mm/mm_init.c: use deferred_init_mem_pfn_range_in_zone() to decide loop condition

If deferred_init_mem_pfn_range_in_zone() return true, we know it finds
some range in (spfn, epfn). Then we can use it directly for the loop
condition.
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Link: https://lore.kernel.org/all/20240605071339.15330-1-richard.weiyang@gmail.comSigned-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

mm/mm_init.c

@@ -2170,20 +2170,15 @@ static int __init deferred_init_memmap(void *data)
 	/* Only the highest zone is deferred */
 	zone = pgdat->node_zones + pgdat->nr_zones - 1;
 
-	/* If the zone is empty somebody else may have cleared out the zone */
-	if (!deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
-						 first_init_pfn))
-		goto zone_empty;
-
 	max_threads = deferred_page_init_max_threads(cpumask);
 
-	while (spfn < epfn) {
-		unsigned long epfn_align = ALIGN(epfn, PAGES_PER_SECTION);
+	while (deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn, first_init_pfn)) {
+		first_init_pfn = ALIGN(epfn, PAGES_PER_SECTION);
 		struct padata_mt_job job = {
 			.thread_fn   = deferred_init_memmap_chunk,
 			.fn_arg      = zone,
 			.start       = spfn,
-			.size        = epfn_align - spfn,
+			.size        = first_init_pfn - spfn,
 			.align       = PAGES_PER_SECTION,
 			.min_chunk   = PAGES_PER_SECTION,
 			.max_threads = max_threads,
@@ -2191,10 +2186,8 @@ static int __init deferred_init_memmap(void *data)
 		};
 
 		padata_do_multithreaded(&job);
-		deferred_init_mem_pfn_range_in_zone(&i, zone, &spfn, &epfn,
-						    epfn_align);
 	}
-zone_empty:
+
 	/* Sanity check that the next zone really is unpopulated */
 	WARN_ON(pgdat->nr_zones < MAX_NR_ZONES && populated_zone(++zone));