From patchwork Mon Jun 20 16:18:57 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dylan Yudaken X-Patchwork-Id: 12887915 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 5594CC43334 for ; Mon, 20 Jun 2022 16:19:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244275AbiFTQTV (ORCPT ); Mon, 20 Jun 2022 12:19:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242819AbiFTQTS (ORCPT ); Mon, 20 Jun 2022 12:19:18 -0400 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 574501A07B for ; Mon, 20 Jun 2022 09:19:16 -0700 (PDT) Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 25KFIAGl016391 for ; Mon, 20 Jun 2022 09:19:15 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=lV4lzCY349TFdxkrXcpzKogMmM0TixG1Hc+Ol5ZaWko=; b=jxY7065UKg8vPQdYbA5EbZ/lRGQgp2vX7asRlr9saOn1tcDxM5JV1pHi1Mo6wkMP8oaL 3D/Cog4OuIajELjfWyWXwVQOonUvX2yF02593rb7CxraXpFyx1gVCTeLcG6QWs6v/oNa SDsTkvBOtcqKP8r/a1z76Zc1+3pFhz71h0o= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3gsc7wsr12-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 20 Jun 2022 09:19:15 -0700 Received: from twshared18317.08.ash9.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.28; Mon, 20 Jun 2022 09:19:14 -0700 Received: by devbig038.lla2.facebook.com (Postfix, from userid 572232) id 919561EB9440; Mon, 20 Jun 2022 09:19:05 -0700 (PDT) From: Dylan Yudaken To: , , CC: , Dylan Yudaken Subject: [PATCH RFC for-next 4/8] io_uring: introduce llist helpers Date: Mon, 20 Jun 2022 09:18:57 -0700 Message-ID: <20220620161901.1181971-5-dylany@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220620161901.1181971-1-dylany@fb.com> References: <20220620161901.1181971-1-dylany@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: 7gjwVQcCe6ZY6wtkLJESmPeW_1pDUDXF X-Proofpoint-ORIG-GUID: 7gjwVQcCe6ZY6wtkLJESmPeW_1pDUDXF X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.64.514 definitions=2022-06-20_05,2022-06-17_01,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Introduce helpers to atomically switch llist. Will later move this into common code Signed-off-by: Dylan Yudaken --- io_uring/io_uring.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index 985b46dfebb6..eb29e3f7da5c 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1009,6 +1009,36 @@ static void handle_tw_list(struct llist_node *node, } while (node); } +/** + * io_llist_xchg - swap all entries in a lock-less list + * @head: the head of lock-less list to delete all entries + * @new: new entry as the head of the list + * + * If list is empty, return NULL, otherwise, return the pointer to the first entry. + * The order of entries returned is from the newest to the oldest added one. + */ +static inline struct llist_node *io_llist_xchg(struct llist_head *head, + struct llist_node *node) +{ + return xchg(&head->first, node); +} + +/** + * io_llist_xchg - possibly swap all entries in a lock-less list + * @head: the head of lock-less list to delete all entries + * @old: expected old value of the first entry of the list + * @new: new entry as the head of the list + * + * perform a cmpxchg on the first entry of the list. + */ + +static inline struct llist_node *io_llist_cmpxchg(struct llist_head *head, + struct llist_node *old, + struct llist_node *new) +{ + return cmpxchg(&head->first, old, new); +} + void tctx_task_work(struct callback_head *cb) { bool uring_locked = false;