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 39418223DE9 for ; Tue, 29 Jul 2025 11:49:39 +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=1753789780; cv=none; b=HMUP28sLgcw2ZDMAJup30+fPekUH2nFbaSZzUKvNddDAtlopM8NUtQ8LQOKCbY80UfExk8hpx7uMywbpqqFTBw5RLRdjxbAaEDnDSDhUtL34uya+8JugugUsH+2e60eodBmOj4TyCMJl640Bx1KU1b69GpA0K4Oiyh9t8gMS4eY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753789780; c=relaxed/simple; bh=BQInsFmLXBySvLYBSX7hpWrDlMtA81A3xR4lNAtmDcA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=O8hNkyph9VggPjzWkgPvIGc2pKC7XhsG6egffYh/CfxE5CZTGQAmmIFeUDFrwq2LG9fRQkhXZGmMTWtjy0+7ZrKyqjCNM8lLBy4a4XcHvGae0ANDMPuXrpg13fXWuAskOh2W8lgPQRQlWNHx3UCfghg2tY3d3O6CxOhgPPDcWl4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=W2EfbADW; 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="W2EfbADW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A903DC4CEEF; Tue, 29 Jul 2025 11:49:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753789779; bh=BQInsFmLXBySvLYBSX7hpWrDlMtA81A3xR4lNAtmDcA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=W2EfbADW6McZP3iNwkJr5WN1mkUohL6C5IMrXDZEYvdosISSMUHZ7v0GKPdg8MT+/ xZurmhuKwZF/68mUeKTQkO7aiDihl25bPmPqY372YMpiGK5wMzRL8O7f6njoHTsXvu 1i2gyiIdFCnZzpl5ZBAaCuQemmdyCq9HC7iCtnvoELFWPrurbbjGMZZNEuIwBNVBuy C4s8OAu5ENME9o6TnDGHEVudM4bq1Yj5fX3+37Dv7ZjOWIlNnmAChlxvdSeZ6uLUUI v5ZUcxZttn2NxxPjAisO3MFERC8U3/6BopCd24M+LachT4yxeoM4Tv1dtVWQfAWjwA 5xnT5LshFjDZw== Date: Tue, 29 Jul 2025 14:49:34 +0300 From: Leon Romanovsky To: Danilo Krummrich Cc: Sean Anderson , Greg Kroah-Hartman , Ira Weiny , linux-kernel@vger.kernel.org, "Rafael J . Wysocki" , Dave Ertman Subject: Re: [PATCH] auxiliary: Automatically generate id Message-ID: <20250729114934.GK402218@unreal> References: <20250728211022.9165-1-sean.anderson@linux.dev> <20250729100132.GH402218@unreal> <20250729111130.GI402218@unreal> Precedence: bulk X-Mailing-List: linux-kernel@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: 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. Their > >> >> > only purpose is to prevent sysfs collisions. To simplify things, just > >> >> > generate a unique id for each auxiliary device. Remove all references 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_type = { > >> >> > .pm = &auxiliary_dev_pm_ops, > >> >> > }; > >> >> > > >> >> > +static DEFINE_IDA(auxiliary_id); > >> >> > >> >> I think this is the correct thing to do, even though the per device IDA drivers > >> >> typically went for so far produces IDs that are easier to handle when debugging > >> >> things. > >> >> > >> >> > + > >> >> > /** > >> >> > * auxiliary_device_init - check auxiliary_device and initialize > >> >> > * @auxdev: auxiliary device struct > >> >> > @@ -331,20 +333,37 @@ int __auxiliary_device_add(struct auxiliary_device *auxdev, const char *modname) > >> >> > return -EINVAL; > >> >> > } > >> >> > > >> >> > + ret = ida_alloc(&auxiliary_id, GFP_KERNEL); > >> >> > + if (ret < 0) { > >> >> > + dev_err(dev, "auxiliary device id_alloc fauiled: %d\n", ret); > >> >> > + return ret; > >> >> > + } > >> >> > + auxdev->id = ret; > >> >> > >> >> This overwrites the ID number set by various drivers that (still) use the > >> >> auxiliary_device_init() and auxiliary_device_add() pair. > >> >> > >> >> While I agree with the general intent, I think it's a very bad idea to just > >> >> perform this change silently leaving drivers with their IDA instances not > >> >> knowing that the set ID numbers do not have an effect anymore. > >> >> > >> >> I think this should be multiple steps: > >> >> > >> >> (1) Remove the id parameter and force an internal ID only for > >> >> auxiliary_device_create(). > >> >> > >> >> (2) Convert applicable drivers (and the Rust abstraction) to use > >> >> auxiliary_device_create() rather than auxiliary_device_init() and > >> >> auxiliary_device_add(). > >> >> > >> >> (3) Treewide change to force an internal ID for all auxiliary devices > >> >> 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 = id; > >> > > >> > 2. Add standalone patches to remove not used ida_alloc/ida_free calls > >> > from the drivers. > >> > >> 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 "treewide > >> 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/dev/dev.c > > as an example. > > That's why I said "*applicable* drivers" everywhere. :) > > 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. The auxiliary_device_create() relies on auxiliary_device_init() under the hood, so most likely the change should be there. > > >> Technically (2) is orthogonal, yet I think it's a bit better to do the desired > >> change right away. Otherwise we end up converting all applicable drivers 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 like 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) > > The common pattern is to have custom release callbacks for class or bus specific > device types. > > In this case drivers would set struct auxiliary_device::release. And the > auxiliary bus would implement the underlying struct device::release to call the > driver provided struct auxiliary_device::release plus the additional cleanup. > > What you propose works as well, but it moves bus or class device specifics 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. Thanks