diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
index 18a94da1f7..ecf044090d 100644
--- a/cmd/zdb/zdb.c
+++ b/cmd/zdb/zdb.c
@@ -128,7 +128,7 @@ uint8_t dump_opt[256];
 
 typedef void object_viewer_t(objset_t *, uint64_t, void *data, size_t size);
 
-uint64_t *zopt_metaslab = NULL;
+static uint64_t *zopt_metaslab = NULL;
 static unsigned zopt_metaslab_args = 0;
 
 typedef struct zopt_object_range {
@@ -136,7 +136,8 @@ typedef struct zopt_object_range {
 	uint64_t zor_obj_end;
 	uint64_t zor_flags;
 } zopt_object_range_t;
-zopt_object_range_t *zopt_object_ranges = NULL;
+
+static zopt_object_range_t *zopt_object_ranges = NULL;
 static unsigned zopt_object_args = 0;
 
 static int flagbits[256];
@@ -160,7 +161,7 @@ static int flagbits[256];
 #define	ZDB_FLAG_PRINT_BLKPTR	0x0040
 #define	ZDB_FLAG_VERBOSE	0x0080
 
-uint64_t max_inflight_bytes = 256 * 1024 * 1024; /* 256MB */
+static uint64_t max_inflight_bytes = 256 * 1024 * 1024; /* 256MB */
 static int leaked_objects = 0;
 static range_tree_t *mos_refd_objs;
 
diff --git a/cmd/zstream/zstream_dump.c b/cmd/zstream/zstream_dump.c
index 4b562c2373..9955a1361e 100644
--- a/cmd/zstream/zstream_dump.c
+++ b/cmd/zstream/zstream_dump.c
@@ -54,10 +54,10 @@
  */
 #define	DUMP_GROUPING	4
 
-uint64_t total_stream_len = 0;
-FILE *send_stream = 0;
-boolean_t do_byteswap = B_FALSE;
-boolean_t do_cksum = B_TRUE;
+static uint64_t total_stream_len = 0;
+static FILE *send_stream = 0;
+static boolean_t do_byteswap = B_FALSE;
+static boolean_t do_cksum = B_TRUE;
 
 void *
 safe_malloc(size_t size)
diff --git a/cmd/ztest.c b/cmd/ztest.c
index b89cdde9ed..a8f9e6b876 100644
--- a/cmd/ztest.c
+++ b/cmd/ztest.c
@@ -423,11 +423,11 @@ ztest_func_t ztest_fletcher;
 ztest_func_t ztest_fletcher_incr;
 ztest_func_t ztest_verify_dnode_bt;
 
-uint64_t zopt_always = 0ULL * NANOSEC;		/* all the time */
-uint64_t zopt_incessant = 1ULL * NANOSEC / 10;	/* every 1/10 second */
-uint64_t zopt_often = 1ULL * NANOSEC;		/* every second */
-uint64_t zopt_sometimes = 10ULL * NANOSEC;	/* every 10 seconds */
-uint64_t zopt_rarely = 60ULL * NANOSEC;		/* every 60 seconds */
+static uint64_t zopt_always = 0ULL * NANOSEC;		/* all the time */
+static uint64_t zopt_incessant = 1ULL * NANOSEC / 10;	/* every 1/10 second */
+static uint64_t zopt_often = 1ULL * NANOSEC;		/* every second */
+static uint64_t zopt_sometimes = 10ULL * NANOSEC;	/* every 10 seconds */
+static uint64_t zopt_rarely = 60ULL * NANOSEC;		/* every 60 seconds */
 
 #define	ZTI_INIT(func, iters, interval) \
 	{   .zi_func = (func), \
@@ -435,7 +435,7 @@ uint64_t zopt_rarely = 60ULL * NANOSEC;		/* every 60 seconds */
 	    .zi_interval = (interval), \
 	    .zi_funcname = # func }
 
