svn commit: r254703 - in head: share/man/man9 sys/sys

[Davide Italiano]

Author: davide
Date: Fri Aug 23 14:12:39 2013
New Revision: 254703
URL: http://svnweb.freebsd.org/changeset/base/254703

Log:
  Introduce callout_init_rm() so that callouts can be used in conjunction
  with rmlocks. This works only with non-sleepable rm because handlers run
  in SWI context. While here, document the new KPI in the timeout(9)
  manpage.
  
  Requested by:	adrian, scottl
  Reviewed by:	mav, remko(manpage)

Modified:
  head/share/man/man9/timeout.9
  head/sys/sys/callout.h

Modified: head/share/man/man9/timeout.9
==============================================================================
--- head/share/man/man9/timeout.9	Fri Aug 23 14:03:48 2013	(r254702)
+++ head/share/man/man9/timeout.9	Fri Aug 23 14:12:39 2013	(r254703)
@@ -38,6 +38,7 @@
 .Nm callout_handle_init ,
 .Nm callout_init ,
 .Nm callout_init_mtx ,
+.Nm callout_init_rm ,
 .Nm callout_init_rw ,
 .Nm callout_stop ,
 .Nm callout_drain ,
@@ -73,6 +74,8 @@ struct callout_handle handle = CALLOUT_H
 .Fn callout_init "struct callout *c" "int mpsafe"
 .Ft void
 .Fn callout_init_mtx "struct callout *c" "struct mtx *mtx" "int flags"
+.Fn void
+.Fn callout_init_rm "struct callout *c" "struct rmlock *rm" "int flags"
 .Ft void
 .Fn callout_init_rw "struct callout *c" "struct rwlock *rw" "int flags"
 .Ft int
@@ -203,6 +206,7 @@ Thus they are protected from re-entrancy
 The functions
 .Fn callout_init ,
 .Fn callout_init_mtx ,
+.Fn callout_init_rm ,
 .Fn callout_init_rw ,
 .Fn callout_stop ,
 .Fn callout_drain ,
@@ -252,15 +256,25 @@ after the callout function returns.
 .Pp
 The
 .Fn callout_init_rw
-function serves the need of using rwlocks in conjunction with callouts.
-The function does basically the same as
-.Fn callout_init_mtx
+and the 
+.Fn callout_init_rm
+fuctions serve the need of using rwlocks and rmlocks in conjunction
+with callouts.
+The functions do the same as
+.Fn callout_init
 with the possibility of specifying an extra
 .Fa rw
+or
+.Fa rm
 argument.
-The usable lock classes are currently limited to mutexes and rwlocks,
-because callout handlers run in softclock swi, so they cannot sleep nor
-acquire sleepable locks like sx or lockmgr.
+If an
+.Fa rm
+argument is specified, the lock should be created without passing the
+.It Dv RM_SLEEPABLE
+flag.
+The usable lock classes are currently limited to mutexes, rwlocks and
+non-sleepable rmlocks, because callout handlers run in softclock swi,
+so they cannot sleep nor acquire sleepable locks like sx or lockmgr.
 The following
 .Fa flags
 may be specified:

Modified: head/sys/sys/callout.h
==============================================================================
--- head/sys/sys/callout.h	Fri Aug 23 14:03:48 2013	(r254702)
+++ head/sys/sys/callout.h	Fri Aug 23 14:12:39 2013	(r254703)
@@ -71,6 +71,9 @@ void	_callout_init_lock(struct callout *
 #define	callout_init_mtx(c, mtx, flags)					\
 	_callout_init_lock((c), ((mtx) != NULL) ? &(mtx)->lock_object :	\
 	    NULL, (flags))
+#define	callout_init_rm(c, rm, flags)
+	_callout_init_lock((c), ((rm != NULL) ? &(rm)->lock_object : \
+	    NULL, (flags))
 #define	callout_init_rw(c, rw, flags)					\
 	_callout_init_lock((c), ((rw) != NULL) ? &(rw)->lock_object :	\
 	   NULL, (flags))