'RELENG_7_0_0_RELEASE'.

This commit was manufactured to restore the state of the 7.0-RELEASE image.

Convert malloc()/bzero() to malloc(M_ZERO).

Obtained from:  OpenBSD
MFC after:      3 days
Approved by:    re (kensmith)

but gcc's optimizer isn't smart enough to see that.  Pre-initializing
seems harmless enough.

Approved by:  re (rwatson)

and its bibliography.

Submitted by:   Tomoyuki Okazaki <okazaki at kick dot gr dot jp>
MFC after:      1 month

and flags with an sxlock.  This leads to a significant and measurable
performance improvement as a result of access to shared locking for
frequent lookup operations, reduced general overhead, and reduced overhead
in the event of contention.  All of these are imported for threaded
applications where simultaneous access to a shared file descriptor array
occurs frequently.  Kris has reported 2x-4x transaction rate improvements
on 8-core MySQL benchmarks; smaller improvements can be expected for many
workloads as a result of reduced overhead.

- Generally eliminate the distinction between "fast" and regular
  acquisisition of the filedesc lock; the plan is that they will now all
  be fast.  Change all locking instances to either shared or exclusive
  locks.

- Correct a bug (pointed out by kib) in fdfree() where previously msleep()
  was called without the mutex held; sx_sleep() is now always called with
  the sxlock held exclusively.

- Universally hold the struct file lock over changes to struct file,
  rather than the filedesc lock or no lock.  Always update the f_ops
  field last. A further memory barrier is required here in the future
  (discussed with jhb).

- Improve locking and reference management in linux_at(), which fails to
  properly acquire vnode references before using vnode pointers.  Annotate
  improper use of vn_fullpath(), which will be replaced at a future date.

In fcntl(), we conservatively acquire an exclusive lock, even though in
some cases a shared lock may be sufficient, which should be revisited.
The dropping of the filedesc lock in fdgrowtable() is no longer required
as the sxlock can be held over the sleep operation; we should consider
removing that (pointed out by attilio).

Tested by:	kris
Discussed with:	jhb, kris, attilio, jeff

o make all crypto drivers have a device_t; pseudo drivers like the s/w
  crypto driver synthesize one
o change the api between the crypto subsystem and drivers to use kobj;
  cryptodev_if.m defines this api
o use the fact that all crypto drivers now have a device_t to add support
  for specifying which of several potential devices to use when doing
  crypto operations
o add new ioctls that allow user apps to select a specific crypto device
  to use (previous ioctls maintained for compatibility)
o overhaul crypto subsystem code to eliminate lots of cruft and hide
  implementation details from drivers
o bring in numerous fixes from Michale Richardson/hifn; mostly for
  795x parts
o add an optional mechanism for mmap'ing the hifn 795x public key h/w
  to user space for use by openssl (not enabled by default)
o update crypto test tools to use new ioctl's and add cmd line options
  to specify a device to use for tests

These changes will also enable much future work on improving the core
crypto subsystem; including proper load balancing and interposing code
between the core and drivers to dispatch small operations to the s/w
driver as appropriate.

These changes were instigated by the work of Michael Richardson.

Reviewed by:	pjd
Approved by:	re

the crypto queue or from the return queue.

  crypto_copyback() functions.
- Add crypto_apply() function.

This will allow for more code simplification.