Fix gcc c90 compliance warnings

Fix non-c90 compliant code, for the most part these changes
simply deal with where a particular variable is declared.
Under c90 it must alway be done at the very start of a block.

Signed-off-by: Brian Behlendorf <[email protected]>

26 files changed, 388 insertions, 217 deletions

diff --git a/module/zcommon/zprop_common.c b/module/zcommon/zprop_common.c
index 0bbf20d4f..df2fdeab8 100644
--- a/module/zcommon/zprop_common.c
+++ b/module/zcommon/zprop_common.c
@@ -162,7 +162,7 @@ int
 zprop_iter_common(zprop_func func, void *cb, boolean_t show_all,
     boolean_t ordered, zfs_type_t type)
 {
-	int i, num_props, size, prop;
+	int i, j, num_props, size, prop;
 	zprop_desc_t *prop_tbl;
 	zprop_desc_t **order;
 
@@ -177,7 +177,7 @@ zprop_iter_common(zprop_func func, void *cb, boolean_t show_all,
 		return (ZPROP_CONT);
 #endif
 
-	for (int j = 0; j < num_props; j++)
+	for (j = 0; j < num_props; j++)
 		order[j] = &prop_tbl[j];
 
 	if (ordered) {
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index a82718e8b..de09ca9a9 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -1426,10 +1426,11 @@ arc_buf_destroy(arc_buf_t *buf, boolean_t recycle, boolean_t all)
 static void
 arc_hdr_destroy(arc_buf_hdr_t *hdr)
 {
+	l2arc_buf_hdr_t *l2hdr = hdr->b_l2hdr;
+
 	ASSERT(refcount_is_zero(&hdr->b_refcnt));
 	ASSERT3P(hdr->b_state, ==, arc_anon);
 	ASSERT(!HDR_IO_IN_PROGRESS(hdr));
-	l2arc_buf_hdr_t *l2hdr = hdr->b_l2hdr;
 
 	if (l2hdr != NULL) {
 		boolean_t buflist_held = MUTEX_HELD(&l2arc_buflist_mtx);
@@ -4235,6 +4236,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz)
 	l2arc_write_callback_t *cb;
 	zio_t *pio, *wzio;
 	uint64_t guid = spa_guid(spa);
+	int try;
 
 	ASSERT(dev->l2ad_vdev != NULL);
 
@@ -4248,7 +4250,7 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz)
 	 * Copy buffers for L2ARC writing.
 	 */
 	mutex_enter(&l2arc_buflist_mtx);
-	for (int try = 0; try <= 3; try++) {
+	for (try = 0; try <= 3; try++) {
 		list = l2arc_list_locked(try, &list_lock);
 		passed_sz = 0;
 
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index 9c4e0296d..82cfd1a2e 100644
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -107,11 +107,15 @@ dbuf_find(dnode_t *dn, uint8_t level, uint64_t blkid)
 {
 	dbuf_hash_table_t *h = &dbuf_hash_table;
 	objset_t *os = dn->dn_objset;
-	uint64_t obj = dn->dn_object;
-	uint64_t hv = DBUF_HASH(os, obj, level, blkid);
-	uint64_t idx = hv & h->hash_table_mask;
+	uint64_t obj;
+	uint64_t hv;
+	uint64_t idx;
 	dmu_buf_impl_t *db;
 
+	obj = dn->dn_object;
+	hv = DBUF_HASH(os, obj, level, blkid);
+	idx = hv & h->hash_table_mask;
+
 	mutex_enter(DBUF_HASH_MUTEX(h, idx));
 	for (db = h->hash_table[idx]; db != NULL; db = db->db_hash_next) {
 		if (DBUF_EQUAL(db, os, obj, level, blkid)) {
@@ -140,11 +144,13 @@ dbuf_hash_insert(dmu_buf_impl_t *db)
 	objset_t *os = db->db_objset;
 	uint64_t obj = db->db.db_object;
 	int level = db->db_level;
-	uint64_t blkid = db->db_blkid;
-	uint64_t hv = DBUF_HASH(os, obj, level, blkid);
-	uint64_t idx = hv & h->hash_table_mask;
+	uint64_t blkid, hv, idx;
 	dmu_buf_impl_t *dbf;
 
+	blkid = db->db_blkid;
+	hv = DBUF_HASH(os, obj, level, blkid);
+	idx = hv & h->hash_table_mask;
+
 	mutex_enter(DBUF_HASH_MUTEX(h, idx));
 	for (dbf = h->hash_table[idx]; dbf != NULL; dbf = dbf->db_hash_next) {
 		if (DBUF_EQUAL(dbf, os, obj, level, blkid)) {
@@ -174,11 +180,13 @@ static void
 dbuf_hash_remove(dmu_buf_impl_t *db)
 {
 	dbuf_hash_table_t *h = &dbuf_hash_table;
-	uint64_t hv = DBUF_HASH(db->db_objset, db->db.db_object,
-	    db->db_level, db->db_blkid);
-	uint64_t idx = hv & h->hash_table_mask;
+	uint64_t hv, idx;
 	dmu_buf_impl_t *dbf, **dbp;
 
+	hv = DBUF_HASH(db->db_objset, db->db.db_object,
+	    db->db_level, db->db_blkid);
+	idx = hv & h->hash_table_mask;
+
 	/*
 	 * We musn't hold db_mtx to maintin lock ordering:
 	 * DBUF_HASH_MUTEX > db_mtx.
diff --git a/module/zfs/ddt.c b/module/zfs/ddt.c
index 718331496..ae9d2a5e1 100644
--- a/module/zfs/ddt.c
+++ b/module/zfs/ddt.c
@@ -244,9 +244,10 @@ ddt_object_name(ddt_t *ddt, enum ddt_type type, enum ddt_class class,
 void
 ddt_bp_fill(const ddt_phys_t *ddp, blkptr_t *bp, uint64_t txg)
 {
+	int d;
 	ASSERT(txg != 0);
 
-	for (int d = 0; d < SPA_DVAS_PER_BP; d++)
+	for (d = 0; d < SPA_DVAS_PER_BP; d++)
 		bp->blk_dva[d] = ddp->ddp_dva[d];
 	BP_SET_BIRTH(bp, txg, ddp->ddp_phys_birth);
 }
@@ -287,9 +288,10 @@ ddt_key_fill(ddt_key_t *ddk, const blkptr_t *bp)
 void
 ddt_phys_fill(ddt_phys_t *ddp, const blkptr_t *bp)
 {
+	int d;
 	ASSERT(ddp->ddp_phys_birth == 0);
 
-	for (int d = 0; d < SPA_DVAS_PER_BP; d++)
+	for (d = 0; d < SPA_DVAS_PER_BP; d++)
 		ddp->ddp_dva[d] = bp->blk_dva[d];
 	ddp->ddp_phys_birth = BP_PHYSICAL_BIRTH(bp);
 }
@@ -327,8 +329,9 @@ ddt_phys_t *
 ddt_phys_select(const ddt_entry_t *dde, const blkptr_t *bp)
 {
 	ddt_phys_t *ddp = (ddt_phys_t *)dde->dde_phys;
+	int p;
 
-	for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
+	for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
 		if (DVA_EQUAL(BP_IDENTITY(bp), &ddp->ddp_dva[0]) &&
 		    BP_PHYSICAL_BIRTH(bp) == ddp->ddp_phys_birth)
 			return (ddp);
@@ -340,8 +343,9 @@ uint64_t
 ddt_phys_total_refcnt(const ddt_entry_t *dde)
 {
 	uint64_t refcnt = 0;
+	int p;
 
-	for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++)
+	for (p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++)
 		refcnt += dde->dde_phys[p].ddp_refcnt;
 
 	return (refcnt);
@@ -355,17 +359,18 @@ ddt_stat_generate(ddt_t *ddt, ddt_entry_t *dde, ddt_stat_t *dds)
 	ddt_key_t *ddk = &dde->dde_key;
 	uint64_t lsize = DDK_GET_LSIZE(ddk);
 	uint64_t psize = DDK_GET_PSIZE(ddk);
+	int p, d;
 
 	bzero(dds, sizeof (*dds));
 
-	for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
+	for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
 		uint64_t dsize = 0;
 		uint64_t refcnt = ddp->ddp_refcnt;
 
 		if (ddp->ddp_phys_birth == 0)
 			continue;
 
-		for (int d = 0; d < SPA_DVAS_PER_BP; d++)
+		for (d = 0; d < SPA_DVAS_PER_BP; d++)
 			dsize += dva_get_dsize_sync(spa, &ddp->ddp_dva[d]);
 
 		dds->dds_blocks += 1;
@@ -413,16 +418,20 @@ ddt_stat_update(ddt_t *ddt, ddt_entry_t *dde, uint64_t neg)
 void
 ddt_histogram_add(ddt_histogram_t *dst, const ddt_histogram_t *src)
 {
-	for (int h = 0; h < 64; h++)
+	int h;
+
+	for (h = 0; h < 64; h++)
 		ddt_stat_add(&dst->ddh_stat[h], &src->ddh_stat[h], 0);
 }
 
 void
 ddt_histogram_stat(ddt_stat_t *dds, const ddt_histogram_t *ddh)
 {
+	int h;
+
 	bzero(dds, sizeof (*dds));
 
-	for (int h = 0; h < 64; h++)
+	for (h = 0; h < 64; h++)
 		ddt_stat_add(dds, &ddh->ddh_stat[h], 0);
 }
 
@@ -442,11 +451,15 @@ ddt_histogram_empty(const ddt_histogram_t *ddh)
 void
 ddt_get_dedup_object_stats(spa_t *spa, ddt_object_t *ddo_total)
 {
+	enum zio_checksum c;
+	enum ddt_type type;
+	enum ddt_class class;
+
 	/* Sum the statistics we cached in ddt_object_sync(). */
-	for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
+	for (c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
 		ddt_t *ddt = spa->spa_ddt[c];
-		for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
-			for (enum ddt_class class = 0; class < DDT_CLASSES;
+		for (type = 0; type < DDT_TYPES; type++) {
+			for (class = 0; class < DDT_CLASSES;
 			    class++) {
 				ddt_object_t *ddo =
 				    &ddt->ddt_object_stats[type][class];
@@ -467,10 +480,14 @@ ddt_get_dedup_object_stats(spa_t *spa, ddt_object_t *ddo_total)
 void
 ddt_get_dedup_histogram(spa_t *spa, ddt_histogram_t *ddh)
 {
-	for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
+	enum zio_checksum c;
+	enum ddt_type type;
+	enum ddt_class class;
+
+	for (c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
 		ddt_t *ddt = spa->spa_ddt[c];
-		for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
-			for (enum ddt_class class = 0; class < DDT_CLASSES;
+		for (type = 0; type < DDT_TYPES; type++) {
+			for (class = 0; class < DDT_CLASSES;
 			    class++) {
 				ddt_histogram_add(ddh,
 				    &ddt->ddt_histogram_cache[type][class]);
@@ -519,8 +536,9 @@ ddt_ditto_copies_needed(ddt_t *ddt, ddt_entry_t *dde, ddt_phys_t *ddp_willref)
 	uint64_t ditto = spa->spa_dedup_ditto;
 	int total_copies = 0;
 	int desired_copies = 0;
+	int p;
 
-	for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
+	for (p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
 		ddt_phys_t *ddp = &dde->dde_phys[p];
 		zio_t *zio = dde->dde_lead_zio[p];
 		uint64_t refcnt = ddp->ddp_refcnt;	/* committed refs */
@@ -553,8 +571,9 @@ ddt_ditto_copies_present(ddt_entry_t *dde)
 	ddt_phys_t *ddp = &dde->dde_phys[DDT_PHYS_DITTO];
 	dva_t *dva = ddp->ddp_dva;
 	int copies = 0 - DVA_GET_GANG(dva);
+	int d;
 
