From nobody Sat Feb 7 18:15:59 2026 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 4238FC001DC for ; Wed, 12 Jul 2023 16:22:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232769AbjGLQWS (ORCPT ); Wed, 12 Jul 2023 12:22:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232192AbjGLQVj (ORCPT ); Wed, 12 Jul 2023 12:21:39 -0400 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7CD2230C0 for ; Wed, 12 Jul 2023 09:20:45 -0700 (PDT) Received: by mail-pf1-x42b.google.com with SMTP id d2e1a72fcca58-66d6a9851f3so1184197b3a.0 for ; Wed, 12 Jul 2023 09:20:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20221208.gappssmtp.com; s=20221208; t=1689178845; x=1691770845; 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=/9IAdtt3/8DuY/QVZDICwnJG5hoGWNTwXHfpUVZziX4=; b=EM+PCGQWHPEVzL/Jc93Q5nC/tU063wfXE0e/0WH0Azz+MQ8bmp/vwQhO8z5thcxBS/ ALTHKAPnHqLlU68wt2akeyFfBAU7SpDe6fJtnjleudk0djnb/RCiifn93hVHVDo06UE3 lXBkJjmCF94KWc+TMT5Hcm16xDWp/POmxLJbMy81WBSJEiNVGN/GEVNd6Dz6LjjxpSmU CBQ5D2AIml3CfkDh3MzOzHxwZ/sE/Gu/Vvw73Dg58bNTx75oe8m61jqJ6SQz1JXHz9Im T0NbV/6u3YknwV7F/AxDvsTUluf0diDhAuQXWTSG4gL98OFv6ECMX0IWq3IS5UKU1Puk BGgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689178845; x=1691770845; 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=/9IAdtt3/8DuY/QVZDICwnJG5hoGWNTwXHfpUVZziX4=; b=Iw8fCRLV7hsB2iY4LRxfs5iX66FQzx0In7OmEFkuSE0DpUmRNOMmQbWObtD/Pk0Rml VSDGoQfuUZfEYVOa8xPGla/1ZFHNocDLiXKA6Bf02V+yvLS3S8rKuz+Qebm16Te3rN6o Ry+i90KSFhHYNkfTLv/v9W8NJoipBVPUfwrdTTaRaKxzGbD3EAnKKshArOlOWqYVhyvT /ASgKdpWi2CPBKomhsZbZggJNHRRCpvZgiFz9aYMnA3XGYYfujTohh6GJpJVOwsMvqCc xB3QkMXyglAevCPa0b0wkVS3zUx4d6HRDSB7P8Gw2fVLSrnrWhX90Up4VCVTc7LtzRHe etow== X-Gm-Message-State: ABy/qLanmFvnn17wmdsOa3s592gMXuVZ4jGBOs1ffv2Q+B0PSqq/aY0D 7aNfAvwc7ECsb7TAQQpUga7XxItdpr1Ax1rzwcI= X-Google-Smtp-Source: APBJJlEtOypA1RFF8/aajtMhumzTpVGIjNpPO69tWC224DdJYo4Sumfefx+Y7aU9ZQQPwkdTtOVHyw== X-Received: by 2002:a05:6602:1490:b0:787:16ec:2699 with SMTP id a16-20020a056602149000b0078716ec2699mr11094280iow.2.1689178824145; Wed, 12 Jul 2023 09:20:24 -0700 (PDT) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id x24-20020a029718000000b0042aec33bc26sm1328775jai.18.2023.07.12.09.20.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Jul 2023 09:20:22 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, andres@anarazel.de, Jens Axboe Subject: [PATCH 1/8] futex: abstract out futex_op_to_flags() helper Date: Wed, 12 Jul 2023 10:20:10 -0600 Message-Id: <20230712162017.391843-2-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230712162017.391843-1-axboe@kernel.dk> References: <20230712162017.391843-1-axboe@kernel.dk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Rather than needing to duplicate this for the io_uring hook of futexes, abstract out a helper. No functional changes intended in this patch. Signed-off-by: Jens Axboe --- kernel/futex/futex.h | 17 +++++++++++++++++ kernel/futex/syscalls.c | 13 +++---------- 2 files changed, 20 insertions(+), 10 deletions(-) diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index b5379c0e6d6d..b8f454792304 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -291,4 +291,21 @@ extern int futex_unlock_pi(u32 __user *uaddr, unsigned= int flags); =20 extern int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *t= ime, int trylock); =20 +static inline bool futex_op_to_flags(int op, int cmd, unsigned int *flags) +{ + *flags =3D 0; + + if (!(op & FUTEX_PRIVATE_FLAG)) + *flags |=3D FLAGS_SHARED; + + if (op & FUTEX_CLOCK_REALTIME) { + *flags |=3D FLAGS_CLOCKRT; + if (cmd !=3D FUTEX_WAIT_BITSET && cmd !=3D FUTEX_WAIT_REQUEUE_PI && + cmd !=3D FUTEX_LOCK_PI2) + return false; + } + + return true; +} + #endif /* _FUTEX_H */ diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c index a8074079b09e..0b63d5bcdc77 100644 --- a/kernel/futex/syscalls.c +++ b/kernel/futex/syscalls.c @@ -86,17 +86,10 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime= _t *timeout, u32 __user *uaddr2, u32 val2, u32 val3) { int cmd =3D op & FUTEX_CMD_MASK; - unsigned int flags =3D 0; + unsigned int flags; =20 - if (!(op & FUTEX_PRIVATE_FLAG)) - flags |=3D FLAGS_SHARED; - - if (op & FUTEX_CLOCK_REALTIME) { - flags |=3D FLAGS_CLOCKRT; - if (cmd !=3D FUTEX_WAIT_BITSET && cmd !=3D FUTEX_WAIT_REQUEUE_PI && - cmd !=3D FUTEX_LOCK_PI2) - return -ENOSYS; - } + if (!futex_op_to_flags(op, cmd, &flags)) + return -ENOSYS; =20 switch (cmd) { case FUTEX_WAIT: --=20 2.40.1 From nobody Sat Feb 7 18:15:59 2026 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 437B8C001DE for ; Wed, 12 Jul 2023 16:21:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229909AbjGLQVr (ORCPT ); Wed, 12 Jul 2023 12:21:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232319AbjGLQVa (ORCPT ); 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Wed, 12 Jul 2023 09:20:25 -0700 (PDT) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id x24-20020a029718000000b0042aec33bc26sm1328775jai.18.2023.07.12.09.20.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Jul 2023 09:20:24 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, andres@anarazel.de, Jens Axboe Subject: [PATCH 2/8] futex: factor out the futex wake handling Date: Wed, 12 Jul 2023 10:20:11 -0600 Message-Id: <20230712162017.391843-3-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230712162017.391843-1-axboe@kernel.dk> References: <20230712162017.391843-1-axboe@kernel.dk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" In preparation for having another waker that isn't futex_wake_mark(), add a wake handler in futex_q. No extra data is associated with the handler outside of struct futex_q itself. futex_wake_mark() is defined as the standard wakeup helper, now set through futex_q_init like other defaults. Normal sync futex waiting relies on wake_q holding tasks that should be woken up. This is what futex_wake_mark() does, it'll unqueue the futex and add the