Fix: Use pthread_self to get threadid on OSX

[urcu.git] / urcu.c

diff --git a/urcu.c b/urcu.c
index 1aa00fec9278929996fed4183ebe2acf40d5b61f..a5568bdbd075ed1edc4539dec460c7cce40ee590 100644 (file)
--- a/urcu.c
+++ b/urcu.c
@@ -37,6 +37,7 @@
 #include <errno.h>
 #include <poll.h>
 
+#include "urcu/arch.h"
 #include "urcu/wfcqueue.h"
 #include "urcu/map/urcu.h"
 #include "urcu/static/urcu.h"
@@ -63,16 +64,9 @@
  */
 #define RCU_QS_ACTIVE_ATTEMPTS 100
 
-/*
- * RCU_MEMBARRIER is only possibly available on Linux.
- */
-#if defined(RCU_MEMBARRIER) && defined(__linux__)
-#include <urcu/syscall-compat.h>
-#endif
-
-/* If the headers do not support SYS_membarrier, fall back on RCU_MB */
-#ifdef SYS_membarrier
-# define membarrier(...)               syscall(SYS_membarrier, __VA_ARGS__)
+/* If the headers do not support membarrier system call, fall back on RCU_MB */
+#ifdef __NR_membarrier
+# define membarrier(...)               syscall(__NR_membarrier, __VA_ARGS__)
 #else
 # define membarrier(...)               -ENOSYS
 #endif
@@ -232,19 +226,27 @@ static void smp_mb_master(void)
 
 /*
  * synchronize_rcu() waiting. Single thread.
+ * Always called with rcu_registry lock held. Releases this lock and
+ * grabs it again. Holds the lock when it returns.
  */
 static void wait_gp(void)
 {
-       /* Read reader_gp before read futex */
+       /*
+        * Read reader_gp before read futex. smp_mb_master() needs to
+        * be called with the rcu registry lock held in RCU_SIGNAL
+        * flavor.
+        */
        smp_mb_master();
+       /* Temporarily unlock the registry lock. */
+       mutex_unlock(&rcu_registry_lock);
        if (uatomic_read(&rcu_gp.futex) != -1)
-               return;
+               goto end;
        while (futex_async(&rcu_gp.futex, FUTEX_WAIT, -1,
                        NULL, NULL, 0)) {
                switch (errno) {
                case EWOULDBLOCK:
                        /* Value already changed. */
-                       return;
+                       goto end;
                case EINTR:
                        /* Retry if interrupted by signal. */
                        break;  /* Get out of switch. */
@@ -253,6 +255,11 @@ static void wait_gp(void)
                        urcu_die(errno);
                }
        }
+end:
+       /*
+        * Re-lock the registry lock before the next loop.
+        */
+       mutex_lock(&rcu_registry_lock);
 }
 
 /*
@@ -315,14 +322,19 @@ static void wait_for_readers(struct cds_list_head *input_readers,
                        }
                        break;
                } else {
-                       /* Temporarily unlock the registry lock. */
-                       mutex_unlock(&rcu_registry_lock);
-                       if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS)
+                       if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) {
+                               /* wait_gp unlocks/locks registry lock. */
                                wait_gp();
-                       else
+                       } else {
+                               /* Temporarily unlock the registry lock. */
+                               mutex_unlock(&rcu_registry_lock);
                                caa_cpu_relax();
-                       /* Re-lock the registry lock before the next loop. */
-                       mutex_lock(&rcu_registry_lock);
+                               /*
+                                * Re-lock the registry lock before the
+                                * next loop.
+                                */
+                               mutex_lock(&rcu_registry_lock);
+                       }
                }
 #else /* #ifndef HAS_INCOHERENT_CACHES */
                /*
@@ -342,16 +354,20 @@ static void wait_for_readers(struct cds_list_head *input_readers,
                                smp_mb_master();
                                wait_gp_loops = 0;
                        }
-                       /* Temporarily unlock the registry lock. */
-                       mutex_unlock(&rcu_registry_lock);
                        if (wait_loops >= RCU_QS_ACTIVE_ATTEMPTS) {
+                               /* wait_gp unlocks/locks registry lock. */
                                wait_gp();
                                wait_gp_loops++;
                        } else {
+                               /* Temporarily unlock the registry lock. */
+                               mutex_unlock(&rcu_registry_lock);
                                caa_cpu_relax();
+                               /*
+                                * Re-lock the registry lock before the
+                                * next loop.
+                                */
+                               mutex_lock(&rcu_registry_lock);
                        }
-                       /* Re-lock the registry lock before the next loop. */
-                       mutex_lock(&rcu_registry_lock);
                }
 #endif /* #else #ifndef HAS_INCOHERENT_CACHES */
        }