From patchwork Thu Jul 20 22:18:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 13321126 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 D414FC001DC for ; Thu, 20 Jul 2023 22:19:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229674AbjGTWTL (ORCPT ); Thu, 20 Jul 2023 18:19:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46518 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229711AbjGTWTK (ORCPT ); Thu, 20 Jul 2023 18:19:10 -0400 Received: from mail-pf1-x436.google.com (mail-pf1-x436.google.com [IPv6:2607:f8b0:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 150BE196 for ; Thu, 20 Jul 2023 15:19:09 -0700 (PDT) Received: by mail-pf1-x436.google.com with SMTP id d2e1a72fcca58-682a5465e9eso264721b3a.1 for ; Thu, 20 Jul 2023 15:19:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20221208.gappssmtp.com; s=20221208; t=1689891548; x=1690496348; 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=WOL067osaUVD2WGIgkXdT50lTOWUWIgvc4AEqkDscXJLFPBMT0ONp5BBak35zLctZZ AMZnsNVfpx8/08fVLo9HjESlx+fL3eg5vh135rKOTWXQyoqVRxwQag9lzCve0IJR+XFl CjPCfU3Bly9kThOZi5HS+8criRD6s8AlmuoTpjK+BT/BgDgU+WFx66UXFOob1Lebb7Gi K75u9i9VpneJ0NC6/5n4gD4z84Kpu0FHcaY+56XRjjmCE2bYfqVG2RuYXd3m9QA47+oj mGBGlTqOKvANBl6jQBINEwv53cFjn14pfgR5YxoEQ0T9KKKTelIe/ggkoaoFs1qS0iD2 inOA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689891548; x=1690496348; 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=Of16SwP+rorqMxRlcsvsHImcirjU421f+y6+8+SLoW5HsSAigi2DM8ygpq6l2WlhHg ZaFWeszp7phraiKsKejkvPCton/Rc+NlLPevWEdjscarr9ieRLJzzV8KDvFyvQI+6B6T sRVg5V7hI2trxX7e7Q2MhPnF61pJQ5uDYk+JCEpOJaMSz7VVXm1G+o0Ug7F3iLjlrANr +x+Z3cVNjn931wO+dKCojEcOVDp6cucFxEs6uGJSBeyJYKD+s6VVGT0HvQ9PNrtKkLVX x8aQPXHY+HwbHq8Mm4Yih/3oZz/DL/+Tr8q1EbDI+iTy5Mj5zKkpEmEY0HKBe6doTRhv 7CNw== X-Gm-Message-State: ABy/qLaWhzEekkl3slZQsWa5olJyQn41FmU7zkl9b+CFTnW4zBO/XvHL jGD9mdoQF6Qa8usmDB3oeIVmR6Uwx8//XgH6vro= X-Google-Smtp-Source: APBJJlHNoXWkTaeiFsQJURdZN83WfpPtpj9P4/mBIuHx8U5G8nUY5PwY02lmoCqavwUbnSiNbkA2Lw== X-Received: by 2002:a05:6a20:42a8:b0:123:3ec2:360d with SMTP id o40-20020a056a2042a800b001233ec2360dmr204903pzj.5.1689891548133; Thu, 20 Jul 2023 15:19:08 -0700 (PDT) Received: from localhost.localdomain ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id q1-20020a63bc01000000b0055b3af821d5sm1762454pge.25.2023.07.20.15.19.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Jul 2023 15:19:07 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Cc: peterz@infradead.org, andres@anarazel.de, Jens Axboe Subject: [PATCH 01/10] futex: Clarify FUTEX2 flags Date: Thu, 20 Jul 2023 16:18:49 -0600 Message-Id: <20230720221858.135240-2-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230720221858.135240-1-axboe@kernel.dk> References: <20230720221858.135240-1-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;