linux-kernel - [PATCH] ARM: mm: initialize pfn limits with find

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Date:   Thu, 27 Dec 2018 15:47:27 -0800
From:   Doug Berger <opendmb@...il.com>
To:     Russell King <linux@...linux.org.uk>
Cc:     Catalin Marinas <catalin.marinas@....com>,
        Michal Hocko <mhocko@...e.com>,
        Mike Rapoport <rppt@...ux.vnet.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Steven Rostedt (VMware)" <rostedt@...dmis.org>,
        Jinbum Park <jinb.park7@...il.com>,
        Nicolas Pitre <nicolas.pitre@...aro.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Doug Berger <opendmb@...il.com>
Subject: [PATCH] ARM: mm: initialize pfn limits with find_limits()

The max_low_pfn value must be set before sparse_init() is called to
keep the early memblock allocations and frees balanced for kmemleak
initialization when sparsemem is enabled.

This commit accomplishes that by replacing the local variables min,
max_low, and max_high with the global limit variables min_low_pfn,
max_low_pfn, and max_pfn respectively in bootmem_init(). The global
variables are initialized directly by find_limits() and used in the
remainder of the function.

Fixes: 9099daed9c69 ("mm: kmemleak: avoid using __va() on addresses that don't have a lowmem mapping")
Signed-off-by: Doug Berger <opendmb@...il.com>
---
 arch/arm/mm/init.c | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 32e4845af2b6..98a733f3a5b9 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -302,15 +302,12 @@ void __init arm_memblock_init(const struct machine_desc *mdesc)
 
 void __init bootmem_init(void)
 {
-	unsigned long min, max_low, max_high;
-
 	memblock_allow_resize();
-	max_low = max_high = 0;
 
-	find_limits(&min, &max_low, &max_high);
+	find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
 
-	early_memtest((phys_addr_t)min << PAGE_SHIFT,
-		      (phys_addr_t)max_low << PAGE_SHIFT);
+	early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
+		      (phys_addr_t)max_low_pfn << PAGE_SHIFT);
 
 	/*
 	 * Sparsemem tries to allocate bootmem in memory_present(),
@@ -328,16 +325,7 @@ void __init bootmem_init(void)
 	 * the sparse mem_map arrays initialized by sparse_init()
 	 * for memmap_init_zone(), otherwise all PFNs are invalid.
 	 */
-	zone_sizes_init(min, max_low, max_high);
-
-	/*
-	 * This doesn't seem to be used by the Linux memory manager any
-	 * more, but is used by ll_rw_block.  If we can get rid of it, we
-	 * also get rid of some of the stuff above as well.
-	 */
-	min_low_pfn = min;
-	max_low_pfn = max_low;
-	max_pfn = max_high;
+	zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
 }
 
 /*
-- 
2.7.4