Changes based on a branch not yet merged back to master

I have a feature branch (A) containing changes awaiting code review. I now need to begin work on new feature (B) that is dependent on new files and changes made in branch (A).

Is there "proper" way to rebase just the changes made in branch (B) back onto master (M) branch resulting from the merge of branch (A)

My tree would look like this:

- x - x - x (master) 

       \ x - x (A) x - x (B)

But after merge of branch (A), I would like it to look like this:

- x - x - x ---- x (master)
       \        / \
        x - x (A)  x - x (B)

Perhaps this?

$ git checkout master $ git pull origin master $ git merge A $ git rebase --onto master A B

Regards.