From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from submarine.notk.org (submarine.notk.org [62.210.214.84]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 862B81D151F for ; Thu, 21 Nov 2024 12:24:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=62.210.214.84 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732191865; cv=none; b=PspdGkwiTxUqluSDZgQZU3e0JNEWNtXRe54ivECWjYAiIo8L0RVubAl9FlWEbD8dMhfTDtjUbgMm1i/G3zI+ezHdbjU5+vxV4KftJBO/hxCJGROEhrLzfICzI8ydBK1zZxalxpYyes5UeAZ/JijZnstcVm0yswdJPgAWDj6UXCs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732191865; c=relaxed/simple; bh=JAGQsSxLiuGZvcrXGZmcaTgiPUwgdxEE2rkDW2GHEEQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=c3H8iUGHxJnAaC4I5FxEInE/KCh5eCget5MeqmlRvRH8zkn6opdohgPMwEYI1YKeeMltCG1R+9FVcKT1CKJskoZbKNDqPdSvHmC2Qp6k5yAmx0G1jyL55bU13PCOB8Tf2CqCjWVMNG29fudfUSRWjm+NntaUslCOQYvYklE7lp4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org; spf=pass smtp.mailfrom=codewreck.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b=yxoUOOXy; arc=none smtp.client-ip=62.210.214.84 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=codewreck.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=codewreck.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=codewreck.org header.i=@codewreck.org header.b="yxoUOOXy" Received: from gaia.codewreck.org (localhost [127.0.0.1]) by submarine.notk.org (Postfix) with ESMTPS id B831D14C1E1; Thu, 21 Nov 2024 13:24:12 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=codewreck.org; s=2; t=1732191855; 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=xHgJ4eJ5XwEZ8MzTd18+kcOaEGlva/2F8o2ACTeVRNM=; b=yxoUOOXyCcnrIh5MIGLKt+gFezI6s3szXY5vlOZNbxeXF6Gzn4daTY6w5q/yYvMcYaa60+ plYDZWqx/gIwpHnaPuMpWb73F4XS3RvEAUfi1IMJQYN7Fi1mo5op7fhaFAtV+D6d+xlE0j hJzfNaUXbNgN9cuSH5NixX1sBzWD2Jj2rbeW0kOdVUvNEBkdTXq5ZGsGoOgG1rDp43DLK9 T5l/xFT2+d3oomX4FHO1rNan20HsNAcRuC42xVDU6QuaadI8HISO4Y0cwhZUdykraEFaH3 PzT0H+Z+XH969qj/PL0KJK2SFq3wfPlmyWOgO/xK2WiA40MyaH/qe1gjDQlDWg== Received: from localhost (gaia.codewreck.org [local]) by gaia.codewreck.org (OpenSMTPD) with ESMTPA id 4797f817; Thu, 21 Nov 2024 12:24:11 +0000 (UTC) Date: Thu, 21 Nov 2024 21:23:55 +0900 From: Dominique Martinet To: Alexander Merritt Cc: v9fs@lists.linux.dev, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, Eric Van Hensbergen , Latchesar Ionkov , Christian Schoenebeck , Simon Horman , Juergen Gross , Alex Zenla , Ariadne Conill Subject: Re: [PATCH] 9p/xen: fix init sequence Message-ID: References: <20241119211633.38321-1-alexander@edera.dev> Precedence: bulk X-Mailing-List: v9fs@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20241119211633.38321-1-alexander@edera.dev> Alexander Merritt wrote on Tue, Nov 19, 2024 at 09:16:33PM +0000: > From: Alex Zenla > > Large amount of mount hangs observed during hotplugging of 9pfs devices. The > 9pfs Xen driver attempts to initialize itself more than once, causing the > frontend and backend to disagree: the backend listens on a channel that the > frontend does not send on, resulting in stalled processing. > > Only allow initialization of 9p frontend once. I'm not familiar with the xen bringup so I don't understand how the patch guarantees this -- otherend_changed calls are guaranted to be seralized for a given frontend? I guess that at least it guaratees that we won't restart the init process after init's been done on our side and before the remote side sends the ack, so if you've all tested this I'll just trust you and Juergen's review and take it as an improvement. Queued to 9p-next; will send this to Linus in ~1week Thanks! -- Dominique