associated task to the wake queue. For async usage of futex waiting, rather than having tasks sleeping on the futex, we'll need to deal with a futex wake differently. For the planned io_uring case, that means posting a completion event for the task in question. Having a definable wake handler can help support that use case. Signed-off-by: Jens Axboe --- kernel/futex/futex.h | 4 ++++ kernel/futex/requeue.c | 3 ++- kernel/futex/waitwake.c | 6 +++--- 3 files changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index b8f454792304..54b7de21ef00 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -69,6 +69,9 @@ struct futex_pi_state { union futex_key key; } __randomize_layout; =20 +struct futex_q; +typedef void (futex_wake_fn)(struct wake_q_head *wake_q, struct futex_q *q= ); + /** * struct futex_q - The hashed futex queue entry, one per waiting task * @list: priority-sorted list of tasks waiting on this futex @@ -98,6 +101,7 @@ struct futex_q { =20 struct task_struct *task; spinlock_t *lock_ptr; + futex_wake_fn *wake; union futex_key key; struct futex_pi_state *pi_state; struct rt_mutex_waiter *rt_waiter; diff --git a/kernel/futex/requeue.c b/kernel/futex/requeue.c index cba8b1a6a4cc..e892bc6c41d8 100644 --- a/kernel/futex/requeue.c +++ b/kernel/futex/requeue.c @@ -58,6 +58,7 @@ enum { =20 const struct futex_q futex_q_init =3D { /* list gets initialized in futex_queue()*/ + .wake =3D futex_wake_mark, .key =3D FUTEX_KEY_INIT, .bitset =3D FUTEX_BITSET_MATCH_ANY, .requeue_state =3D ATOMIC_INIT(Q_REQUEUE_PI_NONE), @@ -591,7 +592,7 @@ int futex_requeue(u32 __user *uaddr1, unsigned int flag= s, u32 __user *uaddr2, /* Plain futexes just wake or requeue and are done */ if (!requeue_pi) { if (++task_count <=3D nr_wake) - futex_wake_mark(&wake_q, this); + this->wake(&wake_q, this); else requeue_futex(this, hb1, hb2, &key2); continue; diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c index ba01b9408203..3471af87cb7d 100644 --- a/kernel/futex/waitwake.c +++ b/kernel/futex/waitwake.c @@ -174,7 +174,7 @@ int futex_wake(u32 __user *uaddr, unsigned int flags, i= nt nr_wake, u32 bitset) if (!(this->bitset & bitset)) continue; =20 - futex_wake_mark(&wake_q, this); + this->wake(&wake_q, this); if (++ret >=3D nr_wake) break; } @@ -289,7 +289,7 @@ int futex_wake_op(u32 __user *uaddr1, unsigned int flag= s, u32 __user *uaddr2, ret =3D -EINVAL; goto out_unlock; } - futex_wake_mark(&wake_q, this); + this->wake(&wake_q, this); if (++ret >=3D nr_wake) break; } @@ -303,7 +303,7 @@ int futex_wake_op(u32 __user *uaddr1, unsigned int flag= s, u32 __user *uaddr2, ret =3D -EINVAL; goto out_unlock; } - futex_wake_mark(&wake_q, this); + this->wake(&wake_q, this); if (++op_ret >=3D nr_wake2) break; } --=20 2.40.1 From nobody Sat Feb 7 18:15:59 2026 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 95F95EB64DA for ; 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Wed, 12 Jul 2023 09:20:27 -0700 (PDT) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id x24-20020a029718000000b0042aec33bc26sm1328775jai.18.2023.07.12.09.20.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Jul 2023 09:20:26 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, andres@anarazel.de, Jens Axboe Subject: [PATCH 3/8] futex: abstract out a __futex_wake_mark() helper Date: Wed, 12 Jul 2023 10:20:12 -0600 Message-Id: <20230712162017.391843-4-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230712162017.391843-1-axboe@kernel.dk> References: <20230712162017.391843-1-axboe@kernel.dk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Move the unqueue and lock_ptr clear into a helper that futex_wake_mark() calls. Add it to the public functions as well, in preparation for using it outside the core futex code. Suggested-by: Peter Zijlstra Signed-off-by: Jens Axboe --- kernel/futex/futex.h | 1 + kernel/futex/waitwake.c | 33 ++++++++++++++++++++++----------- 2 files changed, 23 insertions(+), 11 deletions(-) diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index 54b7de21ef00..1d531244fb71 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -148,6 +148,7 @@ extern int futex_wait_setup(u32 __user *uaddr, u32 val,= unsigned int flags, struct futex_q *q, struct futex_hash_bucket **hb); extern void futex_wait_queue(struct futex_hash_bucket *hb, struct futex_q = *q, struct hrtimer_sleeper *timeout); +extern bool __futex_wake_mark(struct futex_q *q); extern void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q); =20 extern int fault_in_user_writeable(u32 __user *uaddr); diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c index 3471af87cb7d..f8fb6550061d 100644 --- a/kernel/futex/waitwake.c +++ b/kernel/futex/waitwake.c @@ -106,20 +106,11 @@ * double_lock_hb() and double_unlock_hb(), respectively. */ =20 -/* - * The hash bucket lock must be held when this is called. - * Afterwards, the futex_q must not be accessed. Callers - * must ensure to later call wake_up_q() for the actual - * wakeups to occur. - */ -void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q) +bool __futex_wake_mark(struct futex_q *q) { - struct task_struct *p =3D q->task; - if (WARN(q->pi_state || q->rt_waiter, "refusing to wake PI futex\n")) - return; + return false; =20 - get_task_struct(p); __futex_unqueue(q); /* * The waiting task can free the futex_q as soon as q->lock_ptr =3D NULL @@ -130,6 +121,26 @@ void futex_wake_mark(struct wake_q_head *wake_q, struc= t futex_q *q) */ smp_store_release(&q->lock_ptr, NULL); =20 + return true; +} + +/* + * The hash bucket lock must be held when this is called. + * Afterwards, the futex_q must not be accessed. Callers + * must ensure to later call wake_up_q() for the actual + * wakeups to occur. + */ +void futex_wake_mark(struct wake_q_head *wake_q, struct futex_q *q) +{ + struct task_struct *p =3D q->task; + + get_task_struct(p); + + if (!