svn commit: r232331 - head/share/man/man9

[Sergey Kandaurov]

Author: pluknet
Date: Thu Mar  1 11:03:39 2012
New Revision: 232331
URL: http://svn.freebsd.org/changeset/base/232331

Log:
  Document ifnet refcount.
  
  MFC after:	1 week

Modified:
  head/share/man/man9/ifnet.9

Modified: head/share/man/man9/ifnet.9
==============================================================================
--- head/share/man/man9/ifnet.9	Thu Mar  1 10:55:01 2012	(r232330)
+++ head/share/man/man9/ifnet.9	Thu Mar  1 11:03:39 2012	(r232331)
@@ -28,7 +28,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd January 26, 2012
+.Dd March 1, 2012
 .Dt IFNET 9
 .Os
 .Sh NAME
@@ -256,6 +256,11 @@ if a unit number is not associated with 
 (Initialized by driver
 (usually via
 .Fn if_initname ) . )
+.It Va if_refcount
+.Pq Vt u_int
+The reference count.
+(Initialized by
+.Fn if_alloc . )
 .It Va if_addrhead
 .Pq Vt "struct ifaddrhead"
 The head of the
@@ -340,6 +345,20 @@ The output queue.
 .\"(Initialized by driver.)
 .El
 .Pp
+References to
+.Vt ifnet
+structures are gained by calling the
+.Fn if_ref
+function and released by calling the
+.Fn if_rele
+function.
+They are used to allow kernel code walking global interface lists
+to release the
+.Vt ifnet
+lock yet keep the
+.Vt ifnet
+structure stable.
+.Pp
 There are in addition a number of function pointers which the driver
 must initialize to complete its interface with the generic interface
 layer: