[PATCH 09/27] iommu/arm-smmu-v3: Allocate the CD table entry in advance

[Jason Gunthorpe <jgg@nvidia.com>]

Avoid arm_smmu_attach_dev() having to undo the changes to the
smmu_domain->devices list, acquire the cdptr earlier so we don't need to
handle that error.

Now there is a clear break in arm_smmu_attach_dev() where all the
prep-work has been done non-disruptively and we commit to making the HW
change, which cannot fail.

This completes transforming arm_smmu_attach_dev() so that it does not
disturb the HW if it fails.

Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 26 +++++++--------------
 1 file changed, 9 insertions(+), 17 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 57ee7be8523363..e83fe8a1f8eef2 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2571,6 +2571,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	struct arm_smmu_device *smmu;
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 	struct arm_smmu_master *master;
+	struct arm_smmu_cd *cdptr;
 
 	if (!fwspec)
 		return -ENOENT;
@@ -2597,7 +2598,13 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 
 	mutex_unlock(&smmu_domain->init_mutex);
 	if (ret)
-		goto out_unlock;
+		return ret;
+
+	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
+		cdptr = arm_smmu_get_cd_ptr(master, IOMMU_NO_PASID);
+		if (!cdptr)
+			return -ENOMEM;
+	}
 
 	/*
 	 * Prevent arm_smmu_share_asid() from trying to change the ASID
@@ -2618,13 +2625,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	switch (smmu_domain->stage) {
 	case ARM_SMMU_DOMAIN_S1: {
 		struct arm_smmu_cd target_cd;
-		struct arm_smmu_cd *cdptr;
-
-		cdptr = arm_smmu_get_cd_ptr(master, IOMMU_NO_PASID);
-		if (!cdptr) {
-			ret = -ENOMEM;
-			goto out_list_del;
-		}
 
 		arm_smmu_make_s1_cd(&target_cd, master, smmu_domain);
 		arm_smmu_write_cd_entry(master, IOMMU_NO_PASID, cdptr,
@@ -2641,16 +2641,8 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 	}
 
 	arm_smmu_enable_ats(master, smmu_domain);
-	goto out_unlock;
-
-out_list_del:
-	spin_lock_irqsave(&smmu_domain->devices_lock, flags);
-	list_del(&master->domain_head);
-	spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
-
-out_unlock:
 	mutex_unlock(&arm_smmu_asid_lock);
-	return ret;
+	return 0;
 }
 
 static int arm_smmu_attach_dev_ste(struct device *dev,
-- 
2.42.0