diff --git a/include/sys/ddt_impl.h b/include/sys/ddt_impl.h
index 09937c714..d66936588 100644
--- a/include/sys/ddt_impl.h
+++ b/include/sys/ddt_impl.h
@@ -41,15 +41,19 @@ typedef struct {
 	int (*ddt_op_create)(objset_t *os, uint64_t *object, dmu_tx_t *tx,
 	    boolean_t prehash);
 	int (*ddt_op_destroy)(objset_t *os, uint64_t object, dmu_tx_t *tx);
-	int (*ddt_op_lookup)(objset_t *os, uint64_t object, ddt_entry_t *dde);
+	int (*ddt_op_lookup)(objset_t *os, uint64_t object,
+	    const ddt_key_t *ddk, ddt_phys_t *phys, size_t psize);
+	int (*ddt_op_contains)(objset_t *os, uint64_t object,
+	    const ddt_key_t *ddk);
 	void (*ddt_op_prefetch)(objset_t *os, uint64_t object,
-	    ddt_entry_t *dde);
-	int (*ddt_op_update)(objset_t *os, uint64_t object, ddt_entry_t *dde,
+	    const ddt_key_t *ddk);
+	int (*ddt_op_update)(objset_t *os, uint64_t object,
+	    const ddt_key_t *ddk, const ddt_phys_t *phys, size_t psize,
 	    dmu_tx_t *tx);
-	int (*ddt_op_remove)(objset_t *os, uint64_t object, ddt_entry_t *dde,
-	    dmu_tx_t *tx);
-	int (*ddt_op_walk)(objset_t *os, uint64_t object, ddt_entry_t *dde,
-	    uint64_t *walk);
+	int (*ddt_op_remove)(objset_t *os, uint64_t object,
+	    const ddt_key_t *ddk, dmu_tx_t *tx);
+	int (*ddt_op_walk)(objset_t *os, uint64_t object, uint64_t *walk,
+	    ddt_key_t *ddk, ddt_phys_t *phys, size_t psize);
 	int (*ddt_op_count)(objset_t *os, uint64_t object, uint64_t *count);
 } ddt_ops_t;
 
@@ -62,7 +66,7 @@ extern void ddt_stat_update(ddt_t *ddt, ddt_entry_t *dde, uint64_t neg);
  * outside of the DDT implementation proper, and if you do, consider moving
  * them up.
  */
-#define	DDT_NAMELEN	107
+#define	DDT_NAMELEN	110
 
 extern uint64_t ddt_phys_total_refcnt(const ddt_entry_t *dde);
 
diff --git a/module/Makefile.bsd b/module/Makefile.bsd
index 1b0110d3a..e9ad69fc5 100644
--- a/module/Makefile.bsd
+++ b/module/Makefile.bsd
@@ -421,6 +421,7 @@ CFLAGS.gcc+= -Wno-pointer-to-int-cast
 
 CFLAGS.abd.c= -Wno-cast-qual
 CFLAGS.ddt.c= -Wno-cast-qual
+CFLAGS.ddt_zap.c= -Wno-cast-qual
 CFLAGS.dmu.c= -Wno-cast-qual
 CFLAGS.dmu_traverse.c= -Wno-cast-qual
 CFLAGS.dnode.c= ${NO_WUNUSED_BUT_SET_VARIABLE}
diff --git a/module/zfs/ddt.c b/module/zfs/ddt.c
index 1b7063998..df79de74e 100644
--- a/module/zfs/ddt.c
+++ b/module/zfs/ddt.c
@@ -186,18 +186,30 @@ ddt_object_lookup(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
 		return (SET_ERROR(ENOENT));
 
 	return (ddt_ops[type]->ddt_op_lookup(ddt->ddt_os,
-	    ddt->ddt_object[type][class], dde));
+	    ddt->ddt_object[type][class], &dde->dde_key,
+	    dde->dde_phys, sizeof (dde->dde_phys)));
+}
+
+static int
+ddt_object_contains(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
+    const ddt_key_t *ddk)
+{
+	if (!ddt_object_exists(ddt, type, class))
+		return (SET_ERROR(ENOENT));
+
+	return (ddt_ops[type]->ddt_op_contains(ddt->ddt_os,
+	    ddt->ddt_object[type][class], ddk));
 }
 