-	for (int d = 0; d < SPA_DVAS_PER_BP; d++, dva++)
+	for (d = 0; d < SPA_DVAS_PER_BP; d++, dva++)
 		if (DVA_IS_VALID(dva))
 			copies++;
 
@@ -641,9 +660,11 @@ ddt_alloc(const ddt_key_t *ddk)
 static void
 ddt_free(ddt_entry_t *dde)
 {
+	int p;
+
 	ASSERT(!dde->dde_loading);
 
-	for (int p = 0; p < DDT_PHYS_TYPES; p++)
+	for (p = 0; p < DDT_PHYS_TYPES; p++)
 		ASSERT(dde->dde_lead_zio[p] == NULL);
 
 	if (dde->dde_repair_data != NULL)
@@ -731,6 +752,8 @@ ddt_prefetch(spa_t *spa, const blkptr_t *bp)
 {
 	ddt_t *ddt;
 	ddt_entry_t dde;
+	enum ddt_type type;
+	enum ddt_class class;
 
 	if (!zfs_dedup_prefetch || bp == NULL || !BP_GET_DEDUP(bp))
 		return;
@@ -743,8 +766,8 @@ ddt_prefetch(spa_t *spa, const blkptr_t *bp)
 	ddt = ddt_select(spa, bp);
 	ddt_key_fill(&dde.dde_key, bp);
 
-	for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
-		for (enum ddt_class class = 0; class < DDT_CLASSES; class++) {
+	for (type = 0; type < DDT_TYPES; type++) {
+		for (class = 0; class < DDT_CLASSES; class++) {
 			ddt_object_prefetch(ddt, type, class, &dde);
 		}
 	}
@@ -757,8 +780,9 @@ ddt_entry_compare(const void *x1, const void *x2)
 	const ddt_entry_t *dde2 = x2;
 	const uint64_t *u1 = (const uint64_t *)&dde1->dde_key;
 	const uint64_t *u2 = (const uint64_t *)&dde2->dde_key;
+	int i;
 
-	for (int i = 0; i < DDT_KEY_WORDS; i++) {
+	for (i = 0; i < DDT_KEY_WORDS; i++) {
 		if (u1[i] < u2[i])
 			return (-1);
 		if (u1[i] > u2[i])
@@ -801,15 +825,20 @@ ddt_table_free(ddt_t *ddt)
 void
 ddt_create(spa_t *spa)
 {
+	enum zio_checksum c;
+
 	spa->spa_dedup_checksum = ZIO_DEDUPCHECKSUM;
 
-	for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++)
+	for (c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++)
 		spa->spa_ddt[c] = ddt_table_alloc(spa, c);
 }
 
 int
 ddt_load(spa_t *spa)
 {
+	enum zio_checksum c;
+	enum ddt_type type;
+	enum ddt_class class;
 	int error;
 
 	ddt_create(spa);
@@ -821,10 +850,10 @@ ddt_load(spa_t *spa)
 	if (error)
 		return (error == ENOENT ? 0 : error);
 
-	for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
+	for (c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
 		ddt_t *ddt = spa->spa_ddt[c];
-		for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
-			for (enum ddt_class class = 0; class < DDT_CLASSES;
+		for (type = 0; type < DDT_TYPES; type++) {
+			for (class = 0; class < DDT_CLASSES;
 			    class++) {
 				error = ddt_object_load(ddt, type, class);
 				if (error != 0 && error != ENOENT)
@@ -845,7 +874,9 @@ ddt_load(spa_t *spa)
 void
 ddt_unload(spa_t *spa)
 {
-	for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
+	enum zio_checksum c;
+
+	for (c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
 		if (spa->spa_ddt[c]) {
 			ddt_table_free(spa->spa_ddt[c]);
 			spa->spa_ddt[c] = NULL;
@@ -858,6 +889,8 @@ ddt_class_contains(spa_t *spa, enum ddt_class max_class, const blkptr_t *bp)
 {
 	ddt_t *ddt;
 	ddt_entry_t dde;
+	enum ddt_type type;
+	enum ddt_class class;
 
 	if (!BP_GET_DEDUP(bp))
 		return (B_FALSE);
@@ -869,8 +902,8 @@ ddt_class_contains(spa_t *spa, enum ddt_class max_class, const blkptr_t *bp)
 
 	ddt_key_fill(&dde.dde_key, bp);
 
-	for (enum ddt_type type = 0; type < DDT_TYPES; type++)
-		for (enum ddt_class class = 0; class <= max_class; class++)
+	for (type = 0; type < DDT_TYPES; type++)
+		for (class = 0; class <= max_class; class++)
 			if (ddt_object_lookup(ddt, type, class, &dde) == 0)
 				return (B_TRUE);
 
@@ -882,13 +915,15 @@ ddt_repair_start(ddt_t *ddt, const blkptr_t *bp)
 {
 	ddt_key_t ddk;
 	ddt_entry_t *dde;
+	enum ddt_type type;
+	enum ddt_class class;
 
 	ddt_key_fill(&ddk, bp);
 
 	dde = ddt_alloc(&ddk);
 
-	for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
-		for (enum ddt_class class = 0; class < DDT_CLASSES; class++) {
+	for (type = 0; type < DDT_TYPES; type++) {
+		for (class = 0; class < DDT_CLASSES; class++) {
 			/*
 			 * We can only do repair if there are multiple copies
 			 * of the block.  For anything in the UNIQUE class,
@@ -938,11 +973,12 @@ ddt_repair_entry(ddt_t *ddt, ddt_entry_t *dde, ddt_entry_t *rdde, zio_t *rio)
 	ddt_key_t *rddk = &rdde->dde_key;
 	zio_t *zio;
 	blkptr_t blk;
+	int p;
 
 	zio = zio_null(rio, rio->io_spa, NULL,
 	    ddt_repair_entry_done, rdde, rio->io_flags);
 
-	for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++, rddp++) {
+	for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++, rddp++) {
 		if (ddp->ddp_phys_birth == 0 ||
 		    ddp->ddp_phys_birth != rddp->ddp_phys_birth ||
 		    bcmp(ddp->ddp_dva, rddp->ddp_dva, sizeof (ddp->ddp_dva)))
@@ -992,11 +1028,12 @@ ddt_sync_entry(ddt_t *ddt, ddt_entry_t *dde, dmu_tx_t *tx, uint64_t txg)
 	enum ddt_class oclass = dde->dde_class;
 	enum ddt_class nclass;
 	uint64_t total_refcnt = 0;
+	int p;
 
 	ASSERT(dde->dde_loaded);
 	ASSERT(!dde->dde_loading);
 
-	for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
+	for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
 		ASSERT(dde->dde_lead_zio[p] == NULL);
 		ASSERT((int64_t)ddp->ddp_refcnt >= 0);
 		if (ddp->ddp_phys_birth == 0) {
@@ -1054,6 +1091,8 @@ ddt_sync_table(ddt_t *ddt, dmu_tx_t *tx, uint64_t txg)
 	spa_t *spa = ddt->ddt_spa;
 	ddt_entry_t *dde;
 	void *cookie = NULL;
+	enum ddt_type type;
+	enum ddt_class class;
 
 	if (avl_numnodes(&ddt->ddt_tree) == 0)
 		return;
@@ -1073,15 +1112,15 @@ ddt_sync_table(ddt_t *ddt, dmu_tx_t *tx, uint64_t txg)
 		ddt_free(dde);
 	}
 
-	for (enum ddt_type type = 0; type < DDT_TYPES; type++) {
+	for (type = 0; type < DDT_TYPES; type++) {
 		uint64_t count = 0;
-		for (enum ddt_class class = 0; class < DDT_CLASSES; class++) {
+		for (class = 0; class < DDT_CLASSES; class++) {
 			if (ddt_object_exists(ddt, type, class)) {
 				ddt_object_sync(ddt, type, class, tx);
 				count += ddt_object_count(ddt, type, class);
 			}
 		}
-		for (enum ddt_class class = 0; class < DDT_CLASSES; class++) {
+		for (class = 0; class < DDT_CLASSES; class++) {
 			if (count == 0 && ddt_object_exists(ddt, type, class))
 				ddt_object_destroy(ddt, type, class, tx);
 		}
@@ -1097,12 +1136,13 @@ ddt_sync(spa_t *spa, uint64_t txg)
 	dmu_tx_t *tx;
 	zio_t *rio = zio_root(spa, NULL, NULL,
 	    ZIO_FLAG_CANFAIL | ZIO_FLAG_SPECULATIVE);
+	enum zio_checksum c;
 
 	ASSERT(spa_syncing_txg(spa) == txg);
 
 	tx = dmu_tx_create_assigned(spa->spa_dsl_pool, txg);
 
-	for (enum zio_checksum c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
+	for (c = 0; c < ZIO_CHECKSUM_FUNCTIONS; c++) {
 		ddt_t *ddt = spa->spa_ddt[c];
 		if (ddt == NULL)
 			continue;
diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index 39234eba5..f2b3f2ba7 100644
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -1611,6 +1611,7 @@ void
 dmu_object_info_from_dnode(dnode_t *dn, dmu_object_info_t *doi)
 {
 	dnode_phys_t *dnp;
+	int i;
 
 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
 	mutex_enter(&dn->dn_mtx);
@@ -1629,7 +1630,7 @@ dmu_object_info_from_dnode(dnode_t *dn, dmu_object_info_t *doi)
 	doi->doi_physical_blocks_512 = (DN_USED_BYTES(dnp) + 256) >> 9;
 	doi->doi_max_offset = (dnp->dn_maxblkid + 1) * dn->dn_datablksz;
 	doi->doi_fill_count = 0;
-	for (int i = 0; i < dnp->dn_nblkptr; i++)
+	for (i = 0; i < dnp->dn_nblkptr; i++)
 		doi->doi_fill_count += dnp->dn_blkptr[i].blk_fill;
 
 	mutex_exit(&dn->dn_mtx);
diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c
index 7caebd979..bacd62c09 100644
--- a/module/zfs/dmu_objset.c
+++ b/module/zfs/dmu_objset.c
@@ -528,8 +528,9 @@ void
 dmu_objset_evict(objset_t *os)
 {
 	dsl_dataset_t *ds = os->os_dsl_dataset;
+	int t;
 
-	for (int t = 0; t < TXG_SIZE; t++)
+	for (t = 0; t < TXG_SIZE; t++)
 		ASSERT(!dmu_objset_is_dirty(os, t));
 
 	if (ds) {
@@ -1041,6 +1042,8 @@ dmu_objset_sync_dnodes(list_t *list, list_t *newlist, dmu_tx_t *tx)
 static void
 dmu_objset_write_ready(zio_t *zio, arc_buf_t *abuf, void *arg)
 {
+	int i;
+
 	blkptr_t *bp = zio->io_bp;
 	objset_t *os = arg;
 	dnode_phys_t *dnp = &os->os_phys->os_meta_dnode;
@@ -1056,7 +1059,7 @@ dmu_objset_write_ready(zio_t *zio, arc_buf_t *abuf, void *arg)
 	 * dnode and user/group accounting objects).
 	 */
 	bp->blk_fill = 0;
-	for (int i = 0; i < dnp->dn_nblkptr; i++)
+	for (i = 0; i < dnp->dn_nblkptr; i++)
 		bp->blk_fill += dnp->dn_blkptr[i].blk_fill;
 }
 
