iommu/amd: Factor out setting the remap table for a devid

Setting the IRQ remap table for a specific devid (or its alias devid)
includes three steps. Those three steps are always repeated each time
this is done.
Introduce a new helper function, move those steps there and use that
function instead. The compiler can still decide if it is worth to
inline.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/amd_iommu.c

@@ -3617,6 +3617,14 @@ static struct irq_remap_table *get_irq_table(u16 devid)
 	return table;
 }
 
+static void set_remap_table_entry(struct amd_iommu *iommu, u16 devid,
+				  struct irq_remap_table *table)
+{
+	irq_lookup_table[devid] = table;
+	set_dte_irq_entry(devid, table);
+	iommu_flush_dte(iommu, devid);
+}
+
 static struct irq_remap_table *alloc_irq_table(u16 devid)
 {
 	struct irq_remap_table *table = NULL;
@@ -3637,9 +3645,7 @@ static struct irq_remap_table *alloc_irq_table(u16 devid)
 	alias = amd_iommu_alias_table[devid];
 	table = irq_lookup_table[alias];
 	if (table) {
-		irq_lookup_table[devid] = table;
-		set_dte_irq_entry(devid, table);
-		iommu_flush_dte(iommu, devid);
+		set_remap_table_entry(iommu, devid, table);
 		goto out;
 	}
 
@@ -3666,14 +3672,9 @@ static struct irq_remap_table *alloc_irq_table(u16 devid)
 		       (MAX_IRQS_PER_TABLE * (sizeof(u64) * 2)));
 
 
-	irq_lookup_table[devid] = table;
-	set_dte_irq_entry(devid, table);
-	iommu_flush_dte(iommu, devid);
-	if (devid != alias) {
-		irq_lookup_table[alias] = table;
-		set_dte_irq_entry(alias, table);
-		iommu_flush_dte(iommu, alias);
-	}
+	set_remap_table_entry(iommu, devid, table);
+	if (devid != alias)
+		set_remap_table_entry(iommu, alias, table);
 
 out:
 	iommu_completion_wait(iommu);