linux-kernel - [PATCH] mm/spase: never partially remove memmap for early section

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Message-Id: <20200623094258.6705-1-richard.weiyang@linux.alibaba.com>
Date:   Tue, 23 Jun 2020 17:42:58 +0800
From:   Wei Yang <richard.weiyang@...ux.alibaba.com>
To:     akpm@...ux-foundation.org, osalvador@...e.de,
        dan.j.williams@...el.com
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org, david@...hat.com,
        Wei Yang <richard.weiyang@...ux.alibaba.com>
Subject: [PATCH] mm/spase: never partially remove memmap for early section

For early sections, we assumes its memmap will never be partially
removed. But current behavior breaks this.

Let's correct it.

Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug")
Signed-off-by: Wei Yang <richard.weiyang@...ux.alibaba.com>
---
 mm/sparse.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index b2b9a3e34696..1a0069f492f5 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -825,10 +825,10 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
 		ms->section_mem_map &= ~SECTION_HAS_MEM_MAP;
 	}
 
-	if (section_is_early && memmap)
-		free_map_bootmem(memmap);
-	else
+	if (!section_is_early)
 		depopulate_section_memmap(pfn, nr_pages, altmap);
+	else if (memmap)
+		free_map_bootmem(memmap);
 
 	if (empty)
 		ms->section_mem_map = (unsigned long)NULL;
-- 
2.20.1 (Apple Git-117)