Add (and use) generic reference counter, to improve signal:noise ratio
in code defining reference-counted objects.
This commit is contained in:
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36bfb6edbb
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d40761d725
@ -16,7 +16,6 @@
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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*/
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#include <assert.h>
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#include <gpxe/interface.h>
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#include <gpxe/interface.h>
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/** @file
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/** @file
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@ -25,30 +24,6 @@
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*
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*
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*/
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*/
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/**
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* Obtain reference to interface
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*
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* @v intf Interface
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* @ret intf Interface
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*
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* Increases the reference count on the interface.
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*/
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static struct interface * intf_get ( struct interface *intf ) {
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intf->refcnt ( intf, +1 );
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return intf;
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}
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/**
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* Drop reference to interface
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*
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* @v intf Interface
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*
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* Decreases the reference count on the interface.
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*/
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static void intf_put ( struct interface *intf ) {
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intf->refcnt ( intf, -1 );
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}
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/**
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/**
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* Plug an interface into a new destination interface
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* Plug an interface into a new destination interface
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*
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*
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@ -63,19 +38,7 @@ static void intf_put ( struct interface *intf ) {
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* interface into a null interface.
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* interface into a null interface.
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*/
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*/
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void plug ( struct interface *intf, struct interface *dest ) {
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void plug ( struct interface *intf, struct interface *dest ) {
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intf_put ( intf->dest );
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ref_put ( intf->refcnt );
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intf->dest = intf_get ( dest );
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ref_get ( dest->refcnt );
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}
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intf->dest = dest;
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/**
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* Null update reference count
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*
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* @v intf Interface
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* @v delta Change to apply to reference count
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*
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* Use this as the refcnt() method for an interface that does not need
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* to support reference counting.
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*/
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void null_refcnt ( struct interface *intf __unused, int delta __unused ) {
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/* Do nothing */
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}
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}
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@ -71,7 +71,7 @@ struct job_interface_operations null_job_ops = {
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struct job_interface null_job = {
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struct job_interface null_job = {
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.intf = {
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.intf = {
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.dest = &null_job.intf,
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.dest = &null_job.intf,
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.refcnt = null_refcnt,
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.refcnt = NULL,
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},
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},
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.op = &null_job_ops,
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.op = &null_job_ops,
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};
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};
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73
src/core/refcnt.c
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73
src/core/refcnt.c
Normal file
@ -0,0 +1,73 @@
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/*
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* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <stdlib.h>
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#include <gpxe/refcnt.h>
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/** @file
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*
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* Reference counting
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*
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*/
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/**
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* Increment reference count
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*
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* @v refcnt Reference counter, or NULL
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*
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* If @c refcnt is NULL, no action is taken.
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*/
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void ref_get ( struct refcnt *refcnt ) {
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if ( ! refcnt )
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return;
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refcnt->refcnt++;
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DBGC ( refcnt, "REFCNT %p incremented to %d\n",
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refcnt, refcnt->refcnt );
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}
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/**
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* Decrement reference count
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*
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* @v refcnt Reference counter, or NULL
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*
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* If the reference count decreases below zero, the object's free()
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* method will be called.
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*
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* If @c refcnt is NULL, no action is taken.
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*/
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void ref_put ( struct refcnt *refcnt ) {
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if ( ! refcnt )
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return;
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refcnt->refcnt--;
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DBGC ( refcnt, "REFCNT %p decremented to %d\n",
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refcnt, refcnt->refcnt );
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if ( refcnt->refcnt >= 0 )
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return;
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if ( refcnt->free ) {
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refcnt->free ( refcnt );
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} else {
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free ( refcnt );
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}
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}
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@ -230,7 +230,7 @@ struct xfer_interface_operations null_xfer_ops = {
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struct xfer_interface null_xfer = {
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struct xfer_interface null_xfer = {
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.intf = {
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.intf = {
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.dest = &null_xfer.intf,
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.dest = &null_xfer.intf,
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.refcnt = null_refcnt,
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.refcnt = NULL,
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},
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},
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.op = &null_xfer_ops,
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.op = &null_xfer_ops,
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};
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};
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@ -7,6 +7,8 @@
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*
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*
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*/
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*/
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#include <gpxe/refcnt.h>
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/** An object communication interface */
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/** An object communication interface */
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struct interface {
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struct interface {
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/** Destination interface
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/** Destination interface
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@ -18,19 +20,14 @@ struct interface {
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* unplugged, it should point to a null interface.
