diff --git a/add-interactive.c b/add-interactive.c
index 22fcd3412c..2fcad67654 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -430,7 +430,7 @@ struct pathname_entry {
 	struct file_item *item;
 };
 
-static int pathname_entry_cmp(const void *unused_cmp_data,
+static int pathname_entry_cmp(const void *UNUSED(cmp_data),
 			      const struct hashmap_entry *he1,
 			      const struct hashmap_entry *he2,
 			      const void *name)
diff --git a/archive-tar.c b/archive-tar.c
index 3d77e0f750..0d66a1e0a8 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -366,7 +366,8 @@ static struct archiver *find_tar_filter(const char *name, size_t len)
 	return NULL;
 }
 
-static int tar_filter_config(const char *var, const char *value, void *data)
+static int tar_filter_config(const char *var, const char *value,
+			     void *UNUSED(data))
 {
 	struct archiver *ar;
 	const char *name;
@@ -420,7 +421,7 @@ static int git_tar_config(const char *var, const char *value, void *cb)
 	return tar_filter_config(var, value, cb);
 }
 
-static int write_tar_archive(const struct archiver *ar,
+static int write_tar_archive(const struct archiver *UNUSED(ar),
 			     struct archiver_args *args)
 {
 	int err = 0;
diff --git a/archive-zip.c b/archive-zip.c
index 9fe43d740d..d63782dc31 100644
--- a/archive-zip.c
+++ b/archive-zip.c
@@ -612,12 +612,13 @@ static void dos_time(timestamp_t *timestamp, int *dos_date, int *dos_time)
 	*dos_time = tm.tm_sec / 2 + tm.tm_min * 32 + tm.tm_hour * 2048;
 }
 
-static int archive_zip_config(const char *var, const char *value, void *data)
+static int archive_zip_config(const char *var, const char *value,
+			      void *UNUSED(data))
 {
 	return userdiff_config(var, value);
 }
 
-static int write_zip_archive(const struct archiver *ar,
+static int write_zip_archive(const struct archiver *UNUSED(ar),
 			     struct archiver_args *args)
 {
 	int err;
diff --git a/archive.c b/archive.c
index d5109abb89..8b165e935b 100644
--- a/archive.c
+++ b/archive.c
@@ -382,7 +382,8 @@ struct path_exists_context {
 	struct archiver_args *args;
 };
 
-static int reject_entry(const struct object_id *oid, struct strbuf *base,
+static int reject_entry(const struct object_id *UNUSED(oid),
+			struct strbuf *base,
 			const char *filename, unsigned mode,
 			void *context)
 {
diff --git a/attr.c b/attr.c
index 8a78dde69e..63e1a756dd 100644
--- a/attr.c
+++ b/attr.c
@@ -61,10 +61,10 @@ struct attr_hash_entry {
 };
 
 /* attr_hashmap comparison function */
-static int attr_hash_entry_cmp(const void *unused_cmp_data,
+static int attr_hash_entry_cmp(const void *UNUSED(cmp_data),
 			       const struct hashmap_entry *eptr,
 			       const struct hashmap_entry *entry_or_key,
-			       const void *unused_keydata)
+			       const void *UNUSED(keydata))
 {
 	const struct attr_hash_entry *a, *b;
 
diff --git a/bisect.c b/bisect.c
index 38b3891f3a..07ccd1bce6 100644
--- a/bisect.c
+++ b/bisect.c
@@ -441,7 +441,7 @@ void find_bisection(struct commit_list **commit_list, int *reaches,
 }
 
 static int register_ref(const char *refname, const struct object_id *oid,
-			int flags, void *cb_data)
+			int UNUSED(flags), void *UNUSED(cb_data))
 {
 	struct strbuf good_prefix = STRBUF_INIT;
 	strbuf_addstr(&good_prefix, term_good);
@@ -1160,8 +1160,9 @@ int estimate_bisect_steps(int all)
 	return (e < 3 * x) ? n : n - 1;
 }
 
-static int mark_for_removal(const char *refname, const struct object_id *oid,
-			    int flag, void *cb_data)
+static int mark_for_removal(const char *refname,
+			    const struct object_id *UNUSED(oid),
+			    int UNUSED(flag), void *cb_data)
 {
 	struct string_list *refs = cb_data;
 	char *ref = xstrfmt("refs/bisect%s", refname);
diff --git a/bloom.c b/bloom.c
index 816f063dca..94fb97e60e 100644
--- a/bloom.c
+++ b/bloom.c
@@ -163,10 +163,10 @@ void init_bloom_filters(void)
 	init_bloom_filter_slab(&bloom_filters);
 }
 
-static int pathmap_cmp(const void *hashmap_cmp_fn_data,
+static int pathmap_cmp(const void *UNUSED(hashmap_cmp_fn_data),
 		       const struct hashmap_entry *eptr,
 		       const struct hashmap_entry *entry_or_key,
-		       const void *keydata)
+		       const void *UNUSED(keydata))
 {
 	const struct pathmap_hash_entry *e1, *e2;
 
diff --git a/builtin/am.c b/builtin/am.c
index 93bec62afa..0811b9ff67 100644
--- a/builtin/am.c
+++ b/builtin/am.c
@@ -2301,7 +2301,7 @@ static int parse_opt_show_current_patch(const struct option *opt, const char *ar
 	return 0;
 }
 
-static int git_am_config(const char *k, const char *v, void *cb)
+static int git_am_config(const char *k, const char *v, void *UNUSED(cb))
 {
 	int status;
 
diff --git a/builtin/bisect--helper.c b/builtin/bisect--helper.c
index 7097750fc6..2bdbad48e9 100644
--- a/builtin/bisect--helper.c
+++ b/builtin/bisect--helper.c
@@ -329,8 +329,9 @@ static int check_and_set_terms(struct bisect_terms *terms, const char *cmd)
 	return 0;
 }
 
-static int inc_nr(const char *refname, const struct object_id *oid,
-		  int flag, void *cb_data)
+static int inc_nr(const char *UNUSED(refname),
+		  const struct object_id *UNUSED(oid),
+		  int UNUSED(flag), void *cb_data)
 {
 	unsigned int *nr = (unsigned int *)cb_data;
 	(*nr)++;
@@ -518,7 +519,7 @@ static int bisect_append_log_quoted(const char **argv)
 }
 
 static int add_bisect_ref(const char *refname, const struct object_id *oid,
-			  int flags, void *cb)
+			  int UNUSED(flags), void *cb)
 {
 	struct add_bisect_ref_data *data = cb;
 
@@ -1134,8 +1135,9 @@ static int bisect_visualize(struct bisect_terms *terms, const char **argv, int a
 	return res;
 }
 
-static int get_first_good(const char *refname, const struct object_id *oid,
-			  int flag, void *cb_data)
+static int get_first_good(const char *UNUSED(refname),
+			  const struct object_id *oid,
+			  int UNUSED(flag), void *cb_data)
 {
 	oidcpy(cb_data, oid);
 	return 1;
diff --git a/builtin/checkout.c b/builtin/checkout.c
index f9d63d80b9..d18c8c886e 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -125,7 +125,7 @@ static int post_checkout_hook(struct commit *old_commit, struct commit *new_comm
 }
 
 static int update_some(const struct object_id *oid, struct strbuf *base,
-		const char *pathname, unsigned mode, void *context)
+		       const char *pathname, unsigned mode, void *UNUSED(context))
 {
 	int len;
 	struct cache_entry *ce;
@@ -990,7 +990,7 @@ static void update_refs_for_switch(const struct checkout_opts *opts,
 
 static int add_pending_uninteresting_ref(const char *refname,
 					 const struct object_id *oid,
-					 int flags, void *cb_data)
+					 int UNUSED(flags), void *cb_data)
 {
 	add_pending_oid(cb_data, refname, oid, UNINTERESTING);
 	return 0;
diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c
index dc3cc35394..6e3baff6d5 100644
--- a/builtin/commit-graph.c
+++ b/builtin/commit-graph.c
@@ -179,7 +179,7 @@ static int write_option_max_new_filters(const struct option *opt,
 }
 
 static int git_commit_graph_write_config(const char *var, const char *value,
-					 void *cb)
+					 void *UNUSED(cb))
 {
 	if (!strcmp(var, "commitgraph.maxnewfilters"))
 		write_opts.max_new_filters = git_config_int(var, value);
diff --git a/builtin/config.c b/builtin/config.c
index e7b88a9c08..bdc8b1d1a8 100644
--- a/builtin/config.c
+++ b/builtin/config.c
@@ -207,7 +207,8 @@ static void show_config_scope(struct strbuf *buf)
 	strbuf_addch(buf, term);
 }
 
-static int show_all_config(const char *key_, const char *value_, void *cb)
+static int show_all_config(const char *key_, const char *value_,
+			   void *UNUSED(cb))
 {
 	if (show_origin || show_scope) {
 		struct strbuf buf = STRBUF_INIT;
@@ -458,7 +459,8 @@ static const char *get_color_slot;
 static const char *get_colorbool_slot;
 static char parsed_color[COLOR_MAXLEN];
 
-static int git_get_color_config(const char *var, const char *value, void *cb)
+static int git_get_color_config(const char *var, const char *value,
+				void *UNUSED(cb))
 {
 	if (!strcmp(var, get_color_slot)) {
 		if (!value)
@@ -490,7 +492,7 @@ static int get_colorbool_found;
 static int get_diff_color_found;
 static int get_color_ui_found;
 static int git_get_colorbool_config(const char *var, const char *value,
-		void *cb)
+				    void *UNUSED(data))
 {
 	if (!strcmp(var, get_colorbool_slot))
 		get_colorbool_found = git_config_colorbool(var, value);
diff --git a/builtin/describe.c b/builtin/describe.c
index a76f1a1a7a..084fa00f2a 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -63,7 +63,7 @@ static const char *prio_names[] = {
 	N_("head"), N_("lightweight"), N_("annotated"),
 };
 
-static int commit_name_neq(const void *unused_cmp_data,
+static int commit_name_neq(const void *UNUSED(cmp_data),
 			   const struct hashmap_entry *eptr,
 			   const struct hashmap_entry *entry_or_key,
 			   const void *peeled)
@@ -140,7 +140,8 @@ static void add_to_known_names(const char *path,
 	}
 }
 