__futex_wake_mark(q)) { + put_task_struct(p); + return; + } + /* * Queue the task for later wakeup for after we've released * the hb->lock. --=20 2.40.1 From nobody Sat Feb 7 18:15:59 2026 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 A7584EB64DA for ; Wed, 12 Jul 2023 16:21:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232117AbjGLQVz (ORCPT ); Wed, 12 Jul 2023 12:21:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51950 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232887AbjGLQVd (ORCPT ); Wed, 12 Jul 2023 12:21:33 -0400 Received: from mail-io1-xd36.google.com (mail-io1-xd36.google.com [IPv6:2607:f8b0:4864:20::d36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B4632112 for ; Wed, 12 Jul 2023 09:20:31 -0700 (PDT) Received: by mail-io1-xd36.google.com with SMTP id ca18e2360f4ac-760dff4b701so82240239f.0 for ; Wed, 12 Jul 2023 09:20:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20221208.gappssmtp.com; s=20221208; t=1689178829; x=1691770829; 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=wsRgnJksAHT2wfEm8OA9lEtEgO4i8eBvXfNppHEgNto=; b=wFSIxDPsLNlJm5ByiE0aXxDDcwnVXnknXKLz13FN3+j05JuEYUpYhzbsKdSf5w8qxF sZHNq8GPYJwW2x14liIIIOQfbswLxzmmCz3ZxoKVOQqnc4vdetwien0JrPdJIlD1vjLW Rhh7kvqPPaxaXpLsuKxpYkUQyYoYCakvnfgXq/W4P7bGi57MfMU4OQFOry0Aka+a+0Xj vR2ZJY3ltvtzs85btSzVJqX4H0elsMvGCU3OSQoCkgdL/MsOf/yHA961Cgu3eLuj0RDX 9xj/1Um4WDrwHiBcuem8SKlzNogzKrEgEWaq23W4cLYw2PvihtqlEUEsVUnPLrtOu63U GqNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689178829; x=1691770829; 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=wsRgnJksAHT2wfEm8OA9lEtEgO4i8eBvXfNppHEgNto=; b=Dah3HTI/kxD5977yLTrQOXLHPAch7K2FqY+uL5w7JFOUtrtDBSYO+K1v8LrWJ0C4y+ 15izWl1FEdsvd6wfzGEYjqjOZYhNrTX+qba/a3habaMByFVKtd4D1IrFeABZ9swVlPdA VpH2poSSm/IXcMMA8zCLz/OlUhbGesEj+kxJeDDyVWZLtfLTsHbHoOkB1esEP7iNZPjy 95YDNzQDDx0v30Y4JQZxJvsK/jWAjT/Xhv774zVeSZ2HwfzJBP/u7S2bRjKsnni0lhbR TFUy8mwnbyJqoaLdzb7wnXm2otFXMusiPSfGgRqDV+JTp3JYRlnVvokFGeA9WIHaBFb4 Mbog== X-Gm-Message-State: ABy/qLbSupfv0spN2ewgeoxfyvyuw5/GoOMvb1djkRFgDqZA6vGOTbL3 vWj9LylcVLAS+3wvhoIHzSsC4A== X-Google-Smtp-Source: APBJJlFV/nyfq/NedU73XmKJRaQ+BLpy7DF2+q9fLemfl5U/Y/vXFamZ44jsXZpQeaVMHTku0JMa1A== X-Received: by 2002:a6b:5a0a:0:b0:780:cb36:6f24 with SMTP id o10-20020a6b5a0a000000b00780cb366f24mr18730478iob.2.1689178829051; Wed, 12 Jul 2023 09:20:29 -0700 (PDT) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id x24-20020a029718000000b0042aec33bc26sm1328775jai.18.2023.07.12.09.20.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Jul 2023 09:20:28 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, andres@anarazel.de, Jens Axboe Subject: [PATCH 4/8] io_uring: add support for futex wake and wait Date: Wed, 12 Jul 2023 10:20:13 -0600 Message-Id: <20230712162017.391843-5-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230712162017.391843-1-axboe@kernel.dk> References: <20230712162017.391843-1-axboe@kernel.dk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Add support for FUTEX_WAKE/WAIT primitives. IORING_OP_FUTEX_WAKE is mix of FUTEX_WAKE and FUTEX_WAKE_BITSET, as it does support passing in a bitset. Similary, IORING_OP_FUTEX_WAIT is a mix of FUTEX_WAIT and FUTEX_WAIT_BITSET. FUTEX_WAKE is straight forward, as those can always be done directly from the io_uring submission without needing async handling. For FUTEX_WAIT, things are a bit more complicated. If the futex isn't ready, then we rely on a callback via futex_queue->wake() when someone wakes up the futex. From that calback, we queue up task_work with the original task, which will post a CQE and wake it, if necessary. Cancelations are supported, both from the application point-of-view, but also to be able to cancel pending waits if the ring exits before all events have occurred. This is just the barebones wait/wake support. PI or REQUEUE support is not added at this point, unclear if we might look into that later. Likewise, explicit timeouts are not supported either. It is expected that users that need timeouts would do so via the usual io_uring mechanism to do that using linked timeouts. Signed-off-by: Jens Axboe --- include/linux/io_uring_types.h | 3 + include/uapi/linux/io_uring.h | 3 + io_uring/Makefile | 4 +- io_uring/cancel.c | 5 + io_uring/cancel.h | 4 + io_uring/futex.c | 232 +++++++++++++++++++++++++++++++++ io_uring/futex.h | 34 +++++ io_uring/io_uring.c | 5 + io_uring/opdef.c | 24 +++- 9 files changed, 312 insertions(+), 2 deletions(-) create mode 100644 io_uring/futex.c create mode 100644 io_uring/futex.h diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h index f04ce513fadb..a7f03d8d879f 100644 --- a/include/linux/io_uring_types.h +++ b/include/linux/io_uring_types.h @@ -273,6 +273,9 @@ struct io_ring_ctx { struct io_wq_work_list locked_free_list; unsigned int locked_free_nr; =20 + struct hlist_head futex_list; + struct io_alloc_cache futex_cache; + const struct cred *sq_creds; /* cred used for __io_sq_thread() */ struct io_sq_data *sq_data; /* if using sq thread polling */ =20 diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 36f9c73082de..3bd2d765f593 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -65,6 +65,7 @@ struct io_uring_sqe { __u32 xattr_flags; __u32 msg_ring_flags; __u32 uring_cmd_flags; + __u32 futex_flags; }; __u64 user_data; /* data to be passed back at completion time */ /* pack this to avoid bogus arm OABI complaints */ @@ -235,6 +236,8 @@ enum io_uring_op { IORING_OP_URING_CMD, IORING_OP_SEND_ZC, IORING_OP_SENDMSG_ZC, + IORING_OP_FUTEX_WAIT, + IORING_OP_FUTEX_WAKE, =20 /* this goes last, obviously */ IORING_OP_LAST, diff --git a/io_uring/Makefile b/io_uring/Makefile index 8cc8e5387a75..2e4779bc550c 100644 --- a/io_uring/Makefile +++ b/io_uring/Makefile @@ -7,5 +7,7 @@ obj-$(CONFIG_IO_URING) +=3D io_uring.o xattr.o nop.o fs.o = splice.o \ openclose.o uring_cmd.o epoll.o \ statx.o net.o msg_ring.o timeout.o \ sqpoll.o fdinfo.o tctx.o poll.o \ - cancel.o kbuf.o rsrc.o rw.o opdef.o notif.o + cancel.o kbuf.o rsrc.o rw.o opdef.o \ + notif.o obj-$(CONFIG_IO_WQ) +=3D io-wq.o +obj-$(CONFIG_FUTEX) +=3D futex.o diff --git a/io_uring/cancel.c b/io_uring/cancel.c index 7b23607cf4af..3dba8ccb1cd8 100644 --- a/io_uring/cancel.c +++ b/io_uring/cancel.c @@ -15,6 +15,7 @@ #include "tctx.h" #include "poll.h" #include "timeout.h" +#include "futex.h" #include "cancel.h" =20 struct io_cancel { @@ -119,6 +120,10 @@ int io_try_cancel(struct io_uring_task *tctx, struct i= o_cancel_data *cd, if (ret !