string_helpers: Move string_is_valid() to the header

Move string_is_valid() to the header for wider use.

While at it, rename to string_is_terminated() to be
precise about its semantics.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20230208133153.22528-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/linux/string_helpers.h

@@ -11,6 +11,11 @@ struct device;
 struct file;
 struct task_struct;
 
+static inline bool string_is_terminated(const char *s, int len)
+{
+	return memchr(s, '\0', len) ? true : false;
+}
+
 /* Descriptions of the types of units to
  * print in */
 enum string_size_units {

net/tipc/netlink_compat.c

@@ -39,6 +39,7 @@
 #include "node.h"
 #include "net.h"
 #include <net/genetlink.h>
+#include <linux/string_helpers.h>
 #include <linux/tipc_config.h>
 
 /* The legacy API had an artificial message length limit called
@@ -173,11 +174,6 @@ static struct sk_buff *tipc_get_err_tlv(char *str)
 	return buf;
 }
 
-static inline bool string_is_valid(char *s, int len)
-{
-	return memchr(s, '\0', len) ? true : false;
-}
-
 static int __tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd,
 				   struct tipc_nl_compat_msg *msg,
 				   struct sk_buff *arg)
@@ -445,7 +441,7 @@ static int tipc_nl_compat_bearer_enable(struct tipc_nl_compat_cmd_doit *cmd,
 		return -EINVAL;
 
 	len = min_t(int, len, TIPC_MAX_BEARER_NAME);
-	if (!string_is_valid(b->name, len))
+	if (!string_is_terminated(b->name, len))
 		return -EINVAL;
 
 	if (nla_put_string(skb, TIPC_NLA_BEARER_NAME, b->name))
@@ -486,7 +482,7 @@ static int tipc_nl_compat_bearer_disable(struct tipc_nl_compat_cmd_doit *cmd,
 		return -EINVAL;
 
 	len = min_t(int, len, TIPC_MAX_BEARER_NAME);
-	if (!string_is_valid(name, len))
+	if (!string_is_terminated(name, len))
 		return -EINVAL;
 
 	if (nla_put_string(skb, TIPC_NLA_BEARER_NAME, name))
@@ -584,7 +580,7 @@ static int tipc_nl_compat_link_stat_dump(struct tipc_nl_compat_msg *msg,
 		return -EINVAL;
 
 	len = min_t(int, len, TIPC_MAX_LINK_NAME);
-	if (!string_is_valid(name, len))
+	if (!string_is_terminated(name, len))
 		return -EINVAL;
 
 	if (strcmp(name, nla_data(link[TIPC_NLA_LINK_NAME])) != 0)
@@ -819,7 +815,7 @@ static int tipc_nl_compat_link_set(struct tipc_nl_compat_cmd_doit *cmd,
 		return -EINVAL;
 
 	len = min_t(int, len, TIPC_MAX_LINK_NAME);
-	if (!string_is_valid(lc->name, len))
+	if (!string_is_terminated(lc->name, len))
 		return -EINVAL;
 
 	media = tipc_media_find(lc->name);
@@ -856,7 +852,7 @@ static int tipc_nl_compat_link_reset_stats(struct tipc_nl_compat_cmd_doit *cmd,
 		return -EINVAL;
 
 	len = min_t(int, len, TIPC_MAX_LINK_NAME);
-	if (!string_is_valid(name, len))
+	if (!string_is_terminated(name, len))
 		return -EINVAL;
 
 	if (nla_put_string(skb, TIPC_NLA_LINK_NAME, name))