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Subject[PATCH v2 8/8] iommu: Clean up open-coded ownership checks
Date
Some drivers already implement their own defence against the possibility
of being given someone else's device. Since this is now taken care of by
the core code (and via a slightly different path from the original
fwspec-based idea), let's clean them up.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---

v2: No change, but I'll note here that it's really about the fwspec->ops
checks; the !fwspec clauses are just going along for the ride where
that's clearly impossible as well. I plan to sweep for other
redundant checks in future when looking at the relevant flows.

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 3 ---
drivers/iommu/arm/arm-smmu/arm-smmu.c | 9 +--------
drivers/iommu/arm/arm-smmu/qcom_iommu.c | 14 ++------------
drivers/iommu/mtk_iommu.c | 7 +------
drivers/iommu/mtk_iommu_v1.c | 3 ---
drivers/iommu/sprd-iommu.c | 8 +-------
drivers/iommu/virtio-iommu.c | 3 ---
7 files changed, 5 insertions(+), 42 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index ab160198edd6..cb05d9771192 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2642,9 +2642,6 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
struct arm_smmu_master *master;
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);

- if (!fwspec || fwspec->ops != &arm_smmu_ops)
- return ERR_PTR(-ENODEV);
-
if (WARN_ON_ONCE(dev_iommu_priv_get(dev)))
return ERR_PTR(-EBUSY);

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 607f06af01b6..235550db0d59 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -1118,11 +1118,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
struct arm_smmu_device *smmu;
int ret;

- if (!fwspec || fwspec->ops != &arm_smmu_ops) {
- dev_err(dev, "cannot attach to SMMU, is it on the same bus?\n");
- return -ENXIO;
- }
-
/*
* FIXME: The arch/arm DMA API code tries to attach devices to its own
* domains between of_xlate() and probe_device() - we have no way to cope
@@ -1352,10 +1347,8 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
fwspec = dev_iommu_fwspec_get(dev);
if (ret)
goto out_free;
- } else if (fwspec && fwspec->ops == &arm_smmu_ops) {
- smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
} else {
- return ERR_PTR(-ENODEV);
+ smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
}

ret = -EINVAL;
diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index d7be3adee426..3fe02720ab29 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -79,16 +79,6 @@ static struct qcom_iommu_domain *to_qcom_iommu_domain(struct iommu_domain *dom)

static const struct iommu_ops qcom_iommu_ops;

-static struct qcom_iommu_dev * to_iommu(struct device *dev)
-{
- struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
-
- if (!fwspec || fwspec->ops != &qcom_iommu_ops)
- return NULL;
-
- return dev_iommu_priv_get(dev);
-}
-
static struct qcom_iommu_ctx * to_ctx(struct qcom_iommu_domain *d, unsigned asid)
{
struct qcom_iommu_dev *qcom_iommu = d->iommu;
@@ -361,7 +351,7 @@ static void qcom_iommu_domain_free(struct iommu_domain *domain)

static int qcom_iommu_attach_dev(struct iommu_domain *domain, struct device *dev)
{
- struct qcom_iommu_dev *qcom_iommu = to_iommu(dev);
+ struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
struct qcom_iommu_domain *qcom_domain = to_qcom_iommu_domain(domain);
int ret;

@@ -486,7 +476,7 @@ static bool qcom_iommu_capable(struct device *dev, enum iommu_cap cap)

static struct iommu_device *qcom_iommu_probe_device(struct device *dev)
{
- struct qcom_iommu_dev *qcom_iommu = to_iommu(dev);
+ struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
struct device_link *link;

if (!qcom_iommu)
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index d5a4955910ff..ce19a2a21e2a 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -776,16 +776,11 @@ static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
{
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
- struct mtk_iommu_data *data;
+ struct mtk_iommu_data *data = dev_iommu_priv_get(dev);
struct device_link *link;
struct device *larbdev;
unsigned int larbid, larbidx, i;

- if (!fwspec || fwspec->ops != &mtk_iommu_ops)
- return ERR_PTR(-ENODEV); /* Not a iommu client device */
-
- data = dev_iommu_priv_get(dev);
-
if (!MTK_IOMMU_IS_TYPE(data->plat_data, MTK_IOMMU_TYPE_MM))
return &data->iommu;

diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index 78d0a84c704f..328833823181 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -478,9 +478,6 @@ static struct iommu_device *mtk_iommu_v1_probe_device(struct device *dev)
idx++;
}

- if (!fwspec || fwspec->ops != &mtk_iommu_v1_ops)
- return ERR_PTR(-ENODEV); /* Not a iommu client device */
-
data = dev_iommu_priv_get(dev);

/* Link the consumer device with the smi-larb device(supplier) */
diff --git a/drivers/iommu/sprd-iommu.c b/drivers/iommu/sprd-iommu.c
index ae94d74b73f4..85378f7cfd1f 100644
--- a/drivers/iommu/sprd-iommu.c
+++ b/drivers/iommu/sprd-iommu.c
@@ -358,13 +358,7 @@ static phys_addr_t sprd_iommu_iova_to_phys(struct iommu_domain *domain,

static struct iommu_device *sprd_iommu_probe_device(struct device *dev)
{
- struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
- struct sprd_iommu_device *sdev;
-
- if (!fwspec || fwspec->ops != &sprd_iommu_ops)
- return ERR_PTR(-ENODEV);
-
- sdev = dev_iommu_priv_get(dev);
+ struct sprd_iommu_device *sdev = dev_iommu_priv_get(dev);

return &sdev->iommu;
}
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 5b8fe9bfa9a5..59f1abd6ee53 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -945,9 +945,6 @@ static struct iommu_device *viommu_probe_device(struct device *dev)
struct viommu_dev *viommu = NULL;
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);

- if (!fwspec || fwspec->ops != &viommu_ops)
- return ERR_PTR(-ENODEV);
-
viommu = viommu_get_by_fwnode(fwspec->iommu_fwnode);
if (!viommu)
return ERR_PTR(-ENODEV);
--
2.36.1.dirty
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