From: "Ertman, David M" <david.m.ertman@intel.com>
To: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
Parav Pandit <parav@nvidia.com>,
Leon Romanovsky <leon@kernel.org>
Cc: "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>,
"Williams, Dan J" <dan.j.williams@intel.com>,
"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: Wed, 7 Oct 2020 21:22:29 +0000 [thread overview]
Message-ID: <DM6PR11MB284147D4BC3FD081B9F0B8BBDD0A0@DM6PR11MB2841.namprd11.prod.outlook.com> (raw)
In-Reply-To: <c90316f5-a5a9-fe22-ec11-a30a54ff0a9d@linux.intel.com>
> -----Original Message-----
> From: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
> Sent: Wednesday, October 7, 2020 1:59 PM
> To: Ertman, David M <david.m.ertman@intel.com>; Parav Pandit
> <parav@nvidia.com>; Leon Romanovsky <leon@kernel.org>
> Cc: 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
>
>
>
> >> 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.
>
> Kind reminder that we introduced the two functions to allow the caller
> to know if it needed to free memory when initialize() fails, and it
> didn't need to free memory when add() failed since put_device() takes
> care of it. If you have a single init() function it's impossible to know
> which behavior to select on error.
>
> I also have a case with SoundWire where it's nice to first initialize,
> then set some data and then add.
>
The flow as outlined by Parav above does an initialize as the first step,
so every error path out of the function has to do a put_device(), so you
would never need to manually free the memory in the setup function.
It would be freed in the release call.
-DaveE
> >
> > At that point, do we need wrappers on the primitives init, add, del,
> > and put?
> >
> > -DaveE
> >
next prev parent reply other threads:[~2020-10-07 21:22 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 [this message]
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
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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