euleros inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4LOJ6
CVE: NA

------------------------------

provide a switch named read_bypass. If enbale, all IO requests will
bypass the cache. This option could be useful when we enable userspace
prefetch and the cache device is low capacity.
Signed-off-by: NLi Ruilin <liruilin4@huawei.com>
Reviewed-by: NLuan Jianhai <luanjianhai@huawei.com>
Reviewed-by: NPeng Junyi <pengjunyi1@huawei.com>
Acked-by: NXie Xiuqi <xiexiuqi@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>
Reviewed-by: NGuangxing Deng <dengguangxing@huawei.com>
Reviewed-by: Nchao song <chao.song@huawei.com>
Reviewed-by: Nchao song <chao.song@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>