From patchwork Fri Jul 28 16:42:24 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 13332121 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2FF0DC001DE for ; Fri, 28 Jul 2023 16:42:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230271AbjG1Qmq (ORCPT ); Fri, 28 Jul 2023 12:42:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231183AbjG1Qmm (ORCPT ); Fri, 28 Jul 2023 12:42:42 -0400 Received: from mail-io1-xd2b.google.com (mail-io1-xd2b.google.com [IPv6:2607:f8b0:4864:20::d2b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AF6912C for ; Fri, 28 Jul 2023 09:42:41 -0700 (PDT) Received: by mail-io1-xd2b.google.com with SMTP id ca18e2360f4ac-7748ca56133so22687239f.0 for ; Fri, 28 Jul 2023 09:42:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20221208.gappssmtp.com; s=20221208; t=1690562560; x=1691167360; 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=qfXIoWZOPMTUuZ51sHKPtDeshXixERaT1oNJnhO0ex0=; b=It3a8uIRBWBxtFna+HZJERO/3/0f2r4nyuR/E+sjXiG9TQGNLD0TfIGecOO32rhhu/ nQ0XUBk8WmxIZY4qJQaI/VevgEsW/CwC4nLk8hoIU8YxvQl3AwGLhkgFzwIi4tKY+8su Oyl/hwKdVV/FUPnGD472zaZePQjaJGgeRkhyHLD/8mRuCDBX3cOvi9Y040oyMhHLRBrG RlhjY65j/7wF/feBfAD43VQKB3zPIAz3pDn5QXxTz+Cy61LdylA3/pmWHZ7uMGveK7ci pMkLlV0TBFxQdPM9H7ZjTdWt8u9Brkuy2GgG3dCpn0Vy2XHOmVX/Rz+RtnHNAt8sddmh 1lJA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690562560; x=1691167360; 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=qfXIoWZOPMTUuZ51sHKPtDeshXixERaT1oNJnhO0ex0=; b=YGIThXoi2Y3YoCLcbTWO2k3JQCPf0mLIuQD3Q+fm2RHxR+DWzPTxiyp8Vzt0BcvQCb rWc6i+4xarj409AsBtCRMHSnJAs18x4sOnMVb/Ma0I80TSBErd5rwLFjcvO5YeajfaOp t3l7IDSoCDan6gpyIjwXQtldv5K2b9x51jJrzTE+/D+Feh9GjrOeT7vxWcaKrKvLWnIC wwi43IPhEBQXe7L33lm8kLEs9ujlHiC61vCNIF7MhCTiYEKY0ejQyWfAwpkViFxThf3Z FKh2MblimTFfxvtQYCEeCU/GXzY2nfHJ0Nvz8aSgSlJR6cq7zI/3ENQctromdH1JAGML 0GtQ== X-Gm-Message-State: ABy/qLYPVuf8rmF88Twdf9RPCJERWLYqpn/aThnF3v8T3WM9GbfiGMq1 aKuXoxIVdLsNMpiwTlK5s3K7ltCIEkj9u15AJeU= X-Google-Smtp-Source: APBJJlEzCb2GsmXDbZPVVhgPc8nV4zB6aeu8Qzv2AhRcV6ADL3MsZjBM2Km9lPqN+1pk6fm737AOnQ== X-Received: by 2002:a05:6602:14ce:b0:787:16ec:2699 with SMTP id b14-20020a05660214ce00b0078716ec2699mr113690iow.2.1690562560150; Fri, 28 Jul 2023 09:42:40 -0700 (PDT) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id b2-20020a029a02000000b0042b37dda71asm1158808jal.136.2023.07.28.09.42.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Jul 2023 09:42:39 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Cc: peterz@infradead.org, andres@anarazel.de, tglx@linutronix.de, Jens Axboe Subject: [PATCH 01/12] futex: Clarify FUTEX2 flags Date: Fri, 28 Jul 2023 10:42:24 -0600 Message-Id: <20230728164235.1318118-2-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230728164235.1318118-1-axboe@kernel.dk> References: <20230728164235.1318118-1-axboe@kernel.dk> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org From: Peter Zijlstra sys_futex_waitv() is part of the futex2 series (the first and only so far) of syscalls and has a flags field per futex (as opposed to flags being encoded in the futex op). This new flags field has a new namespace, which unfortunately isn't super explicit. Notably it currently takes FUTEX_32 and FUTEX_PRIVATE_FLAG. Introduce the FUTEX2 namespace to clarify this Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Jens Axboe --- include/uapi/linux/futex.h | 16 +++++++++++++--- kernel/futex/syscalls.c | 7 +++---- 2 files changed, 16 insertions(+), 7 deletions(-) diff --git a/include/uapi/linux/futex.h b/include/uapi/linux/futex.h index 71a5df8d2689..0c5abb6aa8f8 100644 --- a/include/uapi/linux/futex.h +++ b/include/uapi/linux/futex.h @@ -44,10 +44,20 @@ FUTEX_PRIVATE_FLAG) /* - * Flags to specify the bit length of the futex word for futex2 syscalls. - * Currently, only 32 is supported. + * Flags for futex2 syscalls. */ -#define FUTEX_32 2 + /* 0x00 */ + /* 0x01 */ +#define FUTEX2_32 0x02 + /* 0x04 */ + /* 0x08 */ + /* 0x10 */ + /* 0x20 */ + /* 0x40 */ +#define FUTEX2_PRIVATE FUTEX_PRIVATE_FLAG + +/* do not use */ +#define FUTEX_32 FUTEX2_32 /* historical accident :-( */ /* * Max numbers of elements in a futex_waitv array diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c index a8074079b09e..42b6c2fac7db 100644 --- a/kernel/futex/syscalls.c +++ b/kernel/futex/syscalls.c @@ -183,8 +183,7 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val, return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3); } -/* Mask of available flags for each futex in futex_waitv list */ -#define FUTEXV_WAITER_MASK (FUTEX_32 | FUTEX_PRIVATE_FLAG) +#define FUTEX2_MASK (FUTEX2_32 | FUTEX2_PRIVATE) /** * futex_parse_waitv - Parse a waitv array from userspace @@ -205,10 +204,10 @@ static int futex_parse_waitv(struct futex_vector *futexv, if (copy_from_user(&aux, &uwaitv[i], sizeof(aux))) return -EFAULT; - if ((aux.flags & ~FUTEXV_WAITER_MASK) || aux.__reserved) + if ((aux.flags & ~FUTEX2_MASK) || aux.__reserved) return -EINVAL; - if (!(aux.flags & FUTEX_32)) + if (!(aux.flags & FUTEX2_32)) return -EINVAL; futexv[i].w.flags = aux.flags;