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Commit 9a4a9d8c authored by Peng Fan's avatar Peng Fan Committed by Will Deacon
Browse files

iommu/arm-smmu: Correct group reference count 



The basic flow for add a device:
 arm_smmu_add_device
        |->iommu_group_get_for_dev
            |->iommu_group_get
                     return group;  (1)
            |->ops->device_group : Init/increase reference count to/by 1.
            |->iommu_group_add_device : Increase reference count by 1.
		     return group   (2)
        |->return 0;

Since we are adding one device, the flow is (2) and the group reference
count will be increased by 2. So, we need to add iommu_group_put at the
end of arm_smmu_add_device to decrease the count by 1.

Also take the failure path into consideration when fail to add a device.

Signed-off-by: default avatarPeng Fan <van.freenix@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent a0eacd89

drivers/iommu/arm-smmu-v3.c

+11 −7
Original line number Diff line number Diff line
@@ -1809,13 +1809,13 @@ static int arm_smmu_add_device(struct device *dev) 
		smmu = arm_smmu_get_for_pci_dev(pdev);

		if (!smmu) {

			ret = -ENOENT;

			goto out_put_group;

			goto out_remove_dev;

		}



		smmu_group = kzalloc(sizeof(*smmu_group), GFP_KERNEL);

		if (!smmu_group) {

			ret = -ENOMEM;

			goto out_put_group;

			goto out_remove_dev;

		}



		smmu_group->ste.valid	= true;
@@ -1831,20 +1831,20 @@ static int arm_smmu_add_device(struct device *dev) 
	for (i = 0; i < smmu_group->num_sids; ++i) {

		/* If we already know about this SID, then we're done */

		if (smmu_group->sids[i] == sid)

			return 0;

			goto out_put_group;

	}



	/* Check the SID is in range of the SMMU and our stream table */

	if (!arm_smmu_sid_in_range(smmu, sid)) {

		ret = -ERANGE;

		goto out_put_group;

		goto out_remove_dev;

	}



	/* Ensure l2 strtab is initialised */

	if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {

		ret = arm_smmu_init_l2_strtab(smmu, sid);

		if (ret)

			goto out_put_group;

			goto out_remove_dev;

	}



	/* Resize the SID array for the group */
@@ -1854,15 +1854,19 @@ static int arm_smmu_add_device(struct device *dev) 
	if (!sids) {

		smmu_group->num_sids--;

		ret = -ENOMEM;

		goto out_put_group;

		goto out_remove_dev;

	}



	/* Add the new SID */

	sids[smmu_group->num_sids - 1] = sid;

	smmu_group->sids = sids;

	return 0;



out_put_group:

	iommu_group_put(group);

	return 0;



out_remove_dev:

	iommu_group_remove_device(dev);

	iommu_group_put(group);

	return ret;

}

drivers/iommu/arm-smmu.c

+1 −0
Original line number Diff line number Diff line
@@ -1355,6 +1355,7 @@ static int arm_smmu_add_device(struct device *dev) 
	if (IS_ERR(group))

		return PTR_ERR(group);



	iommu_group_put(group);

	return 0;

}