@@ -1178,7 +1181,9 @@ dmu_objset_is_dirty(objset_t *os, uint64_t txg)
 boolean_t
 dmu_objset_is_dirty_anywhere(objset_t *os)
 {
-	for (int t = 0; t < TXG_SIZE; t++)
+	int t;
+
+	for (t = 0; t < TXG_SIZE; t++)
 		if (dmu_objset_is_dirty(os, t))
 			return (B_TRUE);
 	return (B_FALSE);
diff --git a/module/zfs/dmu_tx.c b/module/zfs/dmu_tx.c
index bd5c71a22..d292438dc 100644
--- a/module/zfs/dmu_tx.c
+++ b/module/zfs/dmu_tx.c
@@ -216,6 +216,7 @@ dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
 	uint64_t start, end, i;
 	int min_bs, max_bs, min_ibs, max_ibs, epbs, bits;
 	int err = 0;
+	int l;
 
 	if (len == 0)
 		return;
@@ -303,7 +304,7 @@ dmu_tx_count_write(dmu_tx_hold_t *txh, uint64_t off, uint64_t len)
 		 * we need to account for overwrites/unref.
 		 */
 		if (start <= dn->dn_maxblkid) {
-			for (int l = 0; l < DN_MAX_LEVELS; l++)
+			for (l = 0; l < DN_MAX_LEVELS; l++)
 				history[l] = -1ULL;
 		}
 		while (start <= dn->dn_maxblkid) {
diff --git a/module/zfs/dsl_dataset.c b/module/zfs/dsl_dataset.c
index 59ac4a609..667aef37e 100644
--- a/module/zfs/dsl_dataset.c
+++ b/module/zfs/dsl_dataset.c
@@ -85,11 +85,13 @@ parent_delta(dsl_dataset_t *ds, int64_t delta)
 void
 dsl_dataset_block_born(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx)
 {
-	int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
-	int compressed = BP_GET_PSIZE(bp);
-	int uncompressed = BP_GET_UCSIZE(bp);
+	int used, compressed, uncompressed;
 	int64_t delta;
 
+	used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
+	compressed = BP_GET_PSIZE(bp);
+	uncompressed = BP_GET_UCSIZE(bp);
+
 	dprintf_bp(bp, "ds=%p", ds);
 
 	ASSERT(dmu_tx_is_syncing(tx));
@@ -130,15 +132,17 @@ int
 dsl_dataset_block_kill(dsl_dataset_t *ds, const blkptr_t *bp, dmu_tx_t *tx,
     boolean_t async)
 {
+	int used, compressed, uncompressed;
+
 	if (BP_IS_HOLE(bp))
 		return (0);
 
 	ASSERT(dmu_tx_is_syncing(tx));
 	ASSERT(bp->blk_birth <= tx->tx_txg);
 
-	int used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
-	int compressed = BP_GET_PSIZE(bp);
-	int uncompressed = BP_GET_UCSIZE(bp);
+	used = bp_get_dsize_sync(tx->tx_pool->dp_spa, bp);
+	compressed = BP_GET_PSIZE(bp);
+	uncompressed = BP_GET_UCSIZE(bp);
 
 	ASSERT(used > 0);
 	if (ds == NULL) {
@@ -1772,6 +1776,7 @@ dsl_dataset_destroy_sync(void *arg1, void *tag, dmu_tx_t *tx)
 
 		if (dsl_dataset_is_snapshot(ds_next)) {
 			dsl_dataset_t *ds_nextnext;
+			dsl_dataset_t *hds;
 
 			/*
 			 * Update next's unique to include blocks which
@@ -1794,7 +1799,6 @@ dsl_dataset_destroy_sync(void *arg1, void *tag, dmu_tx_t *tx)
 			ASSERT3P(ds_next->ds_prev, ==, NULL);
 
 			/* Collapse range in this head. */
-			dsl_dataset_t *hds;
 			VERIFY3U(0, ==, dsl_dataset_hold_obj(dp,
 			    ds->ds_dir->dd_phys->dd_head_dataset_obj,
 			    FTAG, &hds));
diff --git a/module/zfs/dsl_dir.c b/module/zfs/dsl_dir.c
index 1cd49c827..545dce9a0 100644
--- a/module/zfs/dsl_dir.c
+++ b/module/zfs/dsl_dir.c
@@ -964,11 +964,13 @@ dsl_dir_diduse_space(dsl_dir_t *dd, dd_used_t type,
 		    dd->dd_phys->dd_used_breakdown[type] >= -used);
 		dd->dd_phys->dd_used_breakdown[type] += used;
 #ifdef DEBUG
-		dd_used_t t;
-		uint64_t u = 0;
-		for (t = 0; t < DD_USED_NUM; t++)
-			u += dd->dd_phys->dd_used_breakdown[t];
-		ASSERT3U(u, ==, dd->dd_phys->dd_used_bytes);
+		{
+			dd_used_t t;
+			uint64_t u = 0;
+			for (t = 0; t < DD_USED_NUM; t++)
+				u += dd->dd_phys->dd_used_breakdown[t];
+			ASSERT3U(u, ==, dd->dd_phys->dd_used_bytes);
+		}
 #endif
 	}
 	if (needlock)
diff --git a/module/zfs/dsl_pool.c b/module/zfs/dsl_pool.c
index 700cc9628..a3c1457df 100644
--- a/module/zfs/dsl_pool.c
+++ b/module/zfs/dsl_pool.c
@@ -692,9 +692,10 @@ upgrade_dir_clones_cb(spa_t *spa, uint64_t dsobj, const char *dsname, void *arg)
 void
 dsl_pool_upgrade_dir_clones(dsl_pool_t *dp, dmu_tx_t *tx)
 {
-	ASSERT(dmu_tx_is_syncing(tx));
 	uint64_t obj;
 
+	ASSERT(dmu_tx_is_syncing(tx));
+
 	(void) dsl_dir_create_sync(dp, dp->dp_root_dir, FREE_DIR_NAME, tx);
 	VERIFY(0 == dsl_pool_open_special_dir(dp,
 	    FREE_DIR_NAME, &dp->dp_free_dir));
diff --git a/module/zfs/dsl_scan.c b/module/zfs/dsl_scan.c
index 56d410836..7e6be15a0 100644
--- a/module/zfs/dsl_scan.c
+++ b/module/zfs/dsl_scan.c
@@ -1076,6 +1076,7 @@ dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
 	dsl_pool_t *dp = scn->scn_dp;
 	dsl_dataset_t *ds;
 	objset_t *os;
+	char *dsname;
 
 	VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds));
 
@@ -1098,7 +1099,7 @@ dsl_scan_visitds(dsl_scan_t *scn, uint64_t dsobj, dmu_tx_t *tx)
 	dmu_buf_will_dirty(ds->ds_dbuf, tx);
 	dsl_scan_visit_rootbp(scn, ds, &ds->ds_phys->ds_bp, tx);
 
-	char *dsname = kmem_alloc(ZFS_MAXNAMELEN, KM_SLEEP);
+	dsname = kmem_alloc(ZFS_MAXNAMELEN, KM_SLEEP);
 	dsl_dataset_name(ds, dsname);
 	zfs_dbgmsg("scanned dataset %llu (%s) with min=%llu max=%llu; "
 	    "pausing=%u",
@@ -1294,11 +1295,12 @@ dsl_scan_ddt_entry(dsl_scan_t *scn, enum zio_checksum checksum,
 	ddt_phys_t *ddp = dde->dde_phys;
 	blkptr_t bp;
 	zbookmark_t zb = { 0 };
+	int p;
 
 	if (scn->scn_phys.scn_state != DSS_SCANNING)
 		return;
 
-	for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
+	for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
 		if (ddp->ddp_phys_birth == 0 ||
 		    ddp->ddp_phys_birth > scn->scn_phys.scn_cur_max_txg)
 			continue;
@@ -1658,10 +1660,11 @@ dsl_scan_scrub_cb(dsl_pool_t *dp,
 	size_t size = BP_GET_PSIZE(bp);
 	spa_t *spa = dp->dp_spa;
 	uint64_t phys_birth = BP_PHYSICAL_BIRTH(bp);
-	boolean_t needs_io;
+	boolean_t needs_io = B_FALSE;
 	int zio_flags = ZIO_FLAG_SCAN_THREAD | ZIO_FLAG_RAW | ZIO_FLAG_CANFAIL;
-	int zio_priority;
+	int zio_priority = 0;
 	int scan_delay = 0;
+	int d;
 
 	if (phys_birth <= scn->scn_phys.scn_min_txg ||
 	    phys_birth >= scn->scn_phys.scn_max_txg)
@@ -1686,7 +1689,7 @@ dsl_scan_scrub_cb(dsl_pool_t *dp,
 	if (zb->zb_level == ZB_ZIL_LEVEL)
 		zio_flags |= ZIO_FLAG_SPECULATIVE;
 
-	for (int d = 0; d < BP_GET_NDVAS(bp); d++) {
+	for (d = 0; d < BP_GET_NDVAS(bp); d++) {
 		vdev_t *vd = vdev_lookup_top(spa,
 		    DVA_GET_VDEV(&bp->blk_dva[d]));
 
diff --git a/module/zfs/include/sys/spa.h b/module/zfs/include/sys/spa.h
index 456ec06dc..7ebbbb2cd 100644
--- a/module/zfs/include/sys/spa.h
+++ b/module/zfs/include/sys/spa.h
@@ -350,13 +350,14 @@ typedef struct blkptr {
 	int size = BP_SPRINTF_LEN;					\
 	int len = 0;							\
 	int copies = 0;							\
+	int d;								\
 									\
 	if (bp == NULL) {						\
 		len = func(buf + len, size - len, "<NULL>");		\
 	} else if (BP_IS_HOLE(bp)) {					\
 		len = func(buf + len, size - len, "<hole>");		\
 	} else {							\
-		for (int d = 0; d < BP_GET_NDVAS(bp); d++) {		\
+		for (d = 0; d < BP_GET_NDVAS(bp); d++) {		\
 			const dva_t *dva = &bp->blk_dva[d];		\
 			if (DVA_IS_VALID(dva))				\
 				copies++;				\
diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c
index 17b4b12c4..1722a53fc 100644
--- a/module/zfs/metaslab.c
+++ b/module/zfs/metaslab.c
@@ -730,6 +730,7 @@ void
 metaslab_fini(metaslab_t *msp)
 {
 	metaslab_group_t *mg = msp->ms_group;
+	int t;
 
 	vdev_space_update(mg->mg_vd,
 	    -msp->ms_smo.smo_alloc, 0, -msp->ms_map.sm_size);
@@ -741,12 +742,12 @@ metaslab_fini(metaslab_t *msp)
 	space_map_unload(&msp->ms_map);
 	space_map_destroy(&msp->ms_map);
 
-	for (int t = 0; t < TXG_SIZE; t++) {
+	for (t = 0; t < TXG_SIZE; t++) {
 		space_map_destroy(&msp->ms_allocmap[t]);
 		space_map_destroy(&msp->ms_freemap[t]);
 	}
 
-	for (int t = 0; t < TXG_DEFER_SIZE; t++)
+	for (t = 0; t < TXG_DEFER_SIZE; t++)
 		space_map_destroy(&msp->ms_defermap[t]);
 
 	ASSERT3S(msp->ms_deferspace, ==, 0);
@@ -849,6 +850,7 @@ metaslab_activate(metaslab_t *msp, uint64_t activation_weight, uint64_t size)
 	metaslab_group_t *mg = msp->ms_group;
 	space_map_t *sm = &msp->ms_map;
 	space_map_ops_t *sm_ops = msp->ms_group->mg_class->mc_ops;
+	int t;
 
