etmem:fix kernel stack overflow in do_swapcache_reclaim

euleros inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5GN7K


CVE: NA

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In the do_swapcache_reclaim interface,
there are the following local variables.

unsigned long nr[MAX_NUMNODES],
unsigned long nr_to_reclaim[MAX_NUMNODES],
struct list_head swapcache_list[MAX_NUMNODES],

In the kernel, MAX_NUMNODES is defined as follows:

Under the x86_64 architecture, CONFIG_NODES_SHIFT is
defined as follows:
CONFIG_NODES_SHIFT=10

Therefore, under the X86_64 architecture, local variables
may cause kernel stack overflow.

Modify the above variable acquisition method
and change it to dynamic application.

Signed-off-by: liubo <liubo254@huawei.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: wangkefeng <wangkefeng.wang@huawei.com>
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>