-ztest_info_t ztest_info[] = {
+static ztest_info_t ztest_info[] = {
 	ZTI_INIT(ztest_dmu_read_write, 1, &zopt_always),
 	ZTI_INIT(ztest_dmu_write_parallel, 10, &zopt_always),
 	ZTI_INIT(ztest_dmu_object_alloc_free, 1, &zopt_always),
@@ -515,7 +515,7 @@ typedef struct ztest_shared {
 
 static char ztest_dev_template[] = "%s/%s.%llua";
 static char ztest_aux_template[] = "%s/%s.%s.%llu";
-ztest_shared_t *ztest_shared;
+static ztest_shared_t *ztest_shared;
 
 static spa_t *ztest_spa = NULL;
 static ztest_ds_t *ztest_ds;
@@ -2346,7 +2346,7 @@ ztest_replay_setattr(void *arg1, void *arg2, boolean_t byteswap)
 	return (0);
 }
 
-zil_replay_func_t *ztest_replay_vector[TX_MAX_TYPE] = {
+static zil_replay_func_t *ztest_replay_vector[TX_MAX_TYPE] = {
 	NULL,			/* 0 no such transaction type */
 	ztest_replay_create,	/* TX_CREATE */
 	NULL,			/* TX_MKDIR */
diff --git a/module/os/linux/spl/spl-condvar.c b/module/os/linux/spl/spl-condvar.c
index d0461a9f12..e87954714e 100644
--- a/module/os/linux/spl/spl-condvar.c
+++ b/module/os/linux/spl/spl-condvar.c
@@ -37,7 +37,7 @@
 #endif
 
 #define	MAX_HRTIMEOUT_SLACK_US	1000
-unsigned int spl_schedule_hrtimeout_slack_us = 0;
+static unsigned int spl_schedule_hrtimeout_slack_us = 0;
 
 static int
 param_set_hrtimeout_slack(const char *buf, zfs_kernel_param_t *kp)
diff --git a/module/os/linux/spl/spl-err.c b/module/os/linux/spl/spl-err.c
index 7d3f6127c4..29781b9515 100644
--- a/module/os/linux/spl/spl-err.c
+++ b/module/os/linux/spl/spl-err.c
@@ -32,7 +32,7 @@
  * analysis and other such goodies.
  * But we would still default to the current default of not to do that.
  */
-unsigned int spl_panic_halt;
+static unsigned int spl_panic_halt;
 /* CSTYLED */
 module_param(spl_panic_halt, uint, 0644);
 MODULE_PARM_DESC(spl_panic_halt, "Cause kernel panic on assertion failures");
diff --git a/module/os/linux/spl/spl-generic.c b/module/os/linux/spl/spl-generic.c
index 6efaec592b..e3aa900ba6 100644
--- a/module/os/linux/spl/spl-generic.c
+++ b/module/os/linux/spl/spl-generic.c
@@ -90,7 +90,7 @@ EXPORT_SYMBOL(p0);
  * and use them when in_interrupt() from linux/preempt_mask.h evaluates to
  * true.
  */
-void __percpu *spl_pseudo_entropy;
+static void __percpu *spl_pseudo_entropy;
 
 /*
  * spl_rand_next()/spl_rand_jump() are copied from the following CC-0 licensed
diff --git a/module/os/linux/spl/spl-kmem-cache.c b/module/os/linux/spl/spl-kmem-cache.c
index e355e2bfc3..edd04783b3 100644
--- a/module/os/linux/spl/spl-kmem-cache.c
+++ b/module/os/linux/spl/spl-kmem-cache.c
@@ -151,7 +151,7 @@ MODULE_PARM_DESC(spl_kmem_cache_kmem_threads,
 
 struct list_head spl_kmem_cache_list;   /* List of caches */
 struct rw_semaphore spl_kmem_cache_sem; /* Cache list lock */
-taskq_t *spl_kmem_cache_taskq;		/* Task queue for aging / reclaim */
+static taskq_t *spl_kmem_cache_taskq;   /* Task queue for aging / reclaim */
 
