linux-kernel - [PATCH v3 5/6] mm: Add mirror flag back on initrd memory

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Date:   Tue, 7 Jun 2022 17:38:04 +0800
From:   Wupeng Ma <mawupeng1@...wei.com>
To:     <corbet@....net>, <will@...nel.org>, <ardb@...nel.org>,
        <catalin.marinas@....com>
CC:     <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
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        <linux-mm@...ck.org>, <linux-riscv@...ts.infradead.org>
Subject: [PATCH v3 5/6] mm: Add mirror flag back on initrd memory

From: Ma Wupeng <mawupeng1@...wei.com>

Initrd memory will be removed and then added in arm64_memblock_init() and this
will cause it to lose all of its memblock flags. The lost of MEMBLOCK_MIRROR
flag will lead to error log printed by find_zone_movable_pfns_for_nodes if
the lower 4G range has some non-mirrored memory.

In order to solve this problem, the lost MEMBLOCK_MIRROR flag will be
reinstalled if the origin memblock has this flag.

Signed-off-by: Ma Wupeng <mawupeng1@...wei.com>
---
 arch/arm64/mm/init.c     |  9 +++++++++
 include/linux/memblock.h |  1 +
 mm/memblock.c            | 20 ++++++++++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 339ee84e5a61..11641f924d08 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -350,9 +350,18 @@ void __init arm64_memblock_init(void)
 			"initrd not fully accessible via the linear mapping -- please check your bootloader ...\n")) {
 			phys_initrd_size = 0;
 		} else {
+			int flags, ret;
+
+			ret = memblock_get_flags(base, &flags);
+			if (ret)
+				flags = 0;
+
 			memblock_remove(base, size); /* clear MEMBLOCK_ flags */
 			memblock_add(base, size);
 			memblock_reserve(base, size);
+
+			if (flags & MEMBLOCK_MIRROR)
+				memblock_mark_mirror(base, size);
 		}
 	}
 
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 50ad19662a32..3d6a382ac9c8 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -487,6 +487,7 @@ bool memblock_is_map_memory(phys_addr_t addr);
 bool memblock_is_region_memory(phys_addr_t base, phys_addr_t size);
 bool memblock_is_reserved(phys_addr_t addr);
 bool memblock_is_region_reserved(phys_addr_t base, phys_addr_t size);
+int memblock_get_flags(phys_addr_t base, int *flags);
 
 void memblock_dump_all(void);
 
diff --git a/mm/memblock.c b/mm/memblock.c
index b1d2a0009733..0c5b5699af6e 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1796,6 +1796,26 @@ int __init_memblock memblock_search_pfn_nid(unsigned long pfn,
 	return memblock_get_region_node(&type->regions[mid]);
 }
 
+/**
+ * memblock_get_flags - get a single memblock flags
+ * @base: base of memeblock to get
+ *
+ * Get the flags of memeblock with base: @base
+ *
+ * Return:
+ * 0 if ok, non-zero if fail
+ */
+int __init_memblock memblock_get_flags(phys_addr_t base, int *flags)
+{
+	int idx = memblock_search(&memblock.memory, base);
+
+	if (idx == -1)
+		return -EINVAL;
+
+	*flags = memblock.memory.regions[idx].flags;
+	return 0;
+}
+
 /**
  * memblock_is_region_memory - check if a region is a subset of memory
  * @base: base of region to check
-- 
2.25.1