landlock: Improve kernel-doc "Return:" section consistency

The canonical kernel-doc form is "Return:" (singular, without trailing
"s").  Normalize all existing "Returns:" occurrences across the Landlock
source tree to the canonical form.

Also fix capitalization for consistency.  Balance descriptions to
describe all possible returned values.

Consolidate bullet-point return descriptions into inline text for
functions with simple two-value or three-value returns for consistency.

Cc: Günther Noack <gnoack@google.com>
Reviewed-by: Günther Noack <gnoack3000@gmail.com>
Link: https://lore.kernel.org/r/20260304193134.250495-3-mic@digikod.net
Signed-off-by: Mickaël Salaün <mic@digikod.net>

security/landlock/cred.h

@@ -115,7 +115,7 @@ static inline bool landlocked(const struct task_struct *const task)
  * @handle_layer: returned youngest layer handling a subset of @masks.  Not set
  *                if the function returns NULL.
  *
- * Returns: landlock_cred(@cred) if any access rights specified in @masks is
+ * Return: landlock_cred(@cred) if any access rights specified in @masks is
  * handled, or NULL otherwise.
  */
 static inline const struct landlock_cred_security *

security/landlock/domain.c

@@ -34,7 +34,7 @@
  * @exe_size: Returned size of @exe_str (including the trailing null
  *            character), if any.
  *
- * Returns: A pointer to an allocated buffer where @exe_str point to, %NULL if
+ * Return: A pointer to an allocated buffer where @exe_str point to, %NULL if
  * there is no executable path, or an error otherwise.
  */
 static const void *get_current_exe(const char **const exe_str,
@@ -73,7 +73,7 @@ static const void *get_current_exe(const char **const exe_str,
 }
 
 /*
- * Returns: A newly allocated object describing a domain, or an error
+ * Return: A newly allocated object describing a domain, or an error
  * otherwise.
  */
 static struct landlock_details *get_current_details(void)

security/landlock/fs.c

@@ -119,8 +119,8 @@ static const struct landlock_object_underops landlock_fs_underops = {
  * Any new IOCTL commands that are implemented in fs/ioctl.c's do_vfs_ioctl()
  * should be considered for inclusion here.
  *
- * Returns: true if the IOCTL @cmd can not be restricted with Landlock for
- * device files.
+ * Return: True if the IOCTL @cmd can not be restricted with Landlock for
+ * device files, false otherwise.
  */
 static __attribute_const__ bool is_masked_device_ioctl(const unsigned int cmd)
 {
@@ -428,10 +428,10 @@ static bool may_refer(const struct layer_access_masks *const src_parent,
  * Check that a destination file hierarchy has more restrictions than a source
  * file hierarchy.  This is only used for link and rename actions.
  *
- * Returns: true if child1 may be moved from parent1 to parent2 without
- * increasing its access rights.  If child2 is set, an additional condition is
+ * Return: True if child1 may be moved from parent1 to parent2 without
+ * increasing its access rights (if child2 is set, an additional condition is
  * that child2 may be used from parent2 to parent1 without increasing its access
- * rights.
+ * rights), false otherwise.
  */
 static bool no_more_access(const struct layer_access_masks *const parent1,
 			   const struct layer_access_masks *const child1,
@@ -734,9 +734,7 @@ static void test_is_eacces_with_write(struct kunit *const test)
  * checks that the collected accesses and the remaining ones are enough to
  * allow the request.
  *
- * Returns:
- * - true if the access request is granted;
- * - false otherwise.
+ * Return: True if the access request is granted, false otherwise.
  */
 static bool
 is_access_to_paths_allowed(const struct landlock_ruleset *const domain,
@@ -1022,9 +1020,8 @@ static access_mask_t maybe_remove(const struct dentry *const dentry)
  * only handles walking on the same mount point and only checks one set of
  * accesses.
  *
- * Returns:
- * - true if all the domain access rights are allowed for @dir;
- * - false if the walk reached @mnt_root.
+ * Return: True if all the domain access rights are allowed for @dir, false if
+ * the walk reached @mnt_root.
  */
 static bool collect_domain_accesses(const struct landlock_ruleset *const domain,
 				    const struct dentry *const mnt_root,
@@ -1120,10 +1117,9 @@ static bool collect_domain_accesses(const struct landlock_ruleset *const domain,
  * ephemeral matrices take some space on the stack, which limits the number of
  * layers to a deemed reasonable number: 16.
  *
- * Returns:
- * - 0 if access is allowed;
- * - -EXDEV if @old_dentry would inherit new access rights from @new_dir;
- * - -EACCES if file removal or creation is denied.
+ * Return: 0 if access is allowed, -EXDEV if @old_dentry would inherit new
+ * access rights from @new_dir, or -EACCES if file removal or creation is
+ * denied.
  */
 static int current_check_refer_path(struct dentry *const old_dentry,
 				    const struct path *const new_dir,

