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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 53E7EC433B4 for ; Tue, 11 May 2021 10:41:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1794061932 for ; Tue, 11 May 2021 10:41:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231302AbhEKKmK (ORCPT ); Tue, 11 May 2021 06:42:10 -0400 Received: from out3-smtp.messagingengine.com ([66.111.4.27]:36313 "EHLO out3-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231274AbhEKKmJ (ORCPT ); Tue, 11 May 2021 06:42:09 -0400 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.nyi.internal (Postfix) with ESMTP id A27A35C0153; Tue, 11 May 2021 06:41:02 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute4.internal (MEProxy); Tue, 11 May 2021 06:41:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=eEzsag JXE9j7VxBo+AWmXBF3pphXok7LzgFqbTTuun0=; b=ixCgNh0lNwMsRtRxLx2hRB UzT5a7tnSj8A3K3aN2hRP6BTzJNeXdmsHc9b4a/zoQzdZ9yyypxDPRg7MfbYlZAa kkuU3764t850EhzWsVzrSe0OgRcTwWv79BnG1yRyBi2OXLdk6/MDCzoMBeuD+wUD ZICsyFSPbpssORFFWD4JbFBgr/o1lc8KIq0btOcSKVwT40PXyb/QSd3yuLvG5873 Ur9mvx3OGFcQ7WzBmaXQMXz7fR4Y5LIKFp+wgxG+8K7tOh/FeOje8awSuez58NhD p26x0b6dT6DOk7vjTTTswN0A1oABoyJqkXdN/XW3GiEYJ1cBS3M/Xu3Li6Kau3AA == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrvdehtddgfedvucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepfffhvffukfhfgggtuggjsehgtderredttdejnecuhfhrohhmpeforghrvghk ucforghrtgiihihkohifshhkihdqifpkrhgvtghkihcuoehmrghrmhgrrhgvkhesihhnvh hishhisghlvghthhhinhhgshhlrggsrdgtohhmqeenucggtffrrghtthgvrhhnpeetveff iefghfekhffggeeffffhgeevieektedthfehveeiheeiiedtudegfeetffenucfkpheple durdeijedrjeelrdegnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghi lhhfrhhomhepmhgrrhhmrghrvghksehinhhvihhsihgslhgvthhhihhnghhslhgrsgdrtg homh X-ME-Proxy: Received: from mail-itl (ip5b434f04.dynamic.kabel-deutschland.de [91.67.79.4]) by mail.messagingengine.com (Postfix) with ESMTPA; Tue, 11 May 2021 06:41:00 -0400 (EDT) Date: Tue, 11 May 2021 12:40:54 +0200 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= To: "Durrant, Paul" Cc: Michael Brown , "paul@xen.org" , "xen-devel@lists.xenproject.org" , "netdev@vger.kernel.org" , "wei.liu@kernel.org" Subject: Re: [PATCH] xen-netback: Check for hotplug-status existence before watching Message-ID: References: <54659eec-e315-5dc5-1578-d91633a80077@xen.org> <20210413152512.903750-1-mbrown@fensystems.co.uk> <404130e4-210d-2214-47a8-833c0463d997@fensystems.co.uk> <21f38a92-c8ae-12a7-f1d8-50810c5eb088@fensystems.co.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="p94ypmT+e7ybeaDo" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org --p94ypmT+e7ybeaDo Content-Type: text/plain; protected-headers=v1; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Date: Tue, 11 May 2021 12:40:54 +0200 From: Marek =?utf-8?Q?Marczykowski-G=C3=B3recki?= To: "Durrant, Paul" Cc: Michael Brown , "paul@xen.org" , "xen-devel@lists.xenproject.org" , "netdev@vger.kernel.org" , "wei.liu@kernel.org" Subject: Re: [PATCH] xen-netback: Check for hotplug-status existence before watching On Tue, May 11, 2021 at 07:06:55AM +0000, Durrant, Paul wrote: > > -----Original Message----- > > From: Marek Marczykowski-G=C3=B3recki > > Sent: 10 May 2021 20:43 > > To: Michael Brown ; paul@xen.org > > Cc: paul@xen.org; xen-devel@lists.xenproject.org; netdev@vger.kernel.or= g; wei.liu@kernel.org; Durrant, > > Paul > > Subject: RE: [EXTERNAL] [PATCH] xen-netback: Check for hotplug-status e= xistence before watching > >=20 > > On Mon, May 10, 2021 at 08:06:55PM +0100, Michael Brown wrote: > > > If you have a suggested patch, I'm happy to test that it doesn't rein= troduce > > > the regression bug that was fixed by this commit. > >=20 > > Actually, I've just tested with a simple reloading xen-netfront module.= It > > seems in this case, the hotplug script is not re-executed. In fact, I > > think it should not be re-executed at all, since the vif interface > > remains in place (it just gets NO-CARRIER flag). > >=20 > > This brings a question, why removing hotplug-status in the first place? > > The interface remains correctly configured by the hotplug script after > > all. From the commit message: > >=20 > > xen-netback: remove 'hotplug-status' once it has served its purpose > >=20 > > Removing the 'hotplug-status' node in netback_remove() is wrong; th= e script > > may not have completed. Only remove the node once the watch has fir= ed and > > has been unregistered. > >=20 > > I think the intention was to remove 'hotplug-status' node _later_ in > > case of quickly adding and removing the interface. Is that right, Paul? >=20 > The removal was done to allow unbind/bind to function correctly. IIRC bef= ore the original patch doing a bind would stall forever waiting for the hot= plug status to change, which would never happen. Hmm, in that case maybe don't remove it at all in the backend, and let it be cleaned up by the toolstack, when it removes other backend-related nodes? --=20 Best Regards, Marek Marczykowski-G=C3=B3recki Invisible Things Lab --p94ypmT+e7ybeaDo Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhrpukzGPukRmQqkK24/THMrX1ywFAmCaXzkACgkQ24/THMrX 1yzyiQf+IwD73XUVWyRPGJyFqKFetP/eCbzHBvyKLyaXxN9I3l0kWWExbMpoXd4C 8Hsj4VvjTaA8vf9GHItovqZR0xE0Qy6YcMheLS+/Jjj5RVlcqgWa5GXwh2S+LfsA nCkTCClugpZpmeHIuJF6GhhW9fRfFJNVL7HN+24BCvL26GNjLn5BCOCaoxmr3GnW w0QvxdnTJ1BsJg+Dxi3/7fsdAll/p52fF2DluejJC7wvAQzRUIvIQi+r0K1f71Ue NlFgnI+dhhCVltg/uygZQZr5ykGWA8CgKVN8/SlOtByhiRoY8hn6ciOYF1nvx419 oz3KPLCdp0x90ccPg1lk7RTHDkf3cw== =muMR -----END PGP SIGNATURE----- --p94ypmT+e7ybeaDo--