cityhash: replace invocations with specialized versions when possible

So that we can get actual benefit from last commit.

See more discussion at openzfs#16483.

Acked-by: Alexander Motin <[email protected]>
Signed-off-by: Shengqi Chen <[email protected]>

Author: Harry-Chen

cmd/zstream/zstream_redup.c

@@ -132,7 +132,7 @@ static void
 rdt_insert(redup_table_t *rdt,
     uint64_t guid, uint64_t object, uint64_t offset, uint64_t stream_offset)
 {
-	uint64_t ch = cityhash4(guid, object, offset, 0);
+	uint64_t ch = cityhash3(guid, object, offset);
 	uint64_t hashcode = BF64_GET(ch, 0, rdt->numhashbits);
 	redup_entry_t **rdepp;
 
@@ -152,7 +152,7 @@ rdt_lookup(redup_table_t *rdt,
     uint64_t guid, uint64_t object, uint64_t offset,
     uint64_t *stream_offsetp)
 {
-	uint64_t ch = cityhash4(guid, object, offset, 0);
+	uint64_t ch = cityhash3(guid, object, offset);
 	uint64_t hashcode = BF64_GET(ch, 0, rdt->numhashbits);
 
 	for (redup_entry_t *rde = rdt->redup_hash_array[hashcode];

module/os/linux/zfs/zvol_os.c

@@ -566,8 +566,8 @@ zvol_request_impl(zvol_state_t *zv, struct bio *bio, struct request *rq,
 		    rq->q->queue_hw_ctx[rq->q->mq_map[rq->cpu]]->queue_num;
 #endif
 #endif
-	taskq_hash = cityhash4((uintptr_t)zv, offset >> ZVOL_TASKQ_OFFSET_SHIFT,
-	    blk_mq_hw_queue, 0);
+	taskq_hash = cityhash3((uintptr_t)zv, offset >> ZVOL_TASKQ_OFFSET_SHIFT,
+	    blk_mq_hw_queue);
 	tq_idx = taskq_hash % ztqs->tqs_cnt;
 
 	if (rw == WRITE) {

module/zfs/dmu_objset.c

@@ -391,12 +391,12 @@ dmu_objset_byteswap(void *buf, size_t size)
 }
 
 /*
- * Runs cityhash4 on the objset_t pointer and the object number.
+ * Runs cityhash on the objset_t pointer and the object number.
  */
 static uint64_t
 dnode_hash(const objset_t *os, uint64_t obj)
 {
-	return (cityhash4((uint64_t)os, obj, 0, 0));
+	return (cityhash2((uint64_t)os, obj));
 }
 
 static unsigned int

module/zfs/zio.c

@@ -4157,8 +4157,8 @@ zio_alloc_zil(spa_t *spa, objset_t *os, uint64_t txg, blkptr_t *new_bp,
 	 * some parallelism.
 	 */
 	int flags = METASLAB_ZIL;
-	int allocator = (uint_t)cityhash4(0, 0, 0,
-	    os->os_dsl_dataset->ds_object) % spa->spa_alloc_count;
+	int allocator = (uint_t)cityhash1(os->os_dsl_dataset->ds_object)
+	    % spa->spa_alloc_count;
 	error = metaslab_alloc(spa, spa_log_class(spa), size, new_bp, 1,
 	    txg, NULL, flags, &io_alloc_list, NULL, allocator);
 	*slog = (error == 0);