Throw const on some strings

In C, const indicates to the reader that mutation will not occur.
It can also serve as a hint about ownership.

Add const in a few places where it makes sense.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Ryan Moeller <[email protected]>
Closes #10997 

5 files changed, 27 insertions, 28 deletions

diff --git a/module/zfs/dmu_objset.c b/module/zfs/dmu_objset.c
index b1590d7db..af5935e23 100644
--- a/module/zfs/dmu_objset.c
+++ b/module/zfs/dmu_objset.c
@@ -2413,7 +2413,7 @@ dmu_objset_is_snapshot(objset_t *os)
 }
 
 int
-dmu_snapshot_realname(objset_t *os, char *name, char *real, int maxlen,
+dmu_snapshot_realname(objset_t *os, const char *name, char *real, int maxlen,
     boolean_t *conflict)
 {
 	dsl_dataset_t *ds = os->os_dsl_dataset;
diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index 532f04b91..2c70cf701 100644
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -6225,7 +6225,7 @@ spa_tryimport(nvlist_t *tryconfig)
  * we don't sync the labels or remove the configuration cache.
  */
 static int
-spa_export_common(char *pool, int new_state, nvlist_t **oldconfig,
+spa_export_common(const char *pool, int new_state, nvlist_t **oldconfig,
     boolean_t force, boolean_t hardforce)
 {
 	spa_t *spa;
@@ -6369,7 +6369,7 @@ export_spa:
  * Destroy a storage pool.
  */
 int
-spa_destroy(char *pool)
+spa_destroy(const char *pool)
 {
 	return (spa_export_common(pool, POOL_STATE_DESTROYED, NULL,
 	    B_FALSE, B_FALSE));
@@ -6379,7 +6379,7 @@ spa_destroy(char *pool)
  * Export a storage pool.
  */
 int
-spa_export(char *pool, nvlist_t **oldconfig, boolean_t force,
+spa_export(const char *pool, nvlist_t **oldconfig, boolean_t force,
     boolean_t hardforce)
 {
 	return (spa_export_common(pool, POOL_STATE_EXPORTED, oldconfig,
@@ -6391,7 +6391,7 @@ spa_export(char *pool, nvlist_t **oldconfig, boolean_t force,
  * from the namespace in any way.
  */
 int
-spa_reset(char *pool)
+spa_reset(const char *pool)
 {
 	return (spa_export_common(pool, POOL_STATE_UNINITIALIZED, NULL,
 	    B_FALSE, B_FALSE));
diff --git a/module/zfs/zfeature.c b/module/zfs/zfeature.c
index 3757443a5..9d16fff81 100644
--- a/module/zfs/zfeature.c
+++ b/module/zfs/zfeature.c
@@ -203,7 +203,7 @@ spa_features_check(spa_t *spa, boolean_t for_write,
 			supported = B_FALSE;
 
 			if (NULL != unsup_feat) {
-				char *desc = "";
+				const char *desc = "";
 
 				if (zap_lookup(os, spa->spa_feat_desc_obj,
 				    za->za_name, 1, MAXPATHLEN, buf) == 0)
diff --git a/module/zfs/zfs_ioctl.c b/module/zfs/zfs_ioctl.c
index d2550750c..94cd1a3dc 100644
--- a/module/zfs/zfs_ioctl.c
+++ b/module/zfs/zfs_ioctl.c
@@ -270,7 +270,7 @@ static int zfs_ioc_userspace_upgrade(zfs_cmd_t *zc);
 static int zfs_ioc_id_quota_upgrade(zfs_cmd_t *zc);
 static int zfs_check_settable(const char *name, nvpair_t *property,
     cred_t *cr);
-static int zfs_check_clearable(char *dataset, nvlist_t *props,
+static int zfs_check_clearable(const char *dataset, nvlist_t *props,
     nvlist_t **errors);
 static int zfs_fill_zplprops_root(uint64_t, nvlist_t *, nvlist_t *,
     boolean_t *);
@@ -498,7 +498,7 @@ zfs_secpolicy_write_perms(const char *name, const char *perm, cred_t *cr)
  * Returns 0 for success, non-zero for access and other errors.
  */
 static int
-zfs_set_slabel_policy(const char *name, char *strval, cred_t *cr)
+zfs_set_slabel_policy(const char *name, const char *strval, cred_t *cr)
 {
 #ifdef HAVE_MLSLABEL
 	char		ds_hexsl[MAXNAMELEN];
@@ -553,7 +553,7 @@ zfs_set_slabel_policy(const char *name, char *strval, cred_t *cr)
 	 */
 	if (strcasecmp(ds_hexsl, ZFS_MLSLABEL_DEFAULT) != 0) {
 		objset_t *os;
-		static char *setsl_tag = "setsl_tag";
+		static const char *setsl_tag = "setsl_tag";
 
 		/*
 		 * Try to own the dataset; abort if there is any error,
@@ -680,7 +680,7 @@ zfs_secpolicy_send(zfs_cmd_t *zc, nvlist_t *innvl, cred_t *cr)
 {
 	dsl_pool_t *dp;
 	dsl_dataset_t *ds;
-	char *cp;
+	const char *cp;
 	int error;
 
 	/*
@@ -1443,7 +1443,7 @@ zfs_ioc_pool_create(zfs_cmd_t *zc)
 	nvlist_t *rootprops = NULL;
 	nvlist_t *zplprops = NULL;
 	dsl_crypto_params_t *dcp = NULL;
-	char *spa_name = zc->zc_name;
+	const char *spa_name = zc->zc_name;
 	boolean_t unload_wkey = B_TRUE;
 
 	if ((error = get_nvlist(zc->zc_nvlist_conf, zc->zc_nvlist_conf_size,
@@ -1997,7 +1997,7 @@ static int
 zfs_ioc_vdev_setpath(zfs_cmd_t *zc)
 {
 	spa_t *spa;
-	char *path = zc->zc_value;
+	const char *path = zc->zc_value;
 	uint64_t guid = zc->zc_guid;
 	int error;
 