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* unplugged, it should point to a null interface.
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*/
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*/
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struct interface *dest;
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struct interface *dest;
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/** Update reference count
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/** Reference counter
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*
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*
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* @v intf Interface
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* If this interface is not part of a reference-counted
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* @v delta Change to apply to reference count
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* object, this field may be NULL.
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*
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* This method updates the reference count for the object
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* containing the interface.
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*/
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*/
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void ( * refcnt ) ( struct interface *intf, int delta );
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struct refcnt *refcnt;
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};
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};
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extern void plug ( struct interface *intf, struct interface *dest );
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extern void plug ( struct interface *intf, struct interface *dest );
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extern void null_refcnt ( struct interface *intf, int delta );
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#endif /* _GPXE_INTERFACE_H */
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#endif /* _GPXE_INTERFACE_H */
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@ -76,12 +76,11 @@ extern void ignore_progress ( struct job_interface *job,
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*
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*
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* @v job Job control interface
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* @v job Job control interface
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* @v op Job control interface operations
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* @v op Job control interface operations
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* @v refcnt Job control interface reference counting method
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* @v refcnt Containing object reference counter, or NULL
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*/
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*/
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static inline void job_init ( struct job_interface *job,
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static inline void job_init ( struct job_interface *job,
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struct job_interface_operations *op,
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struct job_interface_operations *op,
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void ( * refcnt ) ( struct interface *intf,
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struct refcnt *refcnt ) {
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int delta ) ) {
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job->intf.dest = &null_job.intf;
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job->intf.dest = &null_job.intf;
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job->intf.refcnt = refcnt;
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job->intf.refcnt = refcnt;
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job->op = op;
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job->op = op;
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39
src/include/gpxe/refcnt.h
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39
src/include/gpxe/refcnt.h
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#ifndef _GPXE_REFCNT_H
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#define _GPXE_REFCNT_H
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/** @file
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*
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* Reference counting
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*
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*/
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/**
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* A reference counter
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*
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* This data structure is designed to be embedded within a
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* reference-counted object.
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*/
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struct refcnt {
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/** Current reference count
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*
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* When this count is decremented below zero, the free()
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* method will be called.
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*/
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int refcnt;
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/** Free containing object
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*
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* This method is called when the reference count is
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* decremented below zero.
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*
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* If this method is left NULL, the standard library free()
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* function will be called. The upshot of this is that you
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* may omit the free() method if the @c refcnt object is the
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* first element of your reference-counted struct.
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*/
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void ( * free ) ( struct refcnt *refcnt );
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};
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extern void ref_get ( struct refcnt *refcnt );
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extern void ref_put ( struct refcnt *refcnt );
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#endif /* _GPXE_REFCNT_H */
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@ -114,12 +114,11 @@ extern int ignore_deliver_raw ( struct xfer_interface *xfer,
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*
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*
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* @v xfer Data transfer interface
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* @v xfer Data transfer interface
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* @v op Data transfer interface operations
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* @v op Data transfer interface operations
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* @v refcnt Data transfer interface reference counting method
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* @v refcnt Containing object reference counter, or NULL
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*/
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*/
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static inline void xfer_init ( struct xfer_interface *xfer,
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static inline void xfer_init ( struct xfer_interface *xfer,
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struct xfer_interface_operations *op,
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struct xfer_interface_operations *op,
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void ( * refcnt ) ( struct interface *intf,
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struct refcnt *refcnt ) {
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int delta ) ) {
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xfer->intf.dest = &null_xfer.intf;
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xfer->intf.dest = &null_xfer.intf;
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xfer->intf.refcnt = refcnt;
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xfer->intf.refcnt = refcnt;
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xfer->op = op;
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xfer->op = op;
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