MFS10 r273767 / MFC r273638:
Revert somewhat hackish geom_disk optimization, committed as part of r256880,
and the following r273143 commit, supposed to workaround introduced issue by
quite innocent-looking change.

While there is no clear understanding why, but r273143 is accused in data
corruption in some environments with high I/O load.  I personally don't see
any problem in that commit, and possibly it is just a trigger to some other
bug somewhere, but better safe then sorry for now.

Requested by:   scottl@
Approved by:	re (kib@)
MFS10 r273814
MFC r273704

Fix ATA CF ERASE breakage caused by 268205

PR:		194606
Approved by:	re (marius)
Sponsored by:	Multiplay
MFS10 r273573, MFC r273356:
Fix a race in pmap_emulate_accessed_dirty() that could trigger a EPT
misconfiguration VM-exit.

MFS10 r273807, MFC r273666:
Don't pass the 'error' return from an I/O port handler directly to vm_run().

Approved by:	re (kib)
Update releng/10.1 to -RC4 as part of the 10.1-RELEASE cycle.

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