From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EF1304E1C5 for ; Mon, 18 Mar 2024 15:16:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710774993; cv=none; b=L9D41ru79t4U6uUpmlIxQIvKpC2TZajUu4YDio7bU6GaMLgoWJGSaLv8T0lx9hqtUOr8srH9KNKfMVu/il8ETbNR2NcJvbwlXjx136m8F4yBXR99s9fI0VNM4/iltLLjvhKM3ASTySwiC2G9rkZR8bcVDHN2GsfX1FWIPIpmNtc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710774993; c=relaxed/simple; bh=YYwlLFQIKS5jC/UjzgUAT6+CqrDlx+LxdURF7l5gdjA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=HSVWAcJXc1HN61GsEZH27nKxTL2TJfKCbTeeasDLkpaI65oKf5b+fxAuh7lf/4v/3+4LfUHX09H14sJqrwYuwpOw01IRNh/iSPrJ+IvnQ7XvOOjuMzEw9YZd6T9maKSEKCklHZn4rQ8k6WdTtK7KzWgyRgTyMLQKXx6JqFk82W0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=ZpBNhSp4; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ZpBNhSp4" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1710774990; 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: in-reply-to:in-reply-to:references:references; bh=5d8KKCyDnnQqane9SYeUcl91rFpck1EhD3b2JjE0D/I=; b=ZpBNhSp4Yv0jHVFUrkK6gav71IlBrVhOCALqi8HJUwKOWhLuVkTOg8kZcmM4poBIOU7b0A xHjPdvkfdwBMCu1EAr+NOS9ORZRDmefkuqJfka4Q8odAggAx/AULqjfUWTCuQ8MzAoupnL QPr7RxF5Hu4gTMVrAZ8jHU+hpu4s8rE= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-427-lb57AxChMPa0p5KFy760Vw-1; Mon, 18 Mar 2024 11:16:26 -0400 X-MC-Unique: lb57AxChMPa0p5KFy760Vw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 49D982803054; Mon, 18 Mar 2024 15:16:26 +0000 (UTC) Received: from fedora (unknown [10.72.116.15]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EC8A210F53; Mon, 18 Mar 2024 15:16:22 +0000 (UTC) Date: Mon, 18 Mar 2024 23:16:14 +0800 From: Ming Lei To: Pavel Begunkov Cc: io-uring@vger.kernel.org, linux-block@vger.kernel.org, Jens Axboe , Kanchan Joshi Subject: Re: [PATCH v2 05/14] ublk: don't hard code IO_URING_F_UNLOCKED Message-ID: References: <61b29658-e6a9-449f-a850-1881af1ecbee@gmail.com> <5025d814-fad3-41da-a5ea-d5bf58c0d292@gmail.com> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5025d814-fad3-41da-a5ea-d5bf58c0d292@gmail.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 On Mon, Mar 18, 2024 at 03:08:19PM +0000, Pavel Begunkov wrote: > On 3/18/24 14:34, Ming Lei wrote: > > On Mon, Mar 18, 2024 at 12:52:33PM +0000, Pavel Begunkov wrote: > > > On 3/18/24 08:16, Ming Lei wrote: > > > > On Mon, Mar 18, 2024 at 12:41:50AM +0000, Pavel Begunkov wrote: > > > > > uring_cmd implementations should not try to guess issue_flags, just use > > > > > a newly added io_uring_cmd_complete(). We're loosing an optimisation in > > > > > the cancellation path in ublk_uring_cmd_cancel_fn(), but the assumption > > > > > is that we don't care that much about it. > > > > > > > > > > Signed-off-by: Pavel Begunkov > > > > > Link: https://lore.kernel.org/r/2f7bc9fbc98b11412d10b8fd88e58e35614e3147.1710514702.git.asml.silence@gmail.com > > > > > Signed-off-by: Jens Axboe > > > > > --- > > > > > drivers/block/ublk_drv.c | 18 ++++++++---------- > > > > > 1 file changed, 8 insertions(+), 10 deletions(-) > > > > > > > > > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > > > > > index bea3d5cf8a83..97dceecadab2 100644 > > > > > --- a/drivers/block/ublk_drv.c > > > > > +++ b/drivers/block/ublk_drv.c > > > > > @@ -1417,8 +1417,7 @@ static bool ublk_abort_requests(struct ublk_device *ub, struct ublk_queue *ubq) > > > > > return true; > > > > > } > > > > > -static void ublk_cancel_cmd(struct ublk_queue *ubq, struct ublk_io *io, > > > > > - unsigned int issue_flags) > > > > > +static void ublk_cancel_cmd(struct ublk_queue *ubq, struct ublk_io *io) > > > > > { > > > > > bool done; > > > > > @@ -1432,15 +1431,14 @@ static void ublk_cancel_cmd(struct ublk_queue *ubq, struct ublk_io *io, > > > > > spin_unlock(&ubq->cancel_lock); > > > > > if (!done) > > > > > - io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0, issue_flags); > > > > > + io_uring_cmd_complete(io->cmd, UBLK_IO_RES_ABORT, 0); > > > > > } > > > > > /* > > > > > * The ublk char device won't be closed when calling cancel fn, so both > > > > > * ublk device and queue are guaranteed to be live > > > > > */ > > > > > -static void ublk_uring_cmd_cancel_fn(struct io_uring_cmd *cmd, > > > > > - unsigned int issue_flags) > > > > > +static void ublk_uring_cmd_cancel_fn(struct io_uring_cmd *cmd) > > > > > { > > > > > struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd); > > > > > struct ublk_queue *ubq = pdu->ubq; > > > > > @@ -1464,7 +1462,7 @@ static void ublk_uring_cmd_cancel_fn(struct io_uring_cmd *cmd, > > > > > io = &ubq->ios[pdu->tag]; > > > > > WARN_ON_ONCE(io->cmd != cmd); > > > > > - ublk_cancel_cmd(ubq, io, issue_flags); > > > > > + ublk_cancel_cmd(ubq, io); > > > > > > > > .cancel_fn is always called with .uring_lock held, so this 'issue_flags' can't > > > > be removed, otherwise double task run is caused because .cancel_fn > > > > can be called multiple times if the request stays in ctx->cancelable_uring_cmd. > > > > > > I see, that's exactly why I was asking whether it can be deferred > > > to tw. Let me see if I can get by without that patch, but honestly > > > it's a horrible abuse of the ring state. Any ideas how that can be > > > cleaned up? > > > > Simply deferring io_uring_cmd_done() in ublk_cancel_cmd() to tw still triggers > > warning in __put_task_struct(), so I'd suggest to add the patch until > > it is root-cause & fixed. > > I mean drop the patch[es] changing how ublk passes issue_flags > around, moving cancellation point and all related, and leave it > to later really hoping we'll figure how to do it better. Looks fine for me. Thanks, Ming