 static void spl_cache_shrink(spl_kmem_cache_t *skc, void *obj);
 
diff --git a/module/os/linux/zfs/abd_os.c b/module/os/linux/zfs/abd_os.c
index 2ab85f8ccc..fcdd768522 100644
--- a/module/os/linux/zfs/abd_os.c
+++ b/module/os/linux/zfs/abd_os.c
@@ -132,7 +132,7 @@ static abd_stats_t abd_stats = {
 	{ "scatter_sg_table_retry",		KSTAT_DATA_UINT64 },
 };
 
-struct {
+static struct {
 	wmsum_t abdstat_struct_size;
 	wmsum_t abdstat_linear_cnt;
 	wmsum_t abdstat_linear_data_size;
diff --git a/module/os/linux/zfs/zfs_debug.c b/module/os/linux/zfs/zfs_debug.c
index 819416b68d..e5a6002506 100644
--- a/module/os/linux/zfs/zfs_debug.c
+++ b/module/os/linux/zfs/zfs_debug.c
@@ -35,7 +35,7 @@ typedef struct zfs_dbgmsg {
 
 static procfs_list_t zfs_dbgmsgs;
 static uint_t zfs_dbgmsg_size = 0;
-uint_t zfs_dbgmsg_maxsize = 4<<20; /* 4MB */
+static uint_t zfs_dbgmsg_maxsize = 4<<20; /* 4MB */
 
 /*
  * Internal ZFS debug messages are enabled by default.
diff --git a/module/os/linux/zfs/zvol_os.c b/module/os/linux/zfs/zvol_os.c
index 0d4e0dcd5a..d76bab3c01 100644
--- a/module/os/linux/zfs/zvol_os.c
+++ b/module/os/linux/zfs/zvol_os.c
@@ -114,7 +114,7 @@ struct zvol_state_os {
 	boolean_t use_blk_mq;
 };
 
-taskq_t *zvol_taskq;
+static taskq_t *zvol_taskq;
 static struct ida zvol_ida;
 
 typedef struct zv_request_stack {
diff --git a/module/zfs/zio.c b/module/zfs/zio.c
index dce94b7b29..3f6847a236 100644
--- a/module/zfs/zio.c
+++ b/module/zfs/zio.c
@@ -3360,7 +3360,7 @@ zio_ddt_write(zio_t *zio)
 	return (zio);
 }
 
-ddt_entry_t *freedde; /* for debugging */
+static ddt_entry_t *freedde; /* for debugging */
 
 static zio_t *
 zio_ddt_free(zio_t *zio)
diff --git a/module/zfs/zio_compress.c b/module/zfs/zio_compress.c
index 4c9cbc9620..0fb91ac815 100644
--- a/module/zfs/zio_compress.c
+++ b/module/zfs/zio_compress.c
@@ -44,7 +44,7 @@
  * If nonzero, every 1/X decompression attempts will fail, simulating
  * an undetected memory error.
  */
-unsigned long zio_decompress_fail_fraction = 0;
+static unsigned long zio_decompress_fail_fraction = 0;
 
 /*
  * Compression vectors.
diff --git a/tests/zfs-tests/cmd/btree_test.c b/tests/zfs-tests/cmd/btree_test.c
index fb9de9c777..9a34bf559b 100644
--- a/tests/zfs-tests/cmd/btree_test.c
+++ b/tests/zfs-tests/cmd/btree_test.c
@@ -23,11 +23,11 @@
 
