message: append KDBUS_MSG_SRC_NAMES
connection: lock name list entries
message: introduce allocation size tracker

This is used to reduce the number of calls to krealloc(), which is
expensive. Let's see if pre-allocated buffers are a good idea in
practice.
all all metadata to "struct kmsg", make reallocation small-sized and less likely
API: append *_ns to nanosecond time values
use NSEC_PER_SEC instead of 1000000000ULL
remove some outdated comments
message: be explicit as to what we are doing with the userspace address

This makes things a bit more obvious, and fixes a sparse warning.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
convert all passed-in data references to inline data
TODO: update
names: fix memleak
consitently return -EFAULT from copy_{from,to}_user()
notify: fix return values
portal: fix return value of conn_poll
minor coding style cleanups.
cosmetics
ep, message: fix two occasions of return-before-unlock
do not fail sending a broadcast message when seeing an unconnected client
test: add fuzzer
message: fix check for empty message list