diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index d8017cd11f..51f912c142 100644
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -685,8 +685,7 @@ dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 			bufoff = offset - db->db_offset;
 			tocpy = (int)MIN(db->db_size - bufoff, size);
 
-			if (!(flags & DMU_READ_ZEROCOPY))
-				bcopy((char *)db->db_data + bufoff, buf, tocpy);
+			bcopy((char *)db->db_data + bufoff, buf, tocpy);
 
 			offset += tocpy;
 			size -= tocpy;
@@ -699,8 +698,8 @@ dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 }
 
 void
-dmu_write_impl(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
-    const void *buf, dmu_tx_t *tx, int flags)
+dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
+    const void *buf, dmu_tx_t *tx)
 {
 	dmu_buf_t **dbp;
 	int numbufs, i;
@@ -728,8 +727,7 @@ dmu_write_impl(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 		else
 			dmu_buf_will_dirty(db, tx);
 
-		if (!(flags & DMU_WRITE_ZEROCOPY))
-			bcopy(buf, (char *)db->db_data + bufoff, tocpy);
+		bcopy(buf, (char *)db->db_data + bufoff, tocpy);
 
 		if (tocpy == db->db_size)
 			dmu_buf_fill_done(db, tx);
@@ -741,13 +739,6 @@ dmu_write_impl(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 	dmu_buf_rele_array(dbp, numbufs, FTAG);
 }
 
-void
-dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
-    const void *buf, dmu_tx_t *tx)
-{
-	dmu_write_impl(os, object, offset, size, buf, tx, 0);
-}
-
 void
 dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
     dmu_tx_t *tx)
@@ -1740,7 +1731,6 @@ dmu_fini(void)
 EXPORT_SYMBOL(dmu_bonus_hold);
 EXPORT_SYMBOL(dmu_free_range);
 EXPORT_SYMBOL(dmu_read);
-EXPORT_SYMBOL(dmu_write_impl);
 EXPORT_SYMBOL(dmu_write);
 
 /* Get information on a DMU object. */
diff --git a/module/zfs/include/sys/dmu.h b/module/zfs/include/sys/dmu.h
index 74406ca315..2cf3584037 100644
--- a/module/zfs/include/sys/dmu.h
+++ b/module/zfs/include/sys/dmu.h
@@ -165,8 +165,8 @@ void zfs_znode_byteswap(void *buf, size_t size);
  * The maximum number of bytes that can be accessed as part of one
  * operation, including metadata.
  */
-#define	DMU_MAX_ACCESS		(10<<20) /* 10MB */
-#define	DMU_MAX_DELETEBLKCNT	(20480) /* ~5MB of indirect blocks */
+#define	DMU_MAX_ACCESS (10<<20) /* 10MB */
+#define	DMU_MAX_DELETEBLKCNT (20480) /* ~5MB of indirect blocks */
 
 #define	DMU_USERUSED_OBJECT	(-1ULL)
 #define	DMU_GROUPUSED_OBJECT	(-2ULL)
@@ -506,12 +506,8 @@ int dmu_free_object(objset_t *os, uint64_t object);
  */
 #define	DMU_READ_PREFETCH	0 /* prefetch */
 #define	DMU_READ_NO_PREFETCH	1 /* don't prefetch */
-#define	DMU_READ_ZEROCOPY	2 /* zerocopy on read (test) */
-#define	DMU_WRITE_ZEROCOPY	4 /* zerocopy on write (test) */
 int dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 	void *buf, uint32_t flags);
-void dmu_write_impl(objset_t *os, uint64_t object, uint64_t offset,
-	uint64_t size, const void *buf, dmu_tx_t *tx, int flags);
 void dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
 	const void *buf, dmu_tx_t *tx);
 void dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,