share_pool: Don't allow concurrent sp_free or sp_unshare_uva calls

ascend inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4EUVI


CVE: NA

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Considering a process get a uva by sp_alloc(), then let multiple
processes call sp_free() to release it. Obviously this is a double-free
problem and not allowed.

The same reason for sp_unshare_uva().

Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Reviewed-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: Zhou Guanghui <zhouguanghui1@huawei.com>
Reviewed-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>