From my reading, it sounded like there was some controversy around whether it was ready to be merged it not. It sounded like some people felt that it wasn't ready, but Linus decided to overrule them and merge it, saying it was ready enough and that merging it would help them improve it more rapidly.

I think just a figure of speech that means that he decided and that decision stands. Like a judge announcing the verdict.

He was just tired of holding it