From nobody Sat Feb 7 13:53:01 2026 Received: from mail-oo1-f43.google.com (mail-oo1-f43.google.com [209.85.161.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5E0F218E750 for ; Thu, 14 Nov 2024 15:28:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.43 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731598094; cv=none; b=jCowK5G4uhLVWRSnjfX1QXRdmJgAN4+dQ1XoXGgVvXdYeugU7x6DkTVlIwXMZcNAnXtsbCxU1mUyA2tC9WBzMl43fARhDZlL9d23/niq8Sr3ClDsGOp+Gzt30SKrBXTbSYTj1g4KQkaaM7nuZUFEvOnlsu8m+SFfWjcSZhKBceA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731598094; c=relaxed/simple; bh=gGKnnveMfZPAg4SgJ2FOiR86boymhVofVZdPadUM3k0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=THKASm2H00E3G0Og/BKvhtY6oskRX4nPTZiCyC0vTt6lNMZ2AqzvNtWaFh4dfIbLF5w/7MDZoeKLvdF1ls9Y+fXscNxarA9l51hgWceOCiSSXefxTptcG5N1UZ3lqc0QUZ4tConxxaL4dBZelGEQ7PmyMSZc096b6tz0R+ufj8c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=z2HqEI9Q; arc=none smtp.client-ip=209.85.161.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="z2HqEI9Q" Received: by mail-oo1-f43.google.com with SMTP id 006d021491bc7-5ebc0c05e25so344617eaf.3 for ; Thu, 14 Nov 2024 07:28:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1731598091; x=1732202891; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=LyRvRhMBG1NsG1pjAu7RsorwHLATahyjt2W9R5OMw+k=; b=z2HqEI9QexiHndBsoUg/10+CpOQf0QjWppiL2AbY+qCvjAF2sEkPM+BxOECc8uUJYP ITB5KEBOakM51jI3hhi+wgtuKCBLO8unSpeLemgdjYbeP9omGt4OXmThSfGFTNzmff+m ySlzVp+v6Cuo65VBbCrNUN7HtWHIZlKpXuHVlrVuSfxmCIZNlztbNMklhaKpOBb49BcK gN8LuzXTsLq82DfHYF3q9nj7SKsBIWYEQk69vqjf1l3tF1khWXVCeNPHEOa6PYU+zwDD uUxT8igok79gqdh0Cjd3rwD8PzXyWGy8D0KOBKjUrMW7GQcn79aTvGRPJBZ+JJ2pxQn5 plhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1731598091; x=1732202891; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=LyRvRhMBG1NsG1pjAu7RsorwHLATahyjt2W9R5OMw+k=; b=CUPwzNDiqPjkFPARusbTlRwEEVtFHzYBdq49BW/tQvT2ObSdyu9Bldg1apKeE7Jfih KsLmHs//oTo6n0IUPXAKKdAefyEFLXqg0w+Vs67o+6EkRk5TqGCSXC2xJ4Aem5Ya7cIE bANwNJ21Oo4G7X9/2wlcvn9IFki3q1lcbJyK76V9N7m5/p/TB9Mcri31jOYgfe1dTksO tl5NqiIbKygSBgK0wIakYn9dGwzgLgvJ52gAvtojzHPfInf0UfkhRuK98htTnGsytYuz p4AWOxeofG95xBCb8wu7T+relkG0o5cTMUI4A5Z5lNN6C4EuT7MgeYgeN2+lDvCyZYTX DgqA== X-Forwarded-Encrypted: i=1; AJvYcCV04UJgaJmhYg3gt5vVqdIzypa/EUNN5Jq5CTrpyDFK+CxsB8aFbFdQjdGxAVMcM1ClYXmUqYjphgUC6S4=@vger.kernel.org X-Gm-Message-State: AOJu0Yy7FrN/Q20ST3LXVk/J6YkNysqaIM2UFmwTjE11REkV4JULe3/p KzhcjHciR944nfQts+W8sn6MAPwvTiYpREZo2NpRKuTIac87wEQ1Y4iG03hFbvY= X-Google-Smtp-Source: AGHT+IHQ/GenKedH6rwQd+su0Ph/MRWIuzytWarVEOsqT+imV9hIASvSe13ZVKnr0H0iVbl20zcXwQ== X-Received: by 2002:a05:6820:4d06:b0:5ba:ec8b:44b5 with SMTP id 006d021491bc7-5ee57c4397bmr19027877eaf.3.1731598091501; Thu, 14 Nov 2024 07:28:11 -0800 (PST) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id 006d021491bc7-5eea026eb41sm368250eaf.39.2024.11.14.07.28.