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 86422C43334 for ; Wed, 15 Jun 2022 09:42:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343756AbiFOJmN (ORCPT ); Wed, 15 Jun 2022 05:42:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243260AbiFOJmM (ORCPT ); Wed, 15 Jun 2022 05:42:12 -0400 Received: from out1.migadu.com (out1.migadu.com [91.121.223.63]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F9063ED17 for ; Wed, 15 Jun 2022 02:42:11 -0700 (PDT) Message-ID: <40197f84-35e3-4e37-fe73-3c7f4c21d513@linux.dev> DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1655286129; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=kMHZ5mKGNISuDqc9lZA1yW24W1DL0prBq14Ki65hun8=; b=je9FyEQWHoHQ+q96G8g0kNDZw5G5tSQgZsXmaQGc/nDGeBdfiYtaaKwH7RjFvdotX0rsjM hvOGR3o7fHuaTYh+4z5u2ibEc28QnhA+E74a7937w42vOs588eqOejA9WYuceggMrYqK5e io72NxRo8a3Ev8+brYegvRp/0RUSbVo= Date: Wed, 15 Jun 2022 17:41:57 +0800 MIME-Version: 1.0 Subject: Re: [PATCH for-next v2 21/25] io_uring: add IORING_SETUP_SINGLE_ISSUER Content-Language: en-US To: Pavel Begunkov , io-uring@vger.kernel.org Cc: Jens Axboe References: X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Hao Xu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On 6/14/22 22:37, Pavel Begunkov wrote: > Add a new IORING_SETUP_SINGLE_ISSUER flag and the userspace visible part > of it, i.e. put limitations of submitters. Also, don't allow it together > with IOPOLL as we're not going to put it to good use. > > Signed-off-by: Pavel Begunkov > --- > include/uapi/linux/io_uring.h | 5 ++++- > io_uring/io_uring.c | 7 +++++-- > io_uring/io_uring_types.h | 1 + > io_uring/tctx.c | 27 ++++++++++++++++++++++++--- > io_uring/tctx.h | 4 ++-- > 5 files changed, 36 insertions(+), 8 deletions(-) > > diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h > index a41ddb8c5e1f..a3a691340d3e 100644 > --- a/include/uapi/linux/io_uring.h > +++ b/include/uapi/linux/io_uring.h > @@ -138,9 +138,12 @@ enum { > * IORING_SQ_TASKRUN in the sq ring flags. Not valid with COOP_TASKRUN. > */ > #define IORING_SETUP_TASKRUN_FLAG (1U << 9) > - > #define IORING_SETUP_SQE128 (1U << 10) /* SQEs are 128 byte */ > #define IORING_SETUP_CQE32 (1U << 11) /* CQEs are 32 byte */ > +/* > + * Only one task is allowed to submit requests > + */ > +#define IORING_SETUP_SINGLE_ISSUER (1U << 12) > > enum io_uring_op { > IORING_OP_NOP, > diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c > index 15d209f334eb..4b90439808e3 100644 > --- a/io_uring/io_uring.c > +++ b/io_uring/io_uring.c > @@ -3020,6 +3020,8 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx) > io_destroy_buffers(ctx); > if (ctx->sq_creds) > put_cred(ctx->sq_creds); > + if (ctx->submitter_task) > + put_task_struct(ctx->submitter_task); > > /* there are no registered resources left, nobody uses it */ > if (ctx->rsrc_node) > @@ -3752,7 +3754,7 @@ static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file) > if (fd < 0) > return fd; > > - ret = io_uring_add_tctx_node(ctx); > + ret = __io_uring_add_tctx_node(ctx, false); > if (ret) { > put_unused_fd(fd); > return ret; > @@ -3972,7 +3974,8 @@ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) > IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ | > IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL | > IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG | > - IORING_SETUP_SQE128 | IORING_SETUP_CQE32)) > + IORING_SETUP_SQE128 | IORING_SETUP_CQE32 | > + IORING_SETUP_SINGLE_ISSUER)) > return -EINVAL; > > return io_uring_create(entries, &p, params); > diff --git a/io_uring/io_uring_types.h b/io_uring/io_uring_types.h > index aba0f8cd6f49..f6d0ad25f377 100644 > --- a/io_uring/io_uring_types.h > +++ b/io_uring/io_uring_types.h > @@ -241,6 +241,7 @@ struct io_ring_ctx { > /* Keep this last, we don't need it for the fast path */ > > struct io_restriction restrictions; > + struct task_struct *submitter_task; > > /* slow path rsrc auxilary data, used by update/register */ > struct io_rsrc_node *rsrc_backup_node; > diff --git a/io_uring/tctx.c b/io_uring/tctx.c > index 6adf659687f8..012be261dc50 100644 > --- a/io_uring/tctx.c > +++ b/io_uring/tctx.c > @@ -81,12 +81,32 @@ __cold int io_uring_alloc_task_context(struct task_struct *task, > return 0; > } > > -int __io_uring_add_tctx_node(struct io_ring_ctx *ctx) > +static int io_register_submitter(struct io_ring_ctx *ctx) > +{ > + int ret = 0; > + > + mutex_lock(&ctx->uring_lock); > + if (!ctx->submitter_task) > + ctx->submitter_task = get_task_struct(current); > + else if (ctx->submitter_task != current) > + ret = -EEXIST; > + mutex_unlock(&ctx->uring_lock); > + > + return ret; > +} Seems we don't need this uring_lock: When we create a ring, we setup ctx->submitter_task before uring fd is installed so at that time nobody else can enter this code. when we enter this code later in io_uring_enter, we just read it.