module/*.ko: prune .data, global .rodata

Evaluated every variable that lives in .data (and globals in .rodata)
in the kernel modules, and constified/eliminated/localised them
appropriately. This means that all read-only data is now actually
read-only data, and, if possible, at file scope. A lot of previously-
global-symbols became inlinable (and inlined!) constants. Probably
not in a big Wowee Performance Moment, but hey.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #12899

module/os/freebsd/zfs/abd_os.c

@@ -93,7 +93,7 @@ struct {
  * of multi-page linear ABDs are expensive operations due to KVA mapping and
  * unmapping, and with time they cause KVA fragmentations.
  */
-size_t zfs_abd_scatter_min_size = PAGE_SIZE + 1;
+static size_t zfs_abd_scatter_min_size = PAGE_SIZE + 1;
 
 #if defined(_KERNEL)
 SYSCTL_DECL(_vfs_zfs);

module/os/freebsd/zfs/crypto_os.c

@@ -198,7 +198,7 @@ zfs_crypto_dispatch(freebsd_crypt_session_t *session, 	struct cryptop *crp)
 static void
 freebsd_crypt_uio_debug_log(boolean_t encrypt,
     freebsd_crypt_session_t *input_sessionp,
-    struct zio_crypt_info *c_info,
+    const struct zio_crypt_info *c_info,
     zfs_uio_t *data_uio,
     crypto_key_t *key,
     uint8_t *ivbuf,
@@ -241,7 +241,7 @@ freebsd_crypt_uio_debug_log(boolean_t encrypt,
 #if __FreeBSD_version >= 1300087
 int
 freebsd_crypt_newsession(freebsd_crypt_session_t *sessp,
-    struct zio_crypt_info *c_info, crypto_key_t *key)
+    const struct zio_crypt_info *c_info, crypto_key_t *key)
 {
 	struct crypto_session_params csp;
 	int error = 0;
@@ -322,7 +322,7 @@ bad:
 int
 freebsd_crypt_uio(boolean_t encrypt,
     freebsd_crypt_session_t *input_sessionp,
-    struct zio_crypt_info *c_info,
+    const struct zio_crypt_info *c_info,
     zfs_uio_t *data_uio,
     crypto_key_t *key,
     uint8_t *ivbuf,
@@ -382,7 +382,7 @@ out:
 #else
 int
 freebsd_crypt_newsession(freebsd_crypt_session_t *sessp,
-    struct zio_crypt_info *c_info, crypto_key_t *key)
+    const struct zio_crypt_info *c_info, crypto_key_t *key)
 {
 	struct cryptoini cria, crie, *crip;
 	struct enc_xform *xform;
@@ -492,7 +492,7 @@ bad:
 int
 freebsd_crypt_uio(boolean_t encrypt,
     freebsd_crypt_session_t *input_sessionp,
-    struct zio_crypt_info *c_info,
+    const struct zio_crypt_info *c_info,
     zfs_uio_t *data_uio,
     crypto_key_t *key,
     uint8_t *ivbuf,

module/os/freebsd/zfs/vdev_file.c

@@ -40,8 +40,8 @@
 
 static taskq_t *vdev_file_taskq;
 
-unsigned long vdev_file_logical_ashift = SPA_MINBLOCKSHIFT;
-unsigned long vdev_file_physical_ashift = SPA_MINBLOCKSHIFT;
+static unsigned long vdev_file_logical_ashift = SPA_MINBLOCKSHIFT;
+static unsigned long vdev_file_physical_ashift = SPA_MINBLOCKSHIFT;
 
 void
 vdev_file_init(void)

module/os/freebsd/zfs/zfs_acl.c

@@ -171,7 +171,7 @@ zfs_ace_v0_data(void *acep, void **datap)
 	return (0);
 }
 
-static acl_ops_t zfs_acl_v0_ops = {
+static const acl_ops_t zfs_acl_v0_ops = {
 	zfs_ace_v0_get_mask,
 	zfs_ace_v0_set_mask,
 	zfs_ace_v0_get_flags,
@@ -307,7 +307,7 @@ zfs_ace_fuid_data(void *acep, void **datap)
 	}
 }
 
