mm: fix mixed zone detection in devm_memremap_pages (5f29a77c) · Commits · 戴 / test

The check for whether we overlap "System RAM" needs to be done at section granularity. For example a system with the following mapping: 100000000-37bffffff : System RAM 37c000000-837ffffff : Persistent Memory ...is unable to use devm_memremap_pages() as it would result in two zones colliding within a given section. Signed-off-by:

Dan Williams <dan.j.williams@intel.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by:

Toshi Kani <toshi.kani@hpe.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

kernel/memremap.c

+6 −5

Original line number	Diff line number	Diff line
		@@ -270,13 +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)
		{
		int is_ram = region_intersects(res->start, resource_size(res),
		"System RAM");
		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",
		@@ -314,8 +317,6 @@ void devm_memremap_pages(struct device dev, struct resource *res,

		mutex_lock(&pgmap_lock);
		error = 0;
		align_start = res->start & ~(SECTION_SIZE - 1);
		align_size = ALIGN(resource_size(res), SECTION_SIZE);
		align_end = align_start + align_size - 1;
		for (key = align_start; key <= align_end; key += SECTION_SIZE) {
		struct dev_pagemap *dup;

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