-static int get_name(const char *path, const struct object_id *oid, int flag, void *cb_data)
+static int get_name(const char *path, const struct object_id *oid,
+		    int UNUSED(flag), void *UNUSED(cb_data))
 {
 	int is_tag = 0;
 	struct object_id peeled;
diff --git a/builtin/difftool.c b/builtin/difftool.c
index 8706f68492..d1f973c481 100644
--- a/builtin/difftool.c
+++ b/builtin/difftool.c
@@ -125,10 +125,10 @@ struct working_tree_entry {
 	char path[FLEX_ARRAY];
 };
 
-static int working_tree_entry_cmp(const void *unused_cmp_data,
+static int working_tree_entry_cmp(const void *UNUSED(cmp_data),
 				  const struct hashmap_entry *eptr,
 				  const struct hashmap_entry *entry_or_key,
-				  const void *unused_keydata)
+				  const void *UNUSED(keydata))
 {
 	const struct working_tree_entry *a, *b;
 
@@ -148,10 +148,10 @@ struct pair_entry {
 	const char path[FLEX_ARRAY];
 };
 
-static int pair_cmp(const void *unused_cmp_data,
+static int pair_cmp(const void *UNUSED(cmp_data),
 		    const struct hashmap_entry *eptr,
 		    const struct hashmap_entry *entry_or_key,
-		    const void *unused_keydata)
+		    const void *UNUSED(keydata))
 {
 	const struct pair_entry *a, *b;
 
@@ -184,7 +184,7 @@ struct path_entry {
 	char path[FLEX_ARRAY];
 };
 
-static int path_entry_cmp(const void *unused_cmp_data,
+static int path_entry_cmp(const void *UNUSED(cmp_data),
 			  const struct hashmap_entry *eptr,
 			  const struct hashmap_entry *entry_or_key,
 			  const void *key)
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index bf3c20dea2..6aa2761ee9 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -119,7 +119,7 @@ struct anonymized_entry_key {
 	size_t orig_len;
 };
 
-static int anonymized_entry_cmp(const void *unused_cmp_data,
+static int anonymized_entry_cmp(const void *UNUSED(cmp_data),
 				const struct hashmap_entry *eptr,
 				const struct hashmap_entry *entry_or_key,
 				const void *keydata)
diff --git a/builtin/fast-import.c b/builtin/fast-import.c
index 14113cfd82..76ed0c2db9 100644
--- a/builtin/fast-import.c
+++ b/builtin/fast-import.c
@@ -46,7 +46,7 @@ struct object_entry {
 		depth : DEPTH_BITS;
 };
 
-static int object_entry_hashcmp(const void *map_data,
+static int object_entry_hashcmp(const void *UNUSED(map_data),
 				const struct hashmap_entry *eptr,
 				const struct hashmap_entry *entry_or_key,
 				const void *keydata)
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 368a0f5329..a07692599c 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -301,7 +301,7 @@ struct refname_hash_entry {
 	char refname[FLEX_ARRAY];
 };
 
-static int refname_hash_entry_cmp(const void *hashmap_cmp_fn_data,
+static int refname_hash_entry_cmp(const void *UNUSED(hashmap_cmp_fn_data),
 				  const struct hashmap_entry *eptr,
 				  const struct hashmap_entry *entry_or_key,
 				  const void *keydata)
@@ -329,7 +329,7 @@ static struct refname_hash_entry *refname_hash_add(struct hashmap *map,
 
 static int add_one_refname(const char *refname,
 			   const struct object_id *oid,
-			   int flag, void *cbdata)
+			   int UNUSED(flag), void *cbdata)
 {
 	struct hashmap *refname_map = cbdata;
 
@@ -1464,8 +1464,9 @@ static void set_option(struct transport *transport, const char *name, const char
 }
 
 
-static int add_oid(const char *refname, const struct object_id *oid, int flags,
-		   void *cb_data)
+static int add_oid(const char *UNUSED(refname),
+		   const struct object_id *oid,
+		   int UNUSED(flags), void *cb_data)
 {
 	struct oid_array *oids = cb_data;
 
diff --git a/builtin/fsck.c b/builtin/fsck.c
index 6c73092f10..31d3da8954 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -488,8 +488,9 @@ static void fsck_handle_reflog_oid(const char *refname, struct object_id *oid,
 }
 
 static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid,
-		const char *email, timestamp_t timestamp, int tz,
-		const char *message, void *cb_data)
+				  const char *UNUSED(email),
+				  timestamp_t timestamp, int UNUSED(tz),
+				  const char *UNUSED(message), void *cb_data)
 {
 	const char *refname = cb_data;
 
@@ -502,8 +503,9 @@ static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid
 	return 0;
 }
 
-static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
-			      int flag, void *cb_data)
+static int fsck_handle_reflog(const char *logname,
+			      const struct object_id *UNUSED(oid),
+			      int UNUSED(flag), void *cb_data)
 {
 	struct strbuf refname = STRBUF_INIT;
 
@@ -514,7 +516,7 @@ static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
 }
 
 static int fsck_handle_ref(const char *refname, const struct object_id *oid,
-			   int flag, void *cb_data)
+			   int UNUSED(flag), void *UNUSED(cb_data))
 {
 	struct object *obj;
 
diff --git a/builtin/gc.c b/builtin/gc.c
index 48eeb2d260..c3c2780c2e 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -782,8 +782,9 @@ struct cg_auto_data {
 	int limit;
 };
 
-static int dfs_on_ref(const char *refname,
-		      const struct object_id *oid, int flags,
+static int dfs_on_ref(const char *UNUSED(refname),
+		      const struct object_id *oid,
+		      int UNUSED(flags),
 		      void *cb_data)
 {
 	struct cg_auto_data *data = (struct cg_auto_data *)cb_data;
diff --git a/builtin/log.c b/builtin/log.c
index 047f9e5278..0a3f2fca28 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -698,9 +698,10 @@ static int show_tag_object(const struct object_id *oid, struct rev_info *rev)
 	return 0;
 }
 
-static int show_tree_object(const struct object_id *oid,
-		struct strbuf *base,
-		const char *pathname, unsigned mode, void *context)
+static int show_tree_object(const struct object_id *UNUSED(oid),
+			    struct strbuf *UNUSED(base),
+			    const char *pathname, unsigned mode,
+			    void *context)
 {
 	FILE *file = context;
 	fprintf(file, "%s%s\n", pathname, S_ISDIR(mode) ? "/" : "");
diff --git a/builtin/ls-tree.c b/builtin/ls-tree.c
index e279be8bb6..48df337605 100644
--- a/builtin/ls-tree.c
+++ b/builtin/ls-tree.c
@@ -142,7 +142,7 @@ static int show_recursive(const char *base, size_t baselen, const char *pathname
 }
 
 static int show_tree_fmt(const struct object_id *oid, struct strbuf *base,
-			 const char *pathname, unsigned mode, void *context)
+			 const char *pathname, unsigned mode, void *UNUSED(context))
 {
 	size_t baselen;
 	int recurse = 0;
@@ -213,7 +213,7 @@ static void show_tree_common_default_long(struct strbuf *base,
 
 static int show_tree_default(const struct object_id *oid, struct strbuf *base,
 			     const char *pathname, unsigned mode,
-			     void *context)
+			     void *UNUSED(context))
 {
 	int early;
 	int recurse;
@@ -230,7 +230,8 @@ static int show_tree_default(const struct object_id *oid, struct strbuf *base,
 }
 
 static int show_tree_long(const struct object_id *oid, struct strbuf *base,
-			  const char *pathname, unsigned mode, void *context)
+			  const char *pathname, unsigned mode,
+			  void *UNUSED(context))
 {
 	int early;
 	int recurse;
@@ -259,7 +260,8 @@ static int show_tree_long(const struct object_id *oid, struct strbuf *base,
 }
 
 static int show_tree_name_only(const struct object_id *oid, struct strbuf *base,
-			       const char *pathname, unsigned mode, void *context)
+			       const char *pathname, unsigned mode,
+			       void *UNUSED(context))
 {
 	int early;
 	int recurse;
@@ -279,7 +281,8 @@ static int show_tree_name_only(const struct object_id *oid, struct strbuf *base,
 }
 
 static int show_tree_object(const struct object_id *oid, struct strbuf *base,
-			    const char *pathname, unsigned mode, void *context)
+			    const char *pathname, unsigned mode,
+			    void *UNUSED(context))
 {
 	int early;
 	int recurse;
diff --git a/builtin/multi-pack-index.c b/builtin/multi-pack-index.c
index 3bfad9149d..f1b1c77741 100644
--- a/builtin/multi-pack-index.c
+++ b/builtin/multi-pack-index.c
@@ -78,7 +78,7 @@ static struct option *add_common_options(struct option *prev)
 }
 
 static int git_multi_pack_index_write_config(const char *var, const char *value,
-					     void *cb)
+					     void *UNUSED(cb))
 {
 	if (!strcmp(var, "pack.writebitmaphashcache")) {
 		if (git_config_bool(var, value))
diff --git a/builtin/name-rev.c b/builtin/name-rev.c
index 580b1eb170..c4dc143c4b 100644
--- a/builtin/name-rev.c
+++ b/builtin/name-rev.c
@@ -344,7 +344,8 @@ static int cmp_by_tag_and_age(const void *a_, const void *b_)
 	return a->taggerdate != b->taggerdate;
 }
 
-static int name_ref(const char *path, const struct object_id *oid, int flags, void *cb_data)
+static int name_ref(const char *path, const struct object_id *oid,
+		    int UNUSED(flags), void *cb_data)
 {
 	struct object *o = parse_object(the_repository, oid);
 	struct name_ref_data *data = cb_data;
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 46e2677496..bf3df7200f 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -759,8 +759,8 @@ static enum write_one_status write_one(struct hashfile *f,
 	return WRITE_ONE_WRITTEN;
 }
 
-static int mark_tagged(const char *path, const struct object_id *oid, int flag,
-		       void *cb_data)
+static int mark_tagged(const char *UNUSED(path), const struct object_id *oid,
+		       int UNUSED(flag), void *UNUSED(cb_data))
 {
 	struct object_id peeled;
 	struct object_entry *entry = packlist_find(&to_pack, oid);
@@ -3035,7 +3035,8 @@ static void add_tag_chain(const struct object_id *oid)
 	}
 }
 
-static int add_ref_tag(const char *tag, const struct object_id *oid, int flag, void *cb_data)
+static int add_ref_tag(const char *UNUSED(tag), const struct object_id *oid,
+		       int UNUSED(flag), void *UNUSED(cb_data))
 {
 	struct object_id peeled;
 
