[PATCH v2 06/10] iommu/amd: Reduce domain lock scope in attach device path

[Vasant Hegde <vasant.hegde@amd.com>]

Protection domain lock is required only when updating domain details.
Hence reduce the scope of protection domain lock.

Also move numa node assignment to pdom_attach_iommu().

Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
---
 drivers/iommu/amd/iommu.c | 49 +++++++++++++++++++++------------------
 1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index a4a4fc7ba689..713d05a85de9 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2016,16 +2016,23 @@ static int pdom_attach_iommu(struct amd_iommu *iommu,
 			     struct protection_domain *pdom)
 {
 	struct pdom_iommu_info *pdom_iommu_info, *curr;
+	struct io_pgtable_cfg *cfg = &pdom->iop.pgtbl.cfg;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&pdom->lock, flags);
 
 	pdom_iommu_info = xa_load(&pdom->iommu_array, iommu->index);
 	if (pdom_iommu_info) {
 		pdom_iommu_info->refcnt++;
-		return 0;
+		goto out_unlock;
 	}
 
 	pdom_iommu_info = kzalloc(sizeof(*pdom_iommu_info), GFP_ATOMIC);
-	if (!pdom_iommu_info)
-		return -ENOMEM;
+	if (!pdom_iommu_info) {
+		ret = -ENOMEM;
+		goto out_unlock;
+	}
 
 	pdom_iommu_info->iommu = iommu;
 	pdom_iommu_info->refcnt = 1;
@@ -2034,43 +2041,52 @@ static int pdom_attach_iommu(struct amd_iommu *iommu,
 			  NULL, pdom_iommu_info, GFP_ATOMIC);
 	if (curr) {
 		kfree(pdom_iommu_info);
-		return -ENOSPC;
+		ret = -ENOSPC;
+		goto out_unlock;
 	}
 
-	return 0;
+	/* Update NUMA Node ID */
+	if (cfg->amd.nid == NUMA_NO_NODE)
+		cfg->amd.nid = dev_to_node(&iommu->dev->dev);
+
+out_unlock:
+	spin_unlock_irqrestore(&pdom->lock, flags);
+	return ret;
 }
 
 static void pdom_detach_iommu(struct amd_iommu *iommu,
 			      struct protection_domain *pdom)
 {
 	struct pdom_iommu_info *pdom_iommu_info;
+	unsigned long flags;
+
+	spin_lock_irqsave(&pdom->lock, flags);
 
 	pdom_iommu_info = xa_load(&pdom->iommu_array, iommu->index);
-	if (!pdom_iommu_info)
+	if (!pdom_iommu_info) {
+		spin_unlock_irqrestore(&pdom->lock, flags);
 		return;
+	}
 
 	pdom_iommu_info->refcnt--;
 	if (pdom_iommu_info->refcnt == 0) {
 		xa_erase(&pdom->iommu_array, iommu->index);
 		kfree(pdom_iommu_info);
 	}
+
+	spin_unlock_irqrestore(&pdom->lock, flags);
 }
 
 static int do_attach(struct iommu_dev_data *dev_data,
 		     struct protection_domain *domain)
 {
 	struct amd_iommu *iommu = get_amd_iommu_from_dev_data(dev_data);
-	struct io_pgtable_cfg *cfg = &domain->iop.pgtbl.cfg;
 	int ret = 0;
 
 	/* Update data structures */
 	dev_data->domain = domain;
 	list_add(&dev_data->list, &domain->dev_list);
 
-	/* Update NUMA Node ID */
-	if (cfg->amd.nid == NUMA_NO_NODE)
-		cfg->amd.nid = dev_to_node(dev_data->dev);
-
 	/* Do reference counting */
 	ret = pdom_attach_iommu(iommu, domain);
 	if (ret)
@@ -2119,11 +2135,8 @@ static int attach_device(struct device *dev,
 			 struct protection_domain *domain)
 {
 	struct iommu_dev_data *dev_data;
-	unsigned long flags;
 	int ret = 0;
 
-	spin_lock_irqsave(&domain->lock, flags);
-
 	dev_data = dev_iommu_priv_get(dev);
 
 	spin_lock(&dev_data->lock);
@@ -2138,8 +2151,6 @@ static int attach_device(struct device *dev,
 out:
 	spin_unlock(&dev_data->lock);
 
-	spin_unlock_irqrestore(&domain->lock, flags);
-
 	return ret;
 }
 
@@ -2149,13 +2160,9 @@ static int attach_device(struct device *dev,
 static void detach_device(struct device *dev)
 {
 	struct iommu_dev_data *dev_data = dev_iommu_priv_get(dev);
-	struct protection_domain *domain = dev_data->domain;
 	struct amd_iommu *iommu = get_amd_iommu_from_dev_data(dev_data);
-	unsigned long flags;
 	bool ppr = dev_data->ppr;
 
-	spin_lock_irqsave(&domain->lock, flags);
-
 	spin_lock(&dev_data->lock);
 
 	/*
@@ -2179,8 +2186,6 @@ static void detach_device(struct device *dev)
 out:
 	spin_unlock(&dev_data->lock);
 
-	spin_unlock_irqrestore(&domain->lock, flags);
-
 	/* Remove IOPF handler */
 	if (ppr)
 		amd_iommu_iopf_remove_device(iommu, dev_data);
-- 
2.31.1