X-Git-Url: https://git.lttng.org/?p=urcu.git;a=blobdiff_plain;f=urcu-bp.c;h=14b200129fe42656ae11e178aa0d3c6442f26061;hp=b457d2bc8f6e49fee5b55565107219aaf02d6ee9;hb=0376e7b2f8d26778ebc4750b34e718c062c92764;hpb=06f22bdbb0c4c4d5db42a2e2dc35818aa61415be

diff --git a/urcu-bp.c b/urcu-bp.c
index b457d2b..14b2001 100644
--- a/urcu-bp.c
+++ b/urcu-bp.c
@@ -35,6 +35,8 @@
 #include <unistd.h>
 #include <sys/mman.h>
 
+#include "urcu-bp-map.h"
+
 #include "urcu-bp-static.h"
 /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
 #include "urcu-bp.h"
@@ -66,7 +68,7 @@ long rcu_gp_ctr = RCU_GP_COUNT;
  */
 struct rcu_reader __thread *rcu_reader;
 
-static LIST_HEAD(registry);
+static CDS_LIST_HEAD(registry);
 
 struct registry_arena {
 	void *p;
@@ -76,6 +78,9 @@ struct registry_arena {
 
 static struct registry_arena registry_arena;
 
+/* Saved fork signal mask, protected by rcu_gp_lock */
+static sigset_t saved_fork_signal_mask;
+
 static void rcu_gc_registry(void);
 
 static void mutex_lock(pthread_mutex_t *mutex)
@@ -95,11 +100,6 @@ static void mutex_lock(pthread_mutex_t *mutex)
 			perror("Error in pthread mutex lock");
 			exit(-1);
 		}
-		if (rcu_reader.need_mb) {
-			cmm_smp_mb();
-			rcu_reader.need_mb = 0;
-			cmm_smp_mb();
-		}
 		poll(NULL,0,10);
 	}
 #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */
@@ -118,18 +118,18 @@ static void mutex_unlock(pthread_mutex_t *mutex)
 
 void update_counter_and_wait(void)
 {
-	LIST_HEAD(qsreaders);
+	CDS_LIST_HEAD(qsreaders);
 	int wait_loops = 0;
 	struct rcu_reader *index, *tmp;
 
 	/* Switch parity: 0 -> 1, 1 -> 0 */
-	CAA_STORE_SHARED(rcu_gp_ctr, rcu_gp_ctr ^ RCU_GP_CTR_PHASE);
+	CMM_STORE_SHARED(rcu_gp_ctr, rcu_gp_ctr ^ RCU_GP_CTR_PHASE);
 
 	/*
 	 * Must commit qparity update to memory before waiting for other parity
 	 * quiescent state. Failure to do so could result in the writer waiting
 	 * forever while new readers are always accessing data (no progress).
-	 * Ensured by CAA_STORE_SHARED and CAA_LOAD_SHARED.
+	 * Ensured by CMM_STORE_SHARED and CMM_LOAD_SHARED.
 	 */
 
 	/*
@@ -144,12 +144,12 @@ void update_counter_and_wait(void)
 	 */
 	for (;;) {
 		wait_loops++;
-		list_for_each_entry_safe(index, tmp, &registry, node) {
+		cds_list_for_each_entry_safe(index, tmp, &registry, node) {
 			if (!rcu_old_gp_ongoing(&index->ctr))
-				list_move(&index->node, &qsreaders);
+				cds_list_move(&index->node, &qsreaders);
 		}
 
-		if (list_empty(&registry)) {
+		if (cds_list_empty(&registry)) {
 			break;
 		} else {
 			if (wait_loops == RCU_QS_ACTIVE_ATTEMPTS)
@@ -159,7 +159,7 @@ void update_counter_and_wait(void)
 		}
 	}
 	/* put back the reader list in the registry */
-	list_splice(&qsreaders, &registry);
+	cds_list_splice(&qsreaders, &registry);
 }
 
 void synchronize_rcu(void)
@@ -174,7 +174,7 @@ void synchronize_rcu(void)
 
 	mutex_lock(&rcu_gp_lock);
 
-	if (list_empty(&registry))
+	if (cds_list_empty(&registry))
 		goto out;
 
 	/* All threads should read qparity before accessing data structure
@@ -279,7 +279,7 @@ static void add_thread(void)
 	/* Add to registry */
 	rcu_reader_reg->tid = pthread_self();
 	assert(rcu_reader_reg->ctr == 0);
-	list_add(&rcu_reader_reg->node, &registry);
+	cds_list_add(&rcu_reader_reg->node, &registry);
 	rcu_reader = rcu_reader_reg;
 }
 
@@ -299,7 +299,7 @@ static void rcu_gc_registry(void)
 		ret = pthread_kill(tid, 0);
 		assert(ret != EINVAL);
 		if (ret == ESRCH) {
-			list_del(&rcu_reader_reg->node);
+			cds_list_del(&rcu_reader_reg->node);
 			rcu_reader_reg->ctr = 0;
 			rcu_reader_reg->alloc = 0;
 			registry_arena.used -= sizeof(struct rcu_reader);
@@ -336,3 +336,47 @@ void rcu_bp_exit()
 {
 	munmap(registry_arena.p, registry_arena.len);
 }
+
+/*
+ * Holding the rcu_gp_lock across fork will make sure we fork() don't race with
+ * a concurrent thread executing with this same lock held. This ensures that the
+ * registry is in a coherent state in the child.
+ */
+void rcu_bp_before_fork(void)
+{
+	sigset_t newmask, oldmask;
+	int ret;
+
+	ret = sigemptyset(&newmask);
+	assert(!ret);
+	ret = pthread_sigmask(SIG_SETMASK, &newmask, &oldmask);
+	assert(!ret);
+	mutex_lock(&rcu_gp_lock);
+	saved_fork_signal_mask = oldmask;
+}
+
+void rcu_bp_after_fork_parent(void)
+{
+	sigset_t oldmask;
+	int ret;
+
+	oldmask = saved_fork_signal_mask;
+	mutex_unlock(&rcu_gp_lock);
+	ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
+	assert(!ret);
+}
+
+void rcu_bp_after_fork_child(void)
+{
+	sigset_t oldmask;
+	int ret;
+
+	rcu_gc_registry();
+	oldmask = saved_fork_signal_mask;
+	mutex_unlock(&rcu_gp_lock);
+	ret = pthread_sigmask(SIG_SETMASK, &oldmask, NULL);
+	assert(!ret);
+}
+
+#include "urcu-call-rcu-impl.h"
+#include "urcu-defer-impl.h"