irqchip/gic-v3-its: Split out pending table allocation

Just as for the property table, let's move the pending table
allocation to a separate function.

Reviewed-by: Thomas Gleixner <[e-mail]>
Reviewed-by: Eric Auger <[e-mail]>
Signed-off-by: Marc Zyngier <[e-mail]>

drivers/irqchip/irq-gic-v3-its.c

···
 	return 0;
 }
 
+static struct page *its_allocate_pending_table(gfp_t gfp_flags)
+{
+	struct page *pend_page;
+	/*
+	 * The pending pages have to be at least 64kB aligned,
+	 * hence the 'max(LPI_PENDBASE_SZ, SZ_64K)' below.
+	 */
+	pend_page = alloc_pages(gfp_flags | __GFP_ZERO,
+				get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K)));
+	if (!pend_page)
+		return NULL;
+
+	/* Make sure the GIC will observe the zero-ed page */
+	gic_flush_dcache_to_poc(page_address(pend_page), LPI_PENDBASE_SZ);
+
+	return pend_page;
+}
+
 static void its_cpu_init_lpis(void)
 {
 	void __iomem *rbase = gic_data_rdist_rd_base();
···
 	pend_page = gic_data_rdist()->pend_page;
 	if (!pend_page) {
 		phys_addr_t paddr;
-		/*
-		 * The pending pages have to be at least 64kB aligned,
-		 * hence the 'max(LPI_PENDBASE_SZ, SZ_64K)' below.
-		 */
-		pend_page = alloc_pages(GFP_NOWAIT | __GFP_ZERO,
-					get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K)));
+
+		pend_page = its_allocate_pending_table(GFP_NOWAIT);
 		if (!pend_page) {
 			pr_err("Failed to allocate PENDBASE for CPU%d\n",
 			       smp_processor_id());
 			return;
 		}
-
-		/* Make sure the GIC will observe the zero-ed page */
-		gic_flush_dcache_to_poc(page_address(pend_page), LPI_PENDBASE_SZ);
 
 		paddr = page_to_phys(pend_page);
 		pr_info("CPU%d: using LPI pending table @%pa\n",