os/bluestore: s/align_down/p2align/

[tchaikov]

we have two implementations of align_{up,down}(). let's consolidate
them.

• s/align_up/p2roundup/
• s/align_down/p2align/
• drop common/align.h

Signed-off-by: Kefu Chai kchai@redhat.com

• References tracker ticket
• Updates documentation if necessary
• Includes tests for new functionality or reproducer for bug

[tchaikov]

but i think align_up() and align_down() are better names than p2roundup() and p2align(). can we rename the latter two ? what do you think?

if yes, i will add a commit in this PR to do this rename.

[xiexingguo]

I am not sure the re-naming proposal since the p2* wrappers only work well if the "align" is a power of 2, e.g., often times it is a block, sector, or page.

[tchaikov]

i see. put in other words, i am using this property of blocksize to replace a more general form of align_{up,down} with their special cases. let's keep it as is then.