@@ -3958,8 +3959,9 @@ static void record_recent_commit(struct commit *commit, void *data)
 }
 
 static int mark_bitmap_preferred_tip(const char *refname,
-				     const struct object_id *oid, int flags,
-				     void *_data)
+				     const struct object_id *oid,
+				     int UNUSED(flags),
+				     void *UNUSED(data))
 {
 	struct object_id peeled;
 	struct object *object;
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 31b48e728b..6882d526e6 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -291,7 +291,7 @@ static void show_ref(const char *path, const struct object_id *oid)
 }
 
 static int show_ref_cb(const char *path_full, const struct object_id *oid,
-		       int flag, void *data)
+		       int UNUSED(flag), void *data)
 {
 	struct oidset *seen = data;
 	const char *path = strip_namespace(path_full);
@@ -465,7 +465,7 @@ static void rp_error(const char *err, ...)
 	va_end(params);
 }
 
-static int copy_to_sideband(int in, int out, void *arg)
+static int copy_to_sideband(int in, int UNUSED(out), void *UNUSED(arg))
 {
 	char data[128];
 	int keepalive_active = 0;
diff --git a/builtin/reflog.c b/builtin/reflog.c
index 461c94f1b2..22c5b6b28c 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -56,7 +56,8 @@ struct worktree_reflogs {
 	struct string_list reflogs;
 };
 
-static int collect_reflog(const char *ref, const struct object_id *oid, int unused, void *cb_data)
+static int collect_reflog(const char *ref, const struct object_id *UNUSED(oid),
+			  int UNUSED(flags), void *cb_data)
 {
 	struct worktree_reflogs *cb = cb_data;
 	struct worktree *worktree = cb->worktree;
diff --git a/builtin/remote.c b/builtin/remote.c
index 07117e4c9a..3bde8cc760 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -264,7 +264,8 @@ static const char *abbrev_ref(const char *name, const char *prefix)
 }
 #define abbrev_branch(name) abbrev_ref((name), "refs/heads/")
 
-static int config_read_branches(const char *key, const char *value, void *cb)
+static int config_read_branches(const char *key, const char *value,
+				void *UNUSED(data))
 {
 	const char *orig_key = key;
 	char *name;
@@ -538,7 +539,8 @@ struct branches_for_remote {
 };
 
 static int add_branch_for_removal(const char *refname,
-	const struct object_id *oid, int flags, void *cb_data)
+				  const struct object_id *UNUSED(oid),
+				  int UNUSED(flags), void *cb_data)
 {
 	struct branches_for_remote *branches = cb_data;
 	struct refspec_item refspec;
@@ -580,7 +582,8 @@ struct rename_info {
 };
 
 static int read_remote_branches(const char *refname,
-	const struct object_id *oid, int flags, void *cb_data)
+				const struct object_id *UNUSED(oid),
+				int UNUSED(flags), void *cb_data)
 {
 	struct rename_info *rename = cb_data;
 	struct strbuf buf = STRBUF_INIT;
@@ -955,7 +958,8 @@ static void free_remote_ref_states(struct ref_states *states)
 }
 
 static int append_ref_to_tracked_list(const char *refname,
-	const struct object_id *oid, int flags, void *cb_data)
+				      const struct object_id *UNUSED(oid),
+				      int flags, void *cb_data)
 {
 	struct ref_states *states = cb_data;
 	struct refspec_item refspec;
@@ -1485,7 +1489,7 @@ static int prune(int argc, const char **argv, const char *prefix)
 	return result;
 }
 
-static int get_remote_default(const char *key, const char *value, void *priv)
+static int get_remote_default(const char *key, const char *UNUSED(value), void *priv)
 {
 	if (strcmp(key, "remotes.default") == 0) {
 		int *found = priv;
diff --git a/builtin/repack.c b/builtin/repack.c
index 482b66f57d..ff952dec48 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -514,9 +514,9 @@ struct midx_snapshot_ref_data {
 	int preferred;
 };
 
-static int midx_snapshot_ref_one(const char *refname,
+static int midx_snapshot_ref_one(const char *UNUSED(refname),
 				 const struct object_id *oid,
-				 int flag, void *_data)
+				 int UNUSED(flag), void *_data)
 {
 	struct midx_snapshot_ref_data *data = _data;
 	struct object_id peeled;
diff --git a/builtin/rev-parse.c b/builtin/rev-parse.c
index 85c271acd7..1310f9cec1 100644
--- a/builtin/rev-parse.c
+++ b/builtin/rev-parse.c
@@ -195,7 +195,8 @@ static int show_default(void)
 	return 0;
 }
 
-static int show_reference(const char *refname, const struct object_id *oid, int flag, void *cb_data)
+static int show_reference(const char *refname, const struct object_id *oid,
+			  int UNUSED(flag), void *UNUSED(cb_data))
 {
 	if (ref_excluded(ref_excludes, refname))
 		return 0;
@@ -203,7 +204,8 @@ static int show_reference(const char *refname, const struct object_id *oid, int
 	return 0;
 }
 
-static int anti_reference(const char *refname, const struct object_id *oid, int flag, void *cb_data)
+static int anti_reference(const char *refname, const struct object_id *oid,
+			  int UNUSED(flag), void *UNUSED(cb_data))
 {
 	show_rev(REVERSED, oid, refname);
 	return 0;
diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index 64c649c6a2..3ec011bea4 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -404,7 +404,7 @@ static int append_ref(const char *refname, const struct object_id *oid,
 }
 
 static int append_head_ref(const char *refname, const struct object_id *oid,
-			   int flag, void *cb_data)
+			   int UNUSED(flag), void *UNUSED(cb_data))
 {
 	struct object_id tmp;
 	int ofs = 11;
@@ -419,7 +419,7 @@ static int append_head_ref(const char *refname, const struct object_id *oid,
 }
 
 static int append_remote_ref(const char *refname, const struct object_id *oid,
-			     int flag, void *cb_data)
+			     int UNUSED(flag), void *UNUSED(cb_data))
 {
 	struct object_id tmp;
 	int ofs = 13;
@@ -434,7 +434,7 @@ static int append_remote_ref(const char *refname, const struct object_id *oid,
 }
 
 static int append_tag_ref(const char *refname, const struct object_id *oid,
-			  int flag, void *cb_data)
+			  int UNUSED(flag), void *UNUSED(cb_data))
 {
 	if (!starts_with(refname, "refs/tags/"))
 		return 0;
diff --git a/builtin/show-ref.c b/builtin/show-ref.c
index 5fa207a044..9746537220 100644
--- a/builtin/show-ref.c
+++ b/builtin/show-ref.c
@@ -47,7 +47,7 @@ static void show_one(const char *refname, const struct object_id *oid)
 }
 
 static int show_ref(const char *refname, const struct object_id *oid,
-		    int flag, void *cbdata)
+		    int UNUSED(flag), void *UNUSED(cbdata))
 {
 	if (show_head && !strcmp(refname, "HEAD"))
 		goto match;
@@ -77,8 +77,9 @@ static int show_ref(const char *refname, const struct object_id *oid,
 	return 0;
 }
 
-static int add_existing(const char *refname, const struct object_id *oid,
-			int flag, void *cbdata)
+static int add_existing(const char *refname,
+			const struct object_id *UNUSED(oid),
+			int UNUSED(flag), void *cbdata)
 {
 	struct string_list *list = (struct string_list *)cbdata;
 	string_list_insert(list, refname);
diff --git a/builtin/stash.c b/builtin/stash.c
index 1ba24c1173..932c6173cf 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -638,9 +638,12 @@ static int apply_stash(int argc, const char **argv, const char *prefix)
 	return ret;
 }
 
-static int reject_reflog_ent(struct object_id *ooid, struct object_id *noid,
-			     const char *email, timestamp_t timestamp, int tz,
-			     const char *message, void *cb_data)
+static int reject_reflog_ent(struct object_id *UNUSED(ooid),
+			     struct object_id *UNUSED(noid),
+			     const char *UNUSED(email),
+			     timestamp_t UNUSED(timestamp),
+			     int UNUSED(tz), const char *UNUSED(message),
+			     void *UNUSED(cb_data))
 {
 	return 1;
 }
diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index c4149f11e7..72e38351ea 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -573,8 +573,9 @@ static void print_status(unsigned int flags, char state, const char *path,
 	printf("\n");
 }
 
-static int handle_submodule_head_ref(const char *refname,
-				     const struct object_id *oid, int flags,
+static int handle_submodule_head_ref(const char *UNUSED(refname),
+				     const struct object_id *oid,
+				     int UNUSED(flags),
 				     void *cb_data)
 {
 	struct object_id *output = cb_data;
diff --git a/color.c b/color.c
index 4f884c6b3d..04ad0a8bf7 100644
--- a/color.c
+++ b/color.c
@@ -415,7 +415,7 @@ int want_color_fd(int fd, int var)
 	return var;
 }
 
-int git_color_config(const char *var, const char *value, void *cb)
+int git_color_config(const char *var, const char *value, void *UNUSED(cb))
 {
 	if (!strcmp(var, "color.ui")) {
 		git_use_color_default = git_config_colorbool(var, value);
diff --git a/commit-graph.c b/commit-graph.c
index aef076e145..2257c333ba 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -1639,9 +1639,9 @@ struct refs_cb_data {
 	struct progress *progress;
 };
 
-static int add_ref_to_set(const char *refname,
+static int add_ref_to_set(const char *UNUSED(refname),
 			  const struct object_id *oid,
-			  int flags, void *cb_data)
+			  int UNUSED(flags), void *cb_data)
 {
 	struct object_id peeled;
 	struct refs_cb_data *data = (struct refs_cb_data *)cb_data;
diff --git a/commit.c b/commit.c
index 0db461f973..cb20082736 100644
--- a/commit.c
+++ b/commit.c
@@ -951,8 +951,9 @@ static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 }
 
 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
-				  const char *ident, timestamp_t timestamp,
-				  int tz, const char *message, void *cbdata)
+				  const char *UNUSED(ident),
+				  timestamp_t UNUSED(timestamp), int UNUSED(tz),
+				  const char *UNUSED(message), void *cbdata)
 {
 	struct rev_collect *revs = cbdata;
 
diff --git a/compat/terminal.c b/compat/terminal.c
index 7db330c52d..0b0caae857 100644
--- a/compat/terminal.c
+++ b/compat/terminal.c
@@ -477,7 +477,7 @@ struct escape_sequence_entry {
 	char sequence[FLEX_ARRAY];
 };
 
