mm: change __remove_pages() to call release_mem_region_adjustable()

Change __remove_pages() to call release_mem_region_adjustable().  This
allows a requested memory range to be released from the iomem_resource
table even if it does not match exactly to an resource entry but still
fits into.  The resource entries initialized at bootup usually cover the
whole contiguous memory ranges and may not necessarily match with the
size of memory hot-delete requests.

If release_mem_region_adjustable() failed, __remove_pages() emits a
warning message and continues to proceed as it was the case with
release_mem_region().  release_mem_region(), which is defined to
__release_region(), emits a warning message and returns no error since a
void function.
Signed-off-by: NToshi Kani <toshi.kani@hp.com>
Reviewed-by : Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: T Makphaibulchoke <tmac@hp.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/memory_hotplug.c

@@ -705,8 +705,10 @@ EXPORT_SYMBOL_GPL(__add_pages);
 int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 		 unsigned long nr_pages)
 {
-	unsigned long i, ret = 0;
+	unsigned long i;
 	int sections_to_remove;
+	resource_size_t start, size;
+	int ret = 0;
 
 	/*
 	 * We can only remove entire sections
@@ -714,7 +716,12 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
 	BUG_ON(phys_start_pfn & ~PAGE_SECTION_MASK);
 	BUG_ON(nr_pages % PAGES_PER_SECTION);
 
-	release_mem_region(phys_start_pfn << PAGE_SHIFT, nr_pages * PAGE_SIZE);
+	start = phys_start_pfn << PAGE_SHIFT;
+	size = nr_pages * PAGE_SIZE;
+	ret = release_mem_region_adjustable(&iomem_resource, start, size);
+	if (ret)
+		pr_warn("Unable to release resource <%016llx-%016llx> (%d)\n",
+				start, start + size - 1, ret);
 
 	sections_to_remove = nr_pages / PAGES_PER_SECTION;
 	for (i = 0; i < sections_to_remove; i++) {