Merge of r4778, r4782, r4783, r4824, r4830, r4834: minor fixes. *) Reorder checks in ngx_shared_memory_add() for more consistent error messages. *) Added "const" to ngx_memcpy() with NGX_MEMCPY_LIMIT defined. This fixes warning produced during compilation of the ngx_http_geoip_module due to const qualifier being discarded. *) Fixed possible use of old cached times if runtime went backwards. If ngx_time_sigsafe_update() updated only ngx_cached_err_log_time, and then clock was adjusted backwards, the cached_time[slot].sec might accidentally match current seconds on next ngx_time_update() call, resulting in various cached times not being updated. Fix is to clear the cached_time[slot].sec to explicitly mark cached times are stale and need updating. *) Radix tree preallocation fix. The preallocation size was calculated incorrectly and was always 8 due to sizeof(ngx_radix_tree_t) accidentally used instead of sizeof(ngx_radix_node_t). *) Fixed overflow if ngx_slab_alloc() is called with very big "size" argument. *) Write filter: replaced unneeded loop with one to free chains. Noted by Gabor Lekeny.

--- a/src/core/ngx_cycle.c
+++ b/src/core/ngx_cycle.c
@@ -1285,6 +1285,14 @@ ngx_shared_memory_add(ngx_conf_t *cf, ng
             continue;
         }
 
+        if (tag != shm_zone[i].tag) {
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+                            "the shared memory zone \"%V\" is "
+                            "already declared for a different use",
+                            &shm_zone[i].shm.name);
+            return NULL;
+        }
+
         if (size && size != shm_zone[i].shm.size) {
             ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                             "the size %uz of shared memory zone \"%V\" "
@@ -1293,14 +1301,6 @@ ngx_shared_memory_add(ngx_conf_t *cf, ng
             return NULL;
         }
 
-        if (tag != shm_zone[i].tag) {
-            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
-                            "the shared memory zone \"%V\" is "
-                            "already declared for a different use",
-                            &shm_zone[i].shm.name);
-            return NULL;
-        }
-
         return &shm_zone[i];
     }