-static int sequence_entry_cmp(const void *hashmap_cmp_fn_data,
+static int sequence_entry_cmp(const void *UNUSED(hashmap_cmp_fn_data),
 			      const struct escape_sequence_entry *e1,
 			      const struct escape_sequence_entry *e2,
 			      const void *keydata)
diff --git a/config.c b/config.c
index e8ebef77d5..c92f1efd6b 100644
--- a/config.c
+++ b/config.c
@@ -362,7 +362,8 @@ static void populate_remote_urls(struct config_include_data *inc)
 	current_parsing_scope = store_scope;
 }
 
-static int forbid_remote_url(const char *var, const char *value, void *data)
+static int forbid_remote_url(const char *var, const char *UNUSED(value),
+			     void *UNUSED(data))
 {
 	const char *remote_name;
 	size_t remote_name_len;
@@ -2337,10 +2338,10 @@ static int configset_add_value(struct config_set *cs, const char *key, const cha
 	return 0;
 }
 
-static int config_set_element_cmp(const void *unused_cmp_data,
+static int config_set_element_cmp(const void *UNUSED(cmp_data),
 				  const struct hashmap_entry *eptr,
 				  const struct hashmap_entry *entry_or_key,
-				  const void *unused_keydata)
+				  const void *UNUSED(keydata))
 {
 	const struct config_set_element *e1, *e2;
 
diff --git a/convert.c b/convert.c
index 4d153729da..25d89fa83b 100644
--- a/convert.c
+++ b/convert.c
@@ -619,7 +619,7 @@ struct filter_params {
 	const char *path;
 };
 
-static int filter_buffer_or_fd(int in, int out, void *data)
+static int filter_buffer_or_fd(int UNUSED(in), int out, void *data)
 {
 	/*
 	 * Spawn cmd and feed the buffer contents through its stdin.
@@ -1008,7 +1008,7 @@ static int apply_filter(const char *path, const char *src, size_t len,
 	return 0;
 }
 
-static int read_convert_config(const char *var, const char *value, void *cb)
+static int read_convert_config(const char *var, const char *value, void *UNUSED(cb))
 {
 	const char *key, *name;
 	size_t namelen;
diff --git a/delta-islands.c b/delta-islands.c
index aa98b2e541..c64333f9de 100644
--- a/delta-islands.c
+++ b/delta-islands.c
@@ -316,7 +316,7 @@ static regex_t *island_regexes;
 static unsigned int island_regexes_alloc, island_regexes_nr;
 static const char *core_island_name;
 
-static int island_config_callback(const char *k, const char *v, void *cb)
+static int island_config_callback(const char *k, const char *v, void *UNUSED(cb))
 {
 	if (!strcmp(k, "pack.island")) {
 		struct strbuf re = STRBUF_INIT;
@@ -365,7 +365,7 @@ static void add_ref_to_island(const char *island_name, const struct object_id *o
 }
 
 static int find_island_for_ref(const char *refname, const struct object_id *oid,
-			       int flags, void *data)
+			       int UNUSED(flags), void *UNUSED(data))
 {
 	/*
 	 * We should advertise 'ARRAY_SIZE(matches) - 2' as the max,
diff --git a/diff.c b/diff.c
index dd68281ba4..0535dcbb2e 100644
--- a/diff.c
+++ b/diff.c
@@ -264,7 +264,8 @@ void init_diff_ui_defaults(void)
 	diff_detect_rename_default = DIFF_DETECT_RENAME;
 }
 
-int git_diff_heuristic_config(const char *var, const char *value, void *cb)
+int git_diff_heuristic_config(const char *var, const char *value,
+			      void *UNUSED(cb))
 {
 	if (!strcmp(var, "diff.indentheuristic"))
 		diff_indent_heuristic = git_config_bool(var, value);
@@ -916,7 +917,7 @@ struct interned_diff_symbol {
 static int interned_diff_symbol_cmp(const void *hashmap_cmp_fn_data,
 				    const struct hashmap_entry *eptr,
 				    const struct hashmap_entry *entry_or_key,
-				    const void *keydata)
+				    const void *UNUSED(keydata))
 {
 	const struct diff_options *diffopt = hashmap_cmp_fn_data;
 	const struct emitted_diff_symbol *a, *b;
diff --git a/dir.c b/dir.c
index 50eeb8b11e..e8b225eed4 100644
--- a/dir.c
+++ b/dir.c
@@ -655,10 +655,10 @@ void parse_path_pattern(const char **pattern,
 	*patternlen = len;
 }
 
-int pl_hashmap_cmp(const void *unused_cmp_data,
+int pl_hashmap_cmp(const void *UNUSED(cmp_data),
 		   const struct hashmap_entry *a,
 		   const struct hashmap_entry *b,
-		   const void *key)
+		   const void *UNUSED(key))
 {
 	const struct pattern_entry *ee1 =
 			container_of(a, struct pattern_entry, ent);
diff --git a/environment.c b/environment.c
index b2004437dc..e5c65b24c4 100644
--- a/environment.c
+++ b/environment.c
@@ -334,10 +334,10 @@ static void set_git_dir_1(const char *path)
 	setup_git_env(path);
 }
 
-static void update_relative_gitdir(const char *name,
+static void update_relative_gitdir(const char *UNUSED(name),
 				   const char *old_cwd,
 				   const char *new_cwd,
-				   void *data)
+				   void *UNUSED(data))
 {
 	char *path = reparent_relative_path(old_cwd, new_cwd, get_git_dir());
 	struct tmp_objdir *tmp_objdir = tmp_objdir_unapply_primary_odb();
diff --git a/fetch-pack.c b/fetch-pack.c
index a1a508ee72..2e98863f81 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -176,8 +176,10 @@ static int rev_list_insert_ref(struct fetch_negotiator *negotiator,
 	return 0;
 }
 
-static int rev_list_insert_ref_oid(const char *refname, const struct object_id *oid,
-				   int flag, void *cb_data)
+static int rev_list_insert_ref_oid(const char *UNUSED(refname),
+				   const struct object_id *oid,
+				   int UNUSED(flag),
+				   void *cb_data)
 {
 	return rev_list_insert_ref(cb_data, oid);
 }
@@ -600,8 +602,10 @@ static int mark_complete(const struct object_id *oid)
 	return 0;
 }
 
-static int mark_complete_oid(const char *refname, const struct object_id *oid,
-			     int flag, void *cb_data)
+static int mark_complete_oid(const char *UNUSED(refname),
+			     const struct object_id *oid,
+			     int UNUSED(flag),
+			     void *UNUSED(cb_data))
 {
 	return mark_complete(oid);
 }
@@ -839,7 +843,7 @@ static int everything_local(struct fetch_pack_args *args,
 	return retval;
 }
 
-static int sideband_demux(int in, int out, void *data)
+static int sideband_demux(int UNUSED(in), int out, void *data)
 {
 	int *xd = data;
 	int ret;
diff --git a/git-compat-util.h b/git-compat-util.h
index 7ebae122d4..bfa5b619c1 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -189,6 +189,12 @@ struct strbuf;
 #define _NETBSD_SOURCE 1
 #define _SGI_SOURCE 1
 
+#if defined(__GNUC__)
+#define UNUSED(var) UNUSED_##var __attribute__((unused))
+#else
+#define UNUSED(var) UNUSED_##var
+#endif
+
 #if defined(WIN32) && !defined(__CYGWIN__) /* Both MinGW and MSVC */
 # if !defined(_WIN32_WINNT)
 #  define _WIN32_WINNT 0x0600
@@ -398,7 +404,9 @@ typedef uintmax_t timestamp_t;
 #endif
 
 #ifndef platform_core_config
-static inline int noop_core_config(const char *var, const char *value, void *cb)
+static inline int noop_core_config(const char *UNUSED(var),
+				   const char *UNUSED(value),
+				   void *UNUSED(cb))
 {
 	return 0;
 }
@@ -491,7 +499,8 @@ static inline void extract_id_from_env(const char *env, uid_t *id)
 	}
 }
 
-static inline int is_path_owned_by_current_uid(const char *path, struct strbuf *report)
+static inline int is_path_owned_by_current_uid(const char *path,
+					       struct strbuf *UNUSED(report))
 {
 	struct stat st;
 	uid_t euid;
diff --git a/gpg-interface.c b/gpg-interface.c
index 6dff241460..721d69bf42 100644
--- a/gpg-interface.c
+++ b/gpg-interface.c
@@ -699,7 +699,7 @@ void set_signing_key(const char *key)
 	configured_signing_key = xstrdup(key);
 }
 
-int git_gpg_config(const char *var, const char *value, void *cb)
+int git_gpg_config(const char *var, const char *value, void *UNUSED(cb))
 {
 	struct gpg_format *fmt = NULL;
 	char *fmtname = NULL;
diff --git a/hashmap.c b/hashmap.c
index 134d2eec80..763aa1d8a3 100644
--- a/hashmap.c
+++ b/hashmap.c
@@ -142,10 +142,10 @@ static inline struct hashmap_entry **find_entry_ptr(const struct hashmap *map,
 	return e;
 }
 
-static int always_equal(const void *unused_cmp_data,
-			const struct hashmap_entry *unused1,
-			const struct hashmap_entry *unused2,
-			const void *unused_keydata)
+static int always_equal(const void *UNUSED(cmp_data),
+			const struct hashmap_entry *UNUSED(entry1),
+			const struct hashmap_entry *UNUSED(entry2),
+			const void *UNUSED(keydata))
 {
 	return 0;
 }
@@ -313,7 +313,7 @@ struct pool_entry {
 	unsigned char data[FLEX_ARRAY];
 };
 
-static int pool_entry_cmp(const void *unused_cmp_data,
+static int pool_entry_cmp(const void *UNUSED(cmp_data),
 			  const struct hashmap_entry *eptr,
 			  const struct hashmap_entry *entry_or_key,
 			  const void *keydata)
diff --git a/help.c b/help.c
index 991e33f8a6..c5b5848188 100644
--- a/help.c
+++ b/help.c
@@ -781,8 +781,9 @@ struct similar_ref_cb {
 	struct string_list *similar_refs;
 };
 
-static int append_similar_ref(const char *refname, const struct object_id *oid,
-			      int flags, void *cb_data)
+static int append_similar_ref(const char *refname,
+			      const struct object_id *UNUSED(oid),
+			      int UNUSED(flags), void *cb_data)
 {
 	struct similar_ref_cb *cb = (struct similar_ref_cb *)(cb_data);
 	char *branch = strrchr(refname, '/') + 1;
diff --git a/http-backend.c b/http-backend.c
index 58b83a9f66..20db0ea620 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -505,7 +505,7 @@ static void run_service(const char **argv, int buffer_input)
 }
 
 static int show_text_ref(const char *name, const struct object_id *oid,
-			 int flag, void *cb_data)
+			 int UNUSED(flag), void *cb_data)
 {
 	const char *name_nons = strip_namespace(name);
 	struct strbuf *buf = cb_data;
diff --git a/ident.c b/ident.c
index 7f66beda42..48745a1f0e 100644
--- a/ident.c
+++ b/ident.c
@@ -668,7 +668,7 @@ static int set_ident(const char *var, const char *value)
 	return 0;
 }
 