=3D -ENOENT) return ret; =20 + ret =3D io_futex_cancel(ctx, cd, issue_flags); + if (ret !=3D -ENOENT) + return ret; + spin_lock(&ctx->completion_lock); if (!(cd->flags & IORING_ASYNC_CANCEL_FD)) ret =3D io_timeout_cancel(ctx, cd); diff --git a/io_uring/cancel.h b/io_uring/cancel.h index fc98622e6166..c0a8e7c520b6 100644 --- a/io_uring/cancel.h +++ b/io_uring/cancel.h @@ -1,4 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 +#ifndef IORING_CANCEL_H +#define IORING_CANCEL_H =20 #include =20 @@ -22,3 +24,5 @@ void init_hash_table(struct io_hash_table *table, unsigne= d size); =20 int io_sync_cancel(struct io_ring_ctx *ctx, void __user *arg); bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data *cd); + +#endif diff --git a/io_uring/futex.c b/io_uring/futex.c new file mode 100644 index 000000000000..fa92ee795c83 --- /dev/null +++ b/io_uring/futex.c @@ -0,0 +1,232 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include + +#include + +#include "../kernel/futex/futex.h" +#include "io_uring.h" +#include "rsrc.h" +#include "futex.h" + +struct io_futex { + struct file *file; + u32 __user *uaddr; + int futex_op; + unsigned int futex_val; + unsigned int futex_flags; + unsigned int futex_mask; +}; + +struct io_futex_data { + union { + struct futex_q q; + struct io_cache_entry cache; + }; + struct io_kiocb *req; +}; + +void io_futex_cache_init(struct io_ring_ctx *ctx) +{ + io_alloc_cache_init(&ctx->futex_cache, IO_NODE_ALLOC_CACHE_MAX, + sizeof(struct io_futex_data)); +} + +static void io_futex_cache_entry_free(struct io_cache_entry *entry) +{ + kfree(container_of(entry, struct io_futex_data, cache)); +} + +void io_futex_cache_free(struct io_ring_ctx *ctx) +{ + io_alloc_cache_free(&ctx->futex_cache, io_futex_cache_entry_free); +} + +static void io_futex_complete(struct io_kiocb *req, struct io_tw_state *ts) +{ + struct io_futex_data *ifd =3D req->async_data; + struct io_ring_ctx *ctx =3D req->ctx; + + io_tw_lock(ctx, ts); + if (!io_alloc_cache_put(&ctx->futex_cache, &ifd->cache)) + kfree(ifd); + req->async_data =3D NULL; + hlist_del_init(&req->hash_node); + io_req_task_complete(req, ts); +} + +static bool __io_futex_cancel(struct io_ring_ctx *ctx, struct io_kiocb *re= q) +{ + struct io_futex_data *ifd =3D req->async_data; + + /* futex wake already done or in progress */ + if (!futex_unqueue(&ifd->q)) + return false; + + hlist_del_init(&req->hash_node); + io_req_set_res(req, -ECANCELED, 0); + req->io_task_work.func =3D io_futex_complete; + io_req_task_work_add(req); + return true; +} + +int io_futex_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd, + unsigned int issue_flags) +{ + struct hlist_node *tmp; + struct io_kiocb *req; + int nr =3D 0; + + if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_FD_FIXED)) + return -ENOENT; + + io_ring_submit_lock(ctx, issue_flags); + hlist_for_each_entry_safe(req, tmp, &ctx->futex_list, hash_node) { + if (req->cqe.user_data !=3D cd->data && + !(cd->flags & IORING_ASYNC_CANCEL_ANY)) + continue; + if (__io_futex_cancel(ctx, req)) + nr++; + if (!(cd->flags & IORING_ASYNC_CANCEL_ALL)) + break; + } + io_ring_submit_unlock(ctx, issue_flags); + + if (nr) + return nr; + + return -ENOENT; +} + +bool io_futex_remove_all(struct io_ring_ctx *ctx, struct task_struct *task, + bool cancel_all) +{ + struct hlist_node *tmp; + struct io_kiocb *req; + bool found =3D false; + + lockdep_assert_held(&ctx->uring_lock); + + hlist_for_each_entry_safe(req, tmp, &ctx->futex_list, hash_node) { + if (!io_match_task_safe(req, task, cancel_all)) + continue; + __io_futex_cancel(ctx, req); + found =3D true; + } + + return found; +} + +int io_futex_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_futex *iof =3D io_kiocb_to_cmd(req, struct io_futex); + + if (unlikely(sqe->addr2 || sqe->buf_index || sqe->addr3)) + return -EINVAL; + + iof->futex_op =3D READ_ONCE(sqe->fd); + iof->uaddr =3D u64_to_user_ptr(READ_ONCE(sqe->addr)); + iof->futex_val =3D READ_ONCE(sqe->len); + iof->futex_mask =3D READ_ONCE(sqe->file_index); + iof->futex_flags =3D READ_ONCE(sqe->futex_flags); + if (iof->futex_flags & FUTEX_CMD_MASK) + return -EINVAL; + + return 0; +} + +static void io_futex_wake_fn(struct wake_q_head *wake_q, struct futex_q *q) +{ + struct io_futex_data *ifd =3D container_of(q, struct io_futex_data, q); + struct io_kiocb *req =3D ifd->req; + + if (unlikely(!__futex_wake_mark(q))) + return; + + io_req_set_res(req, 0, 0); + req->io_task_work.func =3D io_futex_complete; + io_req_task_work_add(req); +} + +static struct io_futex_data *io_alloc_ifd(struct io_ring_ctx *ctx) +{ + struct io_cache_entry *entry; + + entry =3D io_alloc_cache_get(&ctx->futex_cache); + if (entry) + return container_of(entry, struct io_futex_data, cache); + + return kmalloc(sizeof(struct io_futex_data), GFP_NOWAIT); +} + +int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_futex *iof =3D io_kiocb_to_cmd(req, struct io_futex); + struct io_ring_ctx *ctx =3D req->ctx; + struct io_futex_data *ifd =3D NULL; + struct futex_hash_bucket *hb; + unsigned int flags; + int ret; + + if (!iof->futex_mask) { + ret =3D -EINVAL; + goto done; + } + if (!futex_op_to_flags(FUTEX_WAIT, iof->futex_flags, &flags)) { + ret =3D -ENOSYS; + goto done; + } + + io_ring_submit_lock(ctx, issue_flags); + ifd =3D io_alloc_ifd(ctx); + if (!ifd) { + ret =3D -ENOMEM; + goto done_unlock; + } + + req->async_data =3D ifd; + ifd->q =3D futex_q_init; + ifd->q.bitset =3D iof->futex_mask; + ifd->q.wake =3D io_futex_wake_fn; + ifd->req =3D req; + + ret =3D futex_wait_setup(iof->uaddr, iof->futex_val, flags, &ifd->q, &hb); + if (!ret) { + hlist_add_head(&req->hash_node, &ctx->futex_list); + io_ring_submit_unlock(ctx, issue_flags); + + futex_queue(&ifd->q, hb); + return IOU_ISSUE_SKIP_COMPLETE; + } + +done_unlock: + io_ring_submit_unlock(ctx, issue_flags); +done: + if (ret < 0) + req_set_fail(req); + io_req_set_res(req, ret, 0); + kfree(ifd); + return IOU_OK; +} + +int io_futex_wake(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_futex *iof =3D io_kiocb_to_cmd(req, struct io_futex); + unsigned int flags =3D 0; + int ret; + + if (!futex_op_to_flags(FUTEX_WAKE, iof->futex_flags, &flags)) { + ret =3D -ENOSYS; + goto done; + } + + ret =3D futex_wake(iof->uaddr, flags, iof->futex_val, iof->futex_mask); +done: + if (ret < 0) + req_set_fail(req); + io_req_set_res(req, ret, 0); + return IOU_OK; +} diff --git a/io_uring/futex.h b/io_uring/futex.h new file mode 100644 index 000000000000..ddc9e0d73c52 --- /dev/null +++ b/io_uring/futex.h @@ -0,0 +1,34 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include "cancel.h" + +int io_futex_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags); +int io_futex_wake(struct io_kiocb *req, unsigned int issue_flags); + +#if defined(CONFIG_FUTEX) +int io_futex_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd, + unsigned int issue_flags); +bool io_futex_remove_all(struct io_ring_ctx *ctx, struct task_struct *task, + bool cancel_all); +void io_futex_cache_init(struct io_ring_ctx *ctx); +void io_futex_cache_free(struct io_ring_ctx *ctx); +#else +static inline int io_futex_cancel(struct io_ring_ctx *ctx, + struct io_cancel_data *cd, + unsigned int issue_flags) +{ + return 0; +} +static inline bool io_futex_remove_all(struct io_ring_ctx *ctx, + struct task_struct *task, bool cancel_all) +{ + return false; +} +static inline void io_futex_cache_init(struct io_ring_ctx *ctx) +{ +} +static inline void io_futex_cache_free(struct io_ring_ctx *ctx) +{ +} +#endif diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index e8096d502a7c..67ff148bc394 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -92,6 +92,7 @@ #include "cancel.h" #include "net.h" #include "notif.h" +#include "futex.h" =20 #include "timeout.h" #include "poll.h" @@ -314,6 +315,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(str= uct io_uring_params *p) sizeof(struct async_poll)); io_alloc_cache_init(&ctx->netmsg_cache, IO_ALLOC_CACHE_MAX, sizeof(struct io_async_msghdr)); + io_futex_cache_init(ctx); init_completion(&ctx->ref_comp); xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1); mutex_init(&ctx->uring_lock); @@ -333,6 +335,7 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(str= uct io_uring_params *p) INIT_LIST_HEAD(&ctx->tctx_list); ctx->submit_state.free_list.next =3D NULL; INIT_WQ_LIST(&ctx->locked_free_list); + INIT_HLIST_HEAD(&ctx->futex_list); INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func); INIT_WQ_LIST(&ctx->submit_state.compl_reqs); return ctx; @@ -2842,6 +2845,7 @@ static __cold void io_ring_ctx_free(struct io_ring_ct= x *ctx) io_eventfd_unregister(ctx); io_alloc_cache_free(&ctx->apoll_cache, io_apoll_cache_free); io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free); + io_futex_cache_free(ctx); io_destroy_buffers(ctx); mutex_unlock(&ctx->uring_lock); if (ctx->sq_creds) @@ -3254,6 +3258,7 @@ static __cold bool io_uring_try_cancel_requests(struc= t io_ring_ctx *ctx, ret |=3D io_cancel_defer_files(ctx, task, cancel_all); mutex_lock(&ctx->uring_lock); ret |=3D io_poll_remove_all(ctx, task, cancel_all); + ret |=3D io_futex_remove_all(ctx, task, cancel_all); mutex_unlock(&ctx->uring_lock); ret |=3D io_kill_timeouts(ctx, task, cancel_all); if (task) diff --git a/io_uring/opdef.c b/io_uring/opdef.c index 3b9c6489b8b6..c9f23c21a031 100644 --- a/io_uring/opdef.c +++ b/io_uring/opdef.c @@ -33,6 +33,7 @@ #include "poll.h" #include "cancel.h" #include "rw.h" +#include "futex.h" =20 static int io_no_issue(struct io_kiocb *req, unsigned int issue_flags) { @@ -426,11 +427,26 @@ const struct io_issue_def io_issue_defs[] =3D { .issue =3D io_sendmsg_zc, #else .prep =3D io_eopnotsupp_prep, +#endif + }, + [IORING_OP_FUTEX_WAIT] =3D { +#if defined(CONFIG_FUTEX) + .prep =3D io_futex_prep, + .issue =3D io_futex_wait, +#else + .prep =3D io_eopnotsupp_prep, +#endif + }, + [IORING_OP_FUTEX_WAKE] =3D { +#if defined(CONFIG_FUTEX) + .prep =3D io_futex_prep, + .issue =3D io_futex_wake, +#else + .prep =3D io_eopnotsupp_prep, #endif }, }; =20 - const struct io_cold_def io_cold_defs[] =3D { [IORING_OP_NOP] =3D { .name =3D "NOP", @@ -648,6 +664,12 @@ const struct io_cold_def io_cold_defs[] =3D { .fail =3D io_sendrecv_fail, #endif }, + [IORING_OP_FUTEX_WAIT] =3D { + .name =3D "FUTEX_WAIT", + }, + [IORING_OP_FUTEX_WAKE] =3D { + .name =3D "FUTEX_WAKE", + }, }; =20 const char *io_uring_get_opcode(u8 opcode) --=20 2.40.1 From nobody Sat Feb 7 18:15:59 2026 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 E52B6EB64DA for ; Wed, 12 Jul 2023 16:21:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233265AbjGLQV6 (ORCPT ); Wed, 12 Jul 2023 12:21:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231615AbjGLQVe (ORCPT ); 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Wed, 12 Jul 2023 09:20:29 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, andres@anarazel.de, Jens Axboe Subject: [PATCH 5/8] futex: add wake_data to struct futex_q Date: Wed, 12 Jul 2023 10:20:14 -0600 Message-Id: <20230712162017.391843-6-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230712162017.391843-1-axboe@kernel.dk> References: <20230712162017.391843-1-axboe@kernel.dk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" With handling multiple futex_q for waitv, we cannot easily go from the futex_q to