Fix a couple of race conditions in devstat(9) initialization.

In devstat_new_entry(), there is no need to initialize the queue
and the mutex in this function.  There are ways to do static
initialization on both, so use STAILQ_HEAD_INITIALIZER and
MTX_SYSINIT to initialize the queue and the mutex.

In devstat_alloc(), use an atomic test and set routine to guard
making our entry in /dev.  Using just a plain static variable
creates a race condition on multiprocessor machines.  If you
attempt to create a second entry in devfs, the kernel will panic.

Submitted by:	kdm
Reviewed by:	gibbs
Sponsored by:	Spectra Logic Corporation
MFC after:	1 week.

0 files changed, 0 insertions, 0 deletions