-int git_ident_config(const char *var, const char *value, void *data)
+int git_ident_config(const char *var, const char *value, void *UNUSED(data))
 {
 	if (!strcmp(var, "user.useconfigonly")) {
 		ident_use_config_only = git_config_bool(var, value);
diff --git a/ll-merge.c b/ll-merge.c
index 14b8362019..9f3ae1f8fe 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -249,7 +249,8 @@ static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
 static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
 static const char *default_ll_merge;
 
-static int read_merge_config(const char *var, const char *value, void *cb)
+static int read_merge_config(const char *var, const char *value,
+			     void *UNUSED(cb))
 {
 	struct ll_merge_driver *fn;
 	const char *key, *name;
diff --git a/log-tree.c b/log-tree.c
index 3e8c70ddcf..6b93870279 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -135,7 +135,8 @@ static int ref_filter_match(const char *refname,
 }
 
 static int add_ref_decoration(const char *refname, const struct object_id *oid,
-			      int flags, void *cb_data)
+			      int UNUSED(flags),
+			      void *cb_data)
 {
 	int i;
 	struct object *obj;
diff --git a/ls-refs.c b/ls-refs.c
index 98e69373c8..e54b883e87 100644
--- a/ls-refs.c
+++ b/ls-refs.c
@@ -136,7 +136,8 @@ static void send_possibly_unborn_head(struct ls_refs_data *data)
 	strbuf_release(&namespaced);
 }
 
-static int ls_refs_config(const char *var, const char *value, void *data)
+static int ls_refs_config(const char *var, const char *value,
+			  void *UNUSED(data))
 {
 	/*
 	 * We only serve fetches over v2 for now, so respect only "uploadpack"
diff --git a/merge-recursive.c b/merge-recursive.c
index b83a129b43..08c1c36d33 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -45,7 +45,7 @@ struct path_hashmap_entry {
 	char path[FLEX_ARRAY];
 };
 
-static int path_hashmap_cmp(const void *cmp_data,
+static int path_hashmap_cmp(const void *UNUSED(cmp_data),
 			    const struct hashmap_entry *eptr,
 			    const struct hashmap_entry *entry_or_key,
 			    const void *keydata)
@@ -89,10 +89,10 @@ static struct dir_rename_entry *dir_rename_find_entry(struct hashmap *hashmap,
 	return hashmap_get_entry(hashmap, &key, ent, NULL);
 }
 
-static int dir_rename_cmp(const void *unused_cmp_data,
+static int dir_rename_cmp(const void *UNUSED(cmp_data),
 			  const struct hashmap_entry *eptr,
 			  const struct hashmap_entry *entry_or_key,
-			  const void *unused_keydata)
+			  const void *UNUSED(keydata))
 {
 	const struct dir_rename_entry *e1, *e2;
 
@@ -134,10 +134,10 @@ static struct collision_entry *collision_find_entry(struct hashmap *hashmap,
 	return hashmap_get_entry(hashmap, &key, ent, NULL);
 }
 
-static int collision_cmp(const void *unused_cmp_data,
+static int collision_cmp(const void *UNUSED(cmp_data),
 			 const struct hashmap_entry *eptr,
 			 const struct hashmap_entry *entry_or_key,
-			 const void *unused_keydata)
+			 const void *UNUSED(keydata))
 {
 	const struct collision_entry *e1, *e2;
 
@@ -456,7 +456,7 @@ static void unpack_trees_finish(struct merge_options *opt)
 	clear_unpack_trees_porcelain(&opt->priv->unpack_opts);
 }
 
-static int save_files_dirs(const struct object_id *oid,
+static int save_files_dirs(const struct object_id *UNUSED(oid),
 			   struct strbuf *base, const char *path,
 			   unsigned int mode, void *context)
 {
diff --git a/name-hash.c b/name-hash.c
index 7487d33124..d0da6db564 100644
--- a/name-hash.c
+++ b/name-hash.c
@@ -18,7 +18,7 @@ struct dir_entry {
 	char name[FLEX_ARRAY];
 };
 
-static int dir_entry_cmp(const void *unused_cmp_data,
+static int dir_entry_cmp(const void *UNUSED(cmp_data),
 			 const struct hashmap_entry *eptr,
 			 const struct hashmap_entry *entry_or_key,
 			 const void *keydata)
@@ -120,7 +120,7 @@ static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
 		add_dir_entry(istate, ce);
 }
 
-static int cache_entry_cmp(const void *unused_cmp_data,
+static int cache_entry_cmp(const void *UNUSED(cmp_data),
 			   const struct hashmap_entry *eptr,
 			   const struct hashmap_entry *entry_or_key,
 			   const void *remove)
diff --git a/negotiator/default.c b/negotiator/default.c
index 434189ae5d..10f0a46e62 100644
--- a/negotiator/default.c
+++ b/negotiator/default.c
@@ -36,7 +36,8 @@ static void rev_list_push(struct negotiation_state *ns,
 }
 
 static int clear_marks(const char *refname, const struct object_id *oid,
-		       int flag, void *cb_data)
+		       int UNUSED(flag),
+		       void *UNUSED(cb_data))
 {
 	struct object *o = deref_tag(the_repository, parse_object(the_repository, oid), refname, 0);
 
diff --git a/negotiator/skipping.c b/negotiator/skipping.c
index 1236e79224..f2aa58af92 100644
--- a/negotiator/skipping.c
+++ b/negotiator/skipping.c
@@ -72,7 +72,8 @@ static struct entry *rev_list_push(struct data *data, struct commit *commit, int
 }
 
 static int clear_marks(const char *refname, const struct object_id *oid,
-		       int flag, void *cb_data)
+		       int UNUSED(flag),
+		       void *UNUSED(cb_data))
 {
 	struct object *o = deref_tag(the_repository, parse_object(the_repository, oid), refname, 0);
 
diff --git a/notes.c b/notes.c
index 7bade6d8f6..5ddfa70aa4 100644
--- a/notes.c
+++ b/notes.c
@@ -924,8 +924,9 @@ int combine_notes_cat_sort_uniq(struct object_id *cur_oid,
 	return ret;
 }
 
-static int string_list_add_one_ref(const char *refname, const struct object_id *oid,
-				   int flag, void *cb)
+static int string_list_add_one_ref(const char *refname,
+				   const struct object_id *UNUSED(oid),
+				   int UNUSED(flag), void *cb)
 {
 	struct string_list *refs = cb;
 	if (!unsorted_string_list_has_string(refs, refname))
diff --git a/object-name.c b/object-name.c
index 4d2746574c..3f7fce8322 100644
--- a/object-name.c
+++ b/object-name.c
@@ -1306,7 +1306,8 @@ struct handle_one_ref_cb {
 };
 
 static int handle_one_ref(const char *path, const struct object_id *oid,
-			  int flag, void *cb_data)
+			  int UNUSED(flag),
+			  void *cb_data)
 {
 	struct handle_one_ref_cb *cb = cb_data;
 	struct commit_list **list = cb->list;
@@ -1384,8 +1385,11 @@ struct grab_nth_branch_switch_cbdata {
 	struct strbuf *sb;
 };
 
-static int grab_nth_branch_switch(struct object_id *ooid, struct object_id *noid,
-				  const char *email, timestamp_t timestamp, int tz,
+static int grab_nth_branch_switch(struct object_id *UNUSED(ooid),
+				  struct object_id *UNUSED(noid),
+				  const char *UNUSED(email),
+				  timestamp_t UNUSED(timestamp),
+				  int UNUSED(tz),
 				  const char *message, void *cb_data)
 {
 	struct grab_nth_branch_switch_cbdata *cb = cb_data;
diff --git a/object-store.h b/object-store.h
index 5222ee5460..cf5494af80 100644
--- a/object-store.h
+++ b/object-store.h
@@ -141,7 +141,7 @@ struct packed_git {
 
 struct multi_pack_index;
 
-static inline int pack_map_entry_cmp(const void *unused_cmp_data,
+static inline int pack_map_entry_cmp(const void *UNUSED(cmp_data),
 				     const struct hashmap_entry *entry,
 				     const struct hashmap_entry *entry2,
 				     const void *keydata)
diff --git a/oidmap.c b/oidmap.c
index 286a04a53c..32aeb0526f 100644
--- a/oidmap.c
+++ b/oidmap.c
@@ -1,7 +1,7 @@
 #include "cache.h"
 #include "oidmap.h"
 
-static int oidmap_neq(const void *hashmap_cmp_fn_data,
+static int oidmap_neq(const void *UNUSED(hashmap_cmp_fn_data),
 		      const struct hashmap_entry *e1,
 		      const struct hashmap_entry *e2,
 		      const void *keydata)
diff --git a/packfile.c b/packfile.c
index a41887c944..b7c5b28a03 100644
--- a/packfile.c
+++ b/packfile.c
@@ -1392,7 +1392,7 @@ static int delta_base_cache_key_eq(const struct delta_base_cache_key *a,
 	return a->p == b->p && a->base_offset == b->base_offset;
 }
 
-static int delta_base_cache_hash_cmp(const void *unused_cmp_data,
+static int delta_base_cache_hash_cmp(const void *UNUSED(cmp_data),
 				     const struct hashmap_entry *va,
 				     const struct hashmap_entry *vb,
 				     const void *vkey)
diff --git a/pager.c b/pager.c
index 5cfe23b025..19c016ff54 100644
--- a/pager.c
+++ b/pager.c
@@ -38,7 +38,8 @@ static void wait_for_pager_signal(int signo)
 	raise(signo);
 }
 