 #define	BUFSIZE 256
 
-int seed = 0;
-int stress_timeout = 180;
-int contents_frequency = 100;
-int tree_limit = 64 * 1024;
-boolean_t stress_only = B_FALSE;
+static int seed = 0;
+static int stress_timeout = 180;
+static int contents_frequency = 100;
+static int tree_limit = 64 * 1024;
+static boolean_t stress_only = B_FALSE;
 
 static void
 usage(int exit_value)
diff --git a/tests/zfs-tests/cmd/checksum/edonr_test.c b/tests/zfs-tests/cmd/checksum/edonr_test.c
index 3a0a48533c..d010fbfcd4 100644
--- a/tests/zfs-tests/cmd/checksum/edonr_test.c
+++ b/tests/zfs-tests/cmd/checksum/edonr_test.c
@@ -40,16 +40,16 @@
  * Test messages from:
  * http://csrc.nist.gov/groups/ST/toolkit/documents/Examples/SHA_All.pdf
  */
-const char	*test_msg0 = "abc";
-const char	*test_msg1 = "abcdbcdecdefdefgefghfghighijhijkijkljklmklmn"
-	"lmnomnopnopq";
-const char	*test_msg2 = "abcdefghbcdefghicdefghijdefghijkefghijklfghi"
-	"jklmghijklmnhijklmnoijklmnopjklmnopqklmnopqrlmnopqrsmnopqrstnopqrstu";
+static const char *test_msg0 = "abc";
+static const char *test_msg1 = "abcdbcdecdefdefgefghfghighijhijkijkljklmklm"
+	"nlmnomnopnopq";
+static const char *test_msg2 = "abcdefghbcdefghicdefghijdefghijkefghijklfgh"
+	"ijklmghijklmnhijklmnoijklmnopjklmnopqklmnopqrlmnopqrsmnopqrstnopqrstu";
 
 /*
  * Test digests computed by hand. There's no formal standard or spec for edonr.
  */
-const uint8_t	edonr_224_test_digests[][28] = {
+static const uint8_t	edonr_224_test_digests[][28] = {
 	{
 		/* for test_msg0 */
 		0x56, 0x63, 0xc4, 0x93, 0x95, 0x20, 0xfa, 0xf6,
@@ -67,7 +67,7 @@ const uint8_t	edonr_224_test_digests[][28] = {
 	/* no test vector for test_msg2 */
 };
 
-const uint8_t	edonr_256_test_digests[][32] = {
+static const uint8_t	edonr_256_test_digests[][32] = {
 	{
 		/* for test_msg0 */
 		0x54, 0xd7, 0x8b, 0x13, 0xc7, 0x4e, 0xda, 0x5a,
@@ -85,7 +85,7 @@ const uint8_t	edonr_256_test_digests[][32] = {
 	/* no test vectorfor test_msg2 */
 };
 
-const uint8_t	edonr_384_test_digests[][48] = {
+static const uint8_t	edonr_384_test_digests[][48] = {
 	{
 		/* for test_msg0 */
 		0x0e, 0x7c, 0xd7, 0x85, 0x78, 0x77, 0xe0, 0x89,
@@ -110,7 +110,7 @@ const uint8_t	edonr_384_test_digests[][48] = {
 	}
 };
 
-const uint8_t	edonr_512_test_digests[][64] = {
+static const uint8_t	edonr_512_test_digests[][64] = {
 	{
 		/* for test_msg0 */
 		0x1b, 0x14, 0xdb, 0x15, 0x5f, 0x1d, 0x40, 0x65,
diff --git a/tests/zfs-tests/cmd/checksum/sha2_test.c b/tests/zfs-tests/cmd/checksum/sha2_test.c
index bb35531109..d99e8757a2 100644
--- a/tests/zfs-tests/cmd/checksum/sha2_test.c
+++ b/tests/zfs-tests/cmd/checksum/sha2_test.c
@@ -44,17 +44,17 @@
  * http://csrc.nist.gov/groups/ST/toolkit/documents/Examples/SHA_All.pdf
  */
 
