Remove unnecessary "head" arguments from some dlist/slist functions.

dlist_delete, dlist_insert_after, dlist_insert_before, slist_insert_after
do not need access to the list header, and indeed insisting on that negates
one of the main advantages of a doubly-linked list.

In consequence, revert addition of "cache_bucket" field to CatCTup.

3 files changed, 15 insertions, 14 deletions

diff --git a/src/backend/postmaster/autovacuum.c b/src/backend/postmaster/autovacuum.c
index afd15aac973..6977bcf75e4 100644
--- a/src/backend/postmaster/autovacuum.c
+++ b/src/backend/postmaster/autovacuum.c
@@ -580,7 +580,6 @@ AutoVacLauncherMain(int argc, char *argv[])
 		struct timeval nap;
 		TimestampTz current_time = 0;
 		bool		can_launch;
-		avl_dbase  *avdb;
 		int			rc;
 
 		/*
@@ -725,7 +724,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 					worker->wi_tableoid = InvalidOid;
 					worker->wi_proc = NULL;
 					worker->wi_launchtime = 0;
-					dlist_push_head(&AutoVacuumShmem->av_freeWorkers, &worker->wi_links);
+					dlist_push_head(&AutoVacuumShmem->av_freeWorkers,
+									&worker->wi_links);
 					AutoVacuumShmem->av_startingWorker = NULL;
 					elog(WARNING, "worker took too long to start; canceled");
 				}
@@ -760,6 +760,8 @@ AutoVacLauncherMain(int argc, char *argv[])
 			 * distant adl_next_worker first, we obtain our database from the
 			 * tail of the list.
 			 */
+			avl_dbase  *avdb;
+
 			avdb = dlist_tail_element(avl_dbase, adl_node, &DatabaseList);
 
 			/*
@@ -790,8 +792,6 @@ AutoVacLauncherMain(int argc, char *argv[])
 static void
 launcher_determine_sleep(bool canlaunch, bool recursing, struct timeval * nap)
 {
-	avl_dbase  *avdb;
-
 	/*
 	 * We sleep until the next scheduled vacuum.  We trust that when the
 	 * database list was built, care was taken so that no entries have times
@@ -807,6 +807,7 @@ launcher_determine_sleep(bool canlaunch, bool recursing, struct timeval * nap)
 	{
 		TimestampTz current_time = GetCurrentTimestamp();
 		TimestampTz next_wakeup;
+		avl_dbase  *avdb;
 		long		secs;
 		int			usecs;
 
@@ -1677,7 +1678,7 @@ FreeWorkerInfo(int code, Datum arg)
 		 */
 		AutovacuumLauncherPid = AutoVacuumShmem->av_launcherpid;
 
-		dlist_delete(&AutoVacuumShmem->av_runningWorkers, &MyWorkerInfo->wi_links);
+		dlist_delete(&MyWorkerInfo->wi_links);
 		MyWorkerInfo->wi_dboid = InvalidOid;
 		MyWorkerInfo->wi_tableoid = InvalidOid;
 		MyWorkerInfo->wi_proc = NULL;
@@ -1685,7 +1686,8 @@ FreeWorkerInfo(int code, Datum arg)
 		MyWorkerInfo->wi_cost_delay = 0;
 		MyWorkerInfo->wi_cost_limit = 0;
 		MyWorkerInfo->wi_cost_limit_base = 0;
-		dlist_push_head(&AutoVacuumShmem->av_freeWorkers, &MyWorkerInfo->wi_links);
+		dlist_push_head(&AutoVacuumShmem->av_freeWorkers,
+						&MyWorkerInfo->wi_links);
 		/* not mine anymore */
 		MyWorkerInfo = NULL;
 
@@ -2863,7 +2865,8 @@ AutoVacuumShmemInit(void)
 
 		/* initialize the WorkerInfo free list */
 		for (i = 0; i < autovacuum_max_workers; i++)
-			dlist_push_head(&AutoVacuumShmem->av_freeWorkers, &worker[i].wi_links);
+			dlist_push_head(&AutoVacuumShmem->av_freeWorkers,
+							&worker[i].wi_links);
 	}
 	else
 		Assert(found);
diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c
index c8a80f038c4..b223feefbab 100644
--- a/src/backend/postmaster/postmaster.c
+++ b/src/backend/postmaster/postmaster.c
@@ -2696,7 +2696,7 @@ CleanupBackend(int pid,
 				ShmemBackendArrayRemove(bp);
 #endif
 			}
-			dlist_delete(&BackendList, iter.cur);
+			dlist_delete(iter.cur);
 			free(bp);
 			break;
 		}
@@ -2744,7 +2744,7 @@ HandleChildCrash(int pid, int exitstatus, const char *procname)
 				ShmemBackendArrayRemove(bp);
 #endif
 			}
-			dlist_delete(&BackendList, iter.cur);
+			dlist_delete(iter.cur);
 			free(bp);
 			/* Keep looping so we can signal remaining backends */
 		}
diff --git a/src/backend/utils/cache/catcache.c b/src/backend/utils/cache/catcache.c
index 05ceff51cdf..a293f570e1b 100644
--- a/src/backend/utils/cache/catcache.c
+++ b/src/backend/utils/cache/catcache.c
@@ -370,7 +370,7 @@ CatCacheRemoveCTup(CatCache *cache, CatCTup *ct)
 		return;					/* nothing left to do */
 	}
 
-	dlist_delete(ct->cache_bucket, &ct->cache_elem);
+	dlist_delete(&ct->cache_elem);
 
 	/* free associated tuple data */
 	if (ct->tuple.t_data != NULL)
@@ -413,7 +413,7 @@ CatCacheRemoveCList(CatCache *cache, CatCList *cl)
 	}
 
 	/* delink from linked list */
-	dlist_delete(&cache->cc_lists, &cl->cache_elem);
+	dlist_delete(&cl->cache_elem);
 
 	/* free associated tuple data */
 	if (cl->tuple.t_data != NULL)
@@ -1664,15 +1664,13 @@ CatalogCacheCreateEntry(CatCache *cache, HeapTuple ntp,
 	 */
 	ct->ct_magic = CT_MAGIC;
 	ct->my_cache = cache;
-	ct->cache_bucket = &cache->cc_bucket[hashIndex];
-
 	ct->c_list = NULL;
 	ct->refcount = 0;			/* for the moment */
 	ct->dead = false;
 	ct->negative = negative;
 	ct->hash_value = hashValue;
 
-	dlist_push_head(ct->cache_bucket, &ct->cache_elem);
+	dlist_push_head(&cache->cc_bucket[hashIndex], &ct->cache_elem);
 
 	cache->cc_ntup++;
 	CacheHdr->ch_ntup++;