 static void
 ddt_object_prefetch(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
-    ddt_entry_t *dde)
+    const ddt_key_t *ddk)
 {
 	if (!ddt_object_exists(ddt, type, class))
 		return;
 
 	ddt_ops[type]->ddt_op_prefetch(ddt->ddt_os,
-	    ddt->ddt_object[type][class], dde);
+	    ddt->ddt_object[type][class], ddk);
 }
 
 static int
@@ -207,17 +219,18 @@ ddt_object_update(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
 	ASSERT(ddt_object_exists(ddt, type, class));
 
 	return (ddt_ops[type]->ddt_op_update(ddt->ddt_os,
-	    ddt->ddt_object[type][class], dde, tx));
+	    ddt->ddt_object[type][class], &dde->dde_key, dde->dde_phys,
+	    sizeof (dde->dde_phys), tx));
 }
 
 static int
 ddt_object_remove(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
-    ddt_entry_t *dde, dmu_tx_t *tx)
+    const ddt_key_t *ddk, dmu_tx_t *tx)
 {
 	ASSERT(ddt_object_exists(ddt, type, class));
 
 	return (ddt_ops[type]->ddt_op_remove(ddt->ddt_os,
-	    ddt->ddt_object[type][class], dde, tx));
+	    ddt->ddt_object[type][class], ddk, tx));
 }
 
 int
@@ -227,7 +240,8 @@ ddt_object_walk(ddt_t *ddt, ddt_type_t type, ddt_class_t class,
 	ASSERT(ddt_object_exists(ddt, type, class));
 
 	return (ddt_ops[type]->ddt_op_walk(ddt->ddt_os,
-	    ddt->ddt_object[type][class], dde, walk));
+	    ddt->ddt_object[type][class], walk, &dde->dde_key,
+	    dde->dde_phys, sizeof (dde->dde_phys)));
 }
 
 int
@@ -523,7 +537,7 @@ void
 ddt_prefetch(spa_t *spa, const blkptr_t *bp)
 {
 	ddt_t *ddt;
-	ddt_entry_t dde;
+	ddt_key_t ddk;
 
 	if (!zfs_dedup_prefetch || bp == NULL || !BP_GET_DEDUP(bp))
 		return;
@@ -534,11 +548,11 @@ ddt_prefetch(spa_t *spa, const blkptr_t *bp)
 	 * Thus no locking is required as the DDT can't disappear on us.
 	 */
 	ddt = ddt_select(spa, bp);
-	ddt_key_fill(&dde.dde_key, bp);
+	ddt_key_fill(&ddk, bp);
 
 	for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
 		for (ddt_class_t class = 0; class < DDT_CLASSES; class++) {
-			ddt_object_prefetch(ddt, type, class, &dde);
+			ddt_object_prefetch(ddt, type, class, &ddk);
 		}
 	}
 }
@@ -660,7 +674,7 @@ boolean_t
 ddt_class_contains(spa_t *spa, ddt_class_t max_class, const blkptr_t *bp)
 {
 	ddt_t *ddt;
-	ddt_entry_t *dde;
+	ddt_key_t ddk;
 
 	if (!BP_GET_DEDUP(bp))
 		return (B_FALSE);
@@ -669,20 +683,16 @@ ddt_class_contains(spa_t *spa, ddt_class_t max_class, const blkptr_t *bp)
 		return (B_TRUE);
 
 	ddt = spa->spa_ddt[BP_GET_CHECKSUM(bp)];
-	dde = kmem_cache_alloc(ddt_entry_cache, KM_SLEEP);
 
-	ddt_key_fill(&(dde->dde_key), bp);
+	ddt_key_fill(&ddk, bp);
 
 	for (ddt_type_t type = 0; type < DDT_TYPES; type++) {
 		for (ddt_class_t class = 0; class <= max_class; class++) {
-			if (ddt_object_lookup(ddt, type, class, dde) == 0) {
-				kmem_cache_free(ddt_entry_cache, dde);
+			if (ddt_object_contains(ddt, type, class, &ddk) == 0)
 				return (B_TRUE);
-			}
 		}
 	}
 