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Nov 2024 07:28:10 -0800 (PST) From: Jens Axboe To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Cc: hannes@cmpxchg.org, clm@meta.com, linux-kernel@vger.kernel.org, willy@infradead.org, kirill@shutemov.name, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, bfoster@redhat.com, Jens Axboe Subject: [PATCH 07/17] fs: add RWF_UNCACHED iocb and FOP_UNCACHED file_operations flag Date: Thu, 14 Nov 2024 08:25:11 -0700 Message-ID: <20241114152743.2381672-9-axboe@kernel.dk> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20241114152743.2381672-2-axboe@kernel.dk> References: <20241114152743.2381672-2-axboe@kernel.dk> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If a file system supports uncached buffered IO, it may set FOP_UNCACHED and enable RWF_UNCACHED. If RWF_UNCACHED is attempted without the file system supporting it, it'll get errored with -EOPNOTSUPP. Signed-off-by: Jens Axboe --- include/linux/fs.h | 14 +++++++++++++- include/uapi/linux/fs.h | 6 +++++- 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 3559446279c1..45510d0b8de0 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -320,6 +320,7 @@ struct readahead_control; #define IOCB_NOWAIT (__force int) RWF_NOWAIT #define IOCB_APPEND (__force int) RWF_APPEND #define IOCB_ATOMIC (__force int) RWF_ATOMIC +#define IOCB_UNCACHED (__force int) RWF_UNCACHED =20 /* non-RWF related bits - start at 16 */ #define IOCB_EVENTFD (1 << 16) @@ -354,7 +355,8 @@ struct readahead_control; { IOCB_SYNC, "SYNC" }, \ { IOCB_NOWAIT, "NOWAIT" }, \ { IOCB_APPEND, "APPEND" }, \ - { IOCB_ATOMIC, "ATOMIC"}, \ + { IOCB_ATOMIC, "ATOMIC" }, \ + { IOCB_UNCACHED, "UNCACHED" }, \ { IOCB_EVENTFD, "EVENTFD"}, \ { IOCB_DIRECT, "DIRECT" }, \ { IOCB_WRITE, "WRITE" }, \ @@ -2116,6 +2118,8 @@ struct file_operations { #define FOP_HUGE_PAGES ((__force fop_flags_t)(1 << 4)) /* Treat loff_t as unsigned (e.g., /dev/mem) */ #define FOP_UNSIGNED_OFFSET ((__force fop_flags_t)(1 << 5)) +/* File system supports uncached read/write buffered IO */ +#define FOP_UNCACHED ((__force fop_flags_t)(1 << 6)) =20 /* Wrap a directory iterator that needs exclusive inode access */ int wrap_directory_iterator(struct file *, struct dir_context *, @@ -3532,6 +3536,14 @@ static inline int kiocb_set_rw_flags(struct kiocb *k= i, rwf_t flags, if (!(ki->ki_filp->f_mode & FMODE_CAN_ATOMIC_WRITE)) return -EOPNOTSUPP; } + if (flags & RWF_UNCACHED) { + /* file system must support it */ + if (!(ki->ki_filp->f_op->fop_flags & FOP_UNCACHED)) + return -EOPNOTSUPP; + /* DAX mappings not supported */ + if (IS_DAX(ki->ki_filp->f_mapping->host)) + return -EOPNOTSUPP; + } kiocb_flags |=3D (__force int) (flags & RWF_SUPPORTED); if (flags & RWF_SYNC) kiocb_flags |=3D IOCB_DSYNC; diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 753971770733..dc77cd8ae1a3 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -332,9 +332,13 @@ typedef int __bitwise __kernel_rwf_t; /* Atomic Write */ #define RWF_ATOMIC ((__force __kernel_rwf_t)0x00000040) =20 +/* buffered IO that drops the cache after reading or writing data */ +#define RWF_UNCACHED ((__force __kernel_rwf_t)0x00000080) + /* mask of flags supported by the kernel */ #define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\ - RWF_APPEND | RWF_NOAPPEND | RWF_ATOMIC) + RWF_APPEND | RWF_NOAPPEND | RWF_ATOMIC |\ + RWF_UNCACHED) =20 #define PROCFS_IOCTL_MAGIC 'f' =20 --=20 2.45.2