 	ASSERT(MUTEX_HELD(&msp->ms_lock));
 
@@ -862,7 +864,7 @@ metaslab_activate(metaslab_t *msp, uint64_t activation_weight, uint64_t size)
 				metaslab_group_sort(msp->ms_group, msp, 0);
 				return (error);
 			}
-			for (int t = 0; t < TXG_DEFER_SIZE; t++)
+			for (t = 0; t < TXG_DEFER_SIZE; t++)
 				space_map_walk(&msp->ms_defermap[t],
 				    space_map_claim, sm);
 
@@ -922,6 +924,7 @@ metaslab_sync(metaslab_t *msp, uint64_t txg)
 	space_map_obj_t *smo = &msp->ms_smo_syncing;
 	dmu_buf_t *db;
 	dmu_tx_t *tx;
+	int t;
 
 	ASSERT(!vd->vdev_ishole);
 
@@ -977,11 +980,11 @@ metaslab_sync(metaslab_t *msp, uint64_t txg)
 		space_map_walk(sm, space_map_remove, allocmap);
 		space_map_walk(freed_map, space_map_remove, allocmap);
 
-		for (int t = 0; t < TXG_DEFER_SIZE; t++)
+		for (t = 0; t < TXG_DEFER_SIZE; t++)
 			space_map_walk(&msp->ms_defermap[t],
 			    space_map_remove, allocmap);
 
-		for (int t = 1; t < TXG_CONCURRENT_STATES; t++)
+		for (t = 1; t < TXG_CONCURRENT_STATES; t++)
 			space_map_walk(&msp->ms_allocmap[(txg + t) & TXG_MASK],
 			    space_map_remove, allocmap);
 
@@ -1019,6 +1022,7 @@ metaslab_sync_done(metaslab_t *msp, uint64_t txg)
 	metaslab_group_t *mg = msp->ms_group;
 	vdev_t *vd = mg->mg_vd;
 	int64_t alloc_delta, defer_delta;
+	int t;
 
 	ASSERT(!vd->vdev_ishole);
 
@@ -1029,14 +1033,14 @@ metaslab_sync_done(metaslab_t *msp, uint64_t txg)
 	 * allocmaps and freemaps and add its capacity to the vdev.
 	 */
 	if (freed_map->sm_size == 0) {
-		for (int t = 0; t < TXG_SIZE; t++) {
+		for (t = 0; t < TXG_SIZE; t++) {
 			space_map_create(&msp->ms_allocmap[t], sm->sm_start,
 			    sm->sm_size, sm->sm_shift, sm->sm_lock);
 			space_map_create(&msp->ms_freemap[t], sm->sm_start,
 			    sm->sm_size, sm->sm_shift, sm->sm_lock);
 		}
 
-		for (int t = 0; t < TXG_DEFER_SIZE; t++)
+		for (t = 0; t < TXG_DEFER_SIZE; t++)
 			space_map_create(&msp->ms_defermap[t], sm->sm_start,
 			    sm->sm_size, sm->sm_shift, sm->sm_lock);
 
@@ -1082,7 +1086,7 @@ metaslab_sync_done(metaslab_t *msp, uint64_t txg)
 	if (sm->sm_loaded && (msp->ms_weight & METASLAB_ACTIVE_MASK) == 0) {
 		int evictable = 1;
 
-		for (int t = 1; t < TXG_CONCURRENT_STATES; t++)
+		for (t = 1; t < TXG_CONCURRENT_STATES; t++)
 			if (msp->ms_allocmap[(txg + t) & TXG_MASK].sm_space)
 				evictable = 0;
 
@@ -1099,12 +1103,13 @@ void
 metaslab_sync_reassess(metaslab_group_t *mg)
 {
 	vdev_t *vd = mg->mg_vd;
+	int m;
 
 	/*
 	 * Re-evaluate all metaslabs which have lower offsets than the
 	 * bonus area.
 	 */
-	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];
 
 		if (msp->ms_map.sm_start > mg->mg_bonus_area)
@@ -1517,7 +1522,7 @@ 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);
 	ASSERT(BP_PHYSICAL_BIRTH(bp) == 0);
@@ -1533,7 +1538,7 @@ 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) {
@@ -1559,14 +1564,14 @@ 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_syncing_txg(spa));
 
 	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);
@@ -1577,7 +1582,7 @@ 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));
 
@@ -1592,7 +1597,7 @@ 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/sa.c b/module/zfs/sa.c
index 4cb4546b2..d5c985bf1 100644
--- a/module/zfs/sa.c
+++ b/module/zfs/sa.c
@@ -1478,8 +1478,8 @@ sa_find_idx_tab(objset_t *os, dmu_object_type_t bonustype, void *data)
 
 	/* Verify header size is consistent with layout information */
 	ASSERT(tb);
-	ASSERT(IS_SA_BONUSTYPE(bonustype) &&
-	    SA_HDR_SIZE_MATCH_LAYOUT(hdr, tb) || !IS_SA_BONUSTYPE(bonustype) ||
+	ASSERT((IS_SA_BONUSTYPE(bonustype) &&
+	    SA_HDR_SIZE_MATCH_LAYOUT(hdr, tb)) || !IS_SA_BONUSTYPE(bonustype) ||
 	    (IS_SA_BONUSTYPE(bonustype) && hdr->sa_layout_info == 0));
 
 	/*
diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index b6190e4cf..9ae16d316 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -653,8 +653,10 @@ spa_taskq_create(spa_t *spa, const char *name, enum zti_modes mode,
 static void
 spa_create_zio_taskqs(spa_t *spa)
 {
-	for (int t = 0; t < ZIO_TYPES; t++) {
-		for (int q = 0; q < ZIO_TASKQ_TYPES; q++) {
+	int t, q;
+
+	for (t = 0; t < ZIO_TYPES; t++) {
+		for (q = 0; q < ZIO_TASKQ_TYPES; q++) {
 			const zio_taskq_info_t *ztip = &zio_taskqs[t][q];
 			enum zti_modes mode = ztip->zti_mode;
 			uint_t value = ztip->zti_value;
@@ -808,6 +810,8 @@ spa_activate(spa_t *spa, int mode)
 static void
 spa_deactivate(spa_t *spa)
 {
+	int t, q;
+
 	ASSERT(spa->spa_sync_on == B_FALSE);
 	ASSERT(spa->spa_dsl_pool == NULL);
 	ASSERT(spa->spa_root_vdev == NULL);
@@ -819,8 +823,8 @@ spa_deactivate(spa_t *spa)
 	list_destroy(&spa->spa_config_dirty_list);
 	list_destroy(&spa->spa_state_dirty_list);
 
-	for (int t = 0; t < ZIO_TYPES; t++) {
-		for (int q = 0; q < ZIO_TASKQ_TYPES; q++) {
+	for (t = 0; t < ZIO_TYPES; t++) {
+		for (q = 0; q < ZIO_TASKQ_TYPES; q++) {
 			if (spa->spa_zio_taskq[t][q] != NULL)
 				taskq_destroy(spa->spa_zio_taskq[t][q]);
 			spa->spa_zio_taskq[t][q] = NULL;
@@ -883,6 +887,7 @@ spa_config_parse(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent,
 	nvlist_t **child;
 	uint_t children;
 	int error;
+	int c;
 
 	if ((error = vdev_alloc(spa, vdp, nv, parent, id, atype)) != 0)
 		return (error);
@@ -902,7 +907,7 @@ spa_config_parse(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent,
 		return (EINVAL);
 	}
 
-	for (int c = 0; c < children; c++) {
+	for (c = 0; c < children; c++) {
 		vdev_t *vd;
 		if ((error = spa_config_parse(spa, &vd, child[c], *vdp, c,
 		    atype)) != 0) {
@@ -1279,7 +1284,9 @@ load_nvlist(spa_t *spa, uint64_t obj, nvlist_t **value)
 static void
 spa_check_removed(vdev_t *vd)
 {
-	for (int c = 0; c < vd->vdev_children; c++)
+	int c;
+
+	for (c = 0; c < vd->vdev_children; c++)
 		spa_check_removed(vd->vdev_child[c]);
 
 	if (vd->vdev_ops->vdev_op_leaf && vdev_is_dead(vd)) {
@@ -1296,6 +1303,7 @@ spa_config_valid(spa_t *spa, nvlist_t *config)
 {
 	vdev_t *mrvd, *rvd = spa->spa_root_vdev;
 	nvlist_t *nv;
+	int c, i;
 
 	VERIFY(nvlist_lookup_nvlist(config, ZPOOL_CONFIG_VDEV_TREE, &nv) == 0);
 
@@ -1317,7 +1325,7 @@ spa_config_valid(spa_t *spa, nvlist_t *config)
 		    KM_SLEEP);
 		VERIFY(nvlist_alloc(&nv, NV_UNIQUE_NAME, KM_SLEEP) == 0);
 
-		for (int c = 0; c < rvd->vdev_children; c++) {
+		for (c = 0; c < rvd->vdev_children; c++) {
 			vdev_t *tvd = rvd->vdev_child[c];
 			vdev_t *mtvd  = mrvd->vdev_child[c];
 
@@ -1334,7 +1342,7 @@ spa_config_valid(spa_t *spa, nvlist_t *config)
 			VERIFY(nvlist_add_nvlist(spa->spa_load_info,
 			    ZPOOL_CONFIG_MISSING_DEVICES, nv) == 0);
 
-			for (int i = 0; i < idx; i++)
+			for (i = 0; i < idx; i++)
 				nvlist_free(child[i]);
 		}
 		nvlist_free(nv);
@@ -1346,7 +1354,7 @@ spa_config_valid(spa_t *spa, nvlist_t *config)
 	 * from the MOS config (mrvd). Check each top-level vdev
 	 * with the corresponding MOS config top-level (mtvd).
 	 */
-	for (int c = 0; c < rvd->vdev_children; c++) {
+	for (c = 0; c < rvd->vdev_children; c++) {
 		vdev_t *tvd = rvd->vdev_child[c];
 		vdev_t *mtvd  = mrvd->vdev_child[c];
 
@@ -1435,13 +1443,14 @@ spa_passivate_log(spa_t *spa)
 {
 	vdev_t *rvd = spa->spa_root_vdev;
 	boolean_t slog_found = B_FALSE;
+	int c;
 
 	ASSERT(spa_config_held(spa, SCL_ALLOC, RW_WRITER));
 
 	if (!spa_has_slogs(spa))
 		return (B_FALSE);
 
-	for (int c = 0; c < rvd->vdev_children; c++) {
+	for (c = 0; c < rvd->vdev_children; c++) {
 		vdev_t *tvd = rvd->vdev_child[c];
 		metaslab_group_t *mg = tvd->vdev_mg;
 
@@ -1458,10 +1467,11 @@ static void
 spa_activate_log(spa_t *spa)
 {
 	vdev_t *rvd = spa->spa_root_vdev;
+	int c;
 
 	ASSERT(spa_config_held(spa, SCL_ALLOC, RW_WRITER));
 
-	for (int c = 0; c < rvd->vdev_children; c++) {
+	for (c = 0; c < rvd->vdev_children; c++) {
 		vdev_t *tvd = rvd->vdev_child[c];
 		metaslab_group_t *mg = tvd->vdev_mg;
 
@@ -1491,7 +1501,9 @@ spa_offline_log(spa_t *spa)
 static void
 spa_aux_check_removed(spa_aux_vdev_t *sav)
 {
-	for (int i = 0; i < sav->sav_count; i++)
+	int i;
+
+	for (i = 0; i < sav->sav_count; i++)
 		spa_check_removed(sav->sav_vdevs[i]);
 }
 