security/landlock/id.c

@@ -258,7 +258,7 @@ static void test_range2_rand16(struct kunit *const test)
  *
  * @number_of_ids: Number of IDs to hold.  Must be greater than one.
  *
- * Returns: The first ID in the range.
+ * Return: The first ID in the range.
  */
 u64 landlock_get_id_range(size_t number_of_ids)
 {

security/landlock/ruleset.c

@@ -674,7 +674,7 @@ get_access_mask_t(const struct landlock_ruleset *const ruleset,
  * @masks: Layer access masks to populate.
  * @key_type: The key type to switch between access masks of different types.
  *
- * Returns: An access mask where each access right bit is set which is handled
+ * Return: An access mask where each access right bit is set which is handled
  * in any of the active layers in @domain.
  */
 access_mask_t

security/landlock/ruleset.h

@@ -224,7 +224,7 @@ static inline void landlock_get_ruleset(struct landlock_ruleset *const ruleset)
  *
  * @domain: Landlock ruleset (used as a domain)
  *
- * Returns: an access_masks result of the OR of all the domain's access masks.
+ * Return: An access_masks result of the OR of all the domain's access masks.
  */
 static inline struct access_masks
 landlock_union_access_masks(const struct landlock_ruleset *const domain)

security/landlock/task.c

@@ -174,8 +174,8 @@ static int hook_ptrace_traceme(struct task_struct *const parent)
  * @server: IPC receiver domain.
  * @scope: The scope restriction criteria.
  *
- * Returns: True if @server is in a different domain from @client, and @client
- * is scoped to access @server (i.e. access should be denied).
+ * Return: True if @server is in a different domain from @client and @client
+ * is scoped to access @server (i.e. access should be denied), false otherwise.
  */
 static bool domain_is_scoped(const struct landlock_ruleset *const client,
 			     const struct landlock_ruleset *const server,

security/landlock/tsync.c

@@ -183,10 +183,8 @@ struct tsync_works {
  * capacity.  This can legitimately happen if new threads get started after we
  * grew the capacity.
  *
- * Returns:
- *   A pointer to the preallocated context struct, with task filled in.
- *
- *   NULL, if we ran out of preallocated context structs.
+ * Return: A pointer to the preallocated context struct with task filled in, or
+ * NULL if preallocated context structs ran out.
  */
 static struct tsync_work *tsync_works_provide(struct tsync_works *s,
 					      struct task_struct *task)
@@ -243,11 +241,8 @@ static void tsync_works_trim(struct tsync_works *s)
  * On a successful return, the subsequent n calls to tsync_works_provide() are
  * guaranteed to succeed.  (size + n <= capacity)
  *
- * Returns:
- *   -ENOMEM if the (re)allocation fails
-
- *   0       if the allocation succeeds, partially succeeds, or no reallocation
- *           was needed
+ * Return: 0 if sufficient space for n more elements could be provided, -ENOMEM
+ * on allocation errors, -EOVERFLOW in case of integer overflow.
  */
 static int tsync_works_grow_by(struct tsync_works *s, size_t n, gfp_t flags)
 {
@@ -363,8 +358,8 @@ static size_t count_additional_threads(const struct tsync_works *works)
  * For each added task_work, atomically increments shared_ctx->num_preparing and
  * shared_ctx->num_unfinished.
  *
- * Returns:
- *     true, if at least one eligible sibling thread was found
+ * Return: True if at least one eligible sibling thread was found, false
+ * otherwise.
  */
 static bool schedule_task_work(struct tsync_works *works,
 			       struct tsync_shared_context *shared_ctx)