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

MFC r258683:
Escape special XML chars, returned by some devices, confusing XML parsers.

MFC Alexander Motin's GEOM direct dispatch work:

r256603:
Introduce new function devstat_end_transaction_bio_bt(), adding new argument
to specify present time. Use this function to move binuptime() out of lock,
substantially reducing lock congestion when slow timecounter is used.

r256606:
Move g_io_deliver() out of the lock, as required for direct dispatch.
Move g_destroy_bio() out too to reduce lock scope even more.

r256607:
Fix passing uninitialized bio_resid argument to g_trace().

r256610:
Add unmapped I/O support to GEOM RAID.

r256830:
Restore BIO_UNMAPPED and BIO_TRANSIENT_MAPPING in biodonne() when unmapping
temporary mapped buffer. That fixes double unmap if biodone() called twice
for the same BIO (but with different done methods).

r256880:
Merge GEOM direct dispatch changes from the projects/camlock branch.

When safety requirements are met, it allows to avoid passing I/O requests
to GEOM g_up/g_down thread, executing them directly in the caller context.
That allows to avoid CPU bottlenecks in g_up/g_down threads, plus avoid
several context switches per I/O.

r259247:
Fix bug introduced at r256607. We have to recalculate bp_resid here since
sizes of original and completed requests may differ due to end of media.

Testing of the stable/10 merge was done by Netflix, but all of the credit
goes to Alexander and iX Systems.

Submitted by: mav
Sponsored by: iX Systems

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

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

Introduce a kern.geom.notaste sysctl that can be used to temporarily
disable GEOM tasting to avoid the "bouncing GEOM" problem where, when
you shut down the consumer of a provider which can be viewed in multiple
ways (typically a mirror whose members are labeled partitions), GEOM
will immediately taste that provider's alter ego and reattach the
consumer.

Approved by: re (glebius)

Make g_wither_washer() to not loop by itself, but only when there was some
more topology change done that may require its attention. Add few missing
g_do_wither() calls in respective places to signal it.

This fixes potential infinite loop here when some provider is withered, but
still opened or connected for some reason and so can not be destroyed. For
example, see r227009 and r227510.

Use unit number allocation functions for GEOM minor numbers.

Make withering water tight.

When we orphan/wither a provider, an attached geom+consumer could
end up being withered as a result and it may be in front of us in
the normal object scanning order so we need to do multi-pass. On
the other hand, there may be withering stuff we can't get rid off
(yet), so we need to keep track of both the existence of withering
stuff and if there is more we can do at this time.

Rearrange some of the GEOM debugging tools to be more structured.

Retire g_sanity() and corresponding debugflag (0x8)

Retire g_{stall,release}_events().

Under #ifdef DIAGNOSTIC:

Make g_valid_obj() an official function and have it return an an
non-zero integer which indicates the kind of object when found.

Implement G_VALID_{CLASS,GEOM,CONSUMER,PROVIDER}() macros based
on g_valid_obj().

Sprinkle calls to these macros liberally over the infrastructure.

Always check that we do not free a live object.

More of the event stuff can now be private to geom_event.c

Rename g_call_me() to g_post_event(), and give it a flag
argument to determine if we can M_WAITOK in malloc.

Remove the now unused hardcoded g_post_event() event support.

Turn EV_NEW_PROVIDER into a g_call_me() event.

Convert EV_SPOILED event to use g_call_me().

Turn the hardwired NEW_CLASS event into a g_call_me() event.

Move the shutdown eventhandler stuff to a more logical place.

Add handling for cancelled events in the g_call_me() methods.

Change events to have an array of "void *" references, and give the
event posting functions varargs to fill these.

Attribute g_call_me() to appropriate g_geom's where necessary.

Add a flag argument to g_call_me() methods which will be used to signal
cancellation of events in the future.

This commit should be a no-op.

Remove some debugging in the new OAM[*] and add a debug flag for other
parts of it.

