sfxge: access statistics buffers under port lock

[arybchik]

Summary

Allow access to statistics data not only from sysctl handlers.

Submitted by: Boris Misenov <Boris.Misenov at oktetlabs.ru>
Sponsored by: Solarflare Communications, Inc.

[gnn]

If you look at other drivers you'll see they have #define'd macros for the locks, rather than direct calls. This allows us to name the lock in the macro. See, for instance, this example from cxgbe/adapter.h:

#define ADAPTER_LOCK(sc) mtx_lock(&(sc)->sc_lock)
#define ADAPTER_UNLOCK(sc) mtx_unlock(&(sc)->sc_lock)
#define ADAPTER_LOCK_ASSERT_OWNED(sc) mtx_assert(&(sc)->sc_lock, MA_OWNED)
#define ADAPTER_LOCK_ASSERT_NOTOWNED(sc) mtx_assert(&(sc)->sc_lock, MA_NOTOWNED)

You should move to this model and then update the patch.

[arybchik]

I've published review request D1772 to add macros. Please, review.
Also I have a patch to make lock names unique - will follow.

[arybchik]

Use macros to acquire, release and assert locks

[arybchik]

Committed to src head