VT-d: cleanup iommu_flush_iotlb_psi and flush_unmaps

Make iommu_flush_iotlb_psi() and flush_unmaps() more readable.
Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/pci/intel-iommu.c

@@ -948,27 +948,22 @@ static void __iommu_flush_iotlb(struct intel_iommu *iommu, u16 did,
 static void iommu_flush_iotlb_psi(struct intel_iommu *iommu, u16 did,
 				  u64 addr, unsigned int pages)
 {
-	unsigned int mask;
+	unsigned int mask = ilog2(__roundup_pow_of_two(pages));
 
 	BUG_ON(addr & (~VTD_PAGE_MASK));
 	BUG_ON(pages == 0);
 
-	/* Fallback to domain selective flush if no PSI support */
-	if (!cap_pgsel_inv(iommu->cap))
-		return iommu->flush.flush_iotlb(iommu, did, 0, 0,
-						DMA_TLB_DSI_FLUSH);
-
 	/*
+	 * Fallback to domain selective flush if no PSI support or the size is
+	 * too big.
 	 * PSI requires page size to be 2 ^ x, and the base address is naturally
 	 * aligned to the size
 	 */
-	mask = ilog2(__roundup_pow_of_two(pages));
-	/* Fallback to domain selective flush if size is too big */
-	if (mask > cap_max_amask_val(iommu->cap))
-		return iommu->flush.flush_iotlb(iommu, did, 0, 0,
+	if (!cap_pgsel_inv(iommu->cap) || mask > cap_max_amask_val(iommu->cap))
+		iommu->flush.flush_iotlb(iommu, did, 0, 0,
 						DMA_TLB_DSI_FLUSH);
-
-	return iommu->flush.flush_iotlb(iommu, did, addr, mask,
+	else
+		iommu->flush.flush_iotlb(iommu, did, addr, mask,
 						DMA_TLB_PSI_FLUSH);
 }
 
@@ -2260,16 +2255,17 @@ static void flush_unmaps(void)
 		if (!iommu)
 			continue;
 
-		if (deferred_flush[i].next) {
+		if (!deferred_flush[i].next)
+			continue;
+
 		iommu->flush.flush_iotlb(iommu, 0, 0, 0,
-						 DMA_TLB_GLOBAL_FLUSH);
+					 DMA_TLB_GLOBAL_FLUSH, 0);
 		for (j = 0; j < deferred_flush[i].next; j++) {
 			__free_iova(&deferred_flush[i].domain[j]->iovad,
 					deferred_flush[i].iova[j]);
 		}
 		deferred_flush[i].next = 0;
 	}
-	}
 
 	list_size = 0;
 }