From patchwork Thu Sep 21 18:29:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jens Axboe X-Patchwork-Id: 13394286 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 D45C3E7D0AC for ; Thu, 21 Sep 2023 18:37:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229925AbjIUShs (ORCPT ); Thu, 21 Sep 2023 14:37:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35350 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229799AbjIUShR (ORCPT ); Thu, 21 Sep 2023 14:37:17 -0400 Received: from mail-il1-x131.google.com (mail-il1-x131.google.com [IPv6:2607:f8b0:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4B603D7DB6 for ; Thu, 21 Sep 2023 11:29:17 -0700 (PDT) Received: by mail-il1-x131.google.com with SMTP id e9e14a558f8ab-34e1757fe8fso1016745ab.0 for ; Thu, 21 Sep 2023 11:29:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1695320956; x=1695925756; 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=V5m39pK9Sy+s98BPtXb5MPOzqgjCaZT2iuuWI0t83mc=; b=pbeT1sbpkNh70vmMi3c2YLE6X/cRjVCPHP3VLnlyOgV6DtqthEfXH5xxiCUWNyq/aO Uev+MjFXqt/oSR+daovj2eWyBPsl3J/V3e7S4RjbmQ0mEYo65rVU1Faks5HvQjJ8yxm2 wjApNCrR206ws+T0WdYaGkPQoFRu59KCbABM+wp9dRYj2m6dPNeOsW/kFJyYjtoHE6Td 8chLc/WsroHdM7R3Nwb+37BgSrs1iijFll/osPXPuPQQsxBMY3bTCFNqjpuxqmLndUGW JgH/SYxLnTbYMyePJU1yjHhAmuhxwZSJiPznc9pjH3UKrnHOZDgsnnMXfPgxTLf2a+wH +jjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1695320956; x=1695925756; 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=V5m39pK9Sy+s98BPtXb5MPOzqgjCaZT2iuuWI0t83mc=; b=nPodgUEzibZNLu+UYcvMYg4Va3O2yf3UgcuQEyLw1cMlNRW/rwtIgtUtd62KY453Bf yUuo41uoN+tAq6PDn0XF47QS+qk8cyffu2WmRRtzpLgDZJAh44pcjq9OO/wOcidUusSa 4qhZrrHArf1ZMR572DvmcaqgwOtKuwyoOQzctpp3m/xZ8PEDZz5a1Yv50H3Of4q4jZiA pNVEi+sQ/pT+R9xwz5lQkURQH8Lg79UMR9UBUZFxI6oFrlQvdu3IjRDdywzoNiWjBQz0 F7Y4309hldRiaRQkOBTpUXK0IIuwOyV67AX65M05/I4KCvdrt/MeaHHYNvknP83RKopr chgQ== X-Gm-Message-State: AOJu0YzIlbeSkpmBCXnSbdzARzL8eE0JNjwQxPrKe+rkjuRsu8KcEAv7 ZYAxDEtxwH996VRWfukdN/ipyRazXpER7ysa3IyJuA== X-Google-Smtp-Source: AGHT+IGqEzddFnDbKkDtYGA8ktTswxfUZvEcKcJvZukcbX41+WzSSJZjWINRWy9kHKvClMEuc2TsUQ== X-Received: by 2002:a05:6602:4996:b0:79a:c487:2711 with SMTP id eg22-20020a056602499600b0079ac4872711mr7316666iob.0.1695320956283; Thu, 21 Sep 2023 11:29:16 -0700 (PDT) Received: from localhost.localdomain ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id o25-20020a02c6b9000000b0042b227eb1ddsm500441jan.55.2023.09.21.11.29.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Sep 2023 11:29:15 -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 2/8] futex: factor out the futex wake handling Date: Thu, 21 Sep 2023 12:29:02 -0600 Message-Id: <20230921182908.160080-3-axboe@kernel.dk> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230921182908.160080-1-axboe@kernel.dk> References: <20230921182908.160080-1-axboe@kernel.dk> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org 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 | 5 +++++ kernel/futex/requeue.c | 3 ++- kernel/futex/waitwake.c | 6 +++--- 3 files changed, 10 insertions(+), 4 deletions(-) diff --git a/kernel/futex/futex.h b/kernel/futex/futex.h index a173a9d501e1..547f509b2c87 100644 --- a/kernel/futex/futex.h +++ b/kernel/futex/futex.h @@ -139,11 +139,15 @@ struct futex_pi_state { union futex_key key; } __randomize_layout; +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 * @task: the task waiting on the futex * @lock_ptr: the hash bucket lock + * @wake: the wake handler for this queue * @key: the key the futex is hashed on * @pi_state: optional priority inheritance state * @rt_waiter: rt_waiter storage for use with requeue_pi @@ -168,6 +172,7 @@ struct futex_q { 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 a0a79954f506..9dc789399a1a 100644 --- a/kernel/futex/requeue.c +++ b/kernel/futex/requeue.c @@ -58,6 +58,7 @@ enum { const struct futex_q futex_q_init = { /* list gets initialized in futex_queue()*/ + .wake = futex_wake_mark, .key = FUTEX_KEY_INIT, .bitset = FUTEX_BITSET_MATCH_ANY, .requeue_state = ATOMIC_INIT(Q_REQUEUE_PI_NONE), @@ -593,7 +594,7 @@ int futex_requeue(u32 __user *uaddr1, unsigned int flags1, /* Plain futexes just wake or requeue and are done */ if (!requeue_pi) { if (++task_count <= 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 37860f794bf7..35c6a637a4bb 100644 --- a/kernel/futex/waitwake.c +++ b/kernel/futex/waitwake.c @@ -177,7 +177,7 @@ int futex_wake(u32 __user *uaddr, unsigned int flags, int nr_wake, u32 bitset) if (!(this->bitset & bitset)) continue; - futex_wake_mark(&wake_q, this); + this->wake(&wake_q, this); if (++ret >= nr_wake) break; } @@ -292,7 +292,7 @@ int futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2, ret = -EINVAL; goto out_unlock; } - futex_wake_mark(&wake_q, this); + this->wake(&wake_q, this); if (++ret >= nr_wake) break; } @@ -306,7 +306,7 @@ int futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2, ret = -EINVAL; goto out_unlock; } - futex_wake_mark(&wake_q, this); + this->wake(&wake_q, this); if (++op_ret >= nr_wake2) break; }