mm: free_area_init: use maximal zone PFNs rather than zone sizes

Currently, architectures that use free_area_init() to initialize memory
map and node and zone structures need to calculate zone and hole sizes.
We can use free_area_init_nodes() instead and let it detect the zone
boundaries while the architectures will only have to supply the possible
limits for the zones.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Hoan Tran <hoan@os.amperecomputing.com>	[arm64]
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200412194859.12663-5-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 6 insertions, 9 deletions

diff --git a/arch/m68k/mm/init.c b/arch/m68k/mm/init.c
index b88d510d4fe3..6d3147662ff2 100644
--- a/arch/m68k/mm/init.c
+++ b/arch/m68k/mm/init.c
@@ -84,7 +84,7 @@ void __init paging_init(void)
 	 * page_alloc get different views of the world.
 	 */
 	unsigned long end_mem = memory_end & PAGE_MASK;
-	unsigned long zones_size[MAX_NR_ZONES] = { 0, };
+	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0, };
 
 	high_memory = (void *) end_mem;
 
@@ -98,8 +98,8 @@ void __init paging_init(void)
 	 */
 	set_fs (USER_DS);
 
-	zones_size[ZONE_DMA] = (end_mem - PAGE_OFFSET) >> PAGE_SHIFT;
-	free_area_init(zones_size);
+	max_zone_pfn[ZONE_DMA] = end_mem >> PAGE_SHIFT;
+	free_area_init(max_zone_pfn);
 }
 
 #endif /* CONFIG_MMU */
diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
index 0ea375607767..80064e6d064f 100644
--- a/arch/m68k/mm/mcfmmu.c
+++ b/arch/m68k/mm/mcfmmu.c
@@ -39,7 +39,7 @@ void __init paging_init(void)
 	pte_t *pg_table;
 	unsigned long address, size;
 	unsigned long next_pgtable, bootmem_end;
-	unsigned long zones_size[MAX_NR_ZONES];
+	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
 	enum zone_type zone;
 	int i;
 
@@ -80,11 +80,8 @@ void __init paging_init(void)
 	}
 
 	current->mm = NULL;
-
-	for (zone = 0; zone < MAX_NR_ZONES; zone++)
-		zones_size[zone] = 0x0;
-	zones_size[ZONE_DMA] = num_pages;
-	free_area_init(zones_size);
+	max_zone_pfn[ZONE_DMA] = PFN_DOWN(_ramend);
+	free_area_init(max_zone_pfn);
 }
 
 int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)