Another update_presentity patch

deadlock.patch

diff --git a/modules/presence/hash.c b/modules/presence/hash.c
index e67bfc9..8ab5cc1 100644
--- a/modules/presence/hash.c
+++ b/modules/presence/hash.c
@@ -466,6 +466,20 @@ void destroy_phtable(void)
 }
 
 /* entry must be locked before calling this function */
+unsigned short contains_phtable(pres_entry_t* p_p, unsigned int hash_code)
+{
+	pres_entry_t* p;
+
+	for ( p=pres_htable[hash_code].entries->next ; p ; p=p->next ) {
+		if(p==p_p) {
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+/* entry must be locked before calling this function */
 pres_entry_t* search_phtable(str* pres_uri,int event, unsigned int hash_code)
 {
 	pres_entry_t* p;
@@ -588,6 +602,16 @@ void next_turn_phtable(pres_entry_t* p_p, unsigned int hash_code)
 	pres_entry_t* p;
 
 	lock_get(&pres_htable[hash_code].lock);
+	next_turn_phtable_safe(p_p, hash_code);
+	lock_release(&pres_htable[hash_code].lock);
+	return;
+}
+
+/* entry must be locked before calling this function */
+void next_turn_phtable_safe(pres_entry_t* p_p, unsigned_int hash_code)
+{
+	pres_entry_t* p;
+
 	for ( p=pres_htable[hash_code].entries->next ; p ; p=p->next ) {
 		if(p==p_p) {
 			p->current_turn++;
@@ -597,11 +621,9 @@ void next_turn_phtable(pres_entry_t* p_p, unsigned int hash_code)
 		}
 	}
 
-	lock_release(&pres_htable[hash_code].lock);
 	return;
 }
 
-
 int delete_phtable(pres_entry_t* p, unsigned int hash_code)
 {
 	pres_entry_t* prev_p= NULL;
diff --git a/modules/presence/hash.h b/modules/presence/hash.h
index 98ca260..e0684d8 100644
--- a/modules/presence/hash.h
+++ b/modules/presence/hash.h
@@ -143,6 +143,7 @@ typedef struct pres_htable
 
 phtable_t* new_phtable(void);
 
+unsigned short contains_phtable(pres_entry_t* p_p, unsigned int hash_code);
 pres_entry_t* search_phtable(str* pres_uri, int event, unsigned int hash_code);
 pres_entry_t* search_phtable_etag(str* pres_uri, int event,
 		str* etag, unsigned int hash_code);
@@ -154,6 +155,7 @@ pres_entry_t* insert_phtable(str* pres_uri, int event, str* etag, char* sphere,
 int update_phtable(struct presentity* presentity, str pres_uri, str body);
 
 void next_turn_phtable(pres_entry_t* p_p, unsigned int hash_code);
+void next_turn_phtable_safe(pres_entry_t* p_p, unsigned int hash_code);
 
 int delete_phtable(pres_entry_t* p, unsigned int hash_code);
 int delete_phtable_query(str *pres_uri, int event, str* etag);
diff --git a/modules/presence/presentity.c b/modules/presence/presentity.c
index b287925..c30e974 100644
--- a/modules/presence/presentity.c
+++ b/modules/presence/presentity.c
@@ -410,6 +410,7 @@ int update_presentity(struct sip_msg* msg, presentity_t* presentity, int* sent_r
 	str* rules_doc= NULL;
 	str pres_uri= {NULL, 0};
 	pres_entry_t* p= NULL;
+	pres_entry_t* new_p= NULL;
 	unsigned int hash_code;
 	unsigned int turn;
 	str body = presentity->body;
@@ -561,8 +562,30 @@ int update_presentity(struct sip_msg* msg, presentity_t* presentity, int* sent_r
 				lock_release(&pres_htable[hash_code].lock);
 				sleep_us(100);
 				lock_get(&pres_htable[hash_code].lock);
-				p = search_phtable_etag(&pres_uri, presentity->event->evp->parsed,
+				new_p = search_phtable_etag(&pres_uri, presentity->event->evp->parsed,
 					&presentity->etag, hash_code);
+
+				/* if we are about to throw away the old p,
+				   make sure that we increment the turn
+				   (because we said we would take one) */
+				if (new_p != p) {
+
+					/* Check that p hasn't been freed or some shit */
+					p = (contains_phtable(p, hash_code)) ? p : NULL;
+
+					if (p && turn!=p->current_turn) {
+						/* Wait your turn before skipping */
+						continue;
+					} else if (p) {
+						/* Skip your turn */
+						next_turn_phtable_safe(p, hash_code);
+					}
+
+					p = new_p;
+					if (p) {
+						turn = p->last_turn++;
+					}
+				}
 			}
 
 		} else {