linux-kernel - [PATCH RFC 2/5] iommu/vt-d: Replace cache_tag

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Date: Fri, 28 Jun 2024 14:27:40 +0200
From: Joel Granados via B4 Relay <devnull+j.granados.samsung.com@...nel.org>
To: David Woodhouse <dwmw2@...radead.org>, 
 Lu Baolu <baolu.lu@...ux.intel.com>, Joerg Roedel <joro@...tes.org>, 
 Will Deacon <will@...nel.org>, Robin Murphy <robin.murphy@....com>
Cc: iommu@...ts.linux.dev, linux-kernel@...r.kernel.org, 
 Joel Granados <j.granados@...sung.com>
Subject: [PATCH RFC 2/5] iommu/vt-d: Replace cache_tag_match with a tag
 comparison function

From: Joel Granados <j.granados@...sung.com>

Refactor cache_tag_match into a comparison of cache_tag_id. This
clarifies the usage of the function.

Signed-off-by: Joel Granados <j.granados@...sung.com>
---
 drivers/iommu/intel/cache.c | 40 ++++++++++++++++++++++++++--------------
 1 file changed, 26 insertions(+), 14 deletions(-)

diff --git a/drivers/iommu/intel/cache.c b/drivers/iommu/intel/cache.c
index aa8a463b1251..b50ec5520871 100644
--- a/drivers/iommu/intel/cache.c
+++ b/drivers/iommu/intel/cache.c
@@ -19,22 +19,20 @@
 #include "pasid.h"
 #include "trace.h"
 
-/* Check if an existing cache tag can be reused for a new association. */
-static bool cache_tage_match(struct cache_tag *tag, u16 domain_id,
-			     struct intel_iommu *iommu, struct device *dev,
-			     ioasid_t pasid, enum cache_tag_type type)
+static bool cache_tag_cmp(const struct cache_tag_id *left,
+			  const struct cache_tag_id *right)
 {
-	if (tag->id.type != type)
+	if (left->type != right->type)
 		return false;
 
-	if (tag->id.domain_id != domain_id || tag->id.pasid != pasid)
+	if (left->domain_id != right->domain_id || left->pasid != right->pasid)
 		return false;
 
-	if (type == CACHE_TAG_IOTLB || type == CACHE_TAG_NESTING_IOTLB)
-		return tag->id.iommu == iommu;
+	if (left->type == CACHE_TAG_DEVTLB || left->type == CACHE_TAG_NESTING_DEVTLB)
+		return left->dev == right->dev;
 
-	if (type == CACHE_TAG_DEVTLB || type == CACHE_TAG_NESTING_DEVTLB)
-		return tag->id.dev == dev;
+	if (left->type == CACHE_TAG_IOTLB || left->type == CACHE_TAG_NESTING_IOTLB)
+		return left->iommu == right->iommu;
 
 	return false;
 }
@@ -48,6 +46,13 @@ static int cache_tag_assign(struct dmar_domain *domain, u16 did,
 	struct intel_iommu *iommu = info->iommu;
 	struct cache_tag *tag, *temp;
 	unsigned long flags;
+	struct cache_tag_id cmp_tag = {
+		.type = type,
+		.pasid = pasid,
+		.iommu = info->iommu,
+		.dev = dev,
+		.domain_id = did
+	};
 
 	tag = kzalloc(sizeof(*tag), GFP_KERNEL);
 	if (!tag)
@@ -66,7 +71,7 @@ static int cache_tag_assign(struct dmar_domain *domain, u16 did,
 
 	spin_lock_irqsave(&domain->cache_lock, flags);
 	list_for_each_entry(temp, &domain->cache_tags, node) {
-		if (cache_tage_match(temp, did, iommu, dev, pasid, type)) {
+		if (cache_tag_cmp(&temp->id, &cmp_tag)) {
 			temp->users++;
 			spin_unlock_irqrestore(&domain->cache_lock, flags);
 			kfree(tag);
@@ -86,14 +91,21 @@ static void cache_tag_unassign(struct dmar_domain *domain, u16 did,
 			       struct device *dev, ioasid_t pasid,
 			       enum cache_tag_type type)
 {
-	struct device_domain_info *info = dev_iommu_priv_get(dev);
-	struct intel_iommu *iommu = info->iommu;
 	struct cache_tag *tag;
 	unsigned long flags;
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct cache_tag_id cmp_tag = {
+		.type = type,
+		.pasid = pasid,
+		.iommu = info->iommu,
+		.dev = dev,
+		.domain_id = did
+	};
+
 
 	spin_lock_irqsave(&domain->cache_lock, flags);
 	list_for_each_entry(tag, &domain->cache_tags, node) {
-		if (cache_tage_match(tag, did, iommu, dev, pasid, type)) {
+		if (cache_tag_cmp(&tag->id, &cmp_tag)) {
 			trace_cache_tag_unassign(tag);
 			if (--tag->users == 0) {
 				list_del(&tag->node);

-- 
2.43.0