X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=formal-model%2Furcu.spin;h=3e184576d7d39e7b458192936ad0194299d56611;hp=611464b3eb660b61d6269b5c64210afe6754d950;hb=ba59a0c7b244a0939a2298fc76a9002436ef9674;hpb=f321bf383dd9b5940b31e4db6c9e18a5abaa0213

diff --git a/formal-model/urcu.spin b/formal-model/urcu.spin
index 611464b..3e18457 100644
--- a/formal-model/urcu.spin
+++ b/formal-model/urcu.spin
@@ -27,6 +27,10 @@ bit free = 0;     /* Has RCU reclamation happened, e.g., kfree()? */
 bit need_mb = 0;  /* =1 says need reader mb, =0 for reader response. */
 byte reader_progress[4];
 		  /* Count of read-side statement executions. */
+bit reader_done = 0;
+		  /* =0 says reader still running, =1 says done. */
+bit updater_done = 0;
+		  /* =0 says updater still running, =1 says done. */
 
 /* urcu definitions and variables, taken straight from the algorithm. */
 
@@ -50,7 +54,7 @@ proctype urcu_reader()
 	do
 	:: need_mb == 1 ->
 		need_mb = 0;
-	:: 1 -> skip;
+	:: !updater_done -> skip;
 	:: 1 -> break;
 	od;
 
@@ -92,7 +96,7 @@ proctype urcu_reader()
 				    reader_progress[2] +
 				    reader_progress[3] == 0) && need_mb == 1 ->
 					need_mb = 0;
-				:: 1 -> skip;
+				:: !updater_done -> skip;
 				:: 1 -> break;
 				od;
 				urcu_active_readers = tmp;
@@ -150,7 +154,7 @@ proctype urcu_reader()
 			do
 			:: need_mb == 1 ->
 				need_mb = 0;
-			:: 1 -> skip;
+			:: !updater_done -> skip;
 			:: 1 -> break;
 			od;
 		:: else -> skip;
@@ -167,11 +171,14 @@ proctype urcu_reader()
 	od;
 	assert((tmp_free == 0) || (tmp_removed == 1));
 
+	/* Reader has completed. */
+	reader_done = 1;
+
 	/* Process any late-arriving memory-barrier requests. */
 	do
 	:: need_mb == 1 ->
 		need_mb = 0;
-	:: 1 -> skip;
+	:: !updater_done -> skip;
 	:: 1 -> break;
 	od;
 }
@@ -180,10 +187,38 @@ proctype urcu_reader()
 
 proctype urcu_updater()
 {
+	/* prior synchronize_rcu(), second counter flip. */
+	need_mb = 1;
+	do
+	:: need_mb == 1 -> skip;
+	:: need_mb == 0 -> break;
+	od;
+	urcu_gp_ctr = urcu_gp_ctr + RCU_GP_CTR_BIT;
+	need_mb = 1;
+	do
+	:: need_mb == 1 -> skip;
+	:: need_mb == 0 -> break;
+	od;
+	do
+	:: 1 ->
+		if
+		:: (urcu_active_readers & RCU_GP_CTR_NEST_MASK) != 0 &&
+		   (urcu_active_readers & ~RCU_GP_CTR_NEST_MASK) !=
+		   (urcu_gp_ctr & ~RCU_GP_CTR_NEST_MASK) ->
+			skip;
+		:: else -> break;
+		fi;
+	od;
+	need_mb = 1;
+	do
+	:: need_mb == 1 -> skip;
+	:: need_mb == 0 -> break;
+	od;
+
 	/* Removal statement, e.g., list_del_rcu(). */
 	removed = 1;
 
-	/* synchronize_rcu(), first counter flip. */
+	/* current synchronize_rcu(), first counter flip. */
 	need_mb = 1;
 	do
 	:: need_mb == 1 -> skip;
@@ -197,15 +232,13 @@ proctype urcu_updater()
 	od;
 	do
 	:: 1 ->
-		printf("urcu_gp_ctr=%x urcu_active_readers=%x\n", urcu_gp_ctr, urcu_active_readers);
-		printf("urcu_gp_ctr&0x7f=%x urcu_active_readers&0x7f=%x\n", urcu_gp_ctr & ~RCU_GP_CTR_NEST_MASK, urcu_active_readers & ~RCU_GP_CTR_NEST_MASK);
 		if
 		:: (urcu_active_readers & RCU_GP_CTR_NEST_MASK) != 0 &&
 		   (urcu_active_readers & ~RCU_GP_CTR_NEST_MASK) !=
 		   (urcu_gp_ctr & ~RCU_GP_CTR_NEST_MASK) ->
 			skip;
 		:: else -> break;
-		fi
+		fi;
 	od;
 	need_mb = 1;
 	do
@@ -213,10 +246,7 @@ proctype urcu_updater()
 	:: need_mb == 0 -> break;
 	od;
 
-	/* Erroneous removal statement, e.g., list_del_rcu(). */
-	/* removed = 1; */
-
-	/* synchronize_rcu(), second counter flip. */
+	/* current synchronize_rcu(), second counter flip. */
 	need_mb = 1;
 	do
 	:: need_mb == 1 -> skip;
@@ -230,8 +260,6 @@ proctype urcu_updater()
 	od;
 	do
 	:: 1 ->
-		printf("urcu_gp_ctr=%x urcu_active_readers=%x\n", urcu_gp_ctr, urcu_active_readers);
-		printf("urcu_gp_ctr&0x7f=%x urcu_active_readers&0x7f=%x\n", urcu_gp_ctr & ~RCU_GP_CTR_NEST_MASK, urcu_active_readers & ~RCU_GP_CTR_NEST_MASK);
 		if
 		:: (urcu_active_readers & RCU_GP_CTR_NEST_MASK) != 0 &&
 		   (urcu_active_readers & ~RCU_GP_CTR_NEST_MASK) !=
@@ -248,6 +276,12 @@ proctype urcu_updater()
 
 	/* free-up step, e.g., kfree(). */
 	free = 1;
+
+	/*
+	 * Signal updater done, ending any otherwise-infinite loops
+	 * in the reading process.
+	 */
+	updater_done = 1;
 }
 
 /*