Fix signal handler installation

[urcu.git] / urcu.c

diff --git a/urcu.c b/urcu.c
index 2a225c4ed19d4c626b8f7fb9af5efa702bf3f371..c07df2e8cf21384a07da3bb47066cd2b2bb44084 100644 (file)
--- a/urcu.c
+++ b/urcu.c
@@ -36,8 +36,14 @@
 /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
 #include "urcu.h"
 
+#ifndef DEBUG_FULL_MB
 void __attribute__((constructor)) urcu_init(void);
 void __attribute__((destructor)) urcu_exit(void);
+#else
+static inline urcu_init(void)
+{
+}
+#endif
 
 int init_done;
 
@@ -254,12 +260,11 @@ void synchronize_rcu(void)
         */
 
        /*
-        * Current RCU formal verification model assumes sequential execution of
-        * the write-side. Add core synchronization instructions. Can be removed
-        * if the formal model is extended to prove that reordering is still
-        * correct.
+        * Adding a smp_mb() which is _not_ formally required, but makes the
+        * model easier to understand. It does not have a big performance impact
+        * anyway, given this is the write-side.
         */
-       sync_core();    /* Formal model assumes serialized execution */
+       smp_mb();
 
        /*
         * Wait for previous parity to be empty of readers.
@@ -274,7 +279,12 @@ void synchronize_rcu(void)
         * Ensured by STORE_SHARED and LOAD_SHARED.
         */
 
-       sync_core();    /* Formal model assumes serialized execution */
+       /*
+        * Adding a smp_mb() which is _not_ formally required, but makes the
+        * model easier to understand. It does not have a big performance impact
+        * anyway, given this is the write-side.
+        */
+       smp_mb();
 
        switch_next_urcu_qparity();     /* 1 -> 0 */
 
@@ -286,7 +296,12 @@ void synchronize_rcu(void)
         * Ensured by STORE_SHARED and LOAD_SHARED.
         */
 
-       sync_core();    /* Formal model assumes serialized execution */
+       /*
+        * Adding a smp_mb() which is _not_ formally required, but makes the
+        * model easier to understand. It does not have a big performance impact
+        * anyway, given this is the write-side.
+        */
+       smp_mb();
 
        /*
         * Wait for previous parity to be empty of readers.
@@ -436,6 +451,8 @@ void urcu_init(void)
        init_done = 1;
 
        act.sa_sigaction = sigurcu_handler;
+       act.sa_flags = SA_SIGINFO;
+       sigemptyset(&act.sa_mask);
        ret = sigaction(SIGURCU, &act, NULL);
        if (ret) {
                perror("Error in sigaction");