@@ -2163,6 +2175,7 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
 	    spa->spa_load_max_txg == UINT64_MAX)) {
 		dmu_tx_t *tx;
 		int need_update = B_FALSE;
+		int c;
 
 		ASSERT(state != SPA_LOAD_TRYIMPORT);
 
@@ -2209,7 +2222,7 @@ spa_load_impl(spa_t *spa, uint64_t pool_guid, nvlist_t *config,
 		    (spa->spa_import_flags & ZFS_IMPORT_VERBATIM))
 			need_update = B_TRUE;
 
-		for (int c = 0; c < rvd->vdev_children; c++)
+		for (c = 0; c < rvd->vdev_children; c++)
 			if (rvd->vdev_child[c]->vdev_ms_array == 0)
 				need_update = B_TRUE;
 
@@ -2845,6 +2858,7 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
 	nvlist_t **spares, **l2cache;
 	uint_t nspares, nl2cache;
 	uint64_t version, obj;
+	int c;
 
 	/*
 	 * If this pool already exists, return failure.
@@ -2903,7 +2917,7 @@ spa_create(const char *pool, nvlist_t *nvroot, nvlist_t *props,
 	    (error = vdev_create(rvd, txg, B_FALSE)) == 0 &&
 	    (error = spa_validate_aux(spa, nvroot, txg,
 	    VDEV_ALLOC_ADD)) == 0) {
-		for (int c = 0; c < rvd->vdev_children; c++) {
+		for (c = 0; c < rvd->vdev_children; c++) {
 			vdev_metaslab_set_size(rvd->vdev_child[c]);
 			vdev_expand(rvd->vdev_child[c], txg);
 		}
@@ -3103,7 +3117,9 @@ spa_generate_rootconf(char *devpath, char *devid, uint64_t *guid)
 static void
 spa_alt_rootvdev(vdev_t *vd, vdev_t **avd, uint64_t *txg)
 {
-	for (int c = 0; c < vd->vdev_children; c++)
+	int c;
+
+	for (c = 0; c < vd->vdev_children; c++)
 		spa_alt_rootvdev(vd->vdev_child[c], avd, txg);
 
 	if (vd->vdev_ops->vdev_op_leaf) {
@@ -3687,6 +3703,7 @@ spa_vdev_add(spa_t *spa, nvlist_t *nvroot)
 	vdev_t *vd, *tvd;
 	nvlist_t **spares, **l2cache;
 	uint_t nspares, nl2cache;
+	int c;
 
 	ASSERT(spa_writeable(spa));
 
@@ -3723,7 +3740,7 @@ spa_vdev_add(spa_t *spa, nvlist_t *nvroot)
 	/*
 	 * Transfer each new top-level vdev from vd to rvd.
 	 */
-	for (int c = 0; c < vd->vdev_children; c++) {
+	for (c = 0; c < vd->vdev_children; c++) {
 
 		/*
 		 * Set the vdev id to the first hole, if one exists.
@@ -3999,6 +4016,7 @@ spa_vdev_detach(spa_t *spa, uint64_t guid, uint64_t pguid, int replace_done)
 	boolean_t unspare = B_FALSE;
 	uint64_t unspare_guid;
 	char *vdpath;
+	int c, t;
 
 	ASSERT(spa_writeable(spa));
 
@@ -4066,7 +4084,7 @@ spa_vdev_detach(spa_t *spa, uint64_t guid, uint64_t pguid, int replace_done)
 	    vd->vdev_path != NULL) {
 		size_t len = strlen(vd->vdev_path);
 
-		for (int c = 0; c < pvd->vdev_children; c++) {
+		for (c = 0; c < pvd->vdev_children; c++) {
 			cvd = pvd->vdev_child[c];
 
 			if (cvd == vd || cvd->vdev_path == NULL)
@@ -4174,7 +4192,7 @@ spa_vdev_detach(spa_t *spa, uint64_t guid, uint64_t pguid, int replace_done)
 	 * prevent vd from being accessed after it's freed.
 	 */
 	vdpath = spa_strdup(vd->vdev_path);
-	for (int t = 0; t < TXG_SIZE; t++)
+	for (t = 0; t < TXG_SIZE; t++)
 		(void) txg_list_remove_this(&tvd->vdev_dtl_list, vd, t);
 	vd->vdev_detached = B_TRUE;
 	vdev_dirty(tvd, VDD_DTL, vd, txg);
@@ -4509,7 +4527,9 @@ out:
 static nvlist_t *
 spa_nvlist_lookup_by_guid(nvlist_t **nvpp, int count, uint64_t target_guid)
 {
-	for (int i = 0; i < count; i++) {
+	int i;
+
+	for (i = 0; i < count; i++) {
 		uint64_t guid;
 
 		VERIFY(nvlist_lookup_uint64(nvpp[i], ZPOOL_CONFIG_GUID,
@@ -4527,11 +4547,12 @@ spa_vdev_remove_aux(nvlist_t *config, char *name, nvlist_t **dev, int count,
 	nvlist_t *dev_to_remove)
 {
 	nvlist_t **newdev = NULL;
+	int i, j;
 
 	if (count > 1)
 		newdev = kmem_alloc((count - 1) * sizeof (void *), KM_SLEEP);
 
-	for (int i = 0, j = 0; i < count; i++) {
+	for (i = 0, j = 0; i < count; i++) {
 		if (dev[i] == dev_to_remove)
 			continue;
 		VERIFY(nvlist_dup(dev[i], &newdev[j++], KM_SLEEP) == 0);
@@ -4540,7 +4561,7 @@ spa_vdev_remove_aux(nvlist_t *config, char *name, nvlist_t **dev, int count,
 	VERIFY(nvlist_remove(config, name, DATA_TYPE_NVLIST_ARRAY) == 0);
 	VERIFY(nvlist_add_nvlist_array(config, name, newdev, count - 1) == 0);
 
-	for (int i = 0; i < count - 1; i++)
+	for (i = 0; i < count - 1; i++)
 		nvlist_free(newdev[i]);
 
 	if (count > 1)
@@ -4761,8 +4782,9 @@ static vdev_t *
 spa_vdev_resilver_done_hunt(vdev_t *vd)
 {
 	vdev_t *newvd, *oldvd;
+	int c;
 
-	for (int c = 0; c < vd->vdev_children; c++) {
+	for (c = 0; c < vd->vdev_children; c++) {
 		oldvd = spa_vdev_resilver_done_hunt(vd->vdev_child[c]);
 		if (oldvd != NULL)
 			return (oldvd);
@@ -4965,6 +4987,8 @@ spa_scan(spa_t *spa, pool_scan_func_t func)
 static void
 spa_async_remove(spa_t *spa, vdev_t *vd)
 {
+	int c;
+
 	if (vd->vdev_remove_wanted) {
 		vd->vdev_remove_wanted = B_FALSE;
 		vd->vdev_delayed_close = B_FALSE;
@@ -4983,19 +5007,21 @@ spa_async_remove(spa_t *spa, vdev_t *vd)
 		vdev_state_dirty(vd->vdev_top);
 	}
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		spa_async_remove(spa, vd->vdev_child[c]);
 }
 
 static void
 spa_async_probe(spa_t *spa, vdev_t *vd)
 {
+	int c;
+
 	if (vd->vdev_probe_wanted) {
 		vd->vdev_probe_wanted = B_FALSE;
 		vdev_reopen(vd);	/* vdev_open() does the actual probe */
 	}
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		spa_async_probe(spa, vd->vdev_child[c]);
 }
 
@@ -5005,11 +5031,12 @@ spa_async_autoexpand(spa_t *spa, vdev_t *vd)
 	sysevent_id_t eid;
 	nvlist_t *attr;
 	char *physpath;
+	int c;
 
 	if (!spa->spa_autoexpand)
 		return;
 
-	for (int c = 0; c < vd->vdev_children; c++) {
+	for (c = 0; c < vd->vdev_children; c++) {
 		vdev_t *cvd = vd->vdev_child[c];
 		spa_async_autoexpand(spa, cvd);
 	}
@@ -5033,7 +5060,7 @@ spa_async_autoexpand(spa_t *spa, vdev_t *vd)
 static void
 spa_async_thread(spa_t *spa)
 {
-	int tasks;
+	int tasks, i;
 
 	ASSERT(spa->spa_sync_on);
 
@@ -5072,9 +5099,9 @@ spa_async_thread(spa_t *spa)
 	if (tasks & SPA_ASYNC_REMOVE) {
 		spa_vdev_state_enter(spa, SCL_NONE);
 		spa_async_remove(spa, spa->spa_root_vdev);
-		for (int i = 0; i < spa->spa_l2cache.sav_count; i++)
+		for (i = 0; i < spa->spa_l2cache.sav_count; i++)
 			spa_async_remove(spa, spa->spa_l2cache.sav_vdevs[i]);
-		for (int i = 0; i < spa->spa_spares.sav_count; i++)
+		for (i = 0; i < spa->spa_spares.sav_count; i++)
 			spa_async_remove(spa, spa->spa_spares.sav_vdevs[i]);
 		(void) spa_vdev_state_exit(spa, NULL, 0);
 	}
@@ -5460,6 +5487,7 @@ spa_sync(spa_t *spa, uint64_t txg)
 	vdev_t *vd;
 	dmu_tx_t *tx;
 	int error;
+	int c;
 
 	VERIFY(spa_writeable(spa));
 
@@ -5593,7 +5621,7 @@ spa_sync(spa_t *spa, uint64_t txg)
 			int children = rvd->vdev_children;
 			int c0 = spa_get_random(children);
 
-			for (int c = 0; c < children; c++) {
+			for (c = 0; c < children; c++) {
 				vd = rvd->vdev_child[(c0 + c) % children];
 				if (vd->vdev_ms_array == 0 || vd->vdev_islog)
 					continue;
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c
index 1b54afb0b..228ed1376 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;
@@ -311,8 +317,9 @@ void
 spa_config_enter(spa_t *spa, int locks, void *tag, krw_t rw)
 {
 	int wlocks_held = 0;
+	int i;
 
-	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 (scl->scl_writer == curthread)
 			wlocks_held |= (1 << i);
@@ -341,7 +348,9 @@ 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;
@@ -360,9 +369,9 @@ 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;
@@ -424,6 +433,7 @@ spa_add(const char *name, nvlist_t *config, const char *altroot)
 {
 	spa_t *spa;
 	spa_config_dirent_t *dp;
+	int t;
 
 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
 
@@ -444,7 +454,7 @@ spa_add(const char *name, nvlist_t *config, const char *altroot)
 	cv_init(&spa->spa_scrub_io_cv, NULL, CV_DEFAULT, NULL);
 	cv_init(&spa->spa_suspend_cv, NULL, CV_DEFAULT, NULL);
 
-	for (int t = 0; t < TXG_SIZE; t++)
+	for (t = 0; t < TXG_SIZE; t++)
 		bplist_create(&spa->spa_free_bplist[t]);
 
 	(void) strlcpy(spa->spa_name, name, sizeof (spa->spa_name));
@@ -496,6 +506,7 @@ void
 spa_remove(spa_t *spa)
 {
 	spa_config_dirent_t *dp;
+	int t;
 
 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
 	ASSERT(spa->spa_state == POOL_STATE_UNINITIALIZED);
@@ -526,7 +537,7 @@ spa_remove(spa_t *spa)
 
 	spa_config_lock_destroy(spa);
 
