diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index 253a1346a4..ee2923e2c3 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -1389,10 +1389,11 @@ static void
 zdb_leak_init(spa_t *spa)
 {
 	vdev_t *rvd = spa->spa_root_vdev;
+	int c, m;
 
-	for (int c = 0; c < rvd->vdev_children; c++) {
+	for (c = 0; c < rvd->vdev_children; c++) {
 		vdev_t *vd = rvd->vdev_child[c];
-		for (int m = 0; m < vd->vdev_ms_count; m++) {
+		for (m = 0; m < vd->vdev_ms_count; m++) {
 			metaslab_t *msp = vd->vdev_ms[m];
 			mutex_enter(&msp->ms_lock);
 			VERIFY(space_map_load(&msp->ms_map, &zdb_space_map_ops,
@@ -1407,10 +1408,11 @@ static void
 zdb_leak_fini(spa_t *spa)
 {
 	vdev_t *rvd = spa->spa_root_vdev;
+	int c, m;
 
-	for (int c = 0; c < rvd->vdev_children; c++) {
+	for (c = 0; c < rvd->vdev_children; c++) {
 		vdev_t *vd = rvd->vdev_child[c];
-		for (int m = 0; m < vd->vdev_ms_count; m++) {
+		for (m = 0; m < vd->vdev_ms_count; m++) {
 			metaslab_t *msp = vd->vdev_ms[m];
 			mutex_enter(&msp->ms_lock);
 			space_map_unload(&msp->ms_map);
@@ -1445,7 +1447,9 @@ typedef struct zdb_cb {
 static void
 zdb_count_block(spa_t *spa, zdb_cb_t *zcb, blkptr_t *bp, dmu_object_type_t type)
 {
-	for (int i = 0; i < 4; i++) {
+	int i;
+
+	for (i = 0; i < 4; i++) {
 		int l = (i < 2) ? BP_GET_LEVEL(bp) : ZB_TOTAL;
 		int t = (i & 1) ? type : DMU_OT_TOTAL;
 		zdb_blkstats_t *zb = &zcb->zcb_type[l][t];
diff --git a/cmd/ztest/ztest.c b/cmd/ztest/ztest.c
index 4aba991260..232f5255c0 100644
--- a/cmd/ztest/ztest.c
+++ b/cmd/ztest/ztest.c
@@ -834,11 +834,12 @@ static vdev_t *
 vdev_lookup_by_path(vdev_t *vd, const char *path)
 {
 	vdev_t *mvd;
+	int c;
 
 	if (vd->vdev_path != NULL && strcmp(path, vd->vdev_path) == 0)
 		return (vd);
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		if ((mvd = vdev_lookup_by_path(vd->vdev_child[c], path)) !=
 		    NULL)
 			return (mvd);
diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c
index 87727fac2d..9a4b436651 100644
--- a/module/zfs/metaslab.c
+++ b/module/zfs/metaslab.c
@@ -963,7 +963,7 @@ metaslab_alloc(spa_t *spa, metaslab_class_t *mc, uint64_t psize, blkptr_t *bp,
 {
 	dva_t *dva = bp->blk_dva;
 	dva_t *hintdva = hintbp->blk_dva;
-	int error = 0;
+	int d, error = 0;
 
 	ASSERT(bp->blk_birth == 0);
 
@@ -978,7 +978,7 @@ metaslab_alloc(spa_t *spa, metaslab_class_t *mc, uint64_t psize, blkptr_t *bp,
 	ASSERT(BP_GET_NDVAS(bp) == 0);
 	ASSERT(hintbp == NULL || ndvas <= BP_GET_NDVAS(hintbp));
 
-	for (int d = 0; d < ndvas; d++) {
+	for (d = 0; d < ndvas; d++) {
 		error = metaslab_alloc_dva(spa, mc, psize, dva, d, hintdva,
 		    txg, flags);
 		if (error) {
@@ -1004,14 +1004,14 @@ void
 metaslab_free(spa_t *spa, const blkptr_t *bp, uint64_t txg, boolean_t now)
 {
 	const dva_t *dva = bp->blk_dva;
-	int ndvas = BP_GET_NDVAS(bp);
+	int d, ndvas = BP_GET_NDVAS(bp);
 
 	ASSERT(!BP_IS_HOLE(bp));
 	ASSERT(!now || bp->blk_birth >= spa->spa_syncing_txg);
 
 	spa_config_enter(spa, SCL_FREE, FTAG, RW_READER);
 
