From: "Ertman, David M" <david.m.ertman@intel.com>
To: "Williams, Dan J" <dan.j.williams@intel.com>,
Leon Romanovsky <leon@kernel.org>
Cc: Parav Pandit <parav@nvidia.com>,
Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
"alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
"parav@mellanox.com" <parav@mellanox.com>,
"tiwai@suse.de" <tiwai@suse.de>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"ranjani.sridharan@linux.intel.com"
<ranjani.sridharan@linux.intel.com>,
"fred.oh@linux.intel.com" <fred.oh@linux.intel.com>,
"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
"dledford@redhat.com" <dledford@redhat.com>,
"broonie@kernel.org" <broonie@kernel.org>,
Jason Gunthorpe <jgg@nvidia.com>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"kuba@kernel.org" <kuba@kernel.org>,
"Saleem, Shiraz" <shiraz.saleem@intel.com>,
"davem@davemloft.net" <davem@davemloft.net>,
"Patil, Kiran" <kiran.patil@intel.com>
Subject: RE: [PATCH v2 1/6] Add ancillary bus support
Date: Thu, 8 Oct 2020 18:25:20 +0000 [thread overview]
Message-ID: <DM6PR11MB284113CE8F7D4C5A0989E233DD0B0@DM6PR11MB2841.namprd11.prod.outlook.com> (raw)
In-Reply-To: <CAPcyv4gz=mMTfLO4mAa34MEEXgg77o1AWrT6aguLYODAWxbQDQ@mail.gmail.com>
> -----Original Message-----
> From: Dan Williams <dan.j.williams@intel.com>
> Sent: Wednesday, October 7, 2020 11:32 PM
> To: Leon Romanovsky <leon@kernel.org>
> Cc: Ertman, David M <david.m.ertman@intel.com>; Parav Pandit
> <parav@nvidia.com>; Pierre-Louis Bossart <pierre-
> louis.bossart@linux.intel.com>; alsa-devel@alsa-project.org;
> parav@mellanox.com; tiwai@suse.de; netdev@vger.kernel.org;
> ranjani.sridharan@linux.intel.com; fred.oh@linux.intel.com; linux-
> rdma@vger.kernel.org; dledford@redhat.com; broonie@kernel.org; Jason
> Gunthorpe <jgg@nvidia.com>; gregkh@linuxfoundation.org;
> kuba@kernel.org; Saleem, Shiraz <shiraz.saleem@intel.com>;
> davem@davemloft.net; Patil, Kiran <kiran.patil@intel.com>
> Subject: Re: [PATCH v2 1/6] Add ancillary bus support
>
> On Wed, Oct 7, 2020 at 10:21 PM Leon Romanovsky <leon@kernel.org>
> wrote:
> >
> > On Wed, Oct 07, 2020 at 08:46:45PM +0000, Ertman, David M wrote:
> > > > -----Original Message-----
> > > > From: Parav Pandit <parav@nvidia.com>
> > > > Sent: Wednesday, October 7, 2020 1:17 PM
> > > > To: Leon Romanovsky <leon@kernel.org>; Ertman, David M
> > > > <david.m.ertman@intel.com>
> > > > Cc: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>; alsa-
> > > > devel@alsa-project.org; parav@mellanox.com; tiwai@suse.de;
> > > > netdev@vger.kernel.org; ranjani.sridharan@linux.intel.com;
> > > > fred.oh@linux.intel.com; linux-rdma@vger.kernel.org;
> > > > dledford@redhat.com; broonie@kernel.org; Jason Gunthorpe
> > > > <jgg@nvidia.com>; gregkh@linuxfoundation.org; kuba@kernel.org;
> Williams,
> > > > Dan J <dan.j.williams@intel.com>; Saleem, Shiraz
> > > > <shiraz.saleem@intel.com>; davem@davemloft.net; Patil, Kiran
> > > > <kiran.patil@intel.com>
> > > > Subject: RE: [PATCH v2 1/6] Add ancillary bus support
> > > >
> > > >
> > > > > From: Leon Romanovsky <leon@kernel.org>
> > > > > Sent: Thursday, October 8, 2020 12:56 AM
> > > > >
> > > > > > > This API is partially obscures low level driver-core code and needs
> > > > > > > to provide clear and proper abstractions without need to
> remember
> > > > > > > about put_device. There is already _add() interface why don't you
> do
> > > > > > > put_device() in it?
