src/patches/compat-drivers-3.8-1-u-kref_get_unless_zero.patch

   1 --- compat-drivers-3.8-1-u/include/linux/compat-3.8.h.orig      2013-05-16 20:35:27.046386772 +0200
   2 +++ compat-drivers-3.8-1-u/include/linux/compat-3.8.h   2013-05-16 20:35:39.219767618 +0200
   3 @@ -24,35 +24,6 @@
   4
   5  /* This backports:
   6   *
   7 - * commit 4b20db3de8dab005b07c74161cb041db8c5ff3a7
   8 - * Author: Thomas Hellstrom <thellstrom@vmware.com>
   9 - * Date:   Tue Nov 6 11:31:49 2012 +0000
  10 - *
  11 - *     kref: Implement kref_get_unless_zero v3
  12 - */
  13 -/**
  14 - * kref_get_unless_zero - Increment refcount for object unless it is zero.
  15 - * @kref: object.
  16 - *
  17 - * Return non-zero if the increment succeeded. Otherwise return 0.
  18 - *
  19 - * This function is intended to simplify locking around refcounting for
  20 - * objects that can be looked up from a lookup structure, and which are
  21 - * removed from that lookup structure in the object destructor.
  22 - * Operations on such objects require at least a read lock around
  23 - * lookup + kref_get, and a write lock around kref_put + remove from lookup
  24 - * structure. Furthermore, RCU implementations become extremely tricky.
  25 - * With a lookup followed by a kref_get_unless_zero *with return value check*
  26 - * locking in the kref_put path can be deferred to the actual removal from
  27 - * the lookup structure and RCU lookups become trivial.
  28 - */
  29 -static inline int __must_check kref_get_unless_zero(struct kref *kref)
  30 -{
  31 -       return atomic_add_unless(&kref->refcount, 1, 0);
  32 -}
  33 -
  34 -/* This backports:
  35 - *
  36   * commit 83e68189745ad931c2afd45d8ee3303929233e7f
  37   * Author: Matt Fleming <matt.fleming@intel.com>
  38   * Date:   Wed Nov 14 09:42:35 2012 +0000