[PATCH V3 8/8] arm64: dma-mapping: Remove the notifier trick to handle early setting of dma_ops

Sricharan R
2016-10-04T17:03:52Z

With arch_setup_dma_ops now being called late during device's probe after the
device's iommu is probed, the notifier trick required to handle the early
setup of dma_ops before the iommu group gets created is not required.
So removing the notifier's here.

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
---
arch/arm64/mm/dma-mapping.c | 100 ++------------------------------------------
1 file changed, 3 insertions(+), 97 deletions(-)

diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index faf4b92..eb593af 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -799,24 +799,6 @@ static struct dma_map_ops iommu_dma_ops = {
.mapping_error = iommu_dma_mapping_error,
};

-/*
- * TODO: Right now __iommu_setup_dma_ops() gets called too early to do
- * everything it needs to - the device is only partially created and the
- * IOMMU driver hasn't seen it yet, so it can't have a group. Thus we
- * need this delayed attachment dance. Once IOMMU probe ordering is sorted
- * to move the arch_setup_dma_ops() call later, all the notifier bits below
- * become unnecessary, and will go away.
- */
-struct iommu_dma_notifier_data {
- struct list_head list;
- struct device *dev;
- const struct iommu_ops *ops;
- u64 dma_base;
- u64 size;
-};
-static LIST_HEAD(iommu_dma_masters);
-static DEFINE_MUTEX(iommu_dma_notifier_lock);
-
static bool do_iommu_attach(struct device *dev, const struct iommu_ops *ops,
u64 dma_base, u64 size)
{
@@ -837,79 +819,9 @@ static bool do_iommu_attach(struct device *dev, const struct iommu_ops *ops,
return true;
}

-static void queue_iommu_attach(struct device *dev, const struct iommu_ops *ops,
- u64 dma_base, u64 size)
-{
- struct iommu_dma_notifier_data *iommudata;
-
- iommudata = kzalloc(sizeof(*iommudata), GFP_KERNEL);
- if (!iommudata)
- return;
-
- iommudata->dev = dev;
- iommudata->ops = ops;
- iommudata->dma_base = dma_base;
- iommudata->size = size;
-
- mutex_lock(&iommu_dma_notifier_lock);
- list_add(&iommudata->list, &iommu_dma_masters);
- mutex_unlock(&iommu_dma_notifier_lock);
-}
-
-static int __iommu_attach_notifier(struct notifier_block *nb,
- unsigned long action, void *data)
-{
- struct iommu_dma_notifier_data *master, *tmp;
-
- if (action != BUS_NOTIFY_BIND_DRIVER)
- return 0;
-
- mutex_lock(&iommu_dma_notifier_lock);
- list_for_each_entry_safe(master, tmp, &iommu_dma_masters, list) {
- if (data == master->dev && do_iommu_attach(master->dev,
- master->ops, master->dma_base, master->size)) {
- list_del(&master->list);
- kfree(master);
- break;
- }
- }
- mutex_unlock(&iommu_dma_notifier_lock);
- return 0;
-}
-
-static int __init register_iommu_dma_ops_notifier(struct bus_type *bus)
-{
- struct notifier_block *nb = kzalloc(sizeof(*nb), GFP_KERNEL);
- int ret;
-
- if (!nb)
- return -ENOMEM;
-
- nb->notifier_call = __iommu_attach_notifier;
-
- ret = bus_register_notifier(bus, nb);
- if (ret) {
- pr_warn("Failed to register DMA domain notifier; IOMMU DMA ops unavailable on bus '%s'\n",
- bus->name);
- kfree(nb);
- }
- return ret;
-}
-
static int __init __iommu_dma_init(void)
{
- int ret;
-
- ret = iommu_dma_init();
- if (!ret)
- ret = register_iommu_dma_ops_notifier(&platform_bus_type);
- if (!ret)
- ret = register_iommu_dma_ops_notifier(&amba_bustype);
-#ifdef CONFIG_PCI
- if (!ret)
- ret = register_iommu_dma_ops_notifier(&pci_bus_type);
-#endif
- return ret;
+ return iommu_dma_init();
}
arch_initcall(__iommu_dma_init);

@@ -920,18 +832,12 @@ static void __iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,

if (!ops)
return;
- /*
- * TODO: As a concession to the future, we're ready to handle being
- * called both early and late (i.e. after bus_add_device). Once all
- * the platform bus code is reworked to call us late and the notifier
- * junk above goes away, move the body of do_iommu_attach here.
- */
+
group = iommu_group_get(dev);
+
if (group) {
do_iommu_attach(dev, ops, dma_base, size);
iommu_group_put(group);
- } else {
- queue_iommu_attach(dev, ops, dma_base, size);
}
}

--
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