-const char	*test_msg0 = "abc";
-const char	*test_msg1 = "abcdbcdecdefdefgefghfghighijhijkijkljklmklmn"
-	"lmnomnopnopq";
-const char	*test_msg2 = "abcdefghbcdefghicdefghijdefghijkefghijklfghi"
-	"jklmghijklmnhijklmnoijklmnopjklmnopqklmnopqrlmnopqrsmnopqrstnopqrstu";
+static const char *test_msg0 = "abc";
+static const char *test_msg1 = "abcdbcdecdefdefgefghfghighijhijkijkljklmklm"
+	"nlmnomnopnopq";
+static const char *test_msg2 = "abcdefghbcdefghicdefghijdefghijkefghijklfgh"
+	"ijklmghijklmnhijklmnoijklmnopjklmnopqklmnopqrlmnopqrsmnopqrstnopqrstu";
 
 /*
  * Test digests from:
  * http://csrc.nist.gov/groups/ST/toolkit/documents/Examples/SHA_All.pdf
  */
-const uint8_t	sha256_test_digests[][32] = {
+static const uint8_t	sha256_test_digests[][32] = {
 	{
 		/* for test_msg0 */
 		0xBA, 0x78, 0x16, 0xBF, 0x8F, 0x01, 0xCF, 0xEA,
@@ -72,7 +72,7 @@ const uint8_t	sha256_test_digests[][32] = {
 	/* no test vector for test_msg2 */
 };
 
-const uint8_t	sha384_test_digests[][48] = {
+static const uint8_t	sha384_test_digests[][48] = {
 	{
 		/* for test_msg0 */
 		0xCB, 0x00, 0x75, 0x3F, 0x45, 0xA3, 0x5E, 0x8B,
@@ -97,7 +97,7 @@ const uint8_t	sha384_test_digests[][48] = {
 	}
 };
 
-const uint8_t	sha512_test_digests[][64] = {
+static const uint8_t	sha512_test_digests[][64] = {
 	{
 		/* for test_msg0 */
 		0xDD, 0xAF, 0x35, 0xA1, 0x93, 0x61, 0x7A, 0xBA,
@@ -126,7 +126,7 @@ const uint8_t	sha512_test_digests[][64] = {
 	}
 };
 
-const uint8_t	sha512_224_test_digests[][28] = {
+static const uint8_t	sha512_224_test_digests[][28] = {
 	{
 		/* for test_msg0 */
 		0x46, 0x34, 0x27, 0x0F, 0x70, 0x7B, 0x6A, 0x54,
@@ -147,7 +147,7 @@ const uint8_t	sha512_224_test_digests[][28] = {
 	}
 };
 
-const uint8_t	sha512_256_test_digests[][32] = {
+static const uint8_t	sha512_256_test_digests[][32] = {
 	{
 		/* for test_msg0 */
 		0x53, 0x04, 0x8E, 0x26, 0x81, 0x94, 0x1E, 0xF9,
diff --git a/tests/zfs-tests/cmd/checksum/skein_test.c b/tests/zfs-tests/cmd/checksum/skein_test.c
index 13611c860c..20eb36d3e8 100644
--- a/tests/zfs-tests/cmd/checksum/skein_test.c
+++ b/tests/zfs-tests/cmd/checksum/skein_test.c
@@ -44,18 +44,18 @@
 /*
  * Test messages from the Skein spec, Appendix C.
  */
-const uint8_t	test_msg0[] = {
+static const uint8_t	test_msg0[] = {
 	0xFF
 };
 
-const uint8_t	test_msg1[] = {
+static const uint8_t	test_msg1[] = {
 	0xFF, 0xFE, 0xFD, 0xFC, 0xFB, 0xFA, 0xF9, 0xF8,
 	0xF7, 0xF6, 0xF5, 0xF4, 0xF3, 0xF2, 0xF1, 0xF0,
 	0xEF, 0xEE, 0xED, 0xEC, 0xEB, 0xEA, 0xE9, 0xE8,
 	0xE7, 0xE6, 0xE5, 0xE4, 0xE3, 0xE2, 0xE1, 0xE0
 };
 
