linux-kernel - [PATCH 4/5] iommu/vt-d: Refactor prq_event

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Date:   Tue, 17 Mar 2020 15:02:28 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>
Cc:     ashok.raj@...el.com, jacob.jun.pan@...ux.intel.com,
        Liu Yi L <yi.l.liu@...el.com>, kevin.tian@...el.com,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH 4/5] iommu/vt-d: Refactor prq_event_thread()

Move the software processing page request descriptors part from
prq_event_thread() into a separated function. No any functional
changes.

Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/intel-svm.c | 43 +++++++++++++++++++++++----------------
 1 file changed, 26 insertions(+), 17 deletions(-)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 6183016f4269..6ce96dd541a6 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -517,27 +517,21 @@ static bool is_canonical_address(u64 addr)
 	return (((saddr << shift) >> shift) == saddr);
 }
 
-static irqreturn_t prq_event_thread(int irq, void *d)
+static int intel_svm_process_prq(struct intel_iommu *iommu,
+				 struct page_req_dsc *prq,
+				 int head, int tail)
 {
-	struct intel_iommu *iommu = d;
 	struct intel_svm *svm = NULL;
-	int head, tail, handled = 0;
-
-	/* Clear PPR bit before reading head/tail registers, to
-	 * ensure that we get a new interrupt if needed. */
-	writel(DMA_PRS_PPR, iommu->reg + DMAR_PRS_REG);
+	struct intel_svm_dev *sdev;
+	struct vm_area_struct *vma;
+	struct page_req_dsc *req;
+	struct qi_desc resp;
+	int handled = 0;
+	vm_fault_t ret;
+	u64 address;
+	int result;
 
-	tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
-	head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
 	while (head != tail) {
-		struct intel_svm_dev *sdev;
-		struct vm_area_struct *vma;
-		struct page_req_dsc *req;
-		struct qi_desc resp;
-		int result;
-		vm_fault_t ret;
-		u64 address;
-
 		handled = 1;
 
 		req = &iommu->prq[head / sizeof(*req)];
@@ -649,6 +643,21 @@ static irqreturn_t prq_event_thread(int irq, void *d)
 		head = (head + sizeof(*req)) & PRQ_RING_MASK;
 	}
 
+	return handled;
+}
+
+static irqreturn_t prq_event_thread(int irq, void *d)
+{
+	struct intel_iommu *iommu = d;
+	int head, tail, handled;
+
+	/* Clear PPR bit before reading head/tail registers, to
+	 * ensure that we get a new interrupt if needed. */
+	writel(DMA_PRS_PPR, iommu->reg + DMAR_PRS_REG);
+
+	tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
+	head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
+	handled = intel_svm_process_prq(iommu, iommu->prq, head, tail);
 	dmar_writeq(iommu->reg + DMAR_PQH_REG, tail);
 
 	return IRQ_RETVAL(handled);
-- 
2.17.1