iommu/arm-smmu-v3: Allocate the CD table entry in advance

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.

Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Reviewed-by: Michael Shavit <mshavit@google.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/6-v9-5040dc602008+177d7-smmuv3_newapi_p2_jgg@nvidia.com
Signed-off-by: Will Deacon <will@kernel.org>

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 6d04b742a0e055220a9165a5a2d3fd2c7af39f87..d7d532c571add51cecc2973f02d5a5805b196cad 100644 (file)
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2635,6 +2635,7 @@ 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;
@@ -2663,6 +2664,12 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
        if (ret)
                return ret;
 
+       if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
+               cdptr = arm_smmu_alloc_cd_ptr(master, IOMMU_NO_PASID);
+               if (!cdptr)
+                       return -ENOMEM;
+       }
+
        /*
         * Prevent arm_smmu_share_asid() from trying to change the ASID
         * of either the old or new domain while we are working on it.
@@ -2682,13 +2689,6 @@ 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_alloc_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,
@@ -2705,16 +2705,8 @@ 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_init(&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,