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

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Date:   Fri, 10 Dec 2021 09:23:19 +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

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, 
> NULL);
> +}
> +
>   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?

Best regards,
baolu