data related to that request or queue. Add a wake_data argument that belongs to the wake handler assigned. Signed-off-by: Jens Axboe --- kernel/futex/futex.h | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index 1d531244fb71..24180a95bdc8 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -102,6 +102,7 @@ struct futex_q { struct task_struct *task; spinlock_t *lock_ptr; futex_wake_fn *wake; + void *wake_data; union futex_key key; struct futex_pi_state *pi_state; struct rt_mutex_waiter *rt_waiter; --=20 2.40.1 From nobody Sat Feb 7 18:15:59 2026 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 84888EB64DA for ; Wed, 12 Jul 2023 16:22:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231678AbjGLQWD (ORCPT ); Wed, 12 Jul 2023 12:22:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52204 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232278AbjGLQVg (ORCPT ); Wed, 12 Jul 2023 12:21:36 -0400 Received: from mail-io1-xd2a.google.com (mail-io1-xd2a.google.com [IPv6:2607:f8b0:4864:20::d2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67EE02D59 for ; Wed, 12 Jul 2023 09:20:34 -0700 (PDT) Received: by mail-io1-xd2a.google.com with SMTP id ca18e2360f4ac-785ccd731a7so75963539f.0 for ; Wed, 12 Jul 2023 09:20:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20221208.gappssmtp.com; s=20221208; t=1689178832; x=1689783632; 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=77utXKVr289Xtr5SK547E9baZFV+ka7R8kIV3jn3wns=; b=gI7rciFjThQqgqqmYCaizMxtrpZSxtzzwsi+S4mnL2b5gO6BE9BzQPtDNH/9CnF1R2 TYsXynQEGEhMXgqSFBIM0A+iqu1UDPWYs12q2bd/tt0VFJAGL57hR6qvo/h/CmfGDniL Iq9oXIMhd347hbYW0TO+mD1BeprT8njB6m1kIWXvitA8yTVsonbh9Cp+iIP1ew+yPVko lBhPsCWnpvbHm9FMXAHpbMtI9sBUBC0Ko3W2X04aQziXeH5Fozi4QVVWyhMwrQ4tUT5o eD71S3XbQ2wgGPMoqSoi6AdlIQlnbPHk/YsuhIdOQJkgt/luk+Xr2sL3LPqrwph437eG PzDA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1689178832; x=1689783632; 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=77utXKVr289Xtr5SK547E9baZFV+ka7R8kIV3jn3wns=; b=XwoIWOXHK0hhK9bNzNQLyLq6HHdm1YRz8bQMT9eXG9/9Ttj9Het+SkoiupFkSFuzso DscwLjrfmcY/B8GgcJS5E1PGrmkEo0aCZDrmEnyrfET0rNiMU+iipOfaK8xK0sWNwor2 4LBJ0mB0Ao6PeZ0w78jQE2ftYjdMridim30JuakKfMcjRvf1Y4cHrWKpXq/t1M1JaqKG /mPTaxNbMMm/fSERCHqNhIE5H2KLxvgemdMw03ZpSvr1rsma2oIB/9Kp93qToZ4oYHtP DNoBPmKprurvRQkDLYZfGVBewePfgj9Xs6Hoa6Kz256tX27KpYagIHXJ51oNLi+zb2J0 /qxQ== X-Gm-Message-State: ABy/qLZ/Y7Ts01ulsjuL5xReP0/KIMJTwzBq7iQl2U5eGU/y1Kk7uRXS 1w1B5wL9f9aCk5q6KYHf7vpFgA== X-Google-Smtp-Source: APBJJlH06yLgDahSs0qD1tZReckWNo0TVLhdg4jwmBuajcUVoiSOQHr6O3rmk1lUs1zb3/yCDPdADQ== X-Received: by 2002:a05:6602:2f14:b0:783:6ec1:65f6 with SMTP id q20-20020a0566022f1400b007836ec165f6mr24774001iow.1.1689178831951; Wed, 12 Jul 2023 09:20:31 -0700 (PDT) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id x24-20020a029718000000b0042aec33bc26sm1328775jai.18.2023.07.12.09.20.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Jul 2023 09:20:31 -0700 (PDT) From: Jens Axboe To: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, andres@anarazel.de, Jens Axboe Subject: [PATCH 6/8] futex: make futex_parse_waitv() available as a helper Date: Wed, 12 Jul 2023 10:20:15 -0600 Message-Id: <20230712162017.391843-7-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230712162017.391843-1-axboe@kernel.dk> References: <20230712162017.391843-1-axboe@kernel.dk> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" To make it more generically useful, augment it with allowing the caller to pass in the wake handler and wake data. Convert the futex_waitv() syscall, passing in the default handlers. Signed-off-by: Jens Axboe --- kernel/futex/futex.h | 5 +++++ kernel/futex/syscalls.c | 14 ++++++++++---- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index 24180a95bdc8..f6598d8451fb 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -285,6 +285,11 @@ struct futex_vector { struct futex_q q; }; =20 +extern int futex_parse_waitv(struct futex_vector *futexv, + struct futex_waitv __user *uwaitv, + unsigned int nr_futexes, futex_wake_fn *wake, + void *wake_data); + extern int futex_wait_multiple(struct futex_vector *vs, unsigned int count, struct hrtimer_sleeper *to); =20 diff --git a/kernel/futex/syscalls.c b/kernel/futex/syscalls.c index 0b63d5bcdc77..fc3cdd0fefab 100644 --- a/kernel/futex/syscalls.c +++ b/kernel/futex/syscalls.c @@ -184,12 +184,15 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, = u32, val, * @futexv: Kernel side list of waiters to be filled * @uwaitv: Userspace list to be parsed * @nr_futexes: Length of futexv + * @wake: Wake to call when futex is woken + * @wake_data: Data for the wake handler * * Return: Error code on failure, 0 on success */ -static int futex_parse_waitv(struct futex_vector *futexv, - struct futex_waitv __user *uwaitv, - unsigned int nr_futexes) +int futex_parse_waitv(struct futex_vector *futexv, + struct futex_waitv __user *uwaitv, + unsigned int nr_futexes, futex_wake_fn *wake, + void *wake_data) { struct futex_waitv aux; unsigned int i; @@ -208,6 +211,8 @@ static int futex_parse_waitv(struct futex_vector *futex= v, futexv[i].w.val =3D aux.val; futexv[i].w.uaddr =3D aux.uaddr; futexv[i].q =3D futex_q_init; + futexv[i].q.wake =3D wake; + futexv[i].q.wake_data =3D wake_data; } =20 return 0; @@ -284,7 +289,8 @@ SYSCALL_DEFINE5(futex_waitv, struct futex_waitv __user = *, waiters, goto destroy_timer; } =20 - ret =3D futex_parse_waitv(futexv, waiters, nr_futexes); + ret =3D futex_parse_waitv(futexv, waiters, nr_futexes, futex_wake_mark, + NULL); if (!ret) ret =3D futex_wait_multiple(futexv, nr_futexes, timeout ? 