Fix race in devfs by using LIST_FIRST() instead of
 LIST_FOREACH_SAFE() when freeing the devfs private
 data entries.

Approved by:	re (kib)

Add back a bounds check on valid idle priorities that was lost in an
earlier commit.  While here, move the thread lock down in rtp_to_pri().
It is not needed for all of the priority value checks and the computation
of newpri.

Approved by:	re (kib)

If unix socket has a unix socket attached as the rights that has a
unix socket attached as the rights that has a unix socket attached as
the rights ... Kernel may overflow the stack on attempt to close such
socket.

Only close the rights file in the context of the current close if the
file is not unix domain socket. Otherwise, postpone the work to
taskqueue, preventing unlimited recursion.

Approved by:	re (bz)

Account i/o done on cdevs.

Approved by:	re (bz)

Allow shared-locked vnode to be passed to vunref(9).

Approved by:	re (bz)

Allow interrupt driven config hooks to be registered from config hook callbacks.

Interrupt driven configuration hooks serve two purposes: they are a
mechanism for registering for a callback that is invoked once interrupt
services are available, and they hold off root device selection so long
as any configuration hooks are still active.  Before this change, it was
not possible to safely register additional hooks from the context of a
configuration hook callback.  The need for this feature arises when
interrupts are required to discover new devices (e.g. access to the XenStore
to find para-virtualized devices) which in turn also require the ability
to hold off root device selection until some lengthy, interrupt driven,
configuration task has completed (e.g. Xen front/back device driver
negotiation).

More specifically, the mutex protecting the list of active configuration
hooks is never held during a callback, and static information is used
to ensure proper ordering and only a single callback to each hook even
when faced with registration or removal of a hook during an active run.

Sponsored by:	Spectra Logic Corporation
Approved by:	re (kib)

Scan the list in reverse order for the shutdown handlers of loaded modules.
This way, when there is a dependency between two modules, the handler of the
latter probed runs first.

Sponsored by:	Sandvine Incorporated

than one second between calls to tc_windup.

This commit merges the MIPS platform changes that was now stable in
-CURRENT into 8-STABLE. The MIPS changesets are too many (~400) to list
here. But the changesets merged in this commit that affect other platforms
are summarized below:

r204635 : (changes to sys/dev/hwpmc, lib/libpmc, sys/sys/pmc.h)
Add support for hwpmc(4) on the MIPS 24K, 32 bit, embedded processor.

r205845: (changes to sys/modules/Makefile)
Fix for building modules on mips and arm.

r204031: (changes to sys/kern/link_elf_obj.c)
printf fix, as part of kernel module support for MIPS.

r206404: (changes to sys/arm/include/bus.h)
Add BUS_SPACE_UNRESTRICTED and define it to be ~0, just like all the
other platforms - for arm and mips.

r206819: (changes to sys/vm/)
Add VMFS_TLB_ALIGNED_SPACE option and kmem_alloc_nofault_space(), which
is used to allocate kernel stack address on MIPS.

r208165, r211087: (sys/kern/subr_smp.c, sys/kern/sched_ule.c)
Enable ULE scheduler for MIPS, Fix for an issue in SMP when 32 cpus are
enabled.

r208659: (sys/{ia64/ia64,mips/mips,sun4v/sun4v}/pmap.c)
Simplify the inner loop of get_pv_entry()

r208794: (changes to sys/vm/)
Make vm_contig_grow_cache() extern, and use it when vm_phys_alloc_contig()
fails to allocate MIPS page table pages.

r210327:  (changes to sys/vm/)
Support for MIPS page table page allocation.  Add a new function 'vm_page_t
vm_page_alloc_freelist(int flind, int order, int req)' to vm/vm_page.c to
allocate a page from a specified freelist, and other related changes.

Reviewed by:	alc(vm changes only)
Approved by:	kib(re), alc(vm), imp(mips), jmallett(mips), gnn(mips pmc)

Fix a typo.