Core: provided access to previous cycle shared memory zone data.

Currently, the data of shared memory zone with 'noreuse' flag
is not accessible by zone init handler of the new cycle.

The patch makes the pointer to the old zone available during the new
zone initialization, thus allowing for the module to inherit required data.

src/core/ngx_cycle.c

@@ -39,7 +39,7 @@ static ngx_connection_t  dumb;
 ngx_cycle_t *
 ngx_init_cycle(ngx_cycle_t *old_cycle)
 {
-    void                *rv;
+    void                *rv, *old_data;
     char               **senv;
     ngx_uint_t           i, n;
     ngx_log_t           *log;
@@ -446,6 +446,8 @@ ngx_init_cycle(ngx_cycle_t *old_cycle)
         opart = &old_cycle->shared_memory.part;
         oshm_zone = opart->elts;
 
+        old_data = NULL;
+
         for (n = 0; /* void */ ; n++) {
 
             if (n >= opart->nelts) {
@@ -469,10 +471,16 @@ ngx_init_cycle(ngx_cycle_t *old_cycle)
                 continue;
             }
 
-            if (shm_zone[i].tag == oshm_zone[n].tag
-                && shm_zone[i].shm.size == oshm_zone[n].shm.size
-                && !shm_zone[i].noreuse)
-            {
+            if (shm_zone[i].tag != oshm_zone[n].tag) {
+                break;
+            }
+
+            if (shm_zone[i].noreuse) {
+                old_data = oshm_zone[n].data;
+                break;
+            }
+
+            if (shm_zone[i].shm.size == oshm_zone[n].shm.size) {
                 shm_zone[i].shm.addr = oshm_zone[n].shm.addr;
 #if (NGX_WIN32)
                 shm_zone[i].shm.handle = oshm_zone[n].shm.handle;
@@ -498,7 +506,7 @@ ngx_init_cycle(ngx_cycle_t *old_cycle)
             goto failed;
         }
 
-        if (shm_zone[i].init(&shm_zone[i], NULL) != NGX_OK) {
+        if (shm_zone[i].init(&shm_zone[i], old_data) != NGX_OK) {
             goto failed;
         }