tree 33d1c438bb7b67ac64bc537c4f10ce71d4d016df
parent 5e3c149b4dba4d2ee082d1eee2ac2c4424c2c30e
author Barret Rhoden <brho@cs.berkeley.edu> 1532034122 -0400
committer Barret Rhoden <brho@cs.berkeley.edu> 1532034122 -0400

rendez: Make sure we can block before sleeping

A lot of rendezvouses don't block, but any of them could.  By checking in
advance, instead of deep in sem_down(), we'll catch those cases where we
could have blocked but rarely do.

Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>