-	for (int d = 0; d < ndvas; d++)
+	for (d = 0; d < ndvas; d++)
 		metaslab_free_dva(spa, &dva[d], txg, now);
 
 	spa_config_exit(spa, SCL_FREE, FTAG);
@@ -1022,7 +1022,7 @@ metaslab_claim(spa_t *spa, const blkptr_t *bp, uint64_t txg)
 {
 	const dva_t *dva = bp->blk_dva;
 	int ndvas = BP_GET_NDVAS(bp);
-	int error = 0;
+	int d, error = 0;
 
 	ASSERT(!BP_IS_HOLE(bp));
 
@@ -1037,7 +1037,7 @@ metaslab_claim(spa_t *spa, const blkptr_t *bp, uint64_t txg)
 
 	spa_config_enter(spa, SCL_ALLOC, FTAG, RW_READER);
 
-	for (int d = 0; d < ndvas; d++)
+	for (d = 0; d < ndvas; d++)
 		if ((error = metaslab_claim_dva(spa, &dva[d], txg)) != 0)
 			break;
 
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index cdc5fb5f96..032cb7cc74 100644
--- a/module/zfs/spa_misc.c
+++ b/module/zfs/spa_misc.c
@@ -255,7 +255,9 @@ int zfs_recover = 0;
 static void
 spa_config_lock_init(spa_t *spa)
 {
-	for (int i = 0; i < SCL_LOCKS; i++) {
+	int i;
+
+	for (i = 0; i < SCL_LOCKS; i++) {
 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
 		mutex_init(&scl->scl_lock, NULL, MUTEX_DEFAULT, NULL);
 		cv_init(&scl->scl_cv, NULL, CV_DEFAULT, NULL);
@@ -268,7 +270,9 @@ spa_config_lock_init(spa_t *spa)
 static void
 spa_config_lock_destroy(spa_t *spa)
 {
-	for (int i = 0; i < SCL_LOCKS; i++) {
+	int i;
+
+	for (i = 0; i < SCL_LOCKS; i++) {
 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
 		mutex_destroy(&scl->scl_lock);
 		cv_destroy(&scl->scl_cv);
@@ -281,7 +285,9 @@ spa_config_lock_destroy(spa_t *spa)
 int
 spa_config_tryenter(spa_t *spa, int locks, void *tag, krw_t rw)
 {
-	for (int i = 0; i < SCL_LOCKS; i++) {
+	int i;
+
+	for (i = 0; i < SCL_LOCKS; i++) {
 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
 		if (!(locks & (1 << i)))
 			continue;
@@ -310,7 +316,9 @@ spa_config_tryenter(spa_t *spa, int locks, void *tag, krw_t rw)
 void
 spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
 {
-	for (int i = 0; i < SCL_LOCKS; i++) {
+	int i;
+
+	for (i = 0; i < SCL_LOCKS; i++) {
 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
 		if (!(locks & (1 << i)))
 			continue;
@@ -336,7 +344,9 @@ spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
 void
 spa_config_exit(spa_t *spa, int locks, void *tag)
 {
-	for (int i = SCL_LOCKS - 1; i >= 0; i--) {
+	int i;
+
+	for (i = SCL_LOCKS - 1; i >= 0; i--) {
 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
 		if (!(locks & (1 << i)))
 			continue;
@@ -355,9 +365,9 @@ spa_config_exit(spa_t *spa, int locks, void *tag)
 int
 spa_config_held(spa_t *spa, int locks, krw_t rw)
 {
-	int locks_held = 0;
+	int i, locks_held = 0;
 
-	for (int i = 0; i < SCL_LOCKS; i++) {
+	for (i = 0; i < SCL_LOCKS; i++) {
 		spa_config_lock_t *scl = &spa->spa_config_lock[i];
 		if (!(locks & (1 << i)))
 			continue;
diff --git a/module/zfs/vdev.c b/module/zfs/vdev.c
index 6f0cf613d6..f7fc177493 100644
--- a/module/zfs/vdev.c
+++ b/module/zfs/vdev.c
@@ -866,6 +866,7 @@ vdev_probe(vdev_t *vd, zio_t *pio)
 	spa_t *spa = vd->vdev_spa;
 	vdev_probe_stats_t *vps;
 	zio_t *zio;
+	int l;
 
 	vps = kmem_zalloc(sizeof (*vps), KM_SLEEP);
 
