[libvirt] [PATCH v2 0/6] nwfilter adjustments for common object

[John Ferlan]

v1: https://www.redhat.com/archives/libvir-list/2017-June/msg00079.html

Changes since v1 (if I can recall all of them!):

Patches 1, 4, 8-13 were pushed
Patches 2, 3, 5-7 are dropped

This this is a rework of patches 14-17

Patch 1 (former patch14):
 * Requested adjustments made to ACK'd patch, but since this and the
   remaining ones were related I didn't yet push it.

Patch 2 (new):
 * From review though... As it turns out, virNWFilterDefEqual doesn't
   require the @cmpUUIDs patch.

Patch 3 (fromer patch 15):
 * Fixed the line as requested. Patch was ACK'd by like Patch 1 I held
   onto it since it was related.

Patch 4 (former patch 16):
 * Let's call it a complete rewrite. Rather than rely solely on the
   refcnt of the object, I've added/implemented a 'trylock' mechanism
   which essentially will allow the subsequent patch to use the
   virObjectLockable (e.g. a non recursive lock). Of course as I got
   further into the code - I think I've come to the conclusion that
   there isn't a way for a @def to disappear between threads with a
   refcnt only mechanism because there's a few other serialized locks
   which would need to be hurdled before hand.  Still as I found out
   while running the Avocado test 'nwfilter_update_vm_running.update_arp_rule'
   the recursion would occur because the AssignDef code would call the
   Instantiation with the lock from the def being updated and that's
   where all the awful magic needs to occur.  Additionally, I found that
   one wouldn't want to attempt to lock the nwfilters list inside the
   virNWFilterObjListFindInstantiateFilter because AssignDef already
   had that lock. I debated needing a recursive lock there until I
   came to the conclusion that the list couldn't change because the
   DefineXML is protected by a driver level lock (as is the Undefine
   and Reload paths).

Patch 5 (former patch 17):
 * No changes, it was ACK'd, but without 1-4 is useless

Patch 6 (NEW):
 * Remove the need for the driver level lock for a few API's since
   we have self locking nwfilters list. Also left comments in the
   3 places where that lock remained to hopefully cause someone great
   anxiety if they decided to attempt to remove the lock without
   first consulting a specialist.

NB: Ran all of the changes through the 'nwfilter' tests found in
    the Avocado test suite.

John Ferlan (6):
  nwfilter: Add @refs logic to __virNWFilterObj
  nwfilter: Remove unnecessary UUID comparison bypass
  nwfilter: Convert _virNWFilterObjList to be a virObjectLockable
  nwfilter: Remove recursive locking for nwfilter instantiation
  nwfilter: Convert virNWFilterObj to use virObjectLockable
  nwfilter: Remove need for nwfilterDriverLock in some API's

 src/conf/virnwfilterobj.c              | 635 ++++++++++++++++++++++++---------
 src/conf/virnwfilterobj.h              |  12 +-
 src/libvirt_private.syms               |   6 +-
 src/nwfilter/nwfilter_driver.c         |  66 ++--
 src/nwfilter/nwfilter_gentech_driver.c |  66 +++-
 src/util/virobject.c                   |  24 ++
 src/util/virobject.h                   |   4 +
 src/util/virthread.c                   |   5 +
 src/util/virthread.h                   |   1 +
 9 files changed, 586 insertions(+), 233 deletions(-)

-- 
2.9.4