-	kmem_cache_free(ddt_entry_cache, dde);
 	return (B_FALSE);
 }
 
@@ -833,9 +843,9 @@ ddt_sync_entry(ddt_t *ddt, ddt_entry_t *dde, dmu_tx_t *tx, uint64_t txg)
 
 	if (otype != DDT_TYPES &&
 	    (otype != ntype || oclass != nclass || total_refcnt == 0)) {
-		VERIFY0(ddt_object_remove(ddt, otype, oclass, dde, tx));
+		VERIFY0(ddt_object_remove(ddt, otype, oclass, ddk, tx));
 		ASSERT3U(
-		    ddt_object_lookup(ddt, otype, oclass, dde), ==, ENOENT);
+		    ddt_object_contains(ddt, otype, oclass, ddk), ==, ENOENT);
 	}
 
 	if (total_refcnt != 0) {
diff --git a/module/zfs/ddt_zap.c b/module/zfs/ddt_zap.c
index 56312881f..741554de3 100644
--- a/module/zfs/ddt_zap.c
+++ b/module/zfs/ddt_zap.c
@@ -42,7 +42,7 @@ static unsigned int ddt_zap_default_ibs = 15;
 #define	DDT_KEY_WORDS	(sizeof (ddt_key_t) / sizeof (uint64_t))
 
 static size_t
-ddt_zap_compress(void *src, uchar_t *dst, size_t s_len, size_t d_len)
+ddt_zap_compress(const void *src, uchar_t *dst, size_t s_len, size_t d_len)
 {
 	uchar_t *version = dst++;
 	int cpfunc = ZIO_COMPRESS_ZLE;
@@ -51,7 +51,8 @@ ddt_zap_compress(void *src, uchar_t *dst, size_t s_len, size_t d_len)
 
 	ASSERT3U(d_len, >=, s_len + 1);	/* no compression plus version byte */
 
-	c_len = ci->ci_compress(src, dst, s_len, d_len - 1, ci->ci_level);
+	c_len = ci->ci_compress((void *)src, dst, s_len, d_len - 1,
+	    ci->ci_level);
 
 	if (c_len == s_len) {
 		cpfunc = ZIO_COMPRESS_OFF;
@@ -93,8 +94,10 @@ ddt_zap_create(objset_t *os, uint64_t *objectp, dmu_tx_t *tx, boolean_t prehash)
 	*objectp = zap_create_flags(os, 0, flags, DMU_OT_DDT_ZAP,
 	    ddt_zap_default_bs, ddt_zap_default_ibs,
 	    DMU_OT_NONE, 0, tx);
+	if (*objectp == 0)
+		return (SET_ERROR(ENOTSUP));
 
-	return (*objectp == 0 ? SET_ERROR(ENOTSUP) : 0);
+	return (0);
 }
 
 static int
@@ -104,51 +107,57 @@ ddt_zap_destroy(objset_t *os, uint64_t object, dmu_tx_t *tx)
 }
 
 static int
-ddt_zap_lookup(objset_t *os, uint64_t object, ddt_entry_t *dde)
+ddt_zap_lookup(objset_t *os, uint64_t object,
+    const ddt_key_t *ddk, ddt_phys_t *phys, size_t psize)
 {
 	uchar_t *cbuf;
 	uint64_t one, csize;
 	int error;
 
-	error = zap_length_uint64(os, object, (uint64_t *)&dde->dde_key,
+	error = zap_length_uint64(os, object, (uint64_t *)ddk,
 	    DDT_KEY_WORDS, &one, &csize);
 	if (error)
 		return (error);
 
 	ASSERT3U(one, ==, 1);
-	ASSERT3U(csize, <=, (sizeof (dde->dde_phys) + 1));
+	ASSERT3U(csize, <=, psize + 1);
 
 	cbuf = kmem_alloc(csize, KM_SLEEP);
 
-	error = zap_lookup_uint64(os, object, (uint64_t *)&dde->dde_key,
+	error = zap_lookup_uint64(os, object, (uint64_t *)ddk,
 	    DDT_KEY_WORDS, 1, csize, cbuf);
 	if (error == 0)
-		ddt_zap_decompress(cbuf, dde->dde_phys, csize,
-		    sizeof (dde->dde_phys));
+		ddt_zap_decompress(cbuf, phys, csize, psize);
 
 	kmem_free(cbuf, csize);
 