@@ -898,7 +899,7 @@ vdev_probe(vdev_t *vd, zio_t *pio)
 	vps->vps_root = zio;
 	vps->vps_vd = vd;
 
-	for (int l = 1; l < VDEV_LABELS; l++) {
+	for (l = 1; l < VDEV_LABELS; l++) {
 		zio_nowait(zio_read_phys(zio, vd,
 		    vdev_label_offset(vd->vdev_psize, l,
 		    offsetof(vdev_label_t, vl_pad)),
@@ -1792,6 +1793,7 @@ void
 vdev_clear(spa_t *spa, vdev_t *vd)
 {
 	vdev_t *rvd = spa->spa_root_vdev;
+	int c;
 
 	ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
 
@@ -1802,7 +1804,7 @@ vdev_clear(spa_t *spa, vdev_t *vd)
 	vd->vdev_stat.vs_write_errors = 0;
 	vd->vdev_stat.vs_checksum_errors = 0;
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_clear(spa, vd->vdev_child[c]);
 
 	/*
@@ -1885,6 +1887,7 @@ void
 vdev_get_stats(vdev_t *vd, vdev_stat_t *vs)
 {
 	vdev_t *rvd = vd->vdev_spa->spa_root_vdev;
+	int c, t;
 
 	mutex_enter(&vd->vdev_stat_lock);
 	bcopy(&vd->vdev_stat, vs, sizeof (*vs));
@@ -1899,12 +1902,12 @@ vdev_get_stats(vdev_t *vd, vdev_stat_t *vs)
 	 * over all top-level vdevs (i.e. the direct children of the root).
 	 */
 	if (vd == rvd) {
-		for (int c = 0; c < rvd->vdev_children; c++) {
+		for (c = 0; c < rvd->vdev_children; c++) {
 			vdev_t *cvd = rvd->vdev_child[c];
 			vdev_stat_t *cvs = &cvd->vdev_stat;
 
 			mutex_enter(&vd->vdev_stat_lock);
-			for (int t = 0; t < ZIO_TYPES; t++) {
+			for (t = 0; t < ZIO_TYPES; t++) {
 				vs->vs_ops[t] += cvs->vs_ops[t];
 				vs->vs_bytes[t] += cvs->vs_bytes[t];
 			}
diff --git a/module/zfs/vdev_label.c b/module/zfs/vdev_label.c
index 640ab79579..e4d62920b4 100644
--- a/module/zfs/vdev_label.c
+++ b/module/zfs/vdev_label.c
@@ -335,7 +335,7 @@ vdev_label_read_config(vdev_t *vd)
 	nvlist_t *config = NULL;
 	vdev_phys_t *vp;
 	zio_t *zio;
-	int flags =
+	int l, flags =
 	    ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE;
 
 	ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
@@ -345,7 +345,7 @@ vdev_label_read_config(vdev_t *vd)
 
 	vp = zio_buf_alloc(sizeof (vdev_phys_t));
 
-	for (int l = 0; l < VDEV_LABELS; l++) {
+	for (l = 0; l < VDEV_LABELS; l++) {
 
 		zio = zio_root(spa, NULL, NULL, flags);
 
@@ -498,10 +498,11 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 	int error;
 	uint64_t spare_guid, l2cache_guid;
 	int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL;
+	int c, l, n;
 
 	ASSERT(spa_config_held(spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		if ((error = vdev_label_init(vd->vdev_child[c],
 		    crtxg, reason)) != 0)
 			return (error);
@@ -657,7 +658,7 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 	 */
 	zio = zio_root(spa, NULL, NULL, flags);
 
-	for (int l = 0; l < VDEV_LABELS; l++) {
+	for (l = 0; l < VDEV_LABELS; l++) {
 
 		vdev_label_write(zio, vd, l, vp,
 		    offsetof(vdev_label_t, vl_vdev_phys),
@@ -667,7 +668,7 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 		    offsetof(vdev_label_t, vl_boot_header),
 		    sizeof (vdev_boot_header_t), NULL, NULL, flags);
 
