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astobj2: Run weakproxy callbacks outside of lock.

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Copy the list of weakproxy callbacks to temporary memory so they can be
run without holding the weakproxy lock.

Change-Id: Ib167622a8a0f873fd73938f7611b2a5914308047
This commit is contained in:
Corey Farrell
2017-10-10 16:09:14 -04:00
parent 65366a435e
commit fd3101e8ad
2 changed files with 26 additions and 19 deletions
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4
include/asterisk/astobj2.h
View File

@@ -671,6 +671,10 @@ int ao2_weakproxy_subscribe(void *weakproxy, ao2_weakproxy_notification_cb cb, v
* of the cb / data pair. If it was subscribed multiple times it must be * of the cb / data pair. If it was subscribed multiple times it must be
* unsubscribed as many times. The OBJ_MULTIPLE flag can be used to remove * unsubscribed as many times. The OBJ_MULTIPLE flag can be used to remove
* matching subscriptions. * matching subscriptions.
*
* \note When it's time to run callbacks they are copied to a temporary list so the
* weakproxy can be unlocked before running. That means it's possible for
* this function to find nothing before the callback is run in another thread.
*/ */
int ao2_weakproxy_unsubscribe(void *weakproxy, ao2_weakproxy_notification_cb cb, void *data, int flags); int ao2_weakproxy_unsubscribe(void *weakproxy, ao2_weakproxy_notification_cb cb, void *data, int flags);

41
main/astobj2.c
View File

@@ -82,8 +82,6 @@ struct ao2_weakproxy_notification {
AST_LIST_ENTRY(ao2_weakproxy_notification) list; AST_LIST_ENTRY(ao2_weakproxy_notification) list;
}; };
static void weakproxy_run_callbacks(struct ao2_weakproxy *weakproxy);
struct ao2_lock_priv { struct ao2_lock_priv {
ast_mutex_t lock; ast_mutex_t lock;
}; };
@@ -469,7 +467,7 @@ int __ao2_ref(void *user_data, int delta,
struct astobj2_lockobj *obj_lockobj; struct astobj2_lockobj *obj_lockobj;
int current_value; int current_value;
int ret; int ret;
void *weakproxy = NULL; struct ao2_weakproxy *weakproxy = NULL;
if (obj == NULL) { if (obj == NULL) {
if (ref_log && user_data) { if (ref_log && user_data) {
@@ -498,6 +496,8 @@ int __ao2_ref(void *user_data, int delta,
#endif #endif
if (weakproxy) { if (weakproxy) {
struct ao2_weakproxy cbs;
if (current_value == 1) { if (current_value == 1) {
/* The only remaining reference is the one owned by the weak object */ /* The only remaining reference is the one owned by the weak object */
struct astobj2 *internal_weakproxy; struct astobj2 *internal_weakproxy;
@@ -508,8 +508,9 @@ int __ao2_ref(void *user_data, int delta,
internal_weakproxy->priv_data.weakptr = NULL; internal_weakproxy->priv_data.weakptr = NULL;
obj->priv_data.weakptr = NULL; obj->priv_data.weakptr = NULL;
/* Notify the subscribers that weakproxy now points to NULL. */ /* transfer list to local copy so callbacks are run with weakproxy unlocked. */
weakproxy_run_callbacks(weakproxy); cbs.destroyed_cb = weakproxy->destroyed_cb;
AST_LIST_HEAD_INIT_NOLOCK(&weakproxy->destroyed_cb);
/* weak is already unlinked from obj so this won't recurse */ /* weak is already unlinked from obj so this won't recurse */
ao2_ref(user_data, -1); ao2_ref(user_data, -1);
@@ -518,6 +519,14 @@ int __ao2_ref(void *user_data, int delta,
ao2_unlock(weakproxy); ao2_unlock(weakproxy);
if (current_value == 1) { if (current_value == 1) {
struct ao2_weakproxy_notification *destroyed_cb;
/* Notify the subscribers that weakproxy now points to NULL. */
while ((destroyed_cb = AST_LIST_REMOVE_HEAD(&cbs.destroyed_cb, list))) {
destroyed_cb->cb(weakproxy, destroyed_cb->data);
ast_free(destroyed_cb);
}
ao2_ref(weakproxy, -1); ao2_ref(weakproxy, -1);
} }
} }
@@ -796,16 +805,6 @@ void *__ao2_global_obj_ref(struct ao2_global_obj *holder, const char *tag, const
} }
static void weakproxy_run_callbacks(struct ao2_weakproxy *weakproxy)
{
struct ao2_weakproxy_notification *destroyed_cb;
while ((destroyed_cb = AST_LIST_REMOVE_HEAD(&weakproxy->destroyed_cb, list))) {
destroyed_cb->cb(weakproxy, destroyed_cb->data);
ast_free(destroyed_cb);
}
}
void *__ao2_weakproxy_alloc(size_t data_size, ao2_destructor_fn destructor_fn, void *__ao2_weakproxy_alloc(size_t data_size, ao2_destructor_fn destructor_fn,
const char *tag, const char *file, int line, const char *func) const char *tag, const char *file, int line, const char *func)
{ {
@@ -951,6 +950,7 @@ int ao2_weakproxy_subscribe(void *weakproxy, ao2_weakproxy_notification_cb cb, v
{ {
struct astobj2 *weakproxy_internal = INTERNAL_OBJ_CHECK(weakproxy); struct astobj2 *weakproxy_internal = INTERNAL_OBJ_CHECK(weakproxy);
int ret = -1; int ret = -1;
int hasobj;
if (!weakproxy_internal || weakproxy_internal->priv_data.magic != AO2_WEAK) { if (!weakproxy_internal || weakproxy_internal->priv_data.magic != AO2_WEAK) {
return -1; return -1;
@@ -960,7 +960,8 @@ int ao2_weakproxy_subscribe(void *weakproxy, ao2_weakproxy_notification_cb cb, v
ao2_lock(weakproxy); ao2_lock(weakproxy);
} }
if (weakproxy_internal->priv_data.weakptr) { hasobj = weakproxy_internal->priv_data.weakptr != NULL;
if (hasobj) {
struct ao2_weakproxy *weak = weakproxy; struct ao2_weakproxy *weak = weakproxy;
struct ao2_weakproxy_notification *sub = ast_calloc(1, sizeof(*sub)); struct ao2_weakproxy_notification *sub = ast_calloc(1, sizeof(*sub));
@@ -970,15 +971,17 @@ int ao2_weakproxy_subscribe(void *weakproxy, ao2_weakproxy_notification_cb cb, v
AST_LIST_INSERT_HEAD(&weak->destroyed_cb, sub, list); AST_LIST_INSERT_HEAD(&weak->destroyed_cb, sub, list);
ret = 0; ret = 0;
} }
} else {
cb(weakproxy, data);
ret = 0;
} }
if (!(flags & OBJ_NOLOCK)) { if (!(flags & OBJ_NOLOCK)) {
ao2_unlock(weakproxy); ao2_unlock(weakproxy);
} }
if (!hasobj) {
cb(weakproxy, data);
ret = 0;
}
return ret; return ret;
} }