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iommu/arm-smmu-v3: Return -EBUSY when trying to re-add a device 

Although we WARN in arm_smmu_add_device() if the device being added has
been added already without a subsequent call to arm_smmu_remove_device(),
we still continue half-heartedly, initialising the stream-table for any
new StreamIDs that may have magically appeared and re-establishing device
links that should still be there from last time.

Given that calling ->add_device() twice without removing the device in the
meantime is indicative of an error in the caller, just return -EBUSY after
warning.

Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Jean Philippe-Brucker <jean-philippe@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Will Deacon 2020-01-15 15:35:16 +00:00
parent a2be6218e6
commit 92c1d360dc
1 changed files with 16 additions and 21 deletions
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15
drivers/iommu/arm-smmu-v3.c
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@ -2794,18 +2794,14 @@ static int arm_smmu_add_device(struct device *dev)
if (!fwspec || fwspec->ops != &arm_smmu_ops)
return -ENODEV;
/*
* We _can_ actually withstand dodgy bus code re-calling add_device()
* without an intervening remove_device()/of_xlate() sequence, but
* we're not going to do so quietly...
*/
if (WARN_ON_ONCE(fwspec->iommu_priv)) {
master = fwspec->iommu_priv;
smmu = master->smmu;
} else {
if (WARN_ON_ONCE(fwspec->iommu_priv))
return -EBUSY;
smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
if (!smmu)
return -ENODEV;
master = kzalloc(sizeof(*master), GFP_KERNEL);
if (!master)
return -ENOMEM;
@ -2815,7 +2811,6 @@ static int arm_smmu_add_device(struct device *dev)
master->sids = fwspec->ids;
master->num_sids = fwspec->num_ids;
fwspec->iommu_priv = master;
}
/* Check the SIDs are in range of the SMMU and our stream table */
for (i = 0; i < master->num_sids; i++) {