 	return (error);
 }
 
-static void
-ddt_zap_prefetch(objset_t *os, uint64_t object, ddt_entry_t *dde)
+static int
+ddt_zap_contains(objset_t *os, uint64_t object, const ddt_key_t *ddk)
 {
-	(void) zap_prefetch_uint64(os, object, (uint64_t *)&dde->dde_key,
-	    DDT_KEY_WORDS);
+	return (zap_length_uint64(os, object, (uint64_t *)ddk, DDT_KEY_WORDS,
+	    NULL, NULL));
+}
+
+static void
+ddt_zap_prefetch(objset_t *os, uint64_t object, const ddt_key_t *ddk)
+{
+	(void) zap_prefetch_uint64(os, object, (uint64_t *)ddk, DDT_KEY_WORDS);
 }
 
 static int
-ddt_zap_update(objset_t *os, uint64_t object, ddt_entry_t *dde, dmu_tx_t *tx)
+ddt_zap_update(objset_t *os, uint64_t object, const ddt_key_t *ddk,
+    const ddt_phys_t *phys, size_t psize, dmu_tx_t *tx)
 {
-	const size_t cbuf_size = sizeof (dde->dde_phys) + 1;
+	const size_t cbuf_size = psize + 1;
 
 	uchar_t *cbuf = kmem_alloc(cbuf_size, KM_SLEEP);
 
-	uint64_t csize = ddt_zap_compress(dde->dde_phys, cbuf,
-	    sizeof (dde->dde_phys), cbuf_size);
+	uint64_t csize = ddt_zap_compress(phys, cbuf, psize, cbuf_size);
 
-	int error = zap_update_uint64(os, object, (uint64_t *)&dde->dde_key,
+	int error = zap_update_uint64(os, object, (uint64_t *)ddk,
 	    DDT_KEY_WORDS, 1, csize, cbuf, tx);
 
 	kmem_free(cbuf, cbuf_size);
@@ -157,14 +166,16 @@ ddt_zap_update(objset_t *os, uint64_t object, ddt_entry_t *dde, dmu_tx_t *tx)
 }
 
 static int
-ddt_zap_remove(objset_t *os, uint64_t object, ddt_entry_t *dde, dmu_tx_t *tx)
+ddt_zap_remove(objset_t *os, uint64_t object, const ddt_key_t *ddk,
+    dmu_tx_t *tx)
 {
-	return (zap_remove_uint64(os, object, (uint64_t *)&dde->dde_key,
+	return (zap_remove_uint64(os, object, (uint64_t *)ddk,
 	    DDT_KEY_WORDS, tx));
 }
 
 static int
-ddt_zap_walk(objset_t *os, uint64_t object, ddt_entry_t *dde, uint64_t *walk)
+ddt_zap_walk(objset_t *os, uint64_t object, uint64_t *walk, ddt_key_t *ddk,
+    ddt_phys_t *phys, size_t psize)
 {
 	zap_cursor_t zc;
 	zap_attribute_t za;
@@ -186,7 +197,7 @@ ddt_zap_walk(objset_t *os, uint64_t object, ddt_entry_t *dde, uint64_t *walk)
 		uint64_t csize = za.za_num_integers;
 
 		ASSERT3U(za.za_integer_length, ==, 1);
-		ASSERT3U(csize, <=, sizeof (dde->dde_phys) + 1);
+		ASSERT3U(csize, <=, psize + 1);
 
 		uchar_t *cbuf = kmem_alloc(csize, KM_SLEEP);
 
@@ -194,9 +205,8 @@ ddt_zap_walk(objset_t *os, uint64_t object, ddt_entry_t *dde, uint64_t *walk)
 		    DDT_KEY_WORDS, 1, csize, cbuf);
 		ASSERT0(error);
 		if (error == 0) {
-			ddt_zap_decompress(cbuf, dde->dde_phys, csize,
-			    sizeof (dde->dde_phys));
-			dde->dde_key = *(ddt_key_t *)za.za_name;
+			ddt_zap_decompress(cbuf, phys, csize, psize);
+			*ddk = *(ddt_key_t *)za.za_name;
 		}
 
 		kmem_free(cbuf, csize);
@@ -219,6 +229,7 @@ const ddt_ops_t ddt_zap_ops = {
 	ddt_zap_create,
 	ddt_zap_destroy,
 	ddt_zap_lookup,
+	ddt_zap_contains,
 	ddt_zap_prefetch,
 	ddt_zap_update,
 	ddt_zap_remove,