iommu/arm-smmu-v3: Remove arm_smmu_master->domain

Introducing global statics which are of type struct iommu_domain, not
struct arm_smmu_domain makes it difficult to retain
arm_smmu_master->domain, as it can no longer point to an IDENTITY or
BLOCKED domain.

The only place that uses the value is arm_smmu_detach_dev(). Change things
to work like other drivers and call iommu_get_domain_for_dev() to obtain
the current domain.

The master->domain is subtly protecting the master->domain_head against
being unused as only PAGING domains will set master->domain and only
paging domains use the master->domain_head. To make it simple keep the
master->domain_head initialized so that the list_del() logic just does
nothing for attached non-PAGING domains.

Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Moritz Fischer <moritzf@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/10-v6-96275f25c39d+2d4-smmuv3_newapi_p1_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 9d36dde..19a7f04 100644 (file)
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2507,19 +2507,20 @@ static void arm_smmu_disable_pasid(struct arm_smmu_master *master)
 
 static void arm_smmu_detach_dev(struct arm_smmu_master *master)
 {
+       struct iommu_domain *domain = iommu_get_domain_for_dev(master->dev);
+       struct arm_smmu_domain *smmu_domain;
        unsigned long flags;
-       struct arm_smmu_domain *smmu_domain = master->domain;
 
-       if (!smmu_domain)
+       if (!domain)
                return;
 
+       smmu_domain = to_smmu_domain(domain);
        arm_smmu_disable_ats(master, smmu_domain);
 
        spin_lock_irqsave(&smmu_domain->devices_lock, flags);
-       list_del(&master->domain_head);
+       list_del_init(&master->domain_head);
        spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
 
-       master->domain = NULL;
        master->ats_enabled = false;
 }
 
@@ -2573,8 +2574,6 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 
        arm_smmu_detach_dev(master);
 
-       master->domain = smmu_domain;
-
        /*
         * The SMMU does not support enabling ATS with bypass. When the STE is
         * in bypass (STE.Config[2:0] == 0b100), ATS Translation Requests and
@@ -2593,10 +2592,8 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
        case ARM_SMMU_DOMAIN_S1:
                if (!master->cd_table.cdtab) {
                        ret = arm_smmu_alloc_cd_tables(master);
-                       if (ret) {
-                               master->domain = NULL;
+                       if (ret)
                                goto out_list_del;
-                       }
                } else {
                        /*
                         * arm_smmu_write_ctx_desc() relies on the entry being
@@ -2604,17 +2601,13 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
                         */
                        ret = arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID,
                                                      NULL);
-                       if (ret) {
-                               master->domain = NULL;
+                       if (ret)
                                goto out_list_del;
-                       }
                }
 
                ret = arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID, &smmu_domain->cd);
-               if (ret) {
-                       master->domain = NULL;
+               if (ret)
                        goto out_list_del;
-               }
 
                arm_smmu_make_cdtable_ste(&target, master);
                arm_smmu_install_ste_for_dev(master, &target);
@@ -2640,7 +2633,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 
 out_list_del:
        spin_lock_irqsave(&smmu_domain->devices_lock, flags);
-       list_del(&master->domain_head);
+       list_del_init(&master->domain_head);
        spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);
 
 out_unlock:
@@ -2841,6 +2834,7 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
        master->dev = dev;
        master->smmu = smmu;
        INIT_LIST_HEAD(&master->bonds);
+       INIT_LIST_HEAD(&master->domain_head);
        dev_iommu_priv_set(dev, master);
 
        ret = arm_smmu_insert_master(smmu, master);

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index eb66912..6b63ea7 100644 (file)
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -695,7 +695,6 @@ struct arm_smmu_stream {
 struct arm_smmu_master {
        struct arm_smmu_device          *smmu;
        struct device                   *dev;
-       struct arm_smmu_domain          *domain;
        struct list_head                domain_head;
        struct arm_smmu_stream          *streams;
        /* Locked by the iommu core using the group mutex */