-static acl_ops_t zfs_acl_fuid_ops = {
+static const acl_ops_t zfs_acl_fuid_ops = {
 	zfs_ace_fuid_get_mask,
 	zfs_ace_fuid_set_mask,
 	zfs_ace_fuid_get_flags,

module/os/freebsd/zfs/zfs_debug.c

@@ -33,11 +33,11 @@ typedef struct zfs_dbgmsg {
 	char zdm_msg[1]; /* variable length allocation */
 } zfs_dbgmsg_t;
 
-list_t zfs_dbgmsgs;
-int zfs_dbgmsg_size = 0;
-kmutex_t zfs_dbgmsgs_lock;
+static list_t zfs_dbgmsgs;
+static int zfs_dbgmsg_size = 0;
+static kmutex_t zfs_dbgmsgs_lock;
 int zfs_dbgmsg_maxsize = 4<<20; /* 4MB */
-kstat_t *zfs_dbgmsg_kstat;
+static kstat_t *zfs_dbgmsg_kstat;
 
 /*
  * Internal ZFS debug messages are enabled by default.
@@ -51,7 +51,7 @@ kstat_t *zfs_dbgmsg_kstat;
  * # Disable the kernel debug message log.
  * sysctl vfs.zfs.dbgmsg_enable=0
  */
-int zfs_dbgmsg_enable = 1;
+int zfs_dbgmsg_enable = B_TRUE;
 
 static int
 zfs_dbgmsg_headers(char *buf, size_t size)

module/os/freebsd/zfs/zio_crypt.c

@@ -185,13 +185,7 @@
 #define	ZFS_KEY_MAX_SALT_USES_DEFAULT	400000000
 #define	ZFS_CURRENT_MAX_SALT_USES	\
 	(MIN(zfs_key_max_salt_uses, ZFS_KEY_MAX_SALT_USES_DEFAULT))
-unsigned long zfs_key_max_salt_uses = ZFS_KEY_MAX_SALT_USES_DEFAULT;
-
-/*
- * Set to a nonzero value to cause zio_do_crypt_uio() to fail 1/this many
- * calls, to test decryption error handling code paths.
- */
-uint64_t zio_decrypt_fail_fraction = 0;
+static unsigned long zfs_key_max_salt_uses = ZFS_KEY_MAX_SALT_USES_DEFAULT;
 
 typedef struct blkptr_auth_buf {
 	uint64_t bab_prop;			/* blk_prop - portable mask */
@@ -199,7 +193,7 @@ typedef struct blkptr_auth_buf {
 	uint64_t bab_pad;			/* reserved for future use */
 } blkptr_auth_buf_t;
 
-zio_crypt_info_t zio_crypt_table[ZIO_CRYPT_FUNCTIONS] = {
+const zio_crypt_info_t zio_crypt_table[ZIO_CRYPT_FUNCTIONS] = {
 	{"",			ZC_TYPE_NONE,	0,	"inherit"},
 	{"",			ZC_TYPE_NONE,	0,	"on"},
 	{"",			ZC_TYPE_NONE,	0,	"off"},
@@ -237,7 +231,7 @@ zio_crypt_key_init(uint64_t crypt, zio_crypt_key_t *key)
 	int ret;
 	crypto_mechanism_t mech __unused;
 	uint_t keydata_len;
-	zio_crypt_info_t *ci = NULL;
+	const zio_crypt_info_t *ci = NULL;
 
 	ASSERT3P(key, !=, NULL);
 	ASSERT3U(crypt, <, ZIO_CRYPT_FUNCTIONS);
@@ -406,16 +400,13 @@ zio_do_crypt_uio_opencrypto(boolean_t encrypt, freebsd_crypt_session_t *sess,
     uint64_t crypt, crypto_key_t *key, uint8_t *ivbuf, uint_t datalen,
     zfs_uio_t *uio, uint_t auth_len)
 {
-	zio_crypt_info_t *ci;
-	int ret;
-
-	ci = &zio_crypt_table[crypt];
+	const zio_crypt_info_t *ci = &zio_crypt_table[crypt];
 	if (ci->ci_crypt_type != ZC_TYPE_GCM &&
 	    ci->ci_crypt_type != ZC_TYPE_CCM)
 		return (ENOTSUP);
 
 
-	ret = freebsd_crypt_uio(encrypt, sess, ci, uio, key, ivbuf,
+	int ret = freebsd_crypt_uio(encrypt, sess, ci, uio, key, ivbuf,
 	    datalen, auth_len);
 	if (ret != 0) {
 #ifdef FCRYPTO_DEBUG