[CF 5798] v1 - a couple of small cleanup patches for DSM-related code

This branch was automatically generated by a robot using patches from an
email thread registered at:

https://commitfest.postgresql.org/patch/5798

The branch will be overwritten each time a new patch version is posted to
the thread, and also periodically to check for bitrot caused by changes
on the master branch.

Patch(es): https://www.postgresql.org/message-id/aECi_gSD9JnVWQ8T@nathan
Author(s): Nathan Bossart

Author: Commitfest Bot

src/backend/replication/logical/launcher.c

@@ -1016,7 +1016,7 @@ logicalrep_launcher_attach_dshmem(void)
 		last_start_times_dsa = dsa_attach(LogicalRepCtx->last_start_dsa);
 		dsa_pin_mapping(last_start_times_dsa);
 		last_start_times = dshash_attach(last_start_times_dsa, &dsh_params,
-										 LogicalRepCtx->last_start_dsh, 0);
+										 LogicalRepCtx->last_start_dsh, NULL);
 	}
 
 	MemoryContextSwitchTo(oldcontext);

src/backend/utils/activity/pgstat_shmem.c

@@ -183,7 +183,7 @@ StatsShmemInit(void)
 		p += MAXALIGN(pgstat_dsa_init_size());
 		dsa = dsa_create_in_place(ctl->raw_dsa_area,
 								  pgstat_dsa_init_size(),
-								  LWTRANCHE_PGSTATS_DSA, 0);
+								  LWTRANCHE_PGSTATS_DSA, NULL);
 		dsa_pin(dsa);
 
 		/*
@@ -255,7 +255,8 @@ pgstat_attach_shmem(void)
 	dsa_pin_mapping(pgStatLocal.dsa);
 
 	pgStatLocal.shared_hash = dshash_attach(pgStatLocal.dsa, &dsh_params,
-											pgStatLocal.shmem->hash_handle, 0);
+											pgStatLocal.shmem->hash_handle,
+											NULL);
 
 	MemoryContextSwitchTo(oldcontext);
 }

src/test/modules/test_dsm_registry/test_dsm_registry.c

@@ -54,7 +54,7 @@ set_val_in_shmem(PG_FUNCTION_ARGS)
 	tdr_attach_shmem();
 
 	LWLockAcquire(&tdr_state->lck, LW_EXCLUSIVE);
-	tdr_state->val = PG_GETARG_UINT32(0);
+	tdr_state->val = PG_GETARG_INT32(0);
 	LWLockRelease(&tdr_state->lck);
 
 	PG_RETURN_VOID();
@@ -72,5 +72,5 @@ get_val_in_shmem(PG_FUNCTION_ARGS)
 	ret = tdr_state->val;
 	LWLockRelease(&tdr_state->lck);
 
-	PG_RETURN_UINT32(ret);
+	PG_RETURN_INT32(ret);
 }