arm, xtensa: simplify initialization of high memory pages

free_highpages() in both arm and xtensa essentially open-code
for_each_free_mem_range() loop to detect high memory pages that were not
reserved and that should be initialized and passed to the buddy allocator.

Replace open-coded implementation of for_each_free_mem_range() with usage
of memblock API to simplify the code.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>	[xtensa]
Reviewed-by: Max Filippov <jcmvbkbc@gmail.com>	[xtensa]
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-4-rppt@kernel.orgSigned-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/arm/mm/init.c

@@ -347,61 +347,29 @@ static void __init free_unused_memmap(void)
 #endif
 }
 
-#ifdef CONFIG_HIGHMEM
-static inline void free_area_high(unsigned long pfn, unsigned long end)
-{
-	for (; pfn < end; pfn++)
-		free_highmem_page(pfn_to_page(pfn));
-}
-#endif
-
 static void __init free_highpages(void)
 {
 #ifdef CONFIG_HIGHMEM
 	unsigned long max_low = max_low_pfn;
-	struct memblock_region *mem, *res;
+	phys_addr_t range_start, range_end;
+	u64 i;
 
 	/* set highmem page free */
-	for_each_memblock(memory, mem) {
-		unsigned long start = memblock_region_memory_base_pfn(mem);
-		unsigned long end = memblock_region_memory_end_pfn(mem);
+	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
+				&range_start, &range_end, NULL) {
+		unsigned long start = PHYS_PFN(range_start);
+		unsigned long end = PHYS_PFN(range_end);
 
 		/* Ignore complete lowmem entries */
 		if (end <= max_low)
 			continue;
 
-		if (memblock_is_nomap(mem))
-			continue;
-
 		/* Truncate partial highmem entries */
 		if (start < max_low)
 			start = max_low;
 
-		/* Find and exclude any reserved regions */
-		for_each_memblock(reserved, res) {
-			unsigned long res_start, res_end;
-
-			res_start = memblock_region_reserved_base_pfn(res);
-			res_end = memblock_region_reserved_end_pfn(res);
-
-			if (res_end < start)
-				continue;
-			if (res_start < start)
-				res_start = start;
-			if (res_start > end)
-				res_start = end;
-			if (res_end > end)
-				res_end = end;
-			if (res_start != start)
-				free_area_high(start, res_start);
-			start = res_end;
-			if (start == end)
-				break;
-		}
-
-		/* And now free anything which remains */
-		if (start < end)
-			free_area_high(start, end);
+		for (; start < end; start++)
+			free_highmem_page(pfn_to_page(start));
 	}
 #endif
 }

arch/xtensa/mm/init.c

@@ -79,67 +79,32 @@ void __init zones_init(void)
 	free_area_init(max_zone_pfn);
 }
 
-#ifdef CONFIG_HIGHMEM
-static void __init free_area_high(unsigned long pfn, unsigned long end)
-{
-	for (; pfn < end; pfn++)
-		free_highmem_page(pfn_to_page(pfn));
-}
-
 static void __init free_highpages(void)
 {
+#ifdef CONFIG_HIGHMEM
 	unsigned long max_low = max_low_pfn;
-	struct memblock_region *mem, *res;
+	phys_addr_t range_start, range_end;
+	u64 i;
 
-	reset_all_zones_managed_pages();
 	/* set highmem page free */
-	for_each_memblock(memory, mem) {
-		unsigned long start = memblock_region_memory_base_pfn(mem);
-		unsigned long end = memblock_region_memory_end_pfn(mem);
+	for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE,
+				&range_start, &range_end, NULL) {
+		unsigned long start = PHYS_PFN(range_start);
+		unsigned long end = PHYS_PFN(range_end);
 
 		/* Ignore complete lowmem entries */
 		if (end <= max_low)
 			continue;
 
-		if (memblock_is_nomap(mem))
-			continue;
-
 		/* Truncate partial highmem entries */
 		if (start < max_low)
 			start = max_low;
 
-		/* Find and exclude any reserved regions */
-		for_each_memblock(reserved, res) {
-			unsigned long res_start, res_end;
-
-			res_start = memblock_region_reserved_base_pfn(res);
-			res_end = memblock_region_reserved_end_pfn(res);
-
-			if (res_end < start)
-				continue;
-			if (res_start < start)
-				res_start = start;
-			if (res_start > end)
-				res_start = end;
-			if (res_end > end)
-				res_end = end;
-			if (res_start != start)
-				free_area_high(start, res_start);
-			start = res_end;
-			if (start == end)
-				break;
-		}
-
-		/* And now free anything which remains */
-		if (start < end)
-			free_area_high(start, end);
+		for (; start < end; start++)
+			free_highmem_page(pfn_to_page(start));
 	}
-}
-#else
-static void __init free_highpages(void)
-{
-}
 #endif
+}
 
 /*
  * Initialize memory pages.