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This is in preparation for wiring up vectored waits in io_uring. Signed-off-by: Jens Axboe --- kernel/futex/futex.h | 5 +++++ kernel/futex/waitwake.c | 10 +++++----- 2 files changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index f6598d8451fb..4d73d2978e50 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -290,6 +290,11 @@ extern int futex_parse_waitv(struct futex_vector *fute= xv, unsigned int nr_futexes, futex_wake_fn *wake, void *wake_data); =20 +extern int futex_wait_multiple_setup(struct futex_vector *vs, int count, + int *woken); + +extern int futex_unqueue_multiple(struct futex_vector *v, int count); + extern int futex_wait_multiple(struct futex_vector *vs, unsigned int count, struct hrtimer_sleeper *to); =20 diff --git a/kernel/futex/waitwake.c b/kernel/futex/waitwake.c index f8fb6550061d..0383da9f737f 100644 --- a/kernel/futex/waitwake.c +++ b/kernel/futex/waitwake.c @@ -369,7 +369,7 @@ void futex_wait_queue(struct futex_hash_bucket *hb, str= uct futex_q *q, } =20 /** - * unqueue_multiple - Remove various futexes from their hash bucket + * futex_unqueue_multiple - Remove various futexes from their hash bucket * @v: The list of futexes to unqueue * @count: Number of futexes in the list * @@ -379,7 +379,7 @@ void futex_wait_queue(struct futex_hash_bucket *hb, str= uct futex_q *q, * - >=3D0 - Index of the last futex that was awoken; * - -1 - No futex was awoken */ -static int unqueue_multiple(struct futex_vector *v, int count) +int futex_unqueue_multiple(struct futex_vector *v, int count) { int ret =3D -1, i; =20 @@ -407,7 +407,7 @@ static int unqueue_multiple(struct futex_vector *v, int= count) * - 0 - Success * - <0 - -EFAULT, -EWOULDBLOCK or -EINVAL */ -static int futex_wait_multiple_setup(struct futex_vector *vs, int count, i= nt *woken) +int futex_wait_multiple_setup(struct futex_vector *vs, int count, int *wok= en) { struct futex_hash_bucket *hb; bool retry =3D false; @@ -469,7 +469,7 @@ static int futex_wait_multiple_setup(struct futex_vecto= r *vs, int count, int *wo * was woken, we don't return error and return this index to * userspace */ - *woken =3D unqueue_multiple(vs, i); + *woken =3D futex_unqueue_multiple(vs, i); if (*woken >=3D 0) return 1; =20 @@ -554,7 +554,7 @@ int futex_wait_multiple(struct futex_vector *vs, unsign= ed int count, =20 __set_current_state(TASK_RUNNING); =20 - ret =3D unqueue_multiple(vs, count); + ret =3D futex_unqueue_multiple(vs, count); if (ret >=3D 0) return ret; =20 --=20 2.40.1 From nobody Sat Feb 7 18:15:59 2026 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 701EFC001DE for ; Wed, 12 Jul 2023 16:22:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232346AbjGLQWJ (ORCPT ); Wed, 12 Jul 2023 12:22:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232082AbjGLQVg (ORCPT ); Wed, 12 Jul 2023 12:21:36 -0400 Received: from mail-io1-xd32.google.com (mail-io1-xd32.google.com [IPv6:2607:f8b0:4864:20::d32]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADDB72D65 for ; Wed, 12 Jul 2023 09:20:37 -0700 (PDT) Received: by mail-io1-xd32.google.com with SMTP id ca18e2360f4ac-780c89d1998so65378339f.1 for ; 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charset="utf-8" This adds support for IORING_OP_FUTEX_WAITV, which allows registering a notification for a number of futexes at once. If one of the futexes are woken, then the request will complete with the index of the futex that got woken as the result. This is identical to what the normal vectored futex waitv operation does. Use like IORING_OP_FUTEX_WAIT, except sqe->addr must now contain the a pointer to a struct futex_waitv array, and sqe->off must now contain the number of elements in that array. Waiting on N futexes could be done with IORING_OP_FUTEX_WAIT as well, but that punts a lot of the work to the application: 1) Application would need to submit N IORING_OP_FUTEX_WAIT requests, rather than just a single IORING_OP_FUTEX_WAITV. 2) When one futex is woken, application would need to cancel the remaining N-1 requests that didn't trigger. While this is of course doable, having a single vectored futex wait makes for much simpler application code. Signed-off-by: Jens Axboe --- include/uapi/linux/io_uring.h | 1 + io_uring/futex.c | 164 +++++++++++++++++++++++++++++++--- io_uring/futex.h | 2 + io_uring/opdef.c | 11 +++ 4 files changed, 168 insertions(+), 10 deletions(-) diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 3bd2d765f593..420f38675769 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -238,6 +238,7 @@ enum io_uring_op { IORING_OP_SENDMSG_ZC, IORING_OP_FUTEX_WAIT, IORING_OP_FUTEX_WAKE, + IORING_OP_FUTEX_WAITV, =20 /* this goes last, obviously */ IORING_OP_LAST, diff --git a/io_uring/futex.c b/io_uring/futex.c index fa92ee795c83..df65b8f3593f 100644 --- a/io_uring/futex.c +++ b/io_uring/futex.c @@ -14,11 +14,16 @@ =20 struct io_futex { struct file *file; - u32 __user *uaddr; + union { + u32 __user *uaddr; + struct futex_waitv __user *uwaitv; + }; int futex_op; unsigned int futex_val; unsigned int futex_flags; unsigned int futex_mask; + unsigned int futex_nr; + unsigned long futexv_owned; }; =20 struct io_futex_data { @@ -45,6 +50,13 @@ void io_futex_cache_free(struct io_ring_ctx *ctx) io_alloc_cache_free(&ctx->futex_cache, io_futex_cache_entry_free); } =20 +static void __io_futex_complete(struct io_kiocb *req, struct io_tw_state *= ts) +{ + req->async_data =3D NULL; + hlist_del_init(&req->hash_node); + io_req_task_complete(req, ts); +} + static void io_futex_complete(struct io_kiocb *req, struct io_tw_state *ts) { struct io_futex_data *ifd =3D req->async_data; @@ -53,22 +65,59 @@ static void io_futex_complete(struct io_kiocb *req, str= uct io_tw_state *ts) io_tw_lock(ctx, ts); if (!io_alloc_cache_put(&ctx->futex_cache, &ifd->cache)) kfree(ifd); - req->async_data =3D NULL; - hlist_del_init(&req->hash_node); - io_req_task_complete(req, ts); + __io_futex_complete(req, ts); } =20 -static bool __io_futex_cancel(struct io_ring_ctx *ctx, struct io_kiocb *re= q) +static void io_futexv_complete(struct io_kiocb *req, struct io_tw_state *t= s) { - struct io_futex_data *ifd =3D req->async_data; + struct io_futex *iof =3D io_kiocb_to_cmd(req, struct io_futex); + struct futex_vector *futexv =3D req->async_data; + struct io_ring_ctx *ctx =3D req->ctx; + int res =3D 0; =20 - /* futex wake already done or in progress */ - if (!futex_unqueue(&ifd->q)) + io_tw_lock(ctx, ts); + + res =3D futex_unqueue_multiple(futexv, iof->futex_nr); + if (res !