Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (M of N)

[kaktus]

Summary

r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are still not MPSAFE (or already are but aren’t properly marked). Use it in preparation for a general review of all nodes.
This is non-functional change that adds annotations to SYSCTL_NODE and SYSCTL_PROC nodes using one of the soon-to-be-required flags.

You’re asked for a review based on src/MAINTAINERS entry.

[• hselasky]

All sysctls in USB drivers are MPSAFE including uaudio.c .

[kaktus]

Mark the nodes as MPSAFE.

[• hselasky]

SYSCTL_ADD_NODE() and SYSCTL_NODE() are always MPSAFE.

I suggest putting this in by default, instead of everywhere in the code:

CTASSERT(((access) & (CTLFLAG_MPSAFE | CTLFLAG_NEEDGIANT)) == 0);
(access) | CTLFLAG_MPSAFE

--HPS

[kaktus]

SYSCTL_*_NODE is MPSAFE if the handler is NULL (what is true for most of them) or if the handler takes care of locking internally.

[kib]

It is fine to commit after hselasky accepts the revision.

[kaktus]

That was committed in rS357972 and should be auto-closed.