From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=216.71.154.88 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793698737; b=oFlU9THG45hyzW2ShDPCEevUfefTS+ev6Qp9iQVMgjVUJqrlCHR/S7i0ciQZFBiIiu1u QLF1nO3kijPB8/evnloVxq7RxGbGJxukdC8Zz4kzaEMzyEpea5uauJZNDYR3fmIhfO6kA 9RW1c/Jr/t0xT4jioh3vhwpGk+uMTFIU8xCN/O/jcuh1cuPgM2VTnEpGHHkEXV8o3Ob8M NMbFS2UckVhjTsAVxaRue9HQu+32ZPAlkCqh7kyuKyOALefzws9szKXXcReLZRzm2SerZ 2aqYLnaduroAhE5Hn9gQ8ncVs13txyLgMwDa6ebqBd/7vg/KurHcK79oDcG2OvMzLNQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793698737; h=DMARC-Filter:DKIM-Signature:X-CSE-ConnectionGUID:X-CSE-MsgGUID: Received:X-CSE-ConnectionGUID:X-CSE-MsgGUID:IronPort-SDR:Received: X-CSE-ConnectionGUID:X-CSE-MsgGUID:SanDiskIronportException:Received: From:To:Cc:Subject:Date:Message-ID:X-Mailer:In-Reply-To:References: MIME-Version:Content-Transfer-Encoding; bh=kG7hbsIs0LGHYzA8KeJZi3mrT6QUwCifRqpQmdUsJ1U=; b=BNc01PrXRXXOQVZSBfc+gJCUVTwKMA0MjqzCYUvJdf5tLs+OHyDNtlklntorrkpLHDB5 /x+CZnLUsZOVdT1uuemNX4cnTyUkPhkwwhsDqkR7NWCD2Ij/RjLViGztnRLRoBaUOczLa Es7kMM0JY1toncuQKBdFj2ERhahkcgXa7kaUB8NZJk6WcksI/+NjG5rKfmcA/XgnGYJ/D ygG41YUc7IWgAR0cSrdzJcPpngQ5S1UlHt+pyBsN+Fat02CQDTs2fb7kdG2ev0nesb7uw IFpgTrWNVkqktEgMxv8TfrapGAAv6EfJy4OZqV+d1JOGRtVt9U6wT4ipVvYa+M1Sz5w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=sandisk.com; spf=pass smtp.mailfrom=sandisk.com; dkim=pass header.d=sandisk.com header.i=@sandisk.com header.a=rsa-sha256 header.s=dkimnew.sandisk.com header.b="Bq1Zi/7K"; arc=none smtp.remote-ip=216.71.154.88 Received: from esa.hc6817-7.iphmx.com (esa.hc6817-7.iphmx.com [216.71.154.88]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1E62F606A329; Tue, 3 Nov 2026 09:38:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 1E62F606A329 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=sandisk.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sandisk.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=sandisk.com header.i=@sandisk.com header.a=rsa-sha256 header.s=dkimnew.sandisk.com header.b=Bq1Zi/7K DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=sandisk.com; i=@sandisk.com; q=dns/txt; s=dkimnew.sandisk.com; t=1793698737; x=1825234737; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=z6l1B/IO5jaLbJkNRw753wWhduj0VS5+axdNT27du1w=; b=Bq1Zi/7KM0arQkzqfIIItO0xawf27amqCzltCyzQvkybdqhoRNk0+oUd /jfkdDe7NBZNEafppkscbF9UE/PvXIBaU08XgYesO3mdFjAQzYEJNzYdE zxDpIaxDp6PJq06XL0zCpjFUVhTElj/ac/hz0F0Maha+owdByRKcjn5mW ufOQ95d+bFcGj7uvHg6Dkrk1N8SpQMZSJ57QgPT0uj2iJF/QS01SM9pZQ NGclHNZqtChSDq/qIB8adS1mCVFJdcOoN03SOcq13FdCIKYm0517d5GQG JCpe6jtDqqHaJGgJ2ouIHHVVrtCUj9uzhnUkx7xKH0LUnkmWfPJy/8YSB g==; X-CSE-ConnectionGUID: RHfKbv7iRvuxDijqxZFvkg== X-CSE-MsgGUID: yRym0a9eQ/W0XZ/EIAKl6g== Received: from unknown (HELO uls-op-esaep03.corp.sandisk.com) ([129.253.192.43]) by ob1.hc6817-7.iphmx.com with ESMTP; 03 Nov 2026 01:38:56 -0800 X-CSE-ConnectionGUID: fJ32eDA9TD+V843+Vy1UNw== X-CSE-MsgGUID: G82fnQ9jS0qNuswZjHJWGw== IronPort-SDR: 6ae9abb0_orKl6vXLGYs0yO/9mZy2IW3lMGJE7lGcXt4NszywCqCwAdt YyES1Sv6zDgpsjTcW1pZA0yu/5BTkhQ8FVMYLfQ== Received: from unknown (HELO uls-op-esaip04.corp.sandisk.com) ([10.15.0.10]) by uls-op-esaep03.corp.sandisk.com with ESMTP; 03 Nov 2026 01:38:56 -0800 X-CSE-ConnectionGUID: OS8w0ffdSo+rDeEeagDNyQ== X-CSE-MsgGUID: i8IWh6yWTCiN8bzbLaoTOQ== SanDiskIronportException: Internal Received: from ulssdxvpxsnip.corp.sandisk.com (HELO WDAP-ez2C89klLd.corp.sandisk.com) ([10.9.34.160]) by uls-op-esaip04.corp.sandisk.com with ESMTP; 03 Nov 2026 01:38:52 -0800 From: Arthur Simchaev To: Daniel Gomez Cc: Jens Axboe , Keith Busch , Christoph Hellwig , Sagi Grimberg , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, Andres Freund , Pankaj Raghav , GOST , Daniel Gomez , Avi.Shchislowski@sandisk.com, Alex.Lemberg@sandisk.com Subject: Re: [PATCH RFC 1/2] block: add BLK_FEAT_ATOMIC_WRITE_MULTI Date: Tue, 3 Nov 2026 11:38:49 +0200 Message-ID: <20261103093849.203851-1-arthur.simchaev@sandisk.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260929-nvme-mam-v1-1-48dcbe79cece@samsung.com> References: <20260929-nvme-mam-v1-1-48dcbe79cece@samsung.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Tue, Sep 29, 2026 at 01:17:11PM +0200, Daniel Gomez wrote: [...] > diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h > index d003a9d2d1f6c..92efd4ff67f26 100644 > --- a/include/linux/blkdev.h > +++ b/include/linux/blkdev.h > @@ -360,6 +360,9 @@ typedef unsigned int __bitwise blk_features_t; > #define BLK_FEAT_RAID_PARTIAL_STRIPES_EXPENSIVE \ > ((__force blk_features_t)(1u << 15)) > > +/* device writes each atomic write boundary window of a command atomically */ > +#define BLK_FEAT_ATOMIC_WRITE_MULTI ((__force blk_features_t)(1u << 16)) With this flag set, a request with REQ_ATOMIC may now carry several independent atomic writes rather than one. Code that looks at REQ_ATOMIC on a request (e.g. blk_insert_cloned_request(), or a future SCSI WRITE ATOMIC user) needs to know that. Could the comment here (or Documentation/block/) spell out what REQ_ATOMIC means on a merged request, and what a driver must guarantee before setting the flag? It might also be useful to expose the feature in sysfs next to the other atomic_write_* attributes, so users can tell whether merging across boundaries is active on a device. Regards, Arthur