-	for (int t = 0; t < TXG_SIZE; t++)
+	for (t = 0; t < TXG_SIZE; t++)
 		bplist_destroy(&spa->spa_free_bplist[t]);
 
 	cv_destroy(&spa->spa_async_cv);
@@ -877,10 +888,9 @@ spa_vdev_config_enter(spa_t *spa)
 void
 spa_vdev_config_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error, char *tag)
 {
-	ASSERT(MUTEX_HELD(&spa_namespace_lock));
-
 	int config_changed = B_FALSE;
 
+	ASSERT(MUTEX_HELD(&spa_namespace_lock));
 	ASSERT(txg > spa_last_synced_txg(spa));
 
 	spa->spa_pending_vdev = NULL;
@@ -1454,8 +1464,9 @@ uint64_t
 bp_get_dsize_sync(spa_t *spa, const blkptr_t *bp)
 {
 	uint64_t dsize = 0;
+	int d;
 
-	for (int d = 0; d < SPA_DVAS_PER_BP; d++)
+	for (d = 0; d < SPA_DVAS_PER_BP; d++)
 		dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
 
 	return (dsize);
@@ -1465,10 +1476,11 @@ uint64_t
 bp_get_dsize(spa_t *spa, const blkptr_t *bp)
 {
 	uint64_t dsize = 0;
+	int d;
 
 	spa_config_enter(spa, SCL_VDEV, FTAG, RW_READER);
 
-	for (int d = 0; d < SPA_DVAS_PER_BP; d++)
+	for (d = 0; d < SPA_DVAS_PER_BP; d++)
 		dsize += dva_get_dsize_sync(spa, &bp->blk_dva[d]);
 
 	spa_config_exit(spa, SCL_VDEV, FTAG);
diff --git a/module/zfs/vdev.c b/module/zfs/vdev.c
index bac3e8605..604a673f9 100644
--- a/module/zfs/vdev.c
+++ b/module/zfs/vdev.c
@@ -85,8 +85,9 @@ vdev_default_asize(vdev_t *vd, uint64_t psize)
 {
 	uint64_t asize = P2ROUNDUP(psize, 1ULL << vd->vdev_top->vdev_ashift);
 	uint64_t csize;
+	int c;
 
-	for (int c = 0; c < vd->vdev_children; c++) {
+	for (c = 0; c < vd->vdev_children; c++) {
 		csize = vdev_psize_to_asize(vd->vdev_child[c], psize);
 		asize = MAX(asize, csize);
 	}
@@ -132,9 +133,10 @@ vdev_get_min_asize(vdev_t *vd)
 void
 vdev_set_min_asize(vdev_t *vd)
 {
+	int c;
 	vd->vdev_min_asize = vdev_get_min_asize(vd);
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_set_min_asize(vd->vdev_child[c]);
 }
 
@@ -157,11 +159,12 @@ vdev_t *
 vdev_lookup_by_guid(vdev_t *vd, uint64_t guid)
 {
 	vdev_t *mvd;
+	int c;
 
 	if (vd->vdev_guid == guid)
 		return (vd);
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		if ((mvd = vdev_lookup_by_guid(vd->vdev_child[c], guid)) !=
 		    NULL)
 			return (mvd);
@@ -252,16 +255,17 @@ vdev_compact_children(vdev_t *pvd)
 	vdev_t **newchild, *cvd;
 	int oldc = pvd->vdev_children;
 	int newc;
+	int c;
 
 	ASSERT(spa_config_held(pvd->vdev_spa, SCL_ALL, RW_WRITER) == SCL_ALL);
 
-	for (int c = newc = 0; c < oldc; c++)
+	for (c = newc = 0; c < oldc; c++)
 		if (pvd->vdev_child[c])
 			newc++;
 
 	newchild = kmem_alloc(newc * sizeof (vdev_t *), KM_SLEEP);
 
-	for (int c = newc = 0; c < oldc; c++) {
+	for (c = newc = 0; c < oldc; c++) {
 		if ((cvd = pvd->vdev_child[c]) != NULL) {
 			newchild[newc] = cvd;
 			cvd->vdev_id = newc++;
@@ -280,6 +284,7 @@ vdev_t *
 vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
 {
 	vdev_t *vd;
+	int t;
 
 	vd = kmem_zalloc(sizeof (vdev_t), KM_SLEEP);
 
@@ -315,7 +320,7 @@ vdev_alloc_common(spa_t *spa, uint_t id, uint64_t guid, vdev_ops_t *ops)
 	mutex_init(&vd->vdev_dtl_lock, NULL, MUTEX_DEFAULT, NULL);
 	mutex_init(&vd->vdev_stat_lock, NULL, MUTEX_DEFAULT, NULL);
 	mutex_init(&vd->vdev_probe_lock, NULL, MUTEX_DEFAULT, NULL);
-	for (int t = 0; t < DTL_TYPES; t++) {
+	for (t = 0; t < DTL_TYPES; t++) {
 		space_map_create(&vd->vdev_dtl[t], 0, -1ULL, 0,
 		    &vd->vdev_dtl_lock);
 	}
@@ -561,6 +566,7 @@ vdev_alloc(spa_t *spa, vdev_t **vdp, nvlist_t *nv, vdev_t *parent, uint_t id,
 void
 vdev_free(vdev_t *vd)
 {
+	int c, t;
 	spa_t *spa = vd->vdev_spa;
 
 	/*
@@ -575,7 +581,7 @@ vdev_free(vdev_t *vd)
 	/*
 	 * Free all children.
 	 */
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_free(vd->vdev_child[c]);
 
 	ASSERT(vd->vdev_child == NULL);
@@ -624,7 +630,7 @@ vdev_free(vdev_t *vd)
 	txg_list_destroy(&vd->vdev_dtl_list);
 
 	mutex_enter(&vd->vdev_dtl_lock);
-	for (int t = 0; t < DTL_TYPES; t++) {
+	for (t = 0; t < DTL_TYPES; t++) {
 		space_map_unload(&vd->vdev_dtl[t]);
 		space_map_destroy(&vd->vdev_dtl[t]);
 	}
@@ -707,12 +713,14 @@ vdev_top_transfer(vdev_t *svd, vdev_t *tvd)
 static void
 vdev_top_update(vdev_t *tvd, vdev_t *vd)
 {
+	int c;
+
 	if (vd == NULL)
 		return;
 
 	vd->vdev_top = tvd;
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_top_update(tvd, vd->vdev_child[c]);
 }
 
@@ -960,6 +968,7 @@ vdev_probe(vdev_t *vd, zio_t *zio)
 	spa_t *spa = vd->vdev_spa;
 	vdev_probe_stats_t *vps = NULL;
 	zio_t *pio;
+	int l;
 
 	ASSERT(vd->vdev_ops->vdev_op_leaf);
 
@@ -1029,7 +1038,7 @@ vdev_probe(vdev_t *vd, zio_t *zio)
 		return (NULL);
 	}
 
-	for (int l = 1; l < VDEV_LABELS; l++) {
+	for (l = 1; l < VDEV_LABELS; l++) {
 		zio_nowait(zio_read_phys(pio, vd,
 		    vdev_label_offset(vd->vdev_psize, l,
 		    offsetof(vdev_label_t, vl_pad2)),
@@ -1058,10 +1067,12 @@ vdev_open_child(void *arg)
 boolean_t
 vdev_uses_zvols(vdev_t *vd)
 {
+	int c;
+
 	if (vd->vdev_path && strncmp(vd->vdev_path, ZVOL_DIR,
 	    strlen(ZVOL_DIR)) == 0)
 		return (B_TRUE);
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		if (vdev_uses_zvols(vd->vdev_child[c]))
 			return (B_TRUE);
 	return (B_FALSE);
@@ -1072,6 +1083,7 @@ vdev_open_children(vdev_t *vd)
 {
 	taskq_t *tq;
 	int children = vd->vdev_children;
+	int c;
 
 	/*
 	 * in order to handle pools on top of zvols, do the opens
@@ -1079,7 +1091,7 @@ vdev_open_children(vdev_t *vd)
 	 * spa_namespace_lock
 	 */
 	if (vdev_uses_zvols(vd)) {
-		for (int c = 0; c < children; c++)
+		for (c = 0; c < children; c++)
 			vd->vdev_child[c]->vdev_open_error =
 			    vdev_open(vd->vdev_child[c]);
 		return;
@@ -1087,9 +1099,9 @@ vdev_open_children(vdev_t *vd)
 	tq = taskq_create("vdev_open", children, minclsyspri,
 	    children, children, TASKQ_PREPOPULATE);
 
-	for (int c = 0; c < children; c++)
+	for (c = 0; c < children; c++)
 		VERIFY(taskq_dispatch(tq, vdev_open_child, vd->vdev_child[c],
-		    TQ_SLEEP) != NULL);
+		    TQ_SLEEP) != 0);
 
 	taskq_destroy(tq);
 }
@@ -1105,6 +1117,7 @@ vdev_open(vdev_t *vd)
 	uint64_t osize = 0;
 	uint64_t asize, psize;
 	uint64_t ashift = 0;
+	int c;
 
 	ASSERT(vd->vdev_open_thread == curthread ||
 	    spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
@@ -1183,7 +1196,7 @@ vdev_open(vdev_t *vd)
 	if (vd->vdev_ishole || vd->vdev_ops == &vdev_missing_ops)
 		return (0);
 
-	for (int c = 0; c < vd->vdev_children; c++) {
+	for (c = 0; c < vd->vdev_children; c++) {
 		if (vd->vdev_child[c]->vdev_state != VDEV_STATE_HEALTHY) {
 			vdev_set_state(vd, B_TRUE, VDEV_STATE_DEGRADED,
 			    VDEV_AUX_NONE);
@@ -1292,8 +1305,9 @@ vdev_validate(vdev_t *vd)
 	nvlist_t *label;
 	uint64_t guid = 0, top_guid;
 	uint64_t state;
+	int c;
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		if (vdev_validate(vd->vdev_child[c]) != 0)
 			return (EBADF);
 
@@ -1432,12 +1446,13 @@ void
 vdev_hold(vdev_t *vd)
 {
 	spa_t *spa = vd->vdev_spa;
+	int c;
 
 	ASSERT(spa_is_root(spa));
 	if (spa->spa_state == POOL_STATE_UNINITIALIZED)
 		return;
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_hold(vd->vdev_child[c]);
 
 	if (vd->vdev_ops->vdev_op_leaf)
@@ -1447,10 +1462,10 @@ vdev_hold(vdev_t *vd)
 void
 vdev_rele(vdev_t *vd)
 {
-	spa_t *spa = vd->vdev_spa;
+	int c;
 
-	ASSERT(spa_is_root(spa));
-	for (int c = 0; c < vd->vdev_children; c++)
+	ASSERT(spa_is_root(vd->vdev_spa));
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_rele(vd->vdev_child[c]);
 
 	if (vd->vdev_ops->vdev_op_leaf)
@@ -1643,11 +1658,11 @@ vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg, int scrub_done)
 {
 	spa_t *spa = vd->vdev_spa;
 	avl_tree_t reftree;
-	int minref;
+	int c, t, minref;
 
 	ASSERT(spa_config_held(spa, SCL_ALL, RW_READER) != 0);
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_dtl_reassess(vd->vdev_child[c], txg,
 		    scrub_txg, scrub_done);
 
