Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [Xen-devel] [PATCH 2/4] xenbus: limit when state is forced to
 closed
To:     =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= <roger.pau@citrix.com>,
        Paul Durrant <pdurrant@amazon.com>
Cc:     linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org,
        Stefano Stabellini <sstabellini@kernel.org>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>
References: <20191205140123.3817-1-pdurrant@amazon.com>
 <20191205140123.3817-3-pdurrant@amazon.com>
 <20191209113926.GS980@Air-de-Roger>
From:   =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= <jgross@suse.com>
Message-ID: <b8a138ad-5770-65fa-f368-f7b4063702fa@suse.com>
Date:   Mon, 9 Dec 2019 12:55:01 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.2.1
MIME-Version: 1.0
In-Reply-To: <20191209113926.GS980@Air-de-Roger>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 09.12.19 12:39, Roger Pau Monné wrote:
> On Thu, Dec 05, 2019 at 02:01:21PM +0000, Paul Durrant wrote:
>> Only force state to closed in the case when the toolstack may need to
>> clean up. This can be detected by checking whether the state in xenstore
>> has been set to closing prior to device removal.
> 
> I'm not sure I see the point of this, I would expect that a failure to
> probe or the removal of the device would leave the xenbus state as
> closed, which is consistent with the actual driver state.
> 
> Can you explain what's the benefit of leaving a device without a
> driver in such unknown state?

And more concerning: did you check that no frontend/backend is
relying on the closed state to be visible without closing having been
set before?


Juergen