linux-kernel - [PATCH 1/2] mm: Fix memory size alignment in devm_memremap_pages

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Date:   Thu, 18 Jan 2018 01:06:01 +0100
From:   Jan H. Schönherr <jschoenh@...zon.de>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Dan Williams <dan.j.williams@...el.com>
Cc:     Jan H. Schönherr <jschoenh@...zon.de>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] mm: Fix memory size alignment in devm_memremap_pages_release()

The functions devm_memremap_pages() and devm_memremap_pages_release() use
different ways to calculate the section-aligned amount of memory. The
latter function may use an incorrect size if the memory region is small
but straddles a section border.

Use the same code for both.

Fixes: 5f29a77cd957 ("mm: fix mixed zone detection in devm_memremap_pages")
Signed-off-by: Jan H. Schönherr <jschoenh@...zon.de>
---
 kernel/memremap.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/memremap.c b/kernel/memremap.c
index 403ab9c..4712ce6 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -301,7 +301,8 @@ static void devm_memremap_pages_release(struct device *dev, void *data)
 
 	/* pages are dead and unused, undo the arch mapping */
 	align_start = res->start & ~(SECTION_SIZE - 1);
-	align_size = ALIGN(resource_size(res), SECTION_SIZE);
+	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
+		- align_start;
 
 	mem_hotplug_begin();
 	arch_remove_memory(align_start, align_size);
-- 
2.9.3.1.gcba166c.dirty