[PATCH 4.14 110/167] mm: Fix memory size alignment in devm_memremap_pages_release()

Greg Kroah-Hartman
2018-02-21T12:48:41Z

From: Jan H. Schönherr <jschoenh@amazon.de>

commit 10a0cd6e4932b5078215b1ec2c896597eec0eff9 upstream.

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.

Cc: <stable@vger.kernel.org>
Fixes: 5f29a77cd957 ("mm: fix mixed zone detection in devm_memremap_pages")
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/memremap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -301,7 +301,8 @@ static void devm_memremap_pages_release(

/* 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);