diff --git a/include/sys/spa.h b/include/sys/spa.h
index 39971827073f..f172f2af6f07 100644
--- a/include/sys/spa.h
+++ b/include/sys/spa.h
@@ -1030,7 +1030,7 @@ extern void spa_import_progress_set_notes_nolog(spa_t *spa,
 extern int spa_config_tryenter(spa_t *spa, int locks, const void *tag,
     krw_t rw);
 extern void spa_config_enter(spa_t *spa, int locks, const void *tag, krw_t rw);
-extern void spa_config_enter_mmp(spa_t *spa, int locks, const void *tag,
+extern void spa_config_enter_priority(spa_t *spa, int locks, const void *tag,
     krw_t rw);
 extern void spa_config_exit(spa_t *spa, int locks, const void *tag);
 extern int spa_config_held(spa_t *spa, int locks, krw_t rw);
diff --git a/module/zfs/mmp.c b/module/zfs/mmp.c
index 7db72b9b04b0..fd46127b6068 100644
--- a/module/zfs/mmp.c
+++ b/module/zfs/mmp.c
@@ -446,7 +446,7 @@ mmp_write_uberblock(spa_t *spa)
 	uint64_t offset;
 
 	hrtime_t lock_acquire_time = gethrtime();
-	spa_config_enter_mmp(spa, SCL_STATE, mmp_tag, RW_READER);
+	spa_config_enter_priority(spa, SCL_STATE, mmp_tag, RW_READER);
 	lock_acquire_time = gethrtime() - lock_acquire_time;
 	if (lock_acquire_time > (MSEC2NSEC(MMP_MIN_INTERVAL) / 10))
 		zfs_dbgmsg("MMP SCL_STATE acquisition pool '%s' took %llu ns "
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index a539468df6a1..0bead6d49666 100644
--- a/module/zfs/spa_misc.c
+++ b/module/zfs/spa_misc.c
@@ -510,7 +510,7 @@ spa_config_tryenter(spa_t *spa, int locks, const void *tag, krw_t rw)
 
 static void
 spa_config_enter_impl(spa_t *spa, int locks, const void *tag, krw_t rw,
-    int mmp_flag)
+    int priority_flag)
 {
 	(void) tag;
 	int wlocks_held = 0;
@@ -526,7 +526,7 @@ spa_config_enter_impl(spa_t *spa, int locks, const void *tag, krw_t rw,
 		mutex_enter(&scl->scl_lock);
 		if (rw == RW_READER) {
 			while (scl->scl_writer ||
-			    (!mmp_flag && scl->scl_write_wanted)) {
+			    (!priority_flag && scl->scl_write_wanted)) {
 				cv_wait(&scl->scl_cv, &scl->scl_lock);
 			}
 		} else {
@@ -551,7 +551,7 @@ spa_config_enter(spa_t *spa, int locks, const void *tag, krw_t rw)
 }
 
 /*
- * The spa_config_enter_mmp() allows the mmp thread to cut in front of
+ * The spa_config_enter_priority() allows the mmp thread to cut in front of
  * outstanding write lock requests. This is needed since the mmp updates are
  * time sensitive and failure to service them promptly will result in a
  * suspended pool. This pool suspension has been seen in practice when there is
@@ -560,7 +560,7 @@ spa_config_enter(spa_t *spa, int locks, const void *tag, krw_t rw)
  */
 
 void
-spa_config_enter_mmp(spa_t *spa, int locks, const void *tag, krw_t rw)
+spa_config_enter_priority(spa_t *spa, int locks, const void *tag, krw_t rw)
 {
 	spa_config_enter_impl(spa, locks, tag, rw, 1);
 }
diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index 4cf8912d4269..2d5805ce6aeb 100644
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -4574,8 +4574,29 @@ zio_vdev_io_start(zio_t *zio)
 	ASSERT0(zio->io_child_error[ZIO_CHILD_VDEV]);
 
 	if (vd == NULL) {
-		if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER))
-			spa_config_enter(spa, SCL_ZIO, zio, RW_READER);
+		if (!(zio->io_flags & ZIO_FLAG_CONFIG_WRITER)) {
+			/*
+			 * A deadlock workaround. The ddt_prune_unique_entries()
+			 * -> prune_candidates_sync() code path takes the
+			 * SCL_ZIO reader lock and may request it again here.
+			 * If there is another thread who wants the SCL_ZIO
+			 * writer lock, then scl_write_wanted will be set.
+			 * Thus, the spa_config_enter_priority() is used to
+			 * ignore pending writer requests.
+			 *
+			 * The locking should be revised to remove the need
+			 * for this workaround.  If that's not workable then
+			 * it should only be applied to the zios involved in
+			 * the pruning process.  This impacts the read/write
+			 * I/O balance while pruning.
+			 */
+			if (spa->spa_active_ddt_prune)
+				spa_config_enter_priority(spa, SCL_ZIO, zio,
+				    RW_READER);
+			else
+				spa_config_enter(spa, SCL_ZIO, zio,
+				    RW_READER);
+		}
 
 		/*
 		 * The mirror_ops handle multiple DVAs in a single BP.