-static int core_pager_config(const char *var, const char *value, void *data)
+static int core_pager_config(const char *var, const char *value,
+			     void *UNUSED(data))
 {
 	if (!strcmp(var, "core.pager"))
 		return git_config_string(&pager_program, var, value);
diff --git a/patch-ids.c b/patch-ids.c
index 8bf425555d..cdfa513549 100644
--- a/patch-ids.c
+++ b/patch-ids.c
@@ -38,7 +38,7 @@ int commit_patch_id(struct commit *commit, struct diff_options *options,
 static int patch_id_neq(const void *cmpfn_data,
 			const struct hashmap_entry *eptr,
 			const struct hashmap_entry *entry_or_key,
-			const void *unused_keydata)
+			const void *UNUSED(keydata))
 {
 	/* NEEDSWORK: const correctness? */
 	struct diff_options *opt = (void *)cmpfn_data;
diff --git a/pretty.c b/pretty.c
index b7553e3fe0..9257b3400d 100644
--- a/pretty.c
+++ b/pretty.c
@@ -43,7 +43,8 @@ static void save_user_format(struct rev_info *rev, const char *cp, int is_tforma
 	rev->commit_format = CMIT_FMT_USERFORMAT;
 }
 
-static int git_pretty_formats_config(const char *var, const char *value, void *cb)
+static int git_pretty_formats_config(const char *var, const char *value,
+				     void *UNUSED(cb))
 {
 	struct cmt_fmt_map *commit_format = NULL;
 	const char *name;
diff --git a/range-diff.c b/range-diff.c
index 124dd678c3..c9e7787767 100644
--- a/range-diff.c
+++ b/range-diff.c
@@ -224,8 +224,10 @@ static int read_patches(const char *range, struct string_list *list,
 	return ret;
 }
 
-static int patch_util_cmp(const void *dummy, const struct patch_util *a,
-			  const struct patch_util *b, const char *keydata)
+static int patch_util_cmp(const void *UNUSED(cmp_data),
+			  const struct patch_util *a,
+			  const struct patch_util *b,
+			  const char *keydata)
 {
 	return strcmp(a->diff, keydata ? keydata : b->diff);
 }
diff --git a/ref-filter.c b/ref-filter.c
index bdf39fa761..baf252b77d 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -89,7 +89,7 @@ struct ref_to_worktree_entry {
 	struct worktree *wt; /* key is wt->head_ref */
 };
 
-static int ref_to_worktree_map_cmpfnc(const void *unused_lookupdata,
+static int ref_to_worktree_map_cmpfnc(const void *UNUSED(lookupdata),
 				      const struct hashmap_entry *eptr,
 				      const struct hashmap_entry *kptr,
 				      const void *keydata_aka_refname)
diff --git a/reflog.c b/reflog.c
index 135a1a6e41..56ea3ba762 100644
--- a/reflog.c
+++ b/reflog.c
@@ -240,8 +240,9 @@ static int unreachable(struct expire_reflog_policy_cb *cb, struct commit *commit
  * Return true iff the specified reflog entry should be expired.
  */
 int should_expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
-			     const char *email, timestamp_t timestamp, int tz,
-			     const char *message, void *cb_data)
+			     const char *UNUSED(email),
+			     timestamp_t timestamp, int UNUSED(tz),
+			     const char *UNUSED(message), void *cb_data)
 {
 	struct expire_reflog_policy_cb *cb = cb_data;
 	struct commit *old_commit, *new_commit;
@@ -294,7 +295,8 @@ int should_expire_reflog_ent_verbose(struct object_id *ooid,
 	return expire;
 }
 
-static int push_tip_to_list(const char *refname, const struct object_id *oid,
+static int push_tip_to_list(const char *UNUSED(refname),
+			    const struct object_id *oid,
 			    int flags, void *cb_data)
 {
 	struct commit_list **list = cb_data;
@@ -378,9 +380,11 @@ void reflog_expiry_cleanup(void *cb_data)
 	}
 }
 
-int count_reflog_ent(struct object_id *ooid, struct object_id *noid,
-		     const char *email, timestamp_t timestamp, int tz,
-		     const char *message, void *cb_data)
+int count_reflog_ent(struct object_id *UNUSED(ooid),
+		     struct object_id *UNUSED(noid),
+		     const char *UNUSED(email),
+		     timestamp_t timestamp, int UNUSED(tz),
+		     const char *UNUSED(message), void *cb_data)
 {
 	struct cmd_reflog_expire_cb *cb = cb_data;
 	if (!cb->expire_total || timestamp < cb->expire_total)
diff --git a/refs.c b/refs.c
index 92819732ab..607694c266 100644
--- a/refs.c
+++ b/refs.c
@@ -441,7 +441,8 @@ struct warn_if_dangling_data {
 	const char *msg_fmt;
 };
 
-static int warn_if_dangling_symref(const char *refname, const struct object_id *oid,
+static int warn_if_dangling_symref(const char *refname,
+				   const struct object_id *UNUSED(oid),
 				   int flags, void *cb_data)
 {
 	struct warn_if_dangling_data *d = cb_data;
@@ -981,8 +982,9 @@ static void set_read_ref_cutoffs(struct read_ref_at_cb *cb,
 }
 
 static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
-		const char *email, timestamp_t timestamp, int tz,
-		const char *message, void *cb_data)
+			   const char *UNUSED(email),
+			   timestamp_t timestamp, int tz,
+			   const char *message, void *cb_data)
 {
 	struct read_ref_at_cb *cb = cb_data;
 	int reached_count;
@@ -1022,9 +1024,11 @@ static int read_ref_at_ent(struct object_id *ooid, struct object_id *noid,
 	return cb->found_it;
 }
 
-static int read_ref_at_ent_newest(struct object_id *ooid, struct object_id *noid,
-				  const char *email, timestamp_t timestamp,
-				  int tz, const char *message, void *cb_data)
+static int read_ref_at_ent_newest(struct object_id *UNUSED(ooid),
+				  struct object_id *noid,
+				  const char *UNUSED(email),
+				  timestamp_t timestamp, int tz,
+				  const char *message, void *cb_data)
 {
 	struct read_ref_at_cb *cb = cb_data;
 
@@ -1035,8 +1039,9 @@ static int read_ref_at_ent_newest(struct object_id *ooid, struct object_id *noid
 }
 
 static int read_ref_at_ent_oldest(struct object_id *ooid, struct object_id *noid,
-				  const char *email, timestamp_t timestamp,
-				  int tz, const char *message, void *cb_data)
+				  const char *UNUSED(email),
+				  timestamp_t timestamp, int tz,
+				  const char *message, void *cb_data)
 {
 	struct read_ref_at_cb *cb = cb_data;
 
@@ -1899,7 +1904,7 @@ struct ref_store_hash_entry
 	char name[FLEX_ARRAY];
 };
 
-static int ref_store_hash_cmp(const void *unused_cmp_data,
+static int ref_store_hash_cmp(const void *UNUSED(cmp_data),
 			      const struct hashmap_entry *eptr,
 			      const struct hashmap_entry *entry_or_key,
 			      const void *keydata)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 8db7882aac..13bfdb7701 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -2202,8 +2202,8 @@ static int files_reflog_iterator_advance(struct ref_iterator *ref_iterator)
 	return ok;
 }
 
-static int files_reflog_iterator_peel(struct ref_iterator *ref_iterator,
-				      struct object_id *peeled)
+static int files_reflog_iterator_peel(struct ref_iterator *UNUSED(ref_iterator),
+				      struct object_id *UNUSED(peeled))
 {
 	BUG("ref_iterator_peel() called for reflog_iterator");
 }
@@ -2257,7 +2257,7 @@ static struct ref_iterator *reflog_iterator_begin(struct ref_store *ref_store,
 static enum iterator_selection reflog_iterator_select(
 	struct ref_iterator *iter_worktree,
 	struct ref_iterator *iter_common,
-	void *cb_data)
+	void *UNUSED(cb_data))
 {
 	if (iter_worktree) {
 		/*
@@ -2985,7 +2985,7 @@ static int files_transaction_finish(struct ref_store *ref_store,
 
 static int files_transaction_abort(struct ref_store *ref_store,
 				   struct ref_transaction *transaction,
-				   struct strbuf *err)
+				   struct strbuf *UNUSED(err))
 {
 	struct files_ref_store *refs =
 		files_downcast(ref_store, 0, "ref_transaction_abort");
@@ -2995,7 +2995,9 @@ static int files_transaction_abort(struct ref_store *ref_store,
 }
 
 static int ref_present(const char *refname,
-		       const struct object_id *oid, int flags, void *cb_data)
+		       const struct object_id *UNUSED(oid),
+		       int UNUSED(flags),
+		       void *cb_data)
 {
 	struct string_list *affected_refnames = cb_data;
 
@@ -3259,7 +3261,7 @@ static int files_reflog_expire(struct ref_store *ref_store,
 	return -1;
 }
 
-static int files_init_db(struct ref_store *ref_store, struct strbuf *err)
+static int files_init_db(struct ref_store *ref_store, struct strbuf *UNUSED(err))
 {
 	struct files_ref_store *refs =
 		files_downcast(ref_store, REF_STORE_WRITE, "init_db");
diff --git a/refs/iterator.c b/refs/iterator.c
index b2e56bae1c..e34921db72 100644
--- a/refs/iterator.c
+++ b/refs/iterator.c
@@ -51,8 +51,8 @@ static int empty_ref_iterator_advance(struct ref_iterator *ref_iterator)
 	return ref_iterator_abort(ref_iterator);
 }
 
-static int empty_ref_iterator_peel(struct ref_iterator *ref_iterator,
-				   struct object_id *peeled)
+static int empty_ref_iterator_peel(struct ref_iterator *UNUSED(ref_iterator),
+				   struct object_id *UNUSED(peeled))
 {
 	BUG("peel called for empty iterator");
 }
@@ -238,7 +238,7 @@ struct ref_iterator *merge_ref_iterator_begin(
  */
 static enum iterator_selection overlay_iterator_select(
 		struct ref_iterator *front, struct ref_iterator *back,
-		void *cb_data)
+		void *UNUSED(cb_data))
 {
 	int cmp;
 
diff --git a/refs/packed-backend.c b/refs/packed-backend.c
index 97b6837767..a45bb686f0 100644
--- a/refs/packed-backend.c
+++ b/refs/packed-backend.c
@@ -726,7 +726,7 @@ static struct snapshot *get_snapshot(struct packed_ref_store *refs)
 }
 
 static int packed_read_raw_ref(struct ref_store *ref_store, const char *refname,
-			       struct object_id *oid, struct strbuf *referent,
+			       struct object_id *oid, struct strbuf *UNUSED(referent),
 			       unsigned int *type, int *failure_errno)
 {
 	struct packed_ref_store *refs =
@@ -1078,7 +1078,8 @@ int packed_refs_is_locked(struct ref_store *ref_store)
 static const char PACKED_REFS_HEADER[] =
 	"# pack-refs with: peeled fully-peeled sorted \n";
 
