svn commit: r324541 - in head: share/man/man9 sys/kern sys/sys

[Matt Joras]

Author: mjoras
Date: Wed Oct 11 21:53:50 2017
New Revision: 324541
URL: https://svnweb.freebsd.org/changeset/base/324541

Log:
  Add clearing function for unr(9).
  
  Previously before you could call unrhdr_delete you needed to
  individually free every allocated unit. It is useful to be able to tear
  down the unr without having to go through this process, as it is
  significantly faster than freeing the individual units.
  
  Reviewed by:	cem, lidl
  Approved by:	rstone (mentor)
  Sponsored by:	Dell EMC Isilon
  Differential Revision:	https://reviews.freebsd.org/D12591

Modified:
  head/share/man/man9/Makefile
  head/share/man/man9/unr.9
  head/sys/kern/subr_unit.c
  head/sys/sys/systm.h

Modified: head/share/man/man9/Makefile
==============================================================================
--- head/share/man/man9/Makefile	Wed Oct 11 20:36:22 2017	(r324540)
+++ head/share/man/man9/Makefile	Wed Oct 11 21:53:50 2017	(r324541)
@@ -414,6 +414,7 @@ MAN=	accept_filter.9 \
 MLINKS=	unr.9 alloc_unr.9 \
 	unr.9 alloc_unrl.9 \
 	unr.9 alloc_unr_specific.9 \
+	unr.9 clear_unrhdr.9 \
 	unr.9 delete_unrhdr.9 \
 	unr.9 free_unr.9 \
 	unr.9 new_unrhdr.9

Modified: head/share/man/man9/unr.9
==============================================================================
--- head/share/man/man9/unr.9	Wed Oct 11 20:36:22 2017	(r324540)
+++ head/share/man/man9/unr.9	Wed Oct 11 21:53:50 2017	(r324541)
@@ -24,11 +24,12 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 5, 2010
+.Dd October 4, 2017
 .Dt UNR 9
 .Os
 .Sh NAME
 .Nm new_unrhdr ,
+.Nm clear_unrhdr ,
 .Nm delete_unrhdr ,
 .Nm alloc_unr ,
 .Nm alloc_unr_specific ,
@@ -39,6 +40,8 @@
 .Ft "struct unrhdr *"
 .Fn new_unrhdr "int low" "int high" "struct mtx *mutex"
 .Ft void
+.Fn clear_unrhdr "struct unrhdr *uh"
+.Ft void
 .Fn delete_unrhdr "struct unrhdr *uh"
 .Ft int
 .Fn alloc_unr "struct unrhdr *uh"
@@ -70,8 +73,16 @@ is not
 .Dv NULL ,
 it is used for locking when allocating and freeing units.
 Otherwise, internal mutex is used.
+.It Fn clear_unrhdr uh
+Clear all units from the specified unit number allocator entity.
+This function resets the entity as if it were just initialized with
+.Fn new_unrhdr .
 .It Fn delete_unrhdr uh
-Destroy specified unit number allocator entity.
+Delete specified unit number allocator entity.
+This function frees the memory associated with the entity, it does not free
+any units.
+To free all units use
+.Fn clear_unrhdr .
 .It Fn alloc_unr uh
 Return a new unit number.
 The lowest free number is always allocated.

Modified: head/sys/kern/subr_unit.c
==============================================================================
--- head/sys/kern/subr_unit.c	Wed Oct 11 20:36:22 2017	(r324540)
+++ head/sys/kern/subr_unit.c	Wed Oct 11 21:53:50 2017	(r324541)
@@ -366,6 +366,27 @@ delete_unrhdr(struct unrhdr *uh)
 	Free(uh);
 }
 
+void
+clear_unrhdr(struct unrhdr *uh)
+{
+	struct unr *up, *uq;
+
+	KASSERT(TAILQ_EMPTY(&uh->ppfree),
+	    ("unrhdr has postponed item for free"));
+	up = TAILQ_FIRST(&uh->head);
+	while (up != NULL) {
+		uq = TAILQ_NEXT(up, list);
+		if (up->ptr != uh) {
+			Free(up->ptr);
+		}
+		Free(up);
+		up = uq;
+	}
+	TAILQ_INIT(&uh->head);
+	uh->busy = 0;
+	uh->alloc = 0;
+}
+
 static __inline int
 is_bitmap(struct unrhdr *uh, struct unr *up)
 {

Modified: head/sys/sys/systm.h
==============================================================================
--- head/sys/sys/systm.h	Wed Oct 11 20:36:22 2017	(r324540)
+++ head/sys/sys/systm.h	Wed Oct 11 21:53:50 2017	(r324541)
@@ -450,6 +450,7 @@ struct unrhdr;
 struct unrhdr *new_unrhdr(int low, int high, struct mtx *mutex);
 void init_unrhdr(struct unrhdr *uh, int low, int high, struct mtx *mutex);
 void delete_unrhdr(struct unrhdr *uh);
+void clear_unrhdr(struct unrhdr *uh);
 void clean_unrhdr(struct unrhdr *uh);
 void clean_unrhdrl(struct unrhdr *uh);
 int alloc_unr(struct unrhdr *uh);