If all the nodes are marked hotpluggable, alloc node data will fail.
Because __next_mem_range_rev() will skip the hotpluggable memory
regions.  numa_clear_kernel_node_hotplug() is called after alloc node
data.

numa_init()
    ...
    ret = init_func();  // this will mark hotpluggable flag from SRAT
    ...
    memblock_set_bottom_up(false);
    ...
    ret = numa_register_memblks(&numa_meminfo);  // this will alloc node data(pglist_data)
    ...
    numa_clear_kernel_node_hotplug();  // in case all the nodes are hotpluggable
    ...

numa_register_memblks()
    setup_node_data()
        memblock_find_in_range_node()
            __memblock_find_range_top_down()
                for_each_mem_range_rev()
                    __next_mem_range_rev()

This patch moves numa_clear_kernel_node_hotplug() into
numa_register_memblks(), clear kernel node hotpluggable flag before
alloc node data, then alloc node data won't fail even all the nodes
are hotpluggable.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>