iommu/arm-smmu-v3: Return -EBUSY when trying to re-add a device (92c1d360) · Commits · 戴 / test

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>

drivers/iommu/arm-smmu-v3.c

+16 −21

Original line number	Diff line number	Diff line
		@@ -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++) {

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