Xenstore watch call-backs are already abstracted away from XenBus using
the XenWatch data structure but the associated NotifierList manipulation
and file handle registration is still open coded in various xen_bus_...()
functions.
This patch creates a new XenWatchList data structure to allow these
interactions to be abstracted away from XenBus as well. This is in
preparation for a subsequent patch which will introduce separate watch lists
for XenBus and XenDevice objects.
NOTE: This patch also introduces a new notifier_list_empty() helper function
      for the purposes of adding an assertion that a XenWatchList is not
      freed whilst its associated NotifierList is still occupied.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Anthony Perard <anthony.perard@citrix.com>
Message-Id: <20190913082159.31338-2-paul.durrant@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
		
	
			
		
			
				
	
	
		
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			1.7 KiB
		
	
	
	
		
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			77 lines
		
	
	
		
			1.7 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Notifier lists
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 *
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 * Copyright IBM, Corp. 2010
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 *
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 * Authors:
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 *  Anthony Liguori   <aliguori@us.ibm.com>
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 *
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 * This work is licensed under the terms of the GNU GPL, version 2.  See
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 * the COPYING file in the top-level directory.
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 *
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 * Contributions after 2012-01-13 are licensed under the terms of the
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 * GNU GPL, version 2 or (at your option) any later version.
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 */
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#include "qemu/osdep.h"
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#include "qemu/notify.h"
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void notifier_list_init(NotifierList *list)
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{
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    QLIST_INIT(&list->notifiers);
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}
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void notifier_list_add(NotifierList *list, Notifier *notifier)
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{
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    QLIST_INSERT_HEAD(&list->notifiers, notifier, node);
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}
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void notifier_remove(Notifier *notifier)
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{
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    QLIST_REMOVE(notifier, node);
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}
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void notifier_list_notify(NotifierList *list, void *data)
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{
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    Notifier *notifier, *next;
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    QLIST_FOREACH_SAFE(notifier, &list->notifiers, node, next) {
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        notifier->notify(notifier, data);
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    }
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}
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bool notifier_list_empty(NotifierList *list)
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{
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    return QLIST_EMPTY(&list->notifiers);
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}
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void notifier_with_return_list_init(NotifierWithReturnList *list)
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{
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    QLIST_INIT(&list->notifiers);
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}
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void notifier_with_return_list_add(NotifierWithReturnList *list,
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                                   NotifierWithReturn *notifier)
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{
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    QLIST_INSERT_HEAD(&list->notifiers, notifier, node);
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}
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void notifier_with_return_remove(NotifierWithReturn *notifier)
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{
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    QLIST_REMOVE(notifier, node);
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}
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int notifier_with_return_list_notify(NotifierWithReturnList *list, void *data)
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{
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    NotifierWithReturn *notifier, *next;
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    int ret = 0;
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    QLIST_FOREACH_SAFE(notifier, &list->notifiers, node, next) {
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        ret = notifier->notify(notifier, data);
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        if (ret != 0) {
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            break;
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        }
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    }
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    return ret;
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}
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