[PATCH 0/2 v3] blktrace: Fix sparse annotations and warn if enabling multiple traces

[Jan Kara <jack@xxxxxxx>]

Hello Jens,

this series contains a patch from Luis' blktrace series and then my patch
to fix sparse warnings in blktrace. Luis' patch stands on its own, was
reviewed, and changes what I need to change as well so I've decided it's just
simplest to pull it in with my patch.

								Honza