[*] I've been asked what "OAM" means: It's an acronym used in the
telecom industry, "Operations And Maintenance", and there it covers
anything from a single unlabeled led on the frontpanel the the full
nightmare of CMIP for SS7.

Turn /dev/geom.ctl from a GEOM class into a plain character device driver
instead, it will never see a disk-I/O transaction, so this is a lot simpler.

Introduce g_cancel_events() and use it a couple of places where it makes
sense.

Introduce an SX lock which allows us to stall event processing
during OAM operations.

Mitigate deadlock situation pending a more complete solution.

Retire the GEOM private statistics code and use devstat instead.

Implement a handle for efficient implementation of perforations in
lower extremities.

Setting bit 4 in debugflags (sysctl kern.geom.debugflags=16) will
allow any open to succeed on rank#1 providers. This will generally
correspond to the physical disk devices: ad0, da0, md0 etc.

This fundamentally violates the mechanics of GEOMs autoconfiguration,
and is only provided as a debugging facility, so obviously error
reports on GEOM where this bit is or has been set will not be
accepted.

Move the g_stat struct to its own .h file, we will export it to other code.

Insted of embedding a struct g_stat in consumers and providers, merely
include a pointer.

Remove a couple of <sys/time.h> includes now unneeded.

Add a special allocator for struct g_stat. This allocator will allocate
entire pages and hand out g_stat functions from there. The "id" field
indicates free/used status.

Add "/dev/geom.stats" device driver whic exports the pages from the
allocator to userland with mmap(2) in read-only mode.

This mmap(2) interface should be considered a non-public interface and
the functions in libgeom (not yet committed) should be used to access
the statistics data.

Move #defines of major/minor to internal header file so other bits can
share and coordinate with geom_dev.

Commit the correct copy of the g_stat structure.

Add debug.sizeof.g_stat sysctl.

Set the id field of the g_stat when we create consumers and providers.

Remove biocount from consumer, we will use the counters in the g_stat
structure instead. Replace one field which will need to be atomically
manipulated with two fields which will not (stat.nop and stat.nend).

Change add companion field to bio_children: bio_inbed for the exact
same reason.

Don't output the biocount in the confdot output.

Fix KASSERT in g_io_request().

Add sysctl kern.geom.collectstats defaulting to off.

Collect the following raw statistics conditioned on this sysctl:

for each consumer and provider {
total number of operations started.
total number of operations completed.
time last operation completed.
sum of idle-time.
for each of BIO_READ, BIO_WRITE and BIO_DELETE {
number of operations completed.
number of bytes completed.
number of ENOMEM errors.
number of other errors.
sum of transaction time.
}
}

API for getting hold of these statistics data not included yet.

Add the remaning part of the new libdisk interaction.

WARNING: This is not a published interface, it is a stopgap measure for
WARNING: libdisk so we can get 5.0-R out of the door.

Sponsored by: DARPA & NAI Labs

Properly isolate the locking domains of sysctl from the topology lock
for the sysctls which report the configuration.

Sponsored by: DARPA & NAI Labs.

Disable the g_sanity() check unless people ask for it in the debugflags.

Sponsored by: DARPA & NAI Labs.

Style, whitespace and lint fixes.

Sponsored by: DARPA & NAI Labs.

Implement g_call_me() as a way for geom methods to schedule operations
to be performed in the event-thread.

To do this, we need to lock the eventlist with g_eventlock (nee g_doorlock),
since g_call_me() being called from the UP/DOWN paths will not be able to
aquire g_topology_lock.

This also means that for now these events are not referenced on any
particular consumer/provider/geom.

For UP/DOWN path use, this will not become a problem since the access()
function will make sure we drain any bio's before we dismantle.

Sponsored by: DARPA & NAI Labs.

s/classs/classes/ to fixup grammer after the previous global renaming.

Sponsored by: DARPA & NAI Labs

Eliminate some thread pointers which do not make sense anymore.

Split private parts of geom.h into geom_int.h. The latter should
never be included in class implemtations.