> > > > > > >
> > > > > >
> > > > > > The pushback Pierre is referring to was during our mid-tier internal
> > > > > > review. It was primarily a concern of Parav as I recall, so he can
> speak to
> > > > his
> > > > > reasoning.
> > > > > >
> > > > > > What we originally had was a single API call
> > > > > > (ancillary_device_register) that started with a call to
> > > > > > device_initialize(), and every error path out of the function
> performed a
> > > > > put_device().
> > > > > >
> > > > > > Is this the model you have in mind?
> > > > >
> > > > > I don't like this flow:
> > > > > ancillary_device_initialize()
> > > > > if (ancillary_ancillary_device_add()) {
> > > > > put_device(....)
> > > > > ancillary_device_unregister()
> > > > Calling device_unregister() is incorrect, because add() wasn't
> successful.
> > > > Only put_device() or a wrapper ancillary_device_put() is necessary.
> > > >
> > > > > return err;
> > > > > }
> > > > >
> > > > > And prefer this flow:
> > > > > ancillary_device_initialize()
> > > > > if (ancillary_device_add()) {
> > > > > ancillary_device_unregister()
> > > > This is incorrect and a clear deviation from the current core APIs that
> adds the
> > > > confusion.
> > > >
> > > > > return err;
> > > > > }
> > > > >
> > > > > In this way, the ancillary users won't need to do non-intuitive
> put_device();
> > > >
> > > > Below is most simple, intuitive and matching with core APIs for name
> and
> > > > design pattern wise.
> > > > init()
> > > > {
> > > > err = ancillary_device_initialize();
> > > > if (err)
> > > > return ret;
> > > >
> > > > err = ancillary_device_add();
> > > > if (ret)
> > > > goto err_unwind;
> > > >
> > > > err = some_foo();
> > > > if (err)
> > > > goto err_foo;
> > > > return 0;
> > > >
> > > > err_foo:
> > > > ancillary_device_del(adev);
> > > > err_unwind:
> > > > ancillary_device_put(adev->dev);
> > > > return err;
> > > > }
> > > >
> > > > cleanup()
> > > > {
> > > > ancillary_device_de(adev);
> > > > ancillary_device_put(adev);
> > > > /* It is common to have a one wrapper for this as
> > > > ancillary_device_unregister().
> > > > * This will match with core device_unregister() that has precise
> > > > documentation.
> > > > * but given fact that init() code need proper error unwinding, like
> > > > above,
> > > > * it make sense to have two APIs, and no need to export another
> > > > symbol for unregister().
> > > > * This pattern is very easy to audit and code.
> > > > */
> > > > }
> > >
> > > I like this flow +1
> > >
> > > But ... since the init() function is performing both device_init and
> > > device_add - it should probably be called ancillary_device_register,
> > > and we are back to a single exported API for both register and
> > > unregister.
> > >
> > > At that point, do we need wrappers on the primitives init, add, del,
> > > and put?
> >
> > Let me summarize.
> > 1. You are not providing driver/core API but simplification and obfuscation
> > of basic primitives and structures. This is new layer. There is no room for
> > a claim that we must to follow internal API.
>
> Yes, this a driver core api, Greg even questioned why it was in
> drivers/bus instead of drivers/base which I think makes sense.
Will move to drivers/base with next patch set.
