why fscrypt_mergeable_bio use logical block number?

[常凤楠 <changfengnan@xxxxxxxx>]

Hi:
	When I dig into a problem, I found: bio merge may reduce a lot when enable inlinecrypt, the root cause is fscrypt_mergeable_bio use logical block number rather than physical block number. I had read the UFSHCI, but not see any description about why data unit number shoud use logical block number. I want to know why, Is the anyone can explain this?

Thanks.
Fengnan Chang.