From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3DF1A217733 for ; Tue, 29 Jul 2025 12:31:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753792307; cv=none; b=h2jvGYzRCfJHoU762uGMINCoKL7cwWpy9fm9KUuKCXolKwWWtUbbkvBgnEOGn0qwXd3R9CXdJu+rT3r8I1TqBV0erbZ0AG2IPRbx5TeQaAX/mKoc5ynmZeKUwdwGH18VNckR7yRord7avvV/yrw/tpj453EVGaCtHm+s1U7ft9Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753792307; c=relaxed/simple; bh=iGDz1bfi1B9zdWBbgUxD18Ia4HFDKO4cu6nFU0b7MHQ=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:To:From:Subject: References:In-Reply-To; b=MYC5fxet7fiYB3XW/muAFS1TG5Xikg87OhxAK6UA4P/LhYmizKJivdSF0ObbfgdIxlNC6e66cHpt/XvNCWwm8fQVR1nlBmuFkFHcDbPj4peB1yuj2Q1PBsZmxIOwow+liPzY7cFqsJgO3S6rWQHYPM7WDE469l+iJM5C/1EOvMc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HFdZnYtJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HFdZnYtJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3DAE1C4CEEF; Tue, 29 Jul 2025 12:31:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753792306; bh=iGDz1bfi1B9zdWBbgUxD18Ia4HFDKO4cu6nFU0b7MHQ=; h=Date:Cc:To:From:Subject:References:In-Reply-To:From; b=HFdZnYtJrWLj7RFtGFOPWcrPpzHvuUQtDiXLRQjGIYMQ8dvsT/CLoKzaBEtPQomx1 SyOlbNk1ErAdvLnqu5JcKoizboNe3ljxe4Ba7od+KTT17J9tA+ycuvlQ7fakBAYlrE xDD9CuCUp5n9BvvTTs4vg6eVa0N/ykppOBkFzvVpTQ4r9EFzWnTkoQOrJZzQHttRSB NldOedGYXPdeSS6JllZK6gZwWhmoh717DDKc/EbjmxKjIijKzBR8Kn6MHE4t7QO3hc ISWOdEsm12BRo+1Ih6knlqlhxLhgf3CJ0Ln/zYpuQS+YHOCdwKj4R+YtYqqsNyTtIT iBSzRPQDAJM/A== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Tue, 29 Jul 2025 14:31:43 +0200 Message-Id: Cc: "Sean Anderson" , "Greg Kroah-Hartman" , "Ira Weiny" , , "Rafael J . Wysocki" , "Dave Ertman" To: "Leon Romanovsky" From: "Danilo Krummrich" Subject: Re: [PATCH] auxiliary: Automatically generate id References: <20250728211022.9165-1-sean.anderson@linux.dev> <20250729100132.GH402218@unreal> <20250729111130.GI402218@unreal> <20250729114934.GK402218@unreal> In-Reply-To: <20250729114934.GK402218@unreal> On Tue Jul 29, 2025 at 1:49 PM CEST, Leon Romanovsky wrote: > On Tue, Jul 29, 2025 at 01:28:14PM +0200, Danilo Krummrich wrote: >> On Tue Jul 29, 2025 at 1:11 PM CEST, Leon Romanovsky wrote: >> > On Tue, Jul 29, 2025 at 12:51:42PM +0200, Danilo Krummrich wrote: >> >> On Tue Jul 29, 2025 at 12:01 PM CEST, Leon Romanovsky wrote: >> >> > On Tue, Jul 29, 2025 at 11:36:27AM +0200, Danilo Krummrich wrote: >> >> >> On Mon Jul 28, 2025 at 11:10 PM CEST, Sean Anderson wrote: >> >> >> > As it turns out, ids are not allowed to have semantic meaning. T= heir >> >> >> > only purpose is to prevent sysfs collisions. To simplify things,= just >> >> >> > generate a unique id for each auxiliary device. Remove all refer= ences to >> >> >> > filling in the id member of the device. >> >> >> > >> >> >> > Signed-off-by: Sean Anderson >> >> >> > --- >> >> >> > >> >> >> > drivers/base/auxiliary.c | 32 +++++++++++++++++++++++-----= ---- >> >> >> > include/linux/auxiliary_bus.h | 26 ++++++++------------------ >> >> >> > 2 files changed, 31 insertions(+), 27 deletions(-) >> >> >> > >> >> >> > diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c >> >> >> > index dba7c8e13a53..f66067df03ad 100644 >> >> >> > --- a/drivers/base/auxiliary.c >> >> >> > +++ b/drivers/base/auxiliary.c >> >> >> > @@ -264,6 +264,8 @@ static const struct bus_type auxiliary_bus_t= ype =3D { >> >> >> > .pm =3D &auxiliary_dev_pm_ops, >> >> >> > }; >> >> >> > =20 >> >> >> > +static DEFINE_IDA(auxiliary_id); >> >> >>=20 >> >> >> I think this is the correct thing to do, even though the per devic= e IDA drivers >> >> >> typically went for so far produces IDs that are easier to handle w= hen debugging >> >> >> things. >> >> >>=20 >> >> >> > + >> >> >> > /** >> >> >> > * auxiliary_device_init - check auxiliary_device and initializ= e >> >> >> > * @auxdev: auxiliary device struct >> >> >> > @@ -331,20 +333,37 @@ int __auxiliary_device_add(struct auxiliar= y_device *auxdev, const char *modname) >> >> >> > return -EINVAL; >> >> >> > } >> >> >> > =20 >> >> >> > + ret =3D ida_alloc(&auxiliary_id, GFP_KERNEL); >> >> >> > + if (ret < 0) { >> >> >> > + dev_err(dev, "auxiliary device id_alloc fauiled: %d\n", ret); >> >> >> > + return ret; >> >> >> > + } >> >> >> > + auxdev->id =3D ret; >> >> >>=20 >> >> >> This overwrites the ID number set by various drivers that (still) = use the >> >> >> auxiliary_device_init() and auxiliary_device_add() pair. >> >> >>=20 >> >> >> While I agree with the general intent, I think it's a very bad ide= a to just >> >> >> perform this change silently leaving drivers with their IDA instan= ces not >> >> >> knowing that the set ID numbers do not have an effect anymore. >> >> >>=20 >> >> >> I think this should be multiple steps: >> >> >>=20 >> >> >> (1) Remove the id parameter and force an internal ID only for >> >> >> auxiliary_device_create(). >> >> >>=20 >> >> >> (2) Convert applicable drivers (and the Rust abstraction) to use >> >> >> auxiliary_device_create() rather than auxiliary_device_init(= ) and >> >> >> auxiliary_device_add(). >> >> >>=20 >> >> >> (3) Treewide change to force an internal ID for all auxiliary de= vices >> >> >> considering this change in all affected drivers. >> >> > >> >> > I would suggest easier approach. >> >> > 1. Add to the proposal patch, the sed generated line which removes = auxdev->id >> >> > assignment in the drivers. >> >> > Something like this from mlx5: >> >> > - sf_dev->adev.id =3D id; >> >> > >> >> > 2. Add standalone patches to remove not used ida_alloc/ida_free cal= ls >> >> > from the drivers. >> >>=20 >> >> I assume you suggest this as an alternative to (3) above? If so, that= 's what I >> >> meant in (3), I should have written "treewide series" instead of "tre= ewide >> >> change". >> > >> > I would say for all steps. Very important reason to use >> > auxiliary_device_init() and not auxiliary_device_create() is to bind >> > custom release callback, which is needed to release private data. >> > >> > In addition, complex devices embed struct auxiliary_device in their >> > internal struct to rely on container_of to access the data. >> > See mlx5_sf_dev_add() in drivers/net/ethernet/mellanox/mlx5/core/sf/de= v/dev.c >> > as an example. >>=20 >> That's why I said "*applicable* drivers" everywhere. :) >>=20 >> The examples you mention don't fall under this category, but in general = drivers >> that *can* use auxiliary_device_create() should do it. > > Of course, the thing is that even drivers with auxiliary_device_init() > shouldn't set "id" and because they need to be updated. I think we agree here. :) It's only about the ordering between "convert to auxiliary_device_create()" and "use internal IDA". I think it'd be a good synergy to convert applicable drivers to auxiliary_device_create() first, but I'm not insisting on it. > The auxiliary_device_create() relies on auxiliary_device_init() under the= hood, > so most likely the change should be there. > >>=20 >> >> Technically (2) is orthogonal, yet I think it's a bit better to do th= e desired >> >> change right away. Otherwise we end up converting all applicable driv= ers to >> >> implement the auxiliary device release callback (which we need for a = common >> >> ida_free()) first, just to remove it later on when we convert to >> >> auxiliary_device_create(). >> > >> > My expectation is to see extension of driver/base/core.c. Something li= ke that: >> > >> > diff --git a/drivers/base/core.c b/drivers/base/core.c >> > index cbc0099d8ef24..63847c84dbdc0 100644 >> > --- a/drivers/base/core.c >> > +++ b/drivers/base/core.c >> > @@ -2560,8 +2560,10 @@ static void device_release(struct kobject *kobj= ) >> > >> > kfree(dev->dma_range_map); >> > >> > - if (dev->release) >> > + if (dev->release) { >> > + dev->bus_specific_cleanup(dev); >> > dev->release(dev); >> > + } >> > else if (dev->type && dev->type->release) >> > dev->type->release(dev); >> > else if (dev->class && dev->class->dev_release) >>=20 >> The common pattern is to have custom release callbacks for class or bus = specific >> device types. >>=20 >> In this case drivers would set struct auxiliary_device::release. And the >> auxiliary bus would implement the underlying struct device::release to c= all the >> driver provided struct auxiliary_device::release plus the additional cle= anup. >>=20 >> What you propose works as well, but it moves bus or class device specifi= cs into >> the generic struct device, where the normal inheritance pattern already = solves >> this. > > It was just a sketch, everything that allows to set custom release > callback is fine by me. Yeah, what I meant is that we shouldn't add an additional release callback = to struct device for such things in general. device::release() is for the user of the struct device, in this case this i= s struct auxiliary_device. auxiliary_device::release() will be for the user of struct auxiliary_device= , which could be some generic driver specific device structure, let's say struct foo_device. Now, struct foo_device may have another release callback for its specific cleanup. So, the callchain would look like this: device::release { auxiliary_device::release { foo_device::release { // clean up struct foo_device } // clean up struct auxiliary_device } // clean up struct device } Having additional release callbacks on struct device does not scale.