-static int packed_init_db(struct ref_store *ref_store, struct strbuf *err)
+static int packed_init_db(struct ref_store *UNUSED(ref_store),
+			  struct strbuf *UNUSED(err))
 {
 	/* Nothing to do. */
 	return 0;
@@ -1473,7 +1474,7 @@ static int packed_transaction_prepare(struct ref_store *ref_store,
 
 static int packed_transaction_abort(struct ref_store *ref_store,
 				    struct ref_transaction *transaction,
-				    struct strbuf *err)
+				    struct strbuf *UNUSED(err))
 {
 	struct packed_ref_store *refs = packed_downcast(
 			ref_store,
@@ -1512,7 +1513,7 @@ static int packed_transaction_finish(struct ref_store *ref_store,
 	return ret;
 }
 
-static int packed_initial_transaction_commit(struct ref_store *ref_store,
+static int packed_initial_transaction_commit(struct ref_store *UNUSED(ref_store),
 					    struct ref_transaction *transaction,
 					    struct strbuf *err)
 {
@@ -1568,7 +1569,8 @@ static int packed_delete_refs(struct ref_store *ref_store, const char *msg,
 	return ret;
 }
 
-static int packed_pack_refs(struct ref_store *ref_store, unsigned int flags)
+static int packed_pack_refs(struct ref_store *UNUSED(ref_store),
+			    unsigned int UNUSED(flags))
 {
 	/*
 	 * Packed refs are already packed. It might be that loose refs
@@ -1578,7 +1580,7 @@ static int packed_pack_refs(struct ref_store *ref_store, unsigned int flags)
 	return 0;
 }
 
-static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *ref_store)
+static struct ref_iterator *packed_reflog_iterator_begin(struct ref_store *UNUSED(ref_store))
 {
 	return empty_ref_iterator_begin();
 }
diff --git a/remote.c b/remote.c
index 618ad5a0f1..ef12aba91d 100644
--- a/remote.c
+++ b/remote.c
@@ -86,7 +86,7 @@ struct remotes_hash_key {
 	int len;
 };
 
-static int remotes_hash_cmp(const void *unused_cmp_data,
+static int remotes_hash_cmp(const void *UNUSED(cmp_data),
 			    const struct hashmap_entry *eptr,
 			    const struct hashmap_entry *entry_or_key,
 			    const void *keydata)
@@ -170,7 +170,7 @@ struct branches_hash_key {
 	int len;
 };
 
-static int branches_hash_cmp(const void *unused_cmp_data,
+static int branches_hash_cmp(const void *UNUSED(cmp_data),
 			     const struct hashmap_entry *eptr,
 			     const struct hashmap_entry *entry_or_key,
 			     const void *keydata)
@@ -2320,7 +2320,8 @@ int format_tracking_info(struct branch *branch, struct strbuf *sb,
 }
 
 static int one_local_ref(const char *refname, const struct object_id *oid,
-			 int flag, void *cb_data)
+			 int UNUSED(flag),
+			 void *cb_data)
 {
 	struct ref ***local_tail = cb_data;
 	struct ref *ref;
@@ -2576,19 +2577,22 @@ struct check_and_collect_until_cb_data {
 };
 
 /* Get the timestamp of the latest entry. */
-static int peek_reflog(struct object_id *o_oid, struct object_id *n_oid,
-		       const char *ident, timestamp_t timestamp,
-		       int tz, const char *message, void *cb_data)
+static int peek_reflog(struct object_id *UNUSED(o_oid),
+		       struct object_id *UNUSED(n_oid),
+		       const char *UNUSED(ident),
+		       timestamp_t timestamp, int UNUSED(tz),
+		       const char *UNUSED(message), void *cb_data)
 {
 	timestamp_t *ts = cb_data;
 	*ts = timestamp;
 	return 1;
 }
 
-static int check_and_collect_until(struct object_id *o_oid,
+static int check_and_collect_until(struct object_id *UNUSED(o_oid),
 				   struct object_id *n_oid,
-				   const char *ident, timestamp_t timestamp,
-				   int tz, const char *message, void *cb_data)
+				   const char *UNUSED(ident),
+				   timestamp_t timestamp, int UNUSED(tz),
+				   const char *UNUSED(message), void *cb_data)
 {
 	struct commit *commit;
 	struct check_and_collect_until_cb_data *cb = cb_data;
diff --git a/replace-object.c b/replace-object.c
index 7bd9aba6ee..17810e5a3a 100644
--- a/replace-object.c
+++ b/replace-object.c
@@ -9,7 +9,8 @@
 static int register_replace_ref(struct repository *r,
 				const char *refname,
 				const struct object_id *oid,
-				int flag, void *cb_data)
+				int UNUSED(flag),
+				void *UNUSED(cb_data))
 {
 	/* Get sha1 from refname */
 	const char *slash = strrchr(refname, '/');
diff --git a/revision.c b/revision.c
index c516415c48..f19235dd18 100644
--- a/revision.c
+++ b/revision.c
@@ -119,10 +119,10 @@ struct path_and_oids_entry {
 	struct oidset trees;
 };
 
-static int path_and_oids_cmp(const void *hashmap_cmp_fn_data,
+static int path_and_oids_cmp(const void *UNUSED(hashmap_cmp_fn_data),
 			     const struct hashmap_entry *eptr,
 			     const struct hashmap_entry *entry_or_key,
-			     const void *keydata)
+			     const void *UNUSED(keydata))
 {
 	const struct path_and_oids_entry *e1, *e2;
 
@@ -1546,7 +1546,8 @@ int ref_excluded(struct string_list *ref_excludes, const char *path)
 }
 
 static int handle_one_ref(const char *path, const struct object_id *oid,
-			  int flag, void *cb_data)
+			  int UNUSED(flag),
+			  void *cb_data)
 {
 	struct all_refs_cb *cb = cb_data;
 	struct object *object;
@@ -1621,8 +1622,11 @@ static void handle_one_reflog_commit(struct object_id *oid, void *cb_data)
 }
 
 static int handle_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
-		const char *email, timestamp_t timestamp, int tz,
-		const char *message, void *cb_data)
+				 const char *UNUSED(email),
+				 timestamp_t UNUSED(timestamp),
+				 int UNUSED(tz),
+				 const char *UNUSED(message),
+				 void *cb_data)
 {
 	handle_one_reflog_commit(ooid, cb_data);
 	handle_one_reflog_commit(noid, cb_data);
@@ -1630,8 +1634,8 @@ static int handle_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
 }
 
 static int handle_one_reflog(const char *refname_in_wt,
-			     const struct object_id *oid,
-			     int flag, void *cb_data)
+			     const struct object_id *UNUSED(oid),
+			     int UNUSED(flag), void *cb_data)
 {
 	struct all_refs_cb *cb = cb_data;
 	struct strbuf refname = STRBUF_INIT;
diff --git a/send-pack.c b/send-pack.c
index 662f7c2aeb..7e99c64e6b 100644
--- a/send-pack.c
+++ b/send-pack.c
@@ -266,7 +266,7 @@ static int receive_status(struct packet_reader *reader, struct ref *refs)
 	return ret;
 }
 
-static int sideband_demux(int in, int out, void *data)
+static int sideband_demux(int UNUSED(in), int out, void *data)
 {
 	int *fd = data, ret;
 	if (async_with_fork())
diff --git a/sequencer.c b/sequencer.c
index 79dad522f5..34100c8f99 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -5254,7 +5254,8 @@ struct labels_entry {
 	char label[FLEX_ARRAY];
 };
 
-static int labels_cmp(const void *fndata, const struct hashmap_entry *eptr,
+static int labels_cmp(const void *UNUSED(fndata),
+		      const struct hashmap_entry *eptr,
 		      const struct hashmap_entry *entry_or_key, const void *key)
 {
 	const struct labels_entry *a, *b;
@@ -6131,7 +6132,7 @@ struct subject2item_entry {
 	char subject[FLEX_ARRAY];
 };
 
-static int subject2item_cmp(const void *fndata,
+static int subject2item_cmp(const void *UNUSED(fndata),
 			    const struct hashmap_entry *eptr,
 			    const struct hashmap_entry *entry_or_key,
 			    const void *key)
diff --git a/server-info.c b/server-info.c
index 7701d7c20a..d99d9d5f61 100644
--- a/server-info.c
+++ b/server-info.c
@@ -147,7 +147,8 @@ static int update_info_file(char *path,
 }
 
 static int add_info_ref(const char *path, const struct object_id *oid,
-			int flag, void *cb_data)
+			int UNUSED(flag),
+			void *cb_data)
 {
 	struct update_info_ctx *uic = cb_data;
 	struct object *o = parse_object(the_repository, oid);
diff --git a/shallow.c b/shallow.c
index 8cb768ee5f..71ab04f935 100644
--- a/shallow.c
+++ b/shallow.c
@@ -604,8 +604,10 @@ static void paint_down(struct paint_info *info, const struct object_id *oid,
 	free(tmp);
 }
 
-static int mark_uninteresting(const char *refname, const struct object_id *oid,
-			      int flags, void *cb_data)
+static int mark_uninteresting(const char *UNUSED(refname),
+			      const struct object_id *oid,
+			      int UNUSED(flags),
+			      void *UNUSED(cb_data))
 {
 	struct commit *commit = lookup_commit_reference_gently(the_repository,
 							       oid, 1);
@@ -715,8 +717,10 @@ struct commit_array {
 	int nr, alloc;
 };
 
-static int add_ref(const char *refname, const struct object_id *oid,
-		   int flags, void *cb_data)
+static int add_ref(const char *UNUSED(refname),
+		   const struct object_id *oid,
+		   int UNUSED(flags),
+		   void *cb_data)
 {
 	struct commit_array *ca = cb_data;
 	ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc);
diff --git a/streaming.c b/streaming.c
index fe54665d86..4b34e2a748 100644
--- a/streaming.c
+++ b/streaming.c
@@ -328,9 +328,9 @@ static int close_istream_pack_non_delta(struct git_istream *st)
 }
 
 static int open_istream_pack_non_delta(struct git_istream *st,
-				       struct repository *r,
-				       const struct object_id *oid,
-				       enum object_type *type)
+				       struct repository *UNUSED(r),
+				       const struct object_id *UNUSED(oid),
+				       enum object_type *UNUSED(type))
 {
 	struct pack_window *window;
 	enum object_type in_pack_type;
diff --git a/strmap.c b/strmap.c
index ee48635708..4e79734e4f 100644
--- a/strmap.c
+++ b/strmap.c
@@ -2,10 +2,10 @@
 #include "strmap.h"
 #include "mem-pool.h"
 
