offset_out, in + offset_in, temp); + kunmap_local(out); + kunmap_local(in); + __set_bit(sector_out & SECTOR_MASK, t_page_out->bitmap); + + if (is_fua) + null_free_sector(nullb, sector_out, true); + + rem -= temp; + sector_in += temp >> SECTOR_SHIFT; + sector_out += temp >> SECTOR_SHIFT; + } + + ret = 0; +err: + spin_unlock_irq(&nullb->lock); + return ret; +} + static int null_handle_rq(struct nullb_cmd *cmd) { struct request *rq = cmd->rq; @@ -1280,13 +1349,16 @@ static int null_handle_rq(struct nullb_cmd *cmd) sector_t sector = blk_rq_pos(rq); struct req_iterator iter; struct bio_vec bvec; + bool fua = rq->cmd_flags & REQ_FUA; + + if (op_is_copy(req_op(rq))) + return nullb_setup_copy_write(nullb, rq, fua); spin_lock_irq(&nullb->lock); rq_for_each_segment(bvec, rq, iter) { len = bvec.bv_len; err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset, - op_is_write(req_op(rq)), sector, - rq->cmd_flags & REQ_FUA); + op_is_write(req_op(rq)), sector, fua); if (err) { spin_unlock_irq(&nullb->lock); return err; @@ -2042,6 +2114,9 @@ static int null_validate_conf(struct nullb_device *dev) return -EINVAL; } + if (dev->queue_mode == NULL_Q_BIO) + dev->copy_max_bytes = 0; + return 0; } @@ -2161,6 +2236,10 @@ static int null_add_dev(struct nullb_device *dev) dev->max_sectors = queue_max_hw_sectors(nullb->q); dev->max_sectors = min(dev->max_sectors, BLK_DEF_MAX_SECTORS); blk_queue_max_hw_sectors(nullb->q, dev->max_sectors); + blk_queue_max_copy_sectors_hw(nullb->q, + dev->copy_max_bytes >> SECTOR_SHIFT); + if (dev->copy_max_bytes) + blk_queue_flag_set(QUEUE_FLAG_COPY, nullb->disk->queue); if (dev->virt_boundary) blk_queue_virt_boundary(nullb->q, PAGE_SIZE - 1); diff --git a/drivers/block/null_blk/null_blk.h b/drivers/block/null_blk/null_blk.h index 929f659dd255..e82e53a2e2df 100644 --- a/drivers/block/null_blk/null_blk.h +++ b/drivers/block/null_blk/null_blk.h @@ -107,6 +107,7 @@ struct nullb_device { unsigned int queue_mode; /* block interface */ unsigned int blocksize; /* block size */ unsigned int max_sectors; /* Max sectors per command */ + unsigned long copy_max_bytes; /* Max copy offload length in bytes */ unsigned int irqmode; /* IRQ completion handler */ unsigned int hw_queue_depth; /* queue depth */ unsigned int index; /* index of the disk, only valid with a disk */