From mboxrd@z Thu Jan 1 00:00:00 1970 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 1D6D1C05027 for ; Wed, 15 Feb 2023 00:42:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229920AbjBOAma (ORCPT ); Tue, 14 Feb 2023 19:42:30 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229726AbjBOAm2 (ORCPT ); Tue, 14 Feb 2023 19:42:28 -0500 Received: from out3-smtp.messagingengine.com (out3-smtp.messagingengine.com [66.111.4.27]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1ED0529421; Tue, 14 Feb 2023 16:42:27 -0800 (PST) Received: from compute2.internal (compute2.nyi.internal [10.202.2.46]) by mailout.nyi.internal (Postfix) with ESMTP id B1A945C00DB; Tue, 14 Feb 2023 19:42:24 -0500 (EST) Received: from mailfrontend1 ([10.202.2.162]) by compute2.internal (MEProxy); Tue, 14 Feb 2023 19:42:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= joshtriplett.org; h=cc:cc:content-type:date:date:from:from :in-reply-to:message-id:mime-version:reply-to:sender:subject :subject:to:to; s=fm3; t=1676421744; x=1676508144; bh=DHhH1JoeiX 66EERg5p8H+9Bmcu5xlKhXQD6vz214Iuk=; b=hjNr/+igREIXtgBg3t9yDPlab7 T9xJPiiYCfcJ3zYXvQYIvHq0ey6AhKl7lajTVhbsU1cBcnYjCgIOS3Ti2f8M3EAH uK+hyF9G9yGVW57dsV86CRn7QQ3ouyXFp9dCPOWwVJ+vblxwpOiTDeM25zQxHxrz H1gARUO8LFsbSfqyYHBphpFiQWcdrGMw+H/r8rGsb3dHrs7t/POVAmgkaanOu/55 67V2MeqEnIM3rAfJxTng0m4kXP5P9yxs+88SCAITyJLAQugRwuW9DZY28HRDholN 7PN0Iss3ClD1uAiGKBZr+0gXTQ0+BArEgdVGE5rojKL7tBesHTGr5NNCzwqg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:date:date:feedback-id :feedback-id:from:from:in-reply-to:message-id:mime-version :reply-to:sender:subject:subject:to:to:x-me-proxy:x-me-proxy :x-me-sender:x-me-sender:x-sasl-enc; s=fm1; t=1676421744; x= 1676508144; bh=DHhH1JoeiX66EERg5p8H+9Bmcu5xlKhXQD6vz214Iuk=; b=M zEvoM8ZQOezxFY3E1zOLZfw5zN2PrbqpRCU1CA8fvIfqokKLQy6HgbK60cbyBPdg k3v/jhe5BSYr6KTMzwZifuVgHm/e5kEmfPviqxHSd1tNafqMQJ8+FSPb/OqEQ5Cq XFOWO3SfvGSEDFMJSNEd584u7G4g6Xs32RDrFKEuUeMJmDF4jZio7K8HW0V+u/K6 eRPaIvQAIXCg2LYW3/aHyqkRX0qtUmJb9kO/F22Rewqc5RI/3BcJAVAFgUea5RKE G9p9/OP+oCSvtB6MC2UW33xgt5wOdqpT2IBQ7Ffne2q3XokQcv4LS+VY8H0J6lOo /isN7Ngq4VtBP8IZNujiw== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvhedrudeigedgvdehucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvfevuffkgggtugesthdtredttddtvdenucfhrhhomheplfhoshhhucfv rhhiphhlvghtthcuoehjohhshhesjhhoshhhthhrihhplhgvthhtrdhorhhgqeenucggtf frrghtthgvrhhnpeduvdelheettdfgvddvleegueefudegudevffekjeegffefvdeikeeh vdehleekhfenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmhgrihhlfhhroh hmpehjohhshhesjhhoshhhthhrihhplhgvthhtrdhorhhg X-ME-Proxy: Feedback-ID: i83e94755:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 14 Feb 2023 19:42:23 -0500 (EST) Date: Tue, 14 Feb 2023 16:42:22 -0800 From: Josh Triplett To: Jens Axboe , Pavel Begunkov Cc: io-uring@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCHv2] io_uring: Support calling io_uring_register with a registered ring fd Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Add a new flag IORING_REGISTER_USE_REGISTERED_RING (set via the high bit of the opcode) to treat the fd as a registered index rather than a file descriptor. This makes it possible for a library to open an io_uring, register the ring fd, close the ring fd, and subsequently use the ring entirely via registered index. Signed-off-by: Josh Triplett --- v2: Rebase. Change io_uring_register to extract the flag from the opcode first. include/uapi/linux/io_uring.h | 6 +++++- io_uring/io_uring.c | 34 +++++++++++++++++++++++++++------- 2 files changed, 32 insertions(+), 8 deletions(-) diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 2780bce62faf..35e6f8046b9b 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -470,6 +470,7 @@ struct io_uring_params { #define IORING_FEAT_RSRC_TAGS (1U << 10) #define IORING_FEAT_CQE_SKIP (1U << 11) #define IORING_FEAT_LINKED_FILE (1U << 12) +#define IORING_FEAT_REG_REG_RING (1U << 13) /* * io_uring_register(2) opcodes and arguments @@ -517,7 +518,10 @@ enum { IORING_REGISTER_FILE_ALLOC_RANGE = 25, /* this goes last */ - IORING_REGISTER_LAST + IORING_REGISTER_LAST, + + /* flag added to the opcode to use a registered ring fd */ + IORING_REGISTER_USE_REGISTERED_RING = 1U << 31 }; /* io-wq worker categories */ diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index db623b3185c8..1fb743ecba5a 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -3663,7 +3663,7 @@ static __cold int io_uring_create(unsigned entries, struct io_uring_params *p, IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED | IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS | IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP | - IORING_FEAT_LINKED_FILE; + IORING_FEAT_LINKED_FILE | IORING_FEAT_REG_REG_RING; if (copy_to_user(params, p, sizeof(*p))) { ret = -EFAULT; @@ -4177,17 +4177,37 @@ SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, struct io_ring_ctx *ctx; long ret = -EBADF; struct fd f; + bool use_registered_ring; + + use_registered_ring = !!(opcode & IORING_REGISTER_USE_REGISTERED_RING); + opcode &= ~IORING_REGISTER_USE_REGISTERED_RING; if (opcode >= IORING_REGISTER_LAST) return -EINVAL; - f = fdget(fd); - if (!f.file) - return -EBADF; + if (use_registered_ring) { + /* + * Ring fd has been registered via IORING_REGISTER_RING_FDS, we + * need only dereference our task private array to find it. + */ + struct io_uring_task *tctx = current->io_uring; - ret = -EOPNOTSUPP; - if (!io_is_uring_fops(f.file)) - goto out_fput; + if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX)) + return -EINVAL; + fd = array_index_nospec(fd, IO_RINGFD_REG_MAX); + f.file = tctx->registered_rings[fd]; + f.flags = 0; + if (unlikely(!f.file)) + return -EBADF; + opcode &= ~IORING_REGISTER_USE_REGISTERED_RING; + } else { + f = fdget(fd); + if (unlikely(!f.file)) + return -EBADF; + ret = -EOPNOTSUPP; + if (!io_is_uring_fops(f.file)) + goto out_fput; + } ctx = f.file->private_data; -- 2.39.1