linux-kernel - [PATCH] mm: fix 'size' alignment in devm_memremap

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Date:	Tue, 08 Mar 2016 14:32:25 -0800
From:	Dan Williams <dan.j.williams@...el.com>
To:	akpm@...ux-foundation.org
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	Toshi Kani <toshi.kani@....com>
Subject: [PATCH] mm: fix 'size' alignment in devm_memremap_pages()

We need to align the end address, not just the size.

Cc: Toshi Kani <toshi.kani@....com>
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
---
Hi Andrew, one more fixup to devm_memremap_pages().  I was discussing
patch "mm: fix mixed zone detection in devm_memremap_pages" with Toshi
and noticed that it was mishandling the end-of-range alignment.  Please
apply or fold this into the existing patch.

 kernel/memremap.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/kernel/memremap.c b/kernel/memremap.c
index c0f11a498a5a..60baf4d3401e 100644
--- a/kernel/memremap.c
+++ b/kernel/memremap.c
@@ -270,14 +270,16 @@ struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
 void *devm_memremap_pages(struct device *dev, struct resource *res,
 		struct percpu_ref *ref, struct vmem_altmap *altmap)
 {
-	resource_size_t align_start = res->start & ~(SECTION_SIZE - 1);
-	resource_size_t align_size = ALIGN(resource_size(res), SECTION_SIZE);
-	int is_ram = region_intersects(align_start, align_size, "System RAM");
-	resource_size_t key, align_end;
+	resource_size_t key, align_start, align_size, align_end;
 	struct dev_pagemap *pgmap;
 	struct page_map *page_map;
+	int error, nid, is_ram;
 	unsigned long pfn;
-	int error, nid;
+
+	align_start = res->start & ~(SECTION_SIZE - 1);
+	align_size = ALIGN(res->start + resource_size(res), SECTION_SIZE)
+		- align_start;
+	is_ram = region_intersects(align_start, align_size, "System RAM");
 
 	if (is_ram == REGION_MIXED) {
 		WARN_ONCE(1, "%s attempted on mixed region %pr\n",