From: Peng Fan <[email protected]> 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: Peng Fan <[email protected]> Cc: Will Deacon <[email protected]> --- V3 thread: https://lkml.org/lkml/2015/11/9/842 Changes V4: Follow Will's comments and code diff, add the failure path when failed to add a device. V2 thread: https://lkml.org/lkml/2015/11/9/39 Changes V3: This patch version is wrong to fix the group reference issue. V1 thread: https://lkml.org/lkml/2015/11/3/304 Changes V2: I did not see the update about device_group when I worked out V1. So redo the patch and refine commit msg and rebased to latest linus' linux master tree. drivers/iommu/arm-smmu-v3.c | 18 +++++++++++------- drivers/iommu/arm-smmu.c | 2 ++ 2 files changed, 13 insertions(+), 7 deletions(-) diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 4e5118a..42d30ef 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -1804,13 +1804,13 @@ 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; @@ -1826,20 +1826,20 @@ 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 */ @@ -1849,16 +1849,20 @@ 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; } diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 47dc7a7..af6afce 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -1357,6 +1357,8 @@ static int arm_smmu_add_device(struct device *dev) if (IS_ERR(group)) return PTR_ERR(group); + iommu_group_put(group); + return 0; } -- 2.6.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