-int cmp_strmap_entry(const void *hashmap_cmp_fn_data,
+int cmp_strmap_entry(const void *UNUSED(hashmap_cmp_fn_data),
 		     const struct hashmap_entry *entry1,
 		     const struct hashmap_entry *entry2,
-		     const void *keydata)
+		     const void *UNUSED(keydata))
 {
 	const struct strmap_entry *e1, *e2;
 
diff --git a/sub-process.c b/sub-process.c
index cae56ae6b8..bd6a372a67 100644
--- a/sub-process.c
+++ b/sub-process.c
@@ -5,10 +5,10 @@
 #include "sigchain.h"
 #include "pkt-line.h"
 
-int cmd2process_cmp(const void *unused_cmp_data,
+int cmd2process_cmp(const void *UNUSED(cmp_data),
 		    const struct hashmap_entry *eptr,
 		    const struct hashmap_entry *entry_or_key,
-		    const void *unused_keydata)
+		    const void *UNUSED(keydata))
 {
 	const struct subprocess_entry *e1, *e2;
 
diff --git a/submodule-config.c b/submodule-config.c
index c2ac7e7bf3..d7a8ca0269 100644
--- a/submodule-config.c
+++ b/submodule-config.c
@@ -38,10 +38,10 @@ enum lookup_type {
 	lookup_path
 };
 
-static int config_path_cmp(const void *unused_cmp_data,
+static int config_path_cmp(const void *UNUSED(cmp_data),
 			   const struct hashmap_entry *eptr,
 			   const struct hashmap_entry *entry_or_key,
-			   const void *unused_keydata)
+			   const void *UNUSED(keydata))
 {
 	const struct submodule_entry *a, *b;
 
@@ -52,10 +52,10 @@ static int config_path_cmp(const void *unused_cmp_data,
 	       !oideq(&a->config->gitmodules_oid, &b->config->gitmodules_oid);
 }
 
-static int config_name_cmp(const void *unused_cmp_data,
+static int config_name_cmp(const void *UNUSED(cmp_data),
 			   const struct hashmap_entry *eptr,
 			   const struct hashmap_entry *entry_or_key,
-			   const void *unused_keydata)
+			   const void *UNUSED(keydata))
 {
 	const struct submodule_entry *a, *b;
 
diff --git a/submodule.c b/submodule.c
index 1ebda30c50..b41b9d1b78 100644
--- a/submodule.c
+++ b/submodule.c
@@ -213,7 +213,8 @@ void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 }
 
 /* Cheap function that only determines if we're interested in submodules at all */
-int git_default_submodule_config(const char *var, const char *value, void *cb)
+int git_default_submodule_config(const char *var, const char *value,
+				 void *UNUSED(cb))
 {
 	if (!strcmp(var, "submodule.recurse")) {
 		int v = git_config_bool(var, value) ?
@@ -938,8 +939,9 @@ static void free_submodules_data(struct string_list *submodules)
 	string_list_clear(submodules, 1);
 }
 
-static int has_remote(const char *refname, const struct object_id *oid,
-		      int flags, void *cb_data)
+static int has_remote(const char *UNUSED(refname),
+		      const struct object_id *UNUSED(oid),
+		      int UNUSED(flags), void *UNUSED(cb_data))
 {
 	return 1;
 }
@@ -1241,8 +1243,9 @@ int push_unpushed_submodules(struct repository *r,
 	return ret;
 }
 
-static int append_oid_to_array(const char *ref, const struct object_id *oid,
-			       int flags, void *data)
+static int append_oid_to_array(const char *UNUSED(ref),
+			       const struct object_id *oid,
+			       int UNUSED(flags), void *data)
 {
 	struct oid_array *array = data;
 	oid_array_append(array, oid);
diff --git a/t/helper/test-config.c b/t/helper/test-config.c
index a6e936721f..ddd538b838 100644
--- a/t/helper/test-config.c
+++ b/t/helper/test-config.c
@@ -37,7 +37,7 @@
  *
  */
 
-static int iterate_cb(const char *var, const char *value, void *data)
+static int iterate_cb(const char *var, const char *value, void *UNUSED(data))
 {
 	static int nr;
 
diff --git a/t/helper/test-ref-store.c b/t/helper/test-ref-store.c
index 4d18bfb1ca..8f930ad358 100644
--- a/t/helper/test-ref-store.c
+++ b/t/helper/test-ref-store.c
@@ -161,7 +161,7 @@ static int cmd_rename_ref(struct ref_store *refs, const char **argv)
 }
 
 static int each_ref(const char *refname, const struct object_id *oid,
-		    int flags, void *cb_data)
+		    int flags, void *UNUSED(cb_data))
 {
 	printf("%s %s 0x%x\n", oid_to_hex(oid), refname, flags);
 	return 0;
@@ -207,7 +207,7 @@ static int cmd_for_each_reflog(struct ref_store *refs, const char **argv)
 
 static int each_reflog(struct object_id *old_oid, struct object_id *new_oid,
 		       const char *committer, timestamp_t timestamp,
-		       int tz, const char *msg, void *cb_data)
+		       int tz, const char *msg, void *UNUSED(cb_data))
 {
 	printf("%s %s %s %" PRItime " %+05d%s%s", oid_to_hex(old_oid),
 	       oid_to_hex(new_oid), committer, timestamp, tz,
diff --git a/t/helper/test-userdiff.c b/t/helper/test-userdiff.c
index f013f8a31e..64538a0c20 100644
--- a/t/helper/test-userdiff.c
+++ b/t/helper/test-userdiff.c
@@ -12,7 +12,7 @@ static int driver_cb(struct userdiff_driver *driver,
 	return 0;
 }
 
-static int cmd__userdiff_config(const char *var, const char *value, void *cb)
+static int cmd__userdiff_config(const char *var, const char *value, void *UNUSED(cb))
 {
 	if (userdiff_config(var, value) < 0)
 		return -1;
diff --git a/trailer.c b/trailer.c
index d419c20735..a1e80478ab 100644
--- a/trailer.c
+++ b/trailer.c
@@ -478,7 +478,8 @@ static struct {
 	{ "ifmissing", TRAILER_IF_MISSING }
 };
 
-static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
+static int git_trailer_default_config(const char *conf_key, const char *value,
+				      void *UNUSED(cb))
 {
 	const char *trailer_item, *variable_name;
 
@@ -509,7 +510,8 @@ static int git_trailer_default_config(const char *conf_key, const char *value, v
 	return 0;
 }
 
-static int git_trailer_config(const char *conf_key, const char *value, void *cb)
+static int git_trailer_config(const char *conf_key, const char *value,
+			      void *UNUSED(cb))
 {
 	const char *trailer_item, *variable_name;
 	struct arg_item *item;
diff --git a/transport.c b/transport.c
index b51e991e44..551cad22dd 100644
--- a/transport.c
+++ b/transport.c
@@ -142,7 +142,7 @@ static void get_refs_from_bundle_inner(struct transport *transport)
 
 static struct ref *get_refs_from_bundle(struct transport *transport,
 					int for_push,
-					struct transport_ls_refs_options *transport_options)
+					struct transport_ls_refs_options *UNUSED(transport_options))
 {
 	struct bundle_transport_data *data = transport->data;
 	struct ref *result = NULL;
diff --git a/upload-pack.c b/upload-pack.c
index 35fe1a3dbb..6d04de1f74 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -1170,7 +1170,7 @@ static int mark_our_ref(const char *refname, const char *refname_full,
 }
 
 static int check_ref(const char *refname_full, const struct object_id *oid,
-		     int flag, void *cb_data)
+		     int UNUSED(flag), void *UNUSED(cb_data))
 {
 	const char *refname = strip_namespace(refname_full);
 
@@ -1194,7 +1194,7 @@ static void format_session_id(struct strbuf *buf, struct upload_pack_data *d) {
 }
 
 static int send_ref(const char *refname, const struct object_id *oid,
-		    int flag, void *cb_data)
+		    int UNUSED(flag), void *cb_data)
 {
 	static const char *capabilities = "multi_ack thin-pack side-band"
 		" side-band-64k ofs-delta shallow deepen-since deepen-not"
@@ -1236,7 +1236,8 @@ static int send_ref(const char *refname, const struct object_id *oid,
 	return 0;
 }
 
-static int find_symref(const char *refname, const struct object_id *oid,
+static int find_symref(const char *refname,
+		       const struct object_id *UNUSED(oid),
 		       int flag, void *cb_data)
 {
 	const char *symref_target;
diff --git a/walker.c b/walker.c
index c5e2921979..f945d021f8 100644
--- a/walker.c
+++ b/walker.c
@@ -215,8 +215,10 @@ static int interpret_target(struct walker *walker, char *target, struct object_i
 	return -1;
 }
 
-static int mark_complete(const char *path, const struct object_id *oid,
-			 int flag, void *cb_data)
+static int mark_complete(const char *UNUSED(path),
+			 const struct object_id *oid,
+			 int UNUSED(flag),
+			 void *UNUSED(cb_data))
 {
 	struct commit *commit = lookup_commit_reference_gently(the_repository,
 							       oid, 1);
diff --git a/wt-status.c b/wt-status.c
index 867e3e417e..38d0900aa9 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -947,9 +947,11 @@ static void wt_longstatus_print_changed(struct wt_status *s)
 	wt_longstatus_print_trailer(s);
 }
 
-static int stash_count_refs(struct object_id *ooid, struct object_id *noid,
-			    const char *email, timestamp_t timestamp, int tz,
-			    const char *message, void *cb_data)
+static int stash_count_refs(struct object_id *UNUSED(ooid),
+			    struct object_id *UNUSED(noid),
+			    const char *UNUSED(email),
+			    timestamp_t UNUSED(timestamp), int UNUSED(tz),
+			    const char *UNUSED(message), void *cb_data)
 {
 	int *c = cb_data;
 	(*c)++;
@@ -1612,8 +1614,10 @@ struct grab_1st_switch_cbdata {
 	struct object_id noid;
 };
 
-static int grab_1st_switch(struct object_id *ooid, struct object_id *noid,
-			   const char *email, timestamp_t timestamp, int tz,
+static int grab_1st_switch(struct object_id *UNUSED(ooid),
+			   struct object_id *noid,
+			   const char *UNUSED(email),
+			   timestamp_t UNUSED(timestamp), int UNUSED(tz),
 			   const char *message, void *cb_data)
 {
 	struct grab_1st_switch_cbdata *cb = cb_data;