diff mbox series

[v2,2/4] iommu: Pass in the iommu_device to probe for in bus_iommu_probe()

Message ID 2-v2-d2762acaf50a+16d-iommu_group_locking2_jgg@nvidia.com
State New
Headers show
Series Fix device_lock deadlock on two probe() paths | expand

Commit Message

Jason Gunthorpe Aug. 9, 2023, 2:43 p.m. UTC 
This is preparation for the next patch.

Each iommu driver is associated with a 'struct iommu_device' handle. Pass
in the iommu_device to bus_iommu_probe() and all the way through to
probe_iommu_group().

omap is weird, it has a whole bunch of iommu devices that it creates a
struct omap_iommu for, but it only registers some of them with the
subsystem. In the case it doesn't register then it has to open code the
call to bus_iommu_probe() as it's omap_iommu_probe_device() function is
sensitive. Pass in the unregistered iommu_device struct and move this code
into an else block since there is no sense in calling bus_iommu_probe()
twice in a row.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/iommu/iommu.c      | 18 +++++++++++++-----
 drivers/iommu/omap-iommu.c | 11 ++++++++---
 include/linux/iommu.h      |  3 ++-
 3 files changed, 23 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index ecf61bd3cfb076..19fdb1a220240f 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -273,7 +273,7 @@  int iommu_device_register(struct iommu_device *iommu,
 
 	for (int i = 0; i < ARRAY_SIZE(iommu_buses) && !err; i++) {
 		iommu_buses[i]->iommu_ops = ops;
-		err = bus_iommu_probe(iommu_buses[i]);
+		err = bus_iommu_probe(iommu_buses[i], iommu);
 	}
 	if (err)
 		iommu_device_unregister(iommu);
@@ -1792,13 +1792,18 @@  struct iommu_domain *iommu_group_default_domain(struct iommu_group *group)
 	return group->default_domain;
 }
 
+struct probe_iommu_args {
+	struct list_head *group_list;
+	struct iommu_device *iommu;
+};
+
 static int probe_iommu_group(struct device *dev, void *data)
 {
-	struct list_head *group_list = data;
+	struct probe_iommu_args *args = data;
 	int ret;
 
 	device_lock(dev);
-	ret = __iommu_probe_device(dev, group_list);
+	ret = __iommu_probe_device(dev, args->group_list);
 	device_unlock(dev);
 	if (ret == -ENODEV)
 		ret = 0;
@@ -1868,13 +1873,16 @@  static void iommu_group_do_probe_finalize(struct device *dev)
 		ops->probe_finalize(dev);
 }
 
-int bus_iommu_probe(const struct bus_type *bus)
+int bus_iommu_probe(const struct bus_type *bus, struct iommu_device *iommu)
 {
+	struct probe_iommu_args args = {};
 	struct iommu_group *group, *next;
 	LIST_HEAD(group_list);
 	int ret;
 
-	ret = bus_for_each_dev(bus, NULL, &group_list, probe_iommu_group);
+	args.group_list = &group_list;
+	args.iommu = iommu;
+	ret = bus_for_each_dev(bus, NULL, &args, probe_iommu_group);
 	if (ret)
 		return ret;
 
diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
index 97c45f50bf4332..1e4a90ec64322b 100644
--- a/drivers/iommu/omap-iommu.c
+++ b/drivers/iommu/omap-iommu.c
@@ -1234,6 +1234,14 @@  static int omap_iommu_probe(struct platform_device *pdev)
 		if (err)
 			goto out_sysfs;
 		obj->has_iommu_driver = true;
+	} else {
+		/*
+		 * omap_iommu_probe_device() requires all the iommus associated
+		 * with a device to have been probed to succeed. We just created
+		 * an iommu without registering it, so re-run probe again to try
+		 * to match any devices that are waiting for this iommu.
+		 */
+		bus_iommu_probe(&platform_bus_type, &obj->iommu);
 	}
 
 	pm_runtime_enable(obj->dev);
@@ -1242,9 +1250,6 @@  static int omap_iommu_probe(struct platform_device *pdev)
 
 	dev_info(&pdev->dev, "%s registered\n", obj->name);
 
-	/* Re-probe bus to probe device attached to this IOMMU */
-	bus_iommu_probe(&platform_bus_type);
-
 	return 0;
 
 out_sysfs:
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index cb4fc518797039..cc47e4086d69ec 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -465,7 +465,8 @@  static inline const struct iommu_ops *dev_iommu_ops(struct device *dev)
 	return dev->iommu->iommu_dev->ops;
 }
 
-extern int bus_iommu_probe(const struct bus_type *bus);
+extern int bus_iommu_probe(const struct bus_type *bus,
+			   struct iommu_device *iommu);
 extern bool iommu_present(const struct bus_type *bus);
 extern bool device_iommu_capable(struct device *dev, enum iommu_cap cap);
 extern bool iommu_group_has_isolated_msi(struct iommu_group *group);