-DaveE
next prev parent reply other threads:[~2020-10-08 18:25 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 18:24 [PATCH v2 0/6] Ancillary bus implementation and SOF multi-client support Dave Ertman
2020-10-05 18:24 ` [PATCH v2 1/6] Add ancillary bus support Dave Ertman
2020-10-06 7:18 ` Leon Romanovsky
2020-10-06 15:18 ` Pierre-Louis Bossart
2020-10-06 17:02 ` Leon Romanovsky
2020-10-06 17:09 ` Parav Pandit
2020-10-06 17:26 ` Leon Romanovsky
2020-10-06 17:41 ` Saleem, Shiraz
2020-10-06 19:20 ` Leon Romanovsky
2020-10-07 2:49 ` Dan Williams
2020-10-07 13:09 ` Saleem, Shiraz
2020-10-07 13:36 ` Leon Romanovsky
2020-10-07 18:55 ` Dan Williams
2020-10-07 20:01 ` Ertman, David M
2020-10-06 18:35 ` Ranjani Sridharan
2020-10-06 17:50 ` Saleem, Shiraz
2020-10-07 18:06 ` Ertman, David M
2020-10-07 19:26 ` Leon Romanovsky
2020-10-07 19:53 ` Ertman, David M
2020-10-07 19:57 ` Ertman, David M
2020-10-07 20:17 ` Parav Pandit
2020-10-07 20:46 ` Ertman, David M
2020-10-07 20:59 ` Pierre-Louis Bossart
2020-10-07 21:22 ` Ertman, David M
2020-10-07 21:49 ` Pierre-Louis Bossart
2020-10-08 4:56 ` Parav Pandit
2020-10-08 5:26 ` Leon Romanovsky
2020-10-08 7:14 ` Parav Pandit
2020-10-08 7:45 ` Leon Romanovsky
2020-10-08 9:45 ` Parav Pandit
2020-10-08 10:17 ` Leon Romanovsky
2020-10-08 13:29 ` Pierre-Louis Bossart
2020-10-09 11:40 ` Leon Romanovsky
2020-10-08 16:54 ` Ertman, David M
2020-10-08 17:35 ` Parav Pandit
2020-10-08 18:13 ` Ertman, David M
2020-10-08 5:21 ` Leon Romanovsky
2020-10-08 6:32 ` Dan Williams
2020-10-08 7:00 ` Leon Romanovsky
2020-10-08 7:38 ` Dan Williams
2020-10-08 7:50 ` gregkh
2020-10-08 11:10 ` Parav Pandit
2020-10-08 16:39 ` Ertman, David M
2020-10-08 8:00 ` Leon Romanovsky
2020-10-08 8:09 ` Dan Williams
2020-10-08 16:42 ` Ertman, David M
2020-10-08 17:21 ` Leon Romanovsky
2020-10-08 18:25 ` Ertman, David M [this message]
2020-10-07 20:30 ` Ertman, David M
2020-10-07 20:18 ` Ertman, David M
2020-10-06 17:23 ` Leon Romanovsky
2020-10-06 17:45 ` Saleem, Shiraz
2020-10-08 22:04 ` Ertman, David M
2020-10-08 22:41 ` Dan Williams
2020-10-09 14:26 ` Pierre-Louis Bossart
2020-10-09 19:22 ` Dan Williams
2020-10-09 19:39 ` Pierre-Louis Bossart
2020-10-12 18:34 ` Ertman, David M
2020-10-08 17:20 ` Leon Romanovsky
2020-10-08 17:28 ` Ertman, David M
2020-10-05 18:24 ` [PATCH v2 2/6] ASoC: SOF: Introduce descriptors for SOF client Dave Ertman
2020-10-13 1:05 ` Randy Dunlap
2020-10-13 1:31 ` Pierre-Louis Bossart
2020-10-13 1:55 ` Randy Dunlap
2020-10-13 1:56 ` Randy Dunlap
2020-10-13 15:08 ` Pierre-Louis Bossart
2020-10-13 19:35 ` Randy Dunlap
2020-10-13 19:57 ` Pierre-Louis Bossart
2020-10-05 18:24 ` [PATCH v2 3/6] ASoC: SOF: Create client driver for IPC test Dave Ertman
2020-10-05 18:24 ` [PATCH v2 4/6] ASoC: SOF: ops: Add ops for client registration Dave Ertman
2020-10-05 18:24 ` [PATCH v2 5/6] ASoC: SOF: Intel: Define " Dave Ertman
2020-10-05 18:24 ` [PATCH v2 6/6] ASoC: SOF: debug: Remove IPC flood test support in SOF core Dave Ertman
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