diff --git a/drivers/pci/dmar.c b/drivers/pci/dmar.c
index df6af0d4ec036692d1616b9ad7fa2a0225d962ca..faf77a00cafebb800e29faad13381a64bb177d1c 100644
--- a/drivers/pci/dmar.c
+++ b/drivers/pci/dmar.c
@@ -784,7 +784,6 @@ void dmar_disable_qi(struct intel_iommu *iommu)
 		cpu_relax();
 
 	iommu->gcmd &= ~DMA_GCMD_QIE;
-
 	writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
 
 	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG, readl,
@@ -798,7 +797,7 @@ void dmar_disable_qi(struct intel_iommu *iommu)
  */
 static void __dmar_enable_qi(struct intel_iommu *iommu)
 {
-	u32 cmd, sts;
+	u32 sts;
 	unsigned long flags;
 	struct q_inval *qi = iommu->qi;
 
@@ -812,9 +811,8 @@ static void __dmar_enable_qi(struct intel_iommu *iommu)
 
 	dmar_writeq(iommu->reg + DMAR_IQA_REG, virt_to_phys(qi->desc));
 
-	cmd = iommu->gcmd | DMA_GCMD_QIE;
 	iommu->gcmd |= DMA_GCMD_QIE;
-	writel(cmd, iommu->reg + DMAR_GCMD_REG);
+	writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
 
 	/* Make sure hardware complete it */
 	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG, readl, (sts & DMA_GSTS_QIES), sts);
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 2e2c7406131d46144f0d37732d2daf1a31d39d89..bc99b1e47fbc4b869eeafcb3b175737d764b841a 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -819,7 +819,7 @@ static int iommu_alloc_root_entry(struct intel_iommu *iommu)
 static void iommu_set_root_entry(struct intel_iommu *iommu)
 {
 	void *addr;
-	u32 cmd, sts;
+	u32 sts;
 	unsigned long flag;
 
 	addr = iommu->root_entry;
@@ -827,12 +827,11 @@ static void iommu_set_root_entry(struct intel_iommu *iommu)
 	spin_lock_irqsave(&iommu->register_lock, flag);
 	dmar_writeq(iommu->reg + DMAR_RTADDR_REG, virt_to_phys(addr));
 
-	cmd = iommu->gcmd | DMA_GCMD_SRTP;
-	writel(cmd, iommu->reg + DMAR_GCMD_REG);
+	writel(iommu->gcmd | DMA_GCMD_SRTP, iommu->reg + DMAR_GCMD_REG);
 
 	/* Make sure hardware complete it */
 	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
-		readl, (sts & DMA_GSTS_RTPS), sts);
+		      readl, (sts & DMA_GSTS_RTPS), sts);
 
 	spin_unlock_irqrestore(&iommu->register_lock, flag);
 }
@@ -844,12 +843,13 @@ static void iommu_flush_write_buffer(struct intel_iommu *iommu)
 
 	if (!rwbf_quirk && !cap_rwbf(iommu->cap))
 		return;
+
 	spin_lock_irqsave(&iommu->register_lock, flag);
 	writel(iommu->gcmd | DMA_GCMD_WBF, iommu->reg + DMAR_GCMD_REG);
 
 	/* Make sure hardware complete it */
 	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
-			readl, (!(val & DMA_GSTS_WBFS)), val);
+		      readl, (!(val & DMA_GSTS_WBFS)), val);
 
 	spin_unlock_irqrestore(&iommu->register_lock, flag);
 }
@@ -995,13 +995,13 @@ static int iommu_enable_translation(struct intel_iommu *iommu)
 	unsigned long flags;
 
 	spin_lock_irqsave(&iommu->register_lock, flags);
-	writel(iommu->gcmd|DMA_GCMD_TE, iommu->reg + DMAR_GCMD_REG);
+	iommu->gcmd |= DMA_GCMD_TE;
+	writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
 
 	/* Make sure hardware complete it */
 	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
-		readl, (sts & DMA_GSTS_TES), sts);
+		      readl, (sts & DMA_GSTS_TES), sts);
 
-	iommu->gcmd |= DMA_GCMD_TE;
 	spin_unlock_irqrestore(&iommu->register_lock, flags);
 	return 0;
 }
@@ -1017,7 +1017,7 @@ static int iommu_disable_translation(struct intel_iommu *iommu)
 
 	/* Make sure hardware complete it */
 	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
-		readl, (!(sts & DMA_GSTS_TES)), sts);
+		      readl, (!(sts & DMA_GSTS_TES)), sts);
 
 	spin_unlock_irqrestore(&iommu->register_lock, flag);
 	return 0;
diff --git a/drivers/pci/intr_remapping.c b/drivers/pci/intr_remapping.c
index f5e0ea724a6f53a12d26443fba84b01ab898f35d..16695961408720e3c6718fa614ed422c2a19f5d2 100644
--- a/drivers/pci/intr_remapping.c
+++ b/drivers/pci/intr_remapping.c
@@ -404,7 +404,7 @@ int free_irte(int irq)
 static void iommu_set_intr_remapping(struct intel_iommu *iommu, int mode)
 {
 	u64 addr;
-	u32 cmd, sts;
+	u32 sts;
 	unsigned long flags;
 
 	addr = virt_to_phys((void *)iommu->ir_table->base);
@@ -415,9 +415,8 @@ static void iommu_set_intr_remapping(struct intel_iommu *iommu, int mode)
 		    (addr) | IR_X2APIC_MODE(mode) | INTR_REMAP_TABLE_REG_SIZE);
 
 	/* Set interrupt-remapping table pointer */
-	cmd = iommu->gcmd | DMA_GCMD_SIRTP;
 	iommu->gcmd |= DMA_GCMD_SIRTP;
-	writel(cmd, iommu->reg + DMAR_GCMD_REG);
+	writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
 
 	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
 		      readl, (sts & DMA_GSTS_IRTPS), sts);
@@ -427,9 +426,8 @@ static void iommu_set_intr_remapping(struct intel_iommu *iommu, int mode)
 		spin_lock_irqsave(&iommu->register_lock, flags);
 
 		/* enable comaptiblity format interrupt pass through */
-		cmd = iommu->gcmd | DMA_GCMD_CFI;
 		iommu->gcmd |= DMA_GCMD_CFI;
-		writel(cmd, iommu->reg + DMAR_GCMD_REG);
+		writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
 
 		IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
 			      readl, (sts & DMA_GSTS_CFIS), sts);
@@ -446,9 +444,8 @@ static void iommu_set_intr_remapping(struct intel_iommu *iommu, int mode)
 	spin_lock_irqsave(&iommu->register_lock, flags);
 
 	/* Enable interrupt-remapping */
-	cmd = iommu->gcmd | DMA_GCMD_IRE;
 	iommu->gcmd |= DMA_GCMD_IRE;
-	writel(cmd, iommu->reg + DMAR_GCMD_REG);
+	writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);
 
 	IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
 		      readl, (sts & DMA_GSTS_IRES), sts);