vppinfra: make first bihash add thread-safe

[vpp.git] / src / vppinfra / lock.h

diff --git a/src/vppinfra/lock.h b/src/vppinfra/lock.h
index 4645378..c1f0b87 100644 (file)
--- a/src/vppinfra/lock.h
+++ b/src/vppinfra/lock.h
@@ -17,6 +17,7 @@
 #define included_clib_lock_h
 
 #include <vppinfra/clib.h>
+#include <vppinfra/atomics.h>
 
 #if __x86_64__
 #define CLIB_PAUSE() __builtin_ia32_pause ()
@@ -42,6 +43,9 @@ do {                                                  \
 #define CLIB_LOCK_DBG_CLEAR(_p)
 #endif
 
+#define CLIB_SPINLOCK_IS_LOCKED(_p) (*(_p))->lock
+#define CLIB_SPINLOCK_ASSERT_LOCKED(_p) ASSERT(CLIB_SPINLOCK_IS_LOCKED((_p)))
+
 typedef struct
 {
   CLIB_CACHE_LINE_ALIGN_MARK (cacheline0);
@@ -57,7 +61,7 @@ static inline void
 clib_spinlock_init (clib_spinlock_t * p)
 {
   *p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
-  memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
+  clib_memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
 }
 
 static inline void
@@ -73,8 +77,15 @@ clib_spinlock_free (clib_spinlock_t * p)
 static_always_inline void
 clib_spinlock_lock (clib_spinlock_t * p)
 {
-  while (clib_atomic_test_and_set (&(*p)->lock))
-    CLIB_PAUSE ();
+  u32 free = 0;
+  while (!clib_atomic_cmp_and_swap_acq_relax_n (&(*p)->lock, &free, 1, 0))
+    {
+      /* atomic load limits number of compare_exchange executions */
+      while (clib_atomic_load_relax_n (&(*p)->lock))
+       CLIB_PAUSE ();
+      /* on failure, compare_exchange writes (*p)->lock into free */
+      free = 0;
+    }
   CLIB_LOCK_DBG (p);
 }
 
@@ -89,9 +100,8 @@ static_always_inline void
 clib_spinlock_unlock (clib_spinlock_t * p)
 {
   CLIB_LOCK_DBG_CLEAR (p);
-  /* Make sure all writes are complete before releasing the lock */
-  CLIB_MEMORY_BARRIER ();
-  (*p)->lock = 0;
+  /* Make sure all reads/writes are complete before releasing the lock */
+  clib_atomic_release (&(*p)->lock);
 }
 
 static_always_inline void
@@ -122,7 +132,7 @@ always_inline void
 clib_rwlock_init (clib_rwlock_t * p)
 {
   *p = clib_mem_alloc_aligned (CLIB_CACHE_LINE_BYTES, CLIB_CACHE_LINE_BYTES);
-  memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
+  clib_memset ((void *) *p, 0, CLIB_CACHE_LINE_BYTES);
 }
 
 always_inline void
@@ -147,9 +157,7 @@ clib_rwlock_reader_lock (clib_rwlock_t * p)
       while (clib_atomic_test_and_set (&(*p)->writer_lock))
        CLIB_PAUSE ();
     }
-  CLIB_MEMORY_BARRIER ();
-  (*p)->n_readers_lock = 0;
-
+  clib_atomic_release (&(*p)->n_readers_lock);
   CLIB_LOCK_DBG (p);
 }
 
@@ -165,12 +173,9 @@ clib_rwlock_reader_unlock (clib_rwlock_t * p)
   (*p)->n_readers -= 1;
   if ((*p)->n_readers == 0)
     {
-      CLIB_MEMORY_BARRIER ();
-      (*p)->writer_lock = 0;
+      clib_atomic_release (&(*p)->writer_lock);
     }
-
-  CLIB_MEMORY_BARRIER ();
-  (*p)->n_readers_lock = 0;
+  clib_atomic_release (&(*p)->n_readers_lock);
 }
 
 always_inline void
@@ -185,8 +190,7 @@ always_inline void
 clib_rwlock_writer_unlock (clib_rwlock_t * p)
 {
   CLIB_LOCK_DBG_CLEAR (p);
-  CLIB_MEMORY_BARRIER ();
-  (*p)->writer_lock = 0;
+  clib_atomic_release (&(*p)->writer_lock);
 }
 
 #endif