@@ -2014,7 +2014,7 @@ static int
 zfs_ioc_vdev_setfru(zfs_cmd_t *zc)
 {
 	spa_t *spa;
-	char *fru = zc->zc_value;
+	const char *fru = zc->zc_value;
 	uint64_t guid = zc->zc_guid;
 	int error;
 
@@ -2351,8 +2351,7 @@ zfs_prop_set_userquota(const char *dsname, nvpair_t *pair)
 	const char *propname = nvpair_name(pair);
 	uint64_t *valary;
 	unsigned int vallen;
-	const char *domain;
-	char *dash;
+	const char *dash, *domain;
 	zfs_userquota_prop_t type;
 	uint64_t rid;
 	uint64_t quota;
@@ -2405,7 +2404,7 @@ zfs_prop_set_special(const char *dsname, zprop_source_t source,
 	const char *propname = nvpair_name(pair);
 	zfs_prop_t prop = zfs_name_to_prop(propname);
 	uint64_t intval = 0;
-	char *strval = NULL;
+	const char *strval = NULL;
 	int err = -1;
 
 	if (prop == ZPROP_INVAL) {
@@ -2531,7 +2530,7 @@ zfs_set_prop_nvlist(const char *dsname, zprop_source_t source, nvlist_t *nvl,
 	nvpair_t *propval;
 	int rv = 0;
 	uint64_t intval;
-	char *strval;
+	const char *strval;
 
 	nvlist_t *genericnvl = fnvlist_alloc();
 	nvlist_t *retrynvl = fnvlist_alloc();
@@ -3349,7 +3348,7 @@ zfs_ioc_clone(const char *fsname, nvlist_t *innvl, nvlist_t *outnvl)
 {
 	int error = 0;
 	nvlist_t *nvprops = NULL;
-	char *origin_name;
+	const char *origin_name;
 
 	origin_name = fnvlist_lookup_string(innvl, "origin");
 	(void) nvlist_lookup_nvlist(innvl, "props", &nvprops);
@@ -3475,10 +3474,10 @@ static const zfs_ioc_key_t zfs_keys_log_history[] = {
 static int
 zfs_ioc_log_history(const char *unused, nvlist_t *innvl, nvlist_t *outnvl)
 {
-	char *message;
+	const char *message;
+	char *poolname;
 	spa_t *spa;
 	int error;
-	char *poolname;
 
 	/*
 	 * The poolname in the ioctl is not set, we get it from the TSD,
@@ -3574,7 +3573,7 @@ zfs_unmount_snap(const char *snapname)
 	if (strchr(snapname, '@') == NULL)
 		return;
 
-	(void) zfsctl_snapshot_unmount((char *)snapname, MNT_FORCE);
+	(void) zfsctl_snapshot_unmount(snapname, MNT_FORCE);
 }
 
 /* ARGSUSED */
@@ -4617,7 +4616,7 @@ zfs_check_settable(const char *dsname, nvpair_t *pair, cred_t *cr)
  * pointed at by errlist is NULL.
  */
 static int
-zfs_check_clearable(char *dataset, nvlist_t *props, nvlist_t **errlist)
+zfs_check_clearable(const char *dataset, nvlist_t *props, nvlist_t **errlist)
 {
 	zfs_cmd_t *zc;
 	nvpair_t *pair, *next_pair;
diff --git a/module/zfs/zfs_log.c b/module/zfs/zfs_log.c
index fb44007fe..4bb529f78 100644
--- a/module/zfs/zfs_log.c
+++ b/module/zfs/zfs_log.c
@@ -299,7 +299,7 @@ zfs_xattr_owner_unlinked(znode_t *zp)
  */
 void
 zfs_log_create(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
-    znode_t *dzp, znode_t *zp, char *name, vsecattr_t *vsecp,
+    znode_t *dzp, znode_t *zp, const char *name, vsecattr_t *vsecp,
     zfs_fuid_info_t *fuidp, vattr_t *vap)
 {
 	itx_t *itx;
@@ -413,7 +413,7 @@ zfs_log_create(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
  */
 void
 zfs_log_remove(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
-    znode_t *dzp, char *name, uint64_t foid, boolean_t unlinked)
+    znode_t *dzp, const char *name, uint64_t foid, boolean_t unlinked)
 {
 	itx_t *itx;
 	lr_remove_t *lr;
@@ -448,7 +448,7 @@ zfs_log_remove(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
  */
 void
 zfs_log_link(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
-    znode_t *dzp, znode_t *zp, char *name)
+    znode_t *dzp, znode_t *zp, const char *name)
 {
 	itx_t *itx;
 	lr_link_t *lr;
@@ -471,7 +471,7 @@ zfs_log_link(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
  */
 void
 zfs_log_symlink(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
-    znode_t *dzp, znode_t *zp, char *name, char *link)
+    znode_t *dzp, znode_t *zp, const char *name, const char *link)
 {
 	itx_t *itx;
 	lr_create_t *lr;
@@ -502,8 +502,8 @@ zfs_log_symlink(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
  * Handles TX_RENAME transactions.
  */
 void
-zfs_log_rename(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype,
-    znode_t *sdzp, char *sname, znode_t *tdzp, char *dname, znode_t *szp)
+zfs_log_rename(zilog_t *zilog, dmu_tx_t *tx, uint64_t txtype, znode_t *sdzp,
+    const char *sname, znode_t *tdzp, const char *dname, znode_t *szp)
 {
 	itx_t *itx;
 	lr_rename_t *lr;