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

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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?


Are you talking about below change?

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index 68ea1f949daa..368f9e530515 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -577,7 +577,13 @@ static int really_probe(struct device *dev, struct device_driver *drv)
 	if (dev->bus->dma_configure) {
 		ret = dev->bus->dma_configure(dev);
 		if (ret)
-			goto probe_failed;
+			goto pinctrl_bind_failed;
+
+		if (!drv->no_kernel_dma) {
+			ret = iommu_device_set_dma_owner(dev, DMA_OWNER_DMA_API, NULL);
+			if (ret)
+				goto pinctrl_bind_failed;
+                }
 	}

 	ret = driver_sysfs_add(dev);
@@ -660,6 +666,9 @@ 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);
+
+	if (dev->bus->dma_configure && !drv->no_kernel_dma)
+		iommu_device_release_dma_owner(dev, DMA_OWNER_DMA_API);
 pinctrl_bind_failed:
 	device_links_no_driver(dev);
 	devres_release_all(dev);
@@ -1204,6 +1213,9 @@ static void __device_release_driver(struct device *dev, struct device *parent)
 		else if (drv->remove)
 			drv->remove(dev);

+		if (dev->bus->dma_configure && !drv->no_kernel_dma)
+			iommu_device_release_dma_owner(dev, DMA_OWNER_DMA_API);
+
 		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..2cf7b757b28e 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 no_kernel_dma;
 	enum probe_type probe_type;

 	const struct of_device_id	*of_match_table;

Best regards,
baolu



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