@@ -1707,7 +1722,7 @@ vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg, int scrub_done)
 	}
 
 	mutex_enter(&vd->vdev_dtl_lock);
-	for (int t = 0; t < DTL_TYPES; t++) {
+	for (t = 0; t < DTL_TYPES; t++) {
 		/* account for child's outage in parent's missing map */
 		int s = (t == DTL_MISSING) ? DTL_OUTAGE: t;
 		if (t == DTL_SCRUB)
@@ -1719,7 +1734,7 @@ vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg, int scrub_done)
 		else
 			minref = vd->vdev_children;	/* any kind of mirror */
 		space_map_ref_create(&reftree);
-		for (int c = 0; c < vd->vdev_children; c++) {
+		for (c = 0; c < vd->vdev_children; c++) {
 			vdev_t *cvd = vd->vdev_child[c];
 			mutex_enter(&cvd->vdev_dtl_lock);
 			space_map_ref_add_map(&reftree, &cvd->vdev_dtl[s], 1);
@@ -1869,6 +1884,7 @@ vdev_resilver_needed(vdev_t *vd, uint64_t *minp, uint64_t *maxp)
 	boolean_t needed = B_FALSE;
 	uint64_t thismin = UINT64_MAX;
 	uint64_t thismax = 0;
+	int c;
 
 	if (vd->vdev_children == 0) {
 		mutex_enter(&vd->vdev_dtl_lock);
@@ -1884,7 +1900,7 @@ vdev_resilver_needed(vdev_t *vd, uint64_t *minp, uint64_t *maxp)
 		}
 		mutex_exit(&vd->vdev_dtl_lock);
 	} else {
-		for (int c = 0; c < vd->vdev_children; c++) {
+		for (c = 0; c < vd->vdev_children; c++) {
 			vdev_t *cvd = vd->vdev_child[c];
 			uint64_t cmin, cmax;
 
@@ -1906,10 +1922,12 @@ vdev_resilver_needed(vdev_t *vd, uint64_t *minp, uint64_t *maxp)
 void
 vdev_load(vdev_t *vd)
 {
+	int c;
+
 	/*
 	 * Recursively load all children.
 	 */
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_load(vd->vdev_child[c]);
 
 	/*
@@ -1977,6 +1995,7 @@ vdev_remove(vdev_t *vd, uint64_t txg)
 	spa_t *spa = vd->vdev_spa;
 	objset_t *mos = spa->spa_meta_objset;
 	dmu_tx_t *tx;
+	int m;
 
 	tx = dmu_tx_create_assigned(spa_get_dsl(spa), txg);
 
@@ -1987,7 +2006,7 @@ vdev_remove(vdev_t *vd, uint64_t txg)
 	}
 
 	if (vd->vdev_ms != NULL) {
-		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];
 
 			if (msp == NULL || msp->ms_smo.smo_object == 0)
@@ -2324,6 +2343,7 @@ 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);
 
@@ -2334,7 +2354,7 @@ 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]);
 
 	/*
@@ -2448,6 +2468,7 @@ 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));
@@ -2463,12 +2484,12 @@ 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];
 			}
@@ -2492,8 +2513,9 @@ void
 vdev_scan_stat_init(vdev_t *vd)
 {
 	vdev_stat_t *vs = &vd->vdev_stat;
+	int c;
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_scan_stat_init(vd->vdev_child[c]);
 
 	mutex_enter(&vd->vdev_stat_lock);
@@ -2834,9 +2856,10 @@ vdev_propagate_state(vdev_t *vd)
 	int degraded = 0, faulted = 0;
 	int corrupted = 0;
 	vdev_t *child;
+	int c;
 
 	if (vd->vdev_children > 0) {
-		for (int c = 0; c < vd->vdev_children; c++) {
+		for (c = 0; c < vd->vdev_children; c++) {
 			child = vd->vdev_child[c];
 
 			/*
@@ -3026,6 +3049,8 @@ vdev_set_state(vdev_t *vd, boolean_t isopen, vdev_state_t state, vdev_aux_t aux)
 boolean_t
 vdev_is_bootable(vdev_t *vd)
 {
+	int c;
+
 	if (!vd->vdev_ops->vdev_op_leaf) {
 		char *vdev_type = vd->vdev_ops->vdev_op_type;
 
@@ -3040,7 +3065,7 @@ vdev_is_bootable(vdev_t *vd)
 		return (B_FALSE);
 	}
 
-	for (int c = 0; c < vd->vdev_children; c++) {
+	for (c = 0; c < vd->vdev_children; c++) {
 		if (!vdev_is_bootable(vd->vdev_child[c]))
 			return (B_FALSE);
 	}
@@ -3056,13 +3081,13 @@ vdev_is_bootable(vdev_t *vd)
 void
 vdev_load_log_state(vdev_t *nvd, vdev_t *ovd)
 {
-	spa_t *spa = nvd->vdev_spa;
+	int c;
 
 	ASSERT(nvd->vdev_top->vdev_islog);
 	ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
 	ASSERT3U(nvd->vdev_guid, ==, ovd->vdev_guid);
 
-	for (int c = 0; c < nvd->vdev_children; c++)
+	for (c = 0; c < nvd->vdev_children; c++)
 		vdev_load_log_state(nvd->vdev_child[c], ovd->vdev_child[c]);
 
 	if (nvd->vdev_ops->vdev_op_leaf) {
@@ -3084,11 +3109,13 @@ vdev_load_log_state(vdev_t *nvd, vdev_t *ovd)
 boolean_t
 vdev_log_state_valid(vdev_t *vd)
 {
+	int c;
+
 	if (vd->vdev_ops->vdev_op_leaf && !vd->vdev_faulted &&
 	    !vd->vdev_removed)
 		return (B_TRUE);
 
-	for (int c = 0; c < vd->vdev_children; c++)
+	for (c = 0; c < vd->vdev_children; c++)
 		if (vdev_log_state_valid(vd->vdev_child[c]))
 			return (B_TRUE);
 
diff --git a/module/zfs/vdev_label.c b/module/zfs/vdev_label.c
index c08ed8ba0..528710eaf 100644
--- a/module/zfs/vdev_label.c
+++ b/module/zfs/vdev_label.c
@@ -437,6 +437,7 @@ vdev_label_read_config(vdev_t *vd)
 	zio_t *zio;
 	int flags = ZIO_FLAG_CONFIG_WRITER | ZIO_FLAG_CANFAIL |
 	    ZIO_FLAG_SPECULATIVE;
+	int l;
 
 	ASSERT(spa_config_held(spa, SCL_STATE_ALL, RW_WRITER) == SCL_STATE_ALL);
 
@@ -446,7 +447,7 @@ vdev_label_read_config(vdev_t *vd)
 	vp = zio_buf_alloc(sizeof (vdev_phys_t));
 
 retry:
-	for (int l = 0; l < VDEV_LABELS; l++) {
+	for (l = 0; l < VDEV_LABELS; l++) {
 
 		zio = zio_root(spa, NULL, NULL, flags);
 
@@ -611,10 +612,12 @@ 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;
+	vdev_t *pvd;
 
 	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);
@@ -650,7 +653,7 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 
 		vd->vdev_guid += guid_delta;
 
-		for (vdev_t *pvd = vd; pvd != NULL; pvd = pvd->vdev_parent)
+		for (pvd = vd; pvd != NULL; pvd = pvd->vdev_parent)
 			pvd->vdev_guid_sum += guid_delta;
 
 		/*
@@ -670,7 +673,7 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 
 		vd->vdev_guid += guid_delta;
 
-		for (vdev_t *pvd = vd; pvd != NULL; pvd = pvd->vdev_parent)
+		for (pvd = vd; pvd != NULL; pvd = pvd->vdev_parent)
 			pvd->vdev_guid_sum += guid_delta;
 
 		/*
@@ -770,7 +773,7 @@ vdev_label_init(vdev_t *vd, uint64_t crtxg, vdev_labeltype_t reason)
 retry:
 	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),
@@ -881,6 +884,7 @@ 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 | ZIO_FLAG_TRYHARD;
+	int c, l, n;
 
 	if (vd == rvd) {
 		ASSERT(zio == NULL);
@@ -891,12 +895,12 @@ 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),
@@ -932,9 +936,9 @@ 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)
@@ -949,7 +953,7 @@ 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,
@@ -964,10 +968,11 @@ 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);
@@ -979,7 +984,7 @@ 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);
@@ -1032,8 +1037,9 @@ 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)
@@ -1081,12 +1087,13 @@ vdev_label_sync_list(spa_t *spa, int l, uint64_t txg, int flags)
 	zio = zio_root(spa, NULL, NULL, flags);
 
 	for (vd = list_head(dl); vd != NULL; vd = list_next(dl, vd)) {
-		uint64_t *good_writes = kmem_zalloc(sizeof (uint64_t),
-		    KM_SLEEP);
+		uint64_t *good_writes;
+		zio_t *vio;
 
 		ASSERT(!vd->vdev_ishole);
 
-		zio_t *vio = zio_null(zio, spa, NULL,
+		good_writes = kmem_zalloc(sizeof (uint64_t), KM_SLEEP);
+		vio = zio_null(zio, spa, NULL,
 		    (vd->vdev_islog || vd->vdev_aux != NULL) ?
 		    vdev_label_sync_ignore_done : vdev_label_sync_top_done,
 		    good_writes, flags);
diff --git a/module/zfs/vdev_mirror.c b/module/zfs/vdev_mirror.c
index 698c0275d..47181d439 100644
--- a/module/zfs/vdev_mirror.c
+++ b/module/zfs/vdev_mirror.c
@@ -131,6 +131,7 @@ vdev_mirror_open(vdev_t *vd, uint64_t *asize, uint64_t *ashift)
 {
 	int numerrors = 0;
 	int lasterror = 0;
+	int c;
 
 	if (vd->vdev_children == 0) {
 		vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
@@ -139,7 +140,7 @@ vdev_mirror_open(vdev_t *vd, uint64_t *asize, uint64_t *ashift)
 
 	vdev_open_children(vd);
 
-	for (int c = 0; c < vd->vdev_children; c++) {
+	for (c = 0; c < vd->vdev_children; c++) {
 		vdev_t *cvd = vd->vdev_child[c];
 
 		if (cvd->vdev_open_error) {
@@ -163,7 +164,9 @@ vdev_mirror_open(vdev_t *vd, uint64_t *asize, uint64_t *ashift)
 static void
 vdev_mirror_close(vdev_t *vd)
 {
-	for (int c = 0; c < vd->vdev_children; c++)
+	int c;
+
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_close(vd->vdev_child[c]);
 }
 
@@ -311,9 +314,9 @@ 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 5a0d3ee97..8f8663526 100644
--- a/module/zfs/vdev_queue.c
+++ b/module/zfs/vdev_queue.c
@@ -383,12 +383,13 @@ 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 526385e01..af2de40ac 100644
--- a/module/zfs/vdev_raidz.c
+++ b/module/zfs/vdev_raidz.c
@@ -1692,9 +1692,9 @@ static uint64_t raidz_corrected[1 << VDEV_RAIDZ_MAXPARITY];
 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/vdev_root.c b/module/zfs/vdev_root.c
index 879f78f3a..d7ca99a3d 100644
--- a/module/zfs/vdev_root.c
+++ b/module/zfs/vdev_root.c
@@ -54,6 +54,7 @@ vdev_root_open(vdev_t *vd, uint64_t *asize, uint64_t *ashift)
 {
 	int lasterror = 0;
 	int numerrors = 0;
+	int c;
 
 	if (vd->vdev_children == 0) {
 		vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
@@ -62,7 +63,7 @@ vdev_root_open(vdev_t *vd, uint64_t *asize, uint64_t *ashift)
 
 	vdev_open_children(vd);
 
