Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

- Add a private timer to drive the transmit watchdog instead of using
if_watchdog and if_timer.
- Fix some issues in detach for sn(4), ste(4), and ti(4). Primarily this
means calling ether_ifdetach() before anything else.

Rototill vx(4), add locking, and mark MPSAFE:
- Rename vxfoo() functions to vx_foo() to improve readability and
consistency with other drivers.
- Prefix most the softc members with 'vx_' (the other members already had
the prefix).
- Switch to using callout_init_mtx() and callout_*() rather than
timeout() and untimeout().
- Add some missing calls to if_free() in some failure cases in vx_attach().
- Use if_printf() and remove the unit number from the softc.
- Remove uses of the 'register' keyword and spls.
- Add locked variants of vx_init() and vx_start().
- Add a mutex to the softc and lock it in various appropriate places.
- Setup the interrupt handler last during attach.

Tested by: imp
MFC after: 1 week

Stop embedding struct ifnet at the top of driver softcs. Instead the
struct ifnet or the layer 2 common structure it was embedded in have
been replaced with a struct ifnet pointer to be filled by a call to the
new function, if_alloc(). The layer 2 common structure is also allocated
via if_alloc() based on the interface type. It is hung off the new
struct ifnet member, if_l2com.

This change removes the size of these structures from the kernel ABI and
will allow us to better manage them as interfaces come and go.

Other changes of note:
- Struct arpcom is no longer referenced in normal interface code.
Instead the Ethernet address is accessed via the IFP2ENADDR() macro.
To enforce this ac_enaddr has been renamed to _ac_enaddr.
- The second argument to ether_ifattach is now always the mac address
from driver private storage rather than sometimes being ac_enaddr.

Reviewed by: sobomax, sam

Start each of the license/copyright comments with /*-, minor shuffle of lines

ss if_vx through indent, and use ANSI function definitions, prior to adding
if_media and DMA support to the driver. The previous style was inconsistent
making it difficult to emulate existing style.

Replace the if_name and if_unit members of struct ifnet with new members
if_xname, if_dname, and if_dunit. if_xname is the name of the interface
and if_dname/unit are the driver name and instance.

This change paves the way for interface renaming and enhanced pseudo
device creation and configuration symantics.

Approved By: re (in principle)
Reviewed By: njl, imp
Tested On: i386, amd64, sparc64
Obtained From: NetBSD (if_xname)

Start to minimize diffs between vx and ep. These latter is based on a
more advanced version of the chips supported by the former. Matt Dodd
and I are working towards merging them, and this a step on that path.