-		for (int n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) {
+		for (n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) {
 			vdev_label_write(zio, vd, l, ub,
 			    VDEV_UBERBLOCK_OFFSET(vd, n),
 			    VDEV_UBERBLOCK_SIZE(vd), NULL, NULL, flags);
@@ -758,6 +759,7 @@ vdev_uberblock_load(zio_t *zio, vdev_t *vd, uberblock_t *ubbest)
 	vdev_t *rvd = spa->spa_root_vdev;
 	int flags =
 	    ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE;
+	int c, l, n;
 
 	if (vd == rvd) {
 		ASSERT(zio == NULL);
@@ -768,12 +770,12 @@ vdev_uberblock_load(zio_t *zio, vdev_t *vd, uberblock_t *ubbest)
 
 	ASSERT(zio != NULL);
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_uberblock_load(zio, vd->vdev_child[c], ubbest);
 
 	if (vd->vdev_ops->vdev_op_leaf && vdev_readable(vd)) {
-		for (int l = 0; l < VDEV_LABELS; l++) {
-			for (int n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) {
+		for (l = 0; l < VDEV_LABELS; l++) {
+			for (n = 0; n < VDEV_UBERBLOCK_COUNT(vd); n++) {
 				vdev_label_read(zio, vd, l,
 				    zio_buf_alloc(VDEV_UBERBLOCK_SIZE(vd)),
 				    VDEV_UBERBLOCK_OFFSET(vd, n),
@@ -809,9 +811,9 @@ static void
 vdev_uberblock_sync(zio_t *zio, uberblock_t *ub, vdev_t *vd, int flags)
 {
 	uberblock_t *ubbuf;
-	int n;
+	int c, l, n;
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_uberblock_sync(zio, ub, vd->vdev_child[c], flags);
 
 	if (!vd->vdev_ops->vdev_op_leaf)
@@ -826,7 +828,7 @@ vdev_uberblock_sync(zio_t *zio, uberblock_t *ub, vdev_t *vd, int flags)
 	bzero(ubbuf, VDEV_UBERBLOCK_SIZE(vd));
 	*ubbuf = *ub;
 
-	for (int l = 0; l < VDEV_LABELS; l++)
+	for (l = 0; l < VDEV_LABELS; l++)
 		vdev_label_write(zio, vd, l, ubbuf,
 		    VDEV_UBERBLOCK_OFFSET(vd, n), VDEV_UBERBLOCK_SIZE(vd),
 		    vdev_uberblock_sync_done, zio->io_private,
@@ -841,10 +843,11 @@ vdev_uberblock_sync_list(vdev_t **svd, int svdcount, uberblock_t *ub, int flags)
 	spa_t *spa = svd[0]->vdev_spa;
 	zio_t *zio;
 	uint64_t good_writes = 0;
+	int v;
 
 	zio = zio_root(spa, NULL, &good_writes, flags);
 
-	for (int v = 0; v < svdcount; v++)
+	for (v = 0; v < svdcount; v++)
 		vdev_uberblock_sync(zio, ub, svd[v], flags);
 
 	(void) zio_wait(zio);
@@ -856,7 +859,7 @@ vdev_uberblock_sync_list(vdev_t **svd, int svdcount, uberblock_t *ub, int flags)
 	 */
 	zio = zio_root(spa, NULL, NULL, flags);
 
-	for (int v = 0; v < svdcount; v++)
+	for (v = 0; v < svdcount; v++)
 		zio_flush(zio, svd[v]);
 
 	(void) zio_wait(zio);
@@ -909,8 +912,9 @@ vdev_label_sync(zio_t *zio, vdev_t *vd, int l, uint64_t txg, int flags)
 	vdev_phys_t *vp;
 	char *buf;
 	size_t buflen;
+	int c;
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_label_sync(zio, vd->vdev_child[c], l, txg, flags);
 
 	if (!vd->vdev_ops->vdev_op_leaf)
diff --git a/module/zfs/vdev_mirror.c b/module/zfs/vdev_mirror.c
index c4629ff450..ed2c251f5c 100644
--- a/module/zfs/vdev_mirror.c
+++ b/module/zfs/vdev_mirror.c
@@ -313,9 +313,9 @@ vdev_mirror_io_start(zio_t *zio)
 static int
 vdev_mirror_worst_error(mirror_map_t *mm)
 {
-	int error[2] = { 0, 0 };
+	int c, error[2] = { 0, 0 };
 