-const uint8_t	test_msg2[] = {
+static const uint8_t	test_msg2[] = {
 	0xFF, 0xFE, 0xFD, 0xFC, 0xFB, 0xFA, 0xF9, 0xF8,
 	0xF7, 0xF6, 0xF5, 0xF4, 0xF3, 0xF2, 0xF1, 0xF0,
 	0xEF, 0xEE, 0xED, 0xEC, 0xEB, 0xEA, 0xE9, 0xE8,
@@ -66,7 +66,7 @@ const uint8_t	test_msg2[] = {
 	0xC7, 0xC6, 0xC5, 0xC4, 0xC3, 0xC2, 0xC1, 0xC0
 };
 
-const uint8_t	test_msg3[] = {
+static const uint8_t	test_msg3[] = {
 	0xFF, 0xFE, 0xFD, 0xFC, 0xFB, 0xFA, 0xF9, 0xF8,
 	0xF7, 0xF6, 0xF5, 0xF4, 0xF3, 0xF2, 0xF1, 0xF0,
 	0xEF, 0xEE, 0xED, 0xEC, 0xEB, 0xEA, 0xE9, 0xE8,
@@ -85,7 +85,7 @@ const uint8_t	test_msg3[] = {
 	0x87, 0x86, 0x85, 0x84, 0x83, 0x82, 0x81, 0x80
 };
 
-const uint8_t	test_msg4[] = {
+static const uint8_t	test_msg4[] = {
 	0xFF, 0xFE, 0xFD, 0xFC, 0xFB, 0xFA, 0xF9, 0xF8,
 	0xF7, 0xF6, 0xF5, 0xF4, 0xF3, 0xF2, 0xF1, 0xF0,
 	0xEF, 0xEE, 0xED, 0xEC, 0xEB, 0xEA, 0xE9, 0xE8,
@@ -123,7 +123,7 @@ const uint8_t	test_msg4[] = {
 /*
  * Test digests from the Skein spec, Appendix C.
  */
-const uint8_t	skein_256_test_digests[][32] = {
+static const uint8_t	skein_256_test_digests[][32] = {
 	{
 		/* for test_msg0 */
 		0x0B, 0x98, 0xDC, 0xD1, 0x98, 0xEA, 0x0E, 0x50,
@@ -148,7 +148,7 @@ const uint8_t	skein_256_test_digests[][32] = {
 	/* no test digests for test_msg3 and test_msg4 */
 };
 
-const uint8_t	skein_512_test_digests[][64] = {
+static const uint8_t	skein_512_test_digests[][64] = {
 	{
 		/* for test_msg0 */
 		0x71, 0xB7, 0xBC, 0xE6, 0xFE, 0x64, 0x52, 0x22,
@@ -189,7 +189,7 @@ const uint8_t	skein_512_test_digests[][64] = {
 	/* no test digests for test_msg4 */
 };
 
-const uint8_t	skein_1024_test_digests[][128] = {
+static const uint8_t	skein_1024_test_digests[][128] = {
 	{
 		/* for test_msg0 */
 		0xE6, 0x2C, 0x05, 0x80, 0x2E, 0xA0, 0x15, 0x24,
diff --git a/tests/zfs-tests/cmd/mmap_libaio.c b/tests/zfs-tests/cmd/mmap_libaio.c
index 7d76c9b4eb..5ee1f600a7 100644
--- a/tests/zfs-tests/cmd/mmap_libaio.c
+++ b/tests/zfs-tests/cmd/mmap_libaio.c
@@ -33,7 +33,7 @@
 #include <libaio.h>
 #include <err.h>
 
-io_context_t io_ctx;
+static io_context_t io_ctx;
 
 static void
 do_sync_io(struct iocb *iocb)