From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EABC948C41A for ; Fri, 18 Sep 2026 06:29:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789712986; cv=none; b=Qw/XwbnUAgOjRJdvUsGxAJhVPS5s8BgY88+Bb2ToQa8tBzQnJvX1FVemBJpYb82zn5RBGhH9cDMO5LUciUFcowftsMLfyu3ORfBaADjRA/d/mzsjT8QjmLsFRHC56b+3tCl+CFHoa5yWZEJrE1FjO44pGEy1kg2hlBOFMUCZdhw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789712986; c=relaxed/simple; bh=qegM35efXzPK1TBtZrJOh/KVCeCxobUaxm+boxy02IE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HLKnHbExDn9BeEfedXViw9IHt91rUEu8CJd78EclsZffeh5jQnruDPgKXudAvI5mRfisrg1FGLDmVZzXruvqqQTaDY9rTJuSsxrXT6Mmk5JMzbl6LR0B/aNPqRMJiJnbY++mUbJeNwqQdcHgXS2nLZ5sMxXpPd1jUoOMwbdLtf0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZHOVci37; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZHOVci37" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FAF41F000FF; Fri, 18 Sep 2026 06:29:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789712984; bh=S8JWjUvzamv6TAnVeZ3H2kQoqedZNqIbqgyIu3MKDVY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZHOVci37LbHaHFkBVglh/vfB0e8wXllJNV1AOl1FQ3N0klyEg1qk2Xas5wreHepCw wQYTWE6wQ8iY0zK04NpqTPWXEmldKkKoKfWRcKfeX5kzieD7bzWj6f8+AAqAgcf+SR ygSCaXd3z4/FK5fEurwFZq3YLnqOtnDFlJOn9DQT668yK9bhd1IlzlCgNHphFWQgfJ yPTX7msB/iD4Nvr1ijeeh96cnT18cga4IhgNGa3119liKwTsDRWxhRw+txat6A6q9h Qfe0XLtrP5pdKveeHL/TWJP6Q4GixiNnUWF8kkDrAXVM5jTVfsR+I/KBGArlZ0JTc+ Eem0xbklS95rQ== From: Niklas Cassel To: "James E.J. Bottomley" , "Martin K. Petersen" Cc: linux-scsi@vger.kernel.org, Damien Le Moal , John Garry , Niklas Cassel Subject: [PATCH v4 07/10] scsi: scsi_debug: Do not write a partial physical block to a zoned device Date: Fri, 18 Sep 2026 08:29:18 +0200 Message-ID: <20260918062910.1709791-19-cassel@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260918062910.1709791-12-cassel@kernel.org> References: <20260918062910.1709791-12-cassel@kernel.org> Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3470; i=cassel@kernel.org; h=from:subject; bh=qegM35efXzPK1TBtZrJOh/KVCeCxobUaxm+boxy02IE=; b=owGbwMvMwCV2MsVw8cxjvkWMp9WSGLLW3LKf21g+7bhg5Z/X4i0Ldrj7Z7z/0elVbVPycs61t 3y9oX5tHaUsDGJcDLJiiiy+P1z2F3e7TzmueMcGZg4rE8gQBi5OAZjI9jMM/9S2ZIqJPIvq/FL/ 9HN96kOLZ8b3LBQlt5TNfPd//48dLbMZ/tcVTv2tfKQmxmvtyV6tmQr/lzT6nlqe5sG1OPein7q yFQMA X-Developer-Key: i=cassel@kernel.org; a=openpgp; fpr=5ADE635C0E631CBBD5BE065A352FE6582ED9B5DA Content-Transfer-Encoding: 8bit do_device_access() copies one logical block at a time and stops at the first short copy, so when the data-out buffer is smaller than the transfer length of the command it can write part of a physical block. An initiator can arrange that with SG_IO. A write that does not end on a physical block boundary is perfectly acceptable to a device that is not zoned, and to a conventional zone, where the device reads, modifies and writes the physical block that the write falls in. ZBC-3 r06 (T10/BSR INCITS 579), 4.5.3.3.2, does require a write to a sequential write required zone to end on a physical block boundary, though, so a partly written physical block is not a state that such a zone can be left in. Stop at the last whole physical block that the buffer holds, for a sequential write required zone only. The bytes that are left over are not written, and are reported to the initiator as part of the residual. With the default physblk_exp=0 the physical block size equals the logical block size and this changes nothing. Nothing changes either when the buffer holds all of the data that the command asks for, so a command that transfers fewer logical blocks than a physical block is unaffected wherever it is legal. Assisted-by: LLM Signed-off-by: Niklas Cassel --- Tested with: modprobe scsi_debug zbc=managed sector_size=512 physblk_exp=3 \ zone_size_mb=8 dev_size_mb=128 zone_nr_conv=2 issuing a sixteen logical block WRITE(16) through SG_IO with a buffer of twelve blocks. To a sequential write required zone it now transfers eight blocks, one whole physical block, and reports the remaining 2048 bytes as the residual; before this patch it transferred twelve. To a conventional zone it still transfers all twelve and reports no residual. With physblk_exp=0 an eight block write with a buffer of one block still transfers one block, wherever it is addressed. --- drivers/scsi/scsi_debug.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index a4db282ac971..837077a4e740 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -4273,6 +4273,8 @@ static int do_device_access(struct sdeb_store_info *sip, struct scsi_cmnd *scp, u64 block; enum dma_data_direction dir; struct scsi_data_buffer *sdb = &scp->sdb; + struct scsi_device *sdp = scp->device; + struct sdebug_dev_info *devip = (struct sdebug_dev_info *)sdp->hostdata; u8 *fsp; int i, total = 0; @@ -4300,6 +4302,24 @@ static int do_device_access(struct sdeb_store_info *sip, struct scsi_cmnd *scp, fsp = sip->storep; + /* + * A write to a sequential write required zone has to end on a physical + * block boundary, so if the data-out buffer does not hold all of the + * data that the command asks for, write up to the last whole physical + * block that it does hold. What is left over is reported as part of + * the residual. + */ + if (do_write && sdebug_dev_is_zoned(devip)) { + struct sdeb_zone_state *zsp = zbc_zone(devip, lba); + + if (zsp->z_type == ZBC_ZTYPE_SWR) { + u32 avail = (sdb->length - sg_skip) / sdebug_sector_size; + + if (avail < num) + num = round_down(avail, 1U << sdebug_physblk_exp); + } + } + block = do_div(lba, sdebug_store_sectors); /* Only allow 1x atomic write or multiple non-atomic writes at any given time */ -- 2.55.0