linux-kernel - Re: [PATCH v3 04/18] driver core: platform: Add driver dma ownership management

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Date:   Mon, 13 Dec 2021 08:50:05 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Jason Gunthorpe <jgg@...dia.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Christoph Hellwig <hch@...radead.org>
Cc:     baolu.lu@...ux.intel.com, Joerg Roedel <joro@...tes.org>,
        Alex Williamson <alex.williamson@...hat.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Kevin Tian <kevin.tian@...el.com>,
        Ashok Raj <ashok.raj@...el.com>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Dan Williams <dan.j.williams@...el.com>, rafael@...nel.org,
        Diana Craciun <diana.craciun@....nxp.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Eric Auger <eric.auger@...hat.com>,
        Liu Yi L <yi.l.liu@...el.com>,
        Jacob jun Pan <jacob.jun.pan@...el.com>,
        Chaitanya Kulkarni <kch@...dia.com>,
        Stuart Yoder <stuyoder@...il.com>,
        Laurentiu Tudor <laurentiu.tudor@....com>,
        Thierry Reding <thierry.reding@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Li Yang <leoyang.li@....com>,
        Dmitry Osipenko <digetx@...il.com>,
        iommu@...ts.linux-foundation.org, linux-pci@...r.kernel.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 04/18] driver core: platform: Add driver dma ownership
 management

On 12/10/21 9:23 AM, Lu Baolu wrote:
> Hi Greg, Jason and Christoph,
> 
> On 12/9/21 9:20 AM, Lu Baolu wrote:
>> On 12/7/21 9:16 PM, Jason Gunthorpe wrote:
>>> On Tue, Dec 07, 2021 at 10:57:25AM +0800, Lu Baolu wrote:
>>>> On 12/6/21 11:06 PM, Jason Gunthorpe wrote:
>>>>> On Mon, Dec 06, 2021 at 06:36:27AM -0800, Christoph Hellwig wrote:
>>>>>> I really hate the amount of boilerplate code that having this in each
>>>>>> bus type causes.
>>>>> +1
>>>>>
>>>>> I liked the first version of this series better with the code near
>>>>> really_probe().
>>>>>
>>>>> Can we go back to that with some device_configure_dma() wrapper
>>>>> condtionally called by really_probe as we discussed?
> 
> [...]
> 
>>
>> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
>> index 68ea1f949daa..68ca5a579eb1 100644
>> --- a/drivers/base/dd.c
>> +++ b/drivers/base/dd.c
>> @@ -538,6 +538,32 @@ static int call_driver_probe(struct device *dev, 
>> struct device_driver *drv)
>>          return ret;
>>   }
>>
>> +static int device_dma_configure(struct device *dev, struct 
>> device_driver *drv)
>> +{
>> +       int ret;
>> +
>> +       if (!dev->bus->dma_configure)
>> +               return 0;
>> +
>> +       ret = dev->bus->dma_configure(dev);
>> +       if (ret)
>> +               return ret;
>> +
>> +       if (!drv->suppress_auto_claim_dma_owner)
>> +               ret = iommu_device_set_dma_owner(dev, 
>> DMA_OWNER_DMA_API, NULL);
>> +
>> +       return ret;
>> +}
>> +
>> +static void device_dma_cleanup(struct device *dev, struct 
>> device_driver *drv)
>> +{
>> +       if (!dev->bus->dma_configure)
>> +               return;
>> +
>> +       if (!drv->suppress_auto_claim_dma_owner)
>> +               iommu_device_release_dma_owner(dev, DMA_OWNER_DMA_API);
>> +}
>> +
>>   static int really_probe(struct device *dev, struct device_driver *drv)
>>   {
>>          bool test_remove = 
>> IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
>> @@ -574,11 +600,8 @@ static int really_probe(struct device *dev, 
>> struct device_driver *drv)
>>          if (ret)
>>                  goto pinctrl_bind_failed;
>>
>> -       if (dev->bus->dma_configure) {
>> -               ret = dev->bus->dma_configure(dev);
>> -               if (ret)
>> -                       goto probe_failed;
>> -       }
>> +       if (device_dma_configure(dev, drv))
>> +               goto pinctrl_bind_failed;
>>
>>          ret = driver_sysfs_add(dev);
>>          if (ret) {
>> @@ -660,6 +683,8 @@ static int really_probe(struct device *dev, struct 
>> device_driver *drv)
>>          if (dev->bus)
>>                  blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
>>
>> BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
>> +
>> +       device_dma_cleanup(dev, drv);
>>   pinctrl_bind_failed:
>>          device_links_no_driver(dev);
>>          devres_release_all(dev);
>> @@ -1204,6 +1229,7 @@ static void __device_release_driver(struct 
>> device *dev, struct device *parent)
>>                  else if (drv->remove)
>>                          drv->remove(dev);
>>
>> +               device_dma_cleanup(dev, drv);
>>                  device_links_driver_cleanup(dev);
>>
>>                  devres_release_all(dev);
>> diff --git a/include/linux/device/driver.h 
>> b/include/linux/device/driver.h
>> index a498ebcf4993..374a3c2cc10d 100644
>> --- a/include/linux/device/driver.h
>> +++ b/include/linux/device/driver.h
>> @@ -100,6 +100,7 @@ struct device_driver {
>>          const char              *mod_name;      /* used for built-in 
>> modules */
>>
>>          bool suppress_bind_attrs;       /* disables bind/unbind via 
>> sysfs */
>> +       bool suppress_auto_claim_dma_owner;
>>          enum probe_type probe_type;
>>
>>          const struct of_device_id       *of_match_table;
> 
> Does this work for you? Can I work towards this in the next version?

A kindly ping ... Is this heading the right direction? I need your
advice to move ahead. :-)

Best regards,
baolu