CVS commit: src/sys

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Wed Feb 17 00:43:43 UTC 2016

Modified Files:
        src/sys/kern: kern_rndq.c
        src/sys/sys: rndsource.h

Log Message:
Add rnd_add_data_sync for synchronous on-demand rndsource callbacks.

Avoids lock recursion in rndsinks:

rndsink user holds lock
calls rndsink_request
calls rnd_getmore
calls an rndsource callback
calls rnd_add_data
calls rnd_process_events
calls rndsinks_distribute
calls rndsink callback
acquires rndsink user lock.

This can happen only before the rnd_process_events softint is
established, but that's enough to cause a problem and is the main
reason why all our HWRNG drivers are so byzantine (soon to be
fixed!).

ok tls


To generate a diff of this commit:
cvs rdiff -u -r1.75 -r1.76 src/sys/kern/kern_rndq.c
cvs rdiff -u -r1.4 -r1.5 src/sys/sys/rndsource.h

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.