-	for (int c = 0; c < mm->mm_children; c++) {
+	for (c = 0; c < mm->mm_children; c++) {
 		mirror_child_t *mc = &mm->mm_child[c];
 		int s = mc->mc_speculative;
 		error[s] = zio_worst_error(error[s], mc->mc_error);
diff --git a/module/zfs/vdev_queue.c b/module/zfs/vdev_queue.c
index 069c29e9e3..61e8b60640 100644
--- a/module/zfs/vdev_queue.c
+++ b/module/zfs/vdev_queue.c
@@ -285,12 +285,13 @@ void
 vdev_queue_io_done(zio_t *zio)
 {
 	vdev_queue_t *vq = &zio->io_vd->vdev_queue;
+	int i;
 
 	mutex_enter(&vq->vq_lock);
 
 	avl_remove(&vq->vq_pending_tree, zio);
 
-	for (int i = 0; i < zfs_vdev_ramp_rate; i++) {
+	for (i = 0; i < zfs_vdev_ramp_rate; i++) {
 		zio_t *nio = vdev_queue_io_to_issue(vq, zfs_vdev_max_pending);
 		if (nio == NULL)
 			break;
diff --git a/module/zfs/vdev_raidz.c b/module/zfs/vdev_raidz.c
index 33e7f102c3..a06b68093d 100644
--- a/module/zfs/vdev_raidz.c
+++ b/module/zfs/vdev_raidz.c
@@ -775,9 +775,9 @@ static uint64_t raidz_corrected_pq;
 static int
 vdev_raidz_worst_error(raidz_map_t *rm)
 {
-	int error = 0;
+	int c, error = 0;
 
-	for (int c = 0; c < rm->rm_cols; c++)
+	for (c = 0; c < rm->rm_cols; c++)
 		error = zio_worst_error(error, rm->rm_col[c].rc_error);
 
 	return (error);
diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index 495f6e7b65..54d7637adf 100644
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -1047,13 +1047,14 @@ static void
 zio_reexecute(zio_t *pio)
 {
 	zio_t *zio, *zio_next;
+	int c;
 
 	pio->io_flags = pio->io_orig_flags;
 	pio->io_stage = pio->io_orig_stage;
 	pio->io_pipeline = pio->io_orig_pipeline;
 	pio->io_reexecute = 0;
 	pio->io_error = 0;
-	for (int c = 0; c < ZIO_CHILD_TYPES; c++)
+	for (c = 0; c < ZIO_CHILD_TYPES; c++)
 		pio->io_child_error[c] = 0;
 
 	if (IO_IS_ALLOCATING(pio)) {
@@ -1311,8 +1312,9 @@ static void
 zio_gang_node_free(zio_gang_node_t **gnpp)
 {
 	zio_gang_node_t *gn = *gnpp;
+	int g;
 
-	for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
+	for (g = 0; g < SPA_GBH_NBLKPTRS; g++)
 		ASSERT(gn->gn_child[g] == NULL);
 
 	zio_buf_free(gn->gn_gbh, SPA_GANGBLOCKSIZE);
@@ -1324,11 +1326,12 @@ static void
 zio_gang_tree_free(zio_gang_node_t **gnpp)
 {
 	zio_gang_node_t *gn = *gnpp;
+	int g;
 
 	if (gn == NULL)
 		return;
 
-	for (int g = 0; g < SPA_GBH_NBLKPTRS; g++)
+	for (g = 0; g < SPA_GBH_NBLKPTRS; g++)
 		zio_gang_tree_free(&gn->gn_child[g]);
 
 	zio_gang_node_free(gnpp);
@@ -1353,6 +1356,7 @@ zio_gang_tree_assemble_done(zio_t *zio)
 	zio_t *lio = zio->io_logical;
 	zio_gang_node_t *gn = zio->io_private;
 	blkptr_t *bp = zio->io_bp;
+	int g;
 
 	ASSERT(zio->io_parent == lio);
 	ASSERT(zio->io_child == NULL);
@@ -1367,7 +1371,7 @@ zio_gang_tree_assemble_done(zio_t *zio)
 	ASSERT(zio->io_size == SPA_GANGBLOCKSIZE);
 	ASSERT(gn->gn_gbh->zg_tail.zbt_magic == ZBT_MAGIC);
 
-	for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
+	for (g = 0; g < SPA_GBH_NBLKPTRS; g++) {
 		blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
 		if (!BP_IS_GANG(gbp))
 			continue;
@@ -1380,6 +1384,7 @@ zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data)
 {
 	zio_t *lio = pio->io_logical;
 	zio_t *zio;
+	int g;
 