-	for (int c = 0; c < vd->vdev_children; c++) {
+	for (c = 0; c < vd->vdev_children; c++) {
 		vdev_t *cvd = vd->vdev_child[c];
 
 		if (cvd->vdev_open_error && !cvd->vdev_islog) {
@@ -85,7 +86,9 @@ vdev_root_open(vdev_t *vd, uint64_t *asize, uint64_t *ashift)
 static void
 vdev_root_close(vdev_t *vd)
 {
-	for (int c = 0; c < vd->vdev_children; c++)
+	int c;
+
+	for (c = 0; c < vd->vdev_children; c++)
 		vdev_close(vd->vdev_child[c]);
 }
 
diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
index e1e4e9e03..018f12d96 100644
--- a/module/zfs/zfs_znode.c
+++ b/module/zfs/zfs_znode.c
@@ -1919,8 +1919,8 @@ zfs_grab_sa_handle(objset_t *osp, uint64_t obj, sa_handle_t **hdlp,
 	dmu_object_info_from_db(*db, &doi);
 	if ((doi.doi_bonus_type != DMU_OT_SA &&
 	    doi.doi_bonus_type != DMU_OT_ZNODE) ||
-	    doi.doi_bonus_type == DMU_OT_ZNODE &&
-	    doi.doi_bonus_size < sizeof (znode_phys_t)) {
+	    (doi.doi_bonus_type == DMU_OT_ZNODE &&
+	    doi.doi_bonus_size < sizeof (znode_phys_t))) {
 		sa_buf_rele(*db, FTAG);
 		return (ENOTSUP);
 	}
diff --git a/module/zfs/zil.c b/module/zfs/zil.c
index c66313ff6..e89a24e41 100644
--- a/module/zfs/zil.c
+++ b/module/zfs/zil.c
@@ -1620,6 +1620,7 @@ zilog_t *
 zil_alloc(objset_t *os, zil_header_t *zh_phys)
 {
 	zilog_t *zilog;
+	int i;
 
 	zilog = kmem_zalloc(sizeof (zilog_t), KM_SLEEP);
 
@@ -1634,7 +1635,7 @@ zil_alloc(objset_t *os, zil_header_t *zh_phys)
 
 	mutex_init(&zilog->zl_lock, NULL, MUTEX_DEFAULT, NULL);
 
-	for (int i = 0; i < TXG_SIZE; i++) {
+	for (i = 0; i < TXG_SIZE; i++) {
 		mutex_init(&zilog->zl_itxg[i].itxg_lock, NULL,
 		    MUTEX_DEFAULT, NULL);
 	}
@@ -1662,6 +1663,7 @@ void
 zil_free(zilog_t *zilog)
 {
 	lwb_t *head_lwb;
+	int i;
 
 	zilog->zl_stop_sync = 1;
 
@@ -1683,7 +1685,7 @@ zil_free(zilog_t *zilog)
 	ASSERT(list_is_empty(&zilog->zl_itx_commit_list));
 	list_destroy(&zilog->zl_itx_commit_list);
 
-	for (int i = 0; i < TXG_SIZE; i++) {
+	for (i = 0; i < TXG_SIZE; i++) {
 		/*
 		 * It's possible for an itx to be generated that doesn't dirty
 		 * a txg (e.g. ztest TX_TRUNCATE). So there's no zil_clean()
diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index 1ba2330bd..0bf0f6e12 100644
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -366,6 +366,7 @@ void
 zio_add_child(zio_t *pio, zio_t *cio)
 {
 	zio_link_t *zl = kmem_cache_alloc(zio_link_cache, KM_SLEEP);
+	int w;
 
 	/*
 	 * Logical I/Os can have logical, gang, or vdev children.
@@ -383,7 +384,7 @@ zio_add_child(zio_t *pio, zio_t *cio)
 
 	ASSERT(pio->io_state[ZIO_WAIT_DONE] == 0);
 
-	for (int w = 0; w < ZIO_WAIT_TYPES; w++)
+	for (w = 0; w < ZIO_WAIT_TYPES; w++)
 		pio->io_children[cio->io_child_type][w] += !cio->io_state[w];
 
 	list_insert_head(&pio->io_child_list, zl);
@@ -993,8 +994,8 @@ zio_write_bp_init(zio_t *zio)
 	 */
 	if (bp->blk_birth == zio->io_txg && BP_GET_PSIZE(bp) == psize &&
 	    pass > SYNC_PASS_REWRITE) {
-		ASSERT(psize != 0);
 		enum zio_stage gang_stages = zio->io_pipeline & ZIO_GANG_STAGES;
+		ASSERT(psize != 0);
 		zio->io_pipeline = ZIO_REWRITE_PIPELINE | gang_stages;
 		zio->io_flags |= ZIO_FLAG_IO_REWRITE;
 	} else {
@@ -1081,8 +1082,9 @@ zio_taskq_member(zio_t *zio, enum zio_taskq_type q)
 {
 	kthread_t *executor = zio->io_executor;
 	spa_t *spa = zio->io_spa;
+	zio_type_t t;
 
-	for (zio_type_t t = 0; t < ZIO_TYPES; t++)
+	for (t = 0; t < ZIO_TYPES; t++)
 		if (taskq_member(spa->spa_zio_taskq[t][q], executor))
 			return (B_TRUE);
 
@@ -1223,6 +1225,7 @@ static void
 zio_reexecute(zio_t *pio)
 {
 	zio_t *cio, *cio_next;
+	int c, w;
 
 	ASSERT(pio->io_child_type == ZIO_CHILD_LOGICAL);
 	ASSERT(pio->io_orig_stage == ZIO_STAGE_OPEN);
@@ -1234,9 +1237,9 @@ zio_reexecute(zio_t *pio)
 	pio->io_pipeline = pio->io_orig_pipeline;
 	pio->io_reexecute = 0;
 	pio->io_error = 0;
-	for (int w = 0; w < ZIO_WAIT_TYPES; w++)
+	for (w = 0; w < ZIO_WAIT_TYPES; w++)
 		pio->io_state[w] = 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))
@@ -1252,7 +1255,7 @@ zio_reexecute(zio_t *pio)
 	for (cio = zio_walk_children(pio); cio != NULL; cio = cio_next) {
 		cio_next = zio_walk_children(pio);
 		mutex_enter(&pio->io_lock);
-		for (int w = 0; w < ZIO_WAIT_TYPES; w++)
+		for (w = 0; w < ZIO_WAIT_TYPES; w++)
 			pio->io_children[cio->io_child_type][w]++;
 		mutex_exit(&pio->io_lock);
 		zio_reexecute(cio);
@@ -1488,8 +1491,9 @@ 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);
@@ -1501,11 +1505,12 @@ 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);
@@ -1530,6 +1535,7 @@ zio_gang_tree_assemble_done(zio_t *zio)
 	zio_t *gio = zio->io_gang_leader;
 	zio_gang_node_t *gn = zio->io_private;
 	blkptr_t *bp = zio->io_bp;
+	int g;
 
 	ASSERT(gio == zio_unique_parent(zio));
 	ASSERT(zio->io_child_count == 0);
@@ -1544,7 +1550,7 @@ zio_gang_tree_assemble_done(zio_t *zio)
 	ASSERT(zio->io_size == SPA_GANGBLOCKSIZE);
 	ASSERT(gn->gn_gbh->zg_tail.zec_magic == ZEC_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;
@@ -1557,6 +1563,7 @@ zio_gang_tree_issue(zio_t *pio, zio_gang_node_t *gn, blkptr_t *bp, void *data)
 {
 	zio_t *gio = pio->io_gang_leader;
 	zio_t *zio;
+	int g;
 
 	ASSERT(BP_IS_GANG(bp) == !!gn);
 	ASSERT(BP_GET_CHECKSUM(bp) == BP_GET_CHECKSUM(gio->io_bp));
@@ -1571,7 +1578,7 @@ 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.zec_magic == ZEC_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;
@@ -1631,6 +1638,7 @@ 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;
@@ -1644,7 +1652,7 @@ 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]);
@@ -1668,7 +1676,7 @@ zio_write_gang_block(zio_t *pio)
 	int copies = gio->io_prop.zp_copies;
 	int gbh_copies = MIN(copies + 1, spa_max_replication(spa));
 	zio_prop_t zp;
-	int error;
+	int g, error;
 
 	error = metaslab_alloc(spa, spa_normal_class(spa), SPA_GANGBLOCKSIZE,
 	    bp, gbh_copies, txg, pio == gio ? NULL : gio->io_bp,
@@ -1698,7 +1706,7 @@ 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);
@@ -1756,6 +1764,7 @@ static int
 zio_ddt_read_start(zio_t *zio)
 {
 	blkptr_t *bp = zio->io_bp;
+	int p;
 
 	ASSERT(BP_GET_DEDUP(bp));
 	ASSERT(BP_GET_PSIZE(bp) == zio->io_size);
@@ -1774,7 +1783,7 @@ zio_ddt_read_start(zio_t *zio)
 		if (ddp_self == NULL)
 			return (ZIO_PIPELINE_CONTINUE);
 
-		for (int p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
+		for (p = 0; p < DDT_PHYS_TYPES; p++, ddp++) {
 			if (ddp->ddp_phys_birth == 0 || ddp == ddp_self)
 				continue;
 			ddt_bp_create(ddt->ddt_checksum, &dde->dde_key, ddp,
@@ -1836,6 +1845,7 @@ static boolean_t
 zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
 {
 	spa_t *spa = zio->io_spa;
+	int p;
 
 	/*
 	 * Note: we compare the original data, not the transformed data,
@@ -1843,7 +1853,7 @@ zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
 	 * pushed the I/O transforms.  That's an important optimization
 	 * because otherwise we'd compress/encrypt all dmu_sync() data twice.
 	 */
-	for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
+	for (p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
 		zio_t *lio = dde->dde_lead_zio[p];
 
 		if (lio != NULL) {
@@ -1853,7 +1863,7 @@ zio_ddt_collision(zio_t *zio, ddt_t *ddt, ddt_entry_t *dde)
 		}
 	}
 
-	for (int p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
+	for (p = DDT_PHYS_SINGLE; p <= DDT_PHYS_TRIPLE; p++) {
 		ddt_phys_t *ddp = &dde->dde_phys[p];
 
 		if (ddp->ddp_phys_birth != 0) {
@@ -2161,6 +2171,8 @@ zio_dva_claim(zio_t *zio)
 static void
 zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp)
 {
+	int g;
+
 	ASSERT(bp->blk_birth == zio->io_txg || BP_IS_HOLE(bp));
 	ASSERT(zio->io_bp_override == NULL);
 
@@ -2168,7 +2180,7 @@ zio_dva_unallocate(zio_t *zio, zio_gang_node_t *gn, blkptr_t *bp)
 		metaslab_free(zio->io_spa, bp, bp->blk_birth, B_TRUE);
 
 	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]);
 		}
@@ -2655,6 +2667,7 @@ zio_done(zio_t *zio)
 	vdev_t *vd = zio->io_vd;
 	uint64_t psize = zio->io_size;
 	zio_t *pio, *pio_next;
+	int c, w;
 
 	/*
 	 * If our children haven't all completed,
@@ -2666,8 +2679,8 @@ 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) {
diff --git a/module/zfs/zrlock.c b/module/zfs/zrlock.c
index ec94b0855..36134431f 100644
--- a/module/zfs/zrlock.c
+++ b/module/zfs/zrlock.c
@@ -163,9 +163,11 @@ zrl_exit(zrlock_t *zrl)
 int
 zrl_refcount(zrlock_t *zrl)
 {
+	int n;
+
 	ASSERT(zrl->zr_refcount > ZRL_DESTROYED);
 
-	int n = (int)zrl->zr_refcount;
+	n = (int)zrl->zr_refcount;
 	return (n <= 0 ? 0 : n);
 }