=3D -1) + io_req_set_res(req, res, 0); + + kfree(req->async_data); + req->flags &=3D ~REQ_F_ASYNC_DATA; + __io_futex_complete(req, ts); +} + +static bool io_futexv_claimed(struct io_futex *iof) +{ + return test_bit(0, &iof->futexv_owned); +} + +static bool io_futexv_claim(struct io_futex *iof) +{ + if (test_bit(0, &iof->futexv_owned) || + test_and_set_bit(0, &iof->futexv_owned)) return false; + return true; +} + +static bool __io_futex_cancel(struct io_ring_ctx *ctx, struct io_kiocb *re= q) +{ + /* futex wake already done or in progress */ + if (req->opcode =3D=3D IORING_OP_FUTEX_WAIT) { + struct io_futex_data *ifd =3D req->async_data; + + if (!futex_unqueue(&ifd->q)) + return false; + req->io_task_work.func =3D io_futex_complete; + } else { + struct io_futex *iof =3D io_kiocb_to_cmd(req, struct io_futex); + + if (!io_futexv_claim(iof)) + return false; + req->io_task_work.func =3D io_futexv_complete; + } =20 hlist_del_init(&req->hash_node); io_req_set_res(req, -ECANCELED, 0); - req->io_task_work.func =3D io_futex_complete; io_req_task_work_add(req); return true; } @@ -124,7 +173,7 @@ int io_futex_prep(struct io_kiocb *req, const struct io= _uring_sqe *sqe) { struct io_futex *iof =3D io_kiocb_to_cmd(req, struct io_futex); =20 - if (unlikely(sqe->addr2 || sqe->buf_index || sqe->addr3)) + if (unlikely(sqe->buf_index || sqe->addr3)) return -EINVAL; =20 iof->futex_op =3D READ_ONCE(sqe->fd); @@ -135,6 +184,52 @@ int io_futex_prep(struct io_kiocb *req, const struct i= o_uring_sqe *sqe) if (iof->futex_flags & FUTEX_CMD_MASK) return -EINVAL; =20 + iof->futexv_owned =3D 0; + return 0; +} + +static void io_futex_wakev_fn(struct wake_q_head *wake_q, struct futex_q *= q) +{ + struct io_kiocb *req =3D q->wake_data; + struct io_futex *iof =3D io_kiocb_to_cmd(req, struct io_futex); + + if (!io_futexv_claim(iof)) + return; + if (unlikely(!__futex_wake_mark(q))) + return; + + io_req_set_res(req, 0, 0); + req->io_task_work.func =3D io_futexv_complete; + io_req_task_work_add(req); +} + +int io_futexv_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_futex *iof =3D io_kiocb_to_cmd(req, struct io_futex); + struct futex_vector *futexv; + int ret; + + ret =3D io_futex_prep(req, sqe); + if (ret) + return ret; + + iof->futex_nr =3D READ_ONCE(sqe->off); + if (!iof->futex_nr || iof->futex_nr > FUTEX_WAITV_MAX) + return -EINVAL; + + futexv =3D kcalloc(iof->futex_nr, sizeof(*futexv), GFP_KERNEL); + if (!futexv) + return -ENOMEM; + + ret =3D futex_parse_waitv(futexv, iof->uwaitv, iof->futex_nr, + io_futex_wakev_fn, req); + if (ret) { + kfree(futexv); + return ret; + } + + req->flags |=3D REQ_F_ASYNC_DATA; + req->async_data =3D futexv; return 0; } =20 @@ -162,6 +257,55 @@ static struct io_futex_data *io_alloc_ifd(struct io_ri= ng_ctx *ctx) return kmalloc(sizeof(struct io_futex_data), GFP_NOWAIT); } =20 +int io_futex_waitv(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_futex *iof =3D io_kiocb_to_cmd(req, struct io_futex); + struct futex_vector *futexv =3D req->async_data; + struct io_ring_ctx *ctx =3D req->ctx; + int ret, woken =3D -1; + + io_ring_submit_lock(ctx, issue_flags); + + ret =3D futex_wait_multiple_setup(futexv, iof->futex_nr, &woken); + + /* + * The above call leaves us potentially non-running. This is fine + * for the sync syscall as it'll be blocking unless we already got + * one of the futexes woken, but it obviously won't work for an async + * invocation. Mark is runnable again. + */ + __set_current_state(TASK_RUNNING); + + /* + * We got woken while setting up, let that side do the completion + */ + if (io_futexv_claimed(iof)) { +skip: + io_ring_submit_unlock(ctx, issue_flags); + return IOU_ISSUE_SKIP_COMPLETE; + } + + /* + * 0 return means that we successfully setup the waiters, and that + * nobody triggered a wakeup while we were doing so. < 0 or 1 return + * is either an error or we got a wakeup while setting up. + */ + if (!ret) { + hlist_add_head(&req->hash_node, &ctx->futex_list); + goto skip; + } + + io_ring_submit_unlock(ctx, issue_flags); + if (ret < 0) + req_set_fail(req); + else if (woken !=3D -1) + ret =3D woken; + io_req_set_res(req, ret, 0); + kfree(futexv); + req->flags &=3D ~REQ_F_ASYNC_DATA; + return IOU_OK; +} + int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags) { struct io_futex *iof =3D io_kiocb_to_cmd(req, struct io_futex); diff --git a/io_uring/futex.h b/io_uring/futex.h index ddc9e0d73c52..7828e27e4184 100644 --- a/io_uring/futex.h +++ b/io_uring/futex.h @@ -3,7 +3,9 @@ #include "cancel.h" =20 int io_futex_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); +int io_futexv_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe); int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags); +int io_futex_waitv(struct io_kiocb *req, unsigned int issue_flags); int io_futex_wake(struct io_kiocb *req, unsigned int issue_flags); =20 #if defined(CONFIG_FUTEX) diff --git a/io_uring/opdef.c b/io_uring/opdef.c index c9f23c21a031..2034acfe10d0 100644 --- a/io_uring/opdef.c +++ b/io_uring/opdef.c @@ -443,6 +443,14 @@ const struct io_issue_def io_issue_defs[] =3D { .issue =3D io_futex_wake, #else .prep =3D io_eopnotsupp_prep, +#endif + }, + [IORING_OP_FUTEX_WAITV] =3D { +#if defined(CONFIG_FUTEX) + .prep =3D io_futexv_prep, + .issue =3D io_futex_waitv, +#else + .prep =3D io_eopnotsupp_prep, #endif }, }; @@ -670,6 +678,9 @@ const struct io_cold_def io_cold_defs[] =3D { [IORING_OP_FUTEX_WAKE] =3D { .name =3D "FUTEX_WAKE", }, + [IORING_OP_FUTEX_WAITV] =3D { + .name =3D "FUTEX_WAITV", + }, }; =20 const char *io_uring_get_opcode(u8 opcode) --=20 2.40.1