 	ASSERT(BP_IS_GANG(bp) == !!gn);
 	ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(lio->io_bp));
@@ -1394,7 +1399,7 @@ zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data)
 	if (gn != NULL) {
 		ASSERT(gn->gn_gbh->zg_tail.zbt_magic == ZBT_MAGIC);
 
-		for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
+		for (g = 0; g < SPA_GBH_NBLKPTRS; g++) {
 			blkptr_t *gbp = &gn->gn_gbh->zg_blkptr[g];
 			if (BP_IS_HOLE(gbp))
 				continue;
@@ -1451,6 +1456,7 @@ zio_write_gang_member_ready(zio_t *zio)
 	dva_t *cdva = zio->io_bp->blk_dva;
 	dva_t *pdva = pio->io_bp->blk_dva;
 	uint64_t asize;
+	int d;
 
 	if (BP_IS_HOLE(zio->io_bp))
 		return;
@@ -1464,7 +1470,7 @@ zio_write_gang_member_ready(zio_t *zio)
 	ASSERT3U(BP_GET_NDVAS(zio->io_bp), <=, BP_GET_NDVAS(pio->io_bp));
 
 	mutex_enter(&pio->io_lock);
-	for (int d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) {
+	for (d = 0; d < BP_GET_NDVAS(zio->io_bp); d++) {
 		ASSERT(DVA_GET_GANG(&pdva[d]));
 		asize = DVA_GET_ASIZE(&pdva[d]);
 		asize += DVA_GET_ASIZE(&cdva[d]);
@@ -1488,7 +1494,7 @@ zio_write_gang_block(zio_t *pio)
 	int ndvas = lio->io_prop.zp_ndvas;
 	int gbh_ndvas = MIN(ndvas + 1, spa_max_replication(spa));
 	zio_prop_t zp;
-	int error;
+	int g, error;
 
 	error = metaslab_alloc(spa, spa->spa_normal_class, SPA_GANGBLOCKSIZE,
 	    bp, gbh_ndvas, txg, pio == lio ? NULL : lio->io_bp,
@@ -1518,7 +1524,7 @@ zio_write_gang_block(zio_t *pio)
 	/*
 	 * Create and nowait the gang children.
 	 */
-	for (int g = 0; resid != 0; resid -= lsize, g++) {
+	for (g = 0; resid != 0; resid -= lsize, g++) {
 		lsize = P2ROUNDUP(resid / (SPA_GBH_NBLKPTRS - g),
 		    SPA_MINBLOCKSIZE);
 		ASSERT(lsize >= SPA_MINBLOCKSIZE && lsize <= resid);
@@ -1608,6 +1614,7 @@ zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp)
 {
 	spa_t *spa = zio->io_spa;
 	boolean_t now = !(zio->io_flags & ZIO_FLAG_IO_REWRITE);
+	int g;
 
 	ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
 
@@ -1638,7 +1645,7 @@ zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp)
 		metaslab_free(spa, bp, bp->blk_birth, now);
 
 	if (gn != NULL) {
-		for (int g = 0; g < SPA_GBH_NBLKPTRS; g++) {
+		for (g = 0; g < SPA_GBH_NBLKPTRS; g++) {
 			zio_dva_unallocate(zio, gn->gn_child[g],
 			    &gn->gn_gbh->zg_blkptr[g]);
 		}
@@ -2082,6 +2089,7 @@ zio_done(zio_t *zio)
 	blkptr_t *bp = zio->io_bp;
 	vdev_t *vd = zio->io_vd;
 	uint64_t psize = zio->io_size;
+	int c, w;
 
 	/*
 	 * If our of children haven't all completed,
@@ -2092,8 +2100,8 @@ zio_done(zio_t *zio)
 	    zio_wait_for_children(zio, ZIO_CHILD_LOGICAL, ZIO_WAIT_DONE))
 		return (ZIO_PIPELINE_STOP);
 
-	for (int c = 0; c < ZIO_CHILD_TYPES; c++)
-		for (int w = 0; w < ZIO_WAIT_TYPES; w++)
+	for (c = 0; c < ZIO_CHILD_TYPES; c++)
+		for (w = 0; w < ZIO_WAIT_TYPES; w++)
 			ASSERT(zio->io_children[c][w] == 0);
 
 	if (bp != NULL) {