diff --git a/Documentation/technical/api-merge.adoc b/Documentation/technical/api-merge.adoc
index c2ba01828c..b691599393 100644
--- a/Documentation/technical/api-merge.adoc
+++ b/Documentation/technical/api-merge.adoc
@@ -20,11 +20,10 @@ responsible for a few things.
 Data structures
 ---------------
 
-* `mmbuffer_t`, `mmfile_t`
+* `mmfile_t`
 
-These store data usable for use by the xdiff backend, for writing and
-for reading, respectively.  See `xdiff/xdiff.h` for the definitions
-and `diff.c` for examples.
+This stores a buffer and its size for input to or output from the xdiff
+backend. See `xdiff/xdiff.h` for the definition and `diff.c` for examples.
 
 * `struct ll_merge_options`
 
diff --git a/apply.c b/apply.c
index f00b7ba4d3..faf3c1dba0 100644
--- a/apply.c
+++ b/apply.c
@@ -3646,7 +3646,7 @@ static int three_way_merge(struct apply_state *state,
 {
 	mmfile_t base_file, our_file, their_file;
 	struct ll_merge_options merge_opts = LL_MERGE_OPTIONS_INIT;
-	mmbuffer_t result = { NULL };
+	mmfile_t result = { NULL };
 	enum ll_merge_result status;
 
 	/* resolve trivial cases first */
diff --git a/builtin/checkout.c b/builtin/checkout.c
index c0f0d2c700..2d575a4f57 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -320,7 +320,7 @@ static int checkout_merged(int pos, const struct checkout *state,
 	enum ll_merge_result merge_status;
 	int status;
 	struct object_id oid;
-	mmbuffer_t result_buf;
+	mmfile_t result_buf;
 	struct object_id threeway[3];
 	unsigned mode = 0;
 	struct ll_merge_options ll_opts = LL_MERGE_OPTIONS_INIT;
diff --git a/builtin/merge-file.c b/builtin/merge-file.c
index 8fa5765239..ddca408c46 100644
--- a/builtin/merge-file.c
+++ b/builtin/merge-file.c
@@ -64,7 +64,7 @@ int cmd_merge_file(int argc,
 {
 	const char *names[3] = { 0 };
 	mmfile_t mmfs[3] = { 0 };
-	mmbuffer_t result = { 0 };
+	mmfile_t result = { 0 };
 	xmparam_t xmp = { 0 };
 	int ret = 0, i = 0, to_stdout = 0, object_id = 0;
 	int quiet = 0;
diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
index 49f41e520f..552c2ad736 100644
--- a/builtin/merge-tree.c
+++ b/builtin/merge-tree.c
@@ -109,7 +109,7 @@ static void *origin(struct merge_list *entry, size_t *size)
 	return NULL;
 }
 
-static int show_outf(void *priv UNUSED, mmbuffer_t *mb, int nbuf)
+static int show_outf(void *priv UNUSED, mmfile_t *mb, int nbuf)
 {
 	int i;
 	for (i = 0; i < nbuf; i++)
diff --git a/builtin/rerere.c b/builtin/rerere.c
index d39c6e8445..ef03b79f5b 100644
--- a/builtin/rerere.c
+++ b/builtin/rerere.c
@@ -16,7 +16,7 @@ static const char * const rerere_usage[] = {
 	NULL,
 };
 
-static int outf(void *dummy UNUSED, mmbuffer_t *ptr, int nbuf)
+static int outf(void *dummy UNUSED, mmfile_t *ptr, int nbuf)
 {
 	int i;
 	for (i = 0; i < nbuf; i++)
diff --git a/merge-blobs.c b/merge-blobs.c
index 16a75bd1e3..49dbec9529 100644
--- a/merge-blobs.c
+++ b/merge-blobs.c
@@ -38,7 +38,7 @@ static void *three_way_filemerge(struct index_state *istate,
 				 size_t *size)
 {
 	enum ll_merge_result merge_status;
-	mmbuffer_t res;
+	mmfile_t res;
 
 	/*
 	 * This function is only used by cmd_merge_tree, which
diff --git a/merge-ll.c b/merge-ll.c
index ef5287dee8..dfed6411a8 100644
--- a/merge-ll.c
+++ b/merge-ll.c
@@ -21,7 +21,7 @@
 struct ll_merge_driver;
 
 typedef enum ll_merge_result (*ll_merge_fn)(const struct ll_merge_driver *,
-			   mmbuffer_t *result,
+			   mmfile_t *result,
 			   const char *path,
 			   mmfile_t *orig, const char *orig_name,
 			   mmfile_t *src1, const char *name1,
@@ -56,7 +56,7 @@ void reset_merge_attributes(void)
  * Built-in low-levels
  */
 static enum ll_merge_result ll_binary_merge(const struct ll_merge_driver *drv UNUSED,
-			   mmbuffer_t *result,
+			   mmfile_t *result,
 			   const char *path UNUSED,
 			   mmfile_t *orig, const char *orig_name UNUSED,
 			   mmfile_t *src1, const char *name1 UNUSED,
@@ -101,7 +101,7 @@ static enum ll_merge_result ll_binary_merge(const struct ll_merge_driver *drv UN
 }
 
 static enum ll_merge_result ll_xdl_merge(const struct ll_merge_driver *drv_unused,
-			mmbuffer_t *result,
+			mmfile_t *result,
 			const char *path,
 			mmfile_t *orig, const char *orig_name,
 			mmfile_t *src1, const char *name1,
@@ -147,7 +147,7 @@ static enum ll_merge_result ll_xdl_merge(const struct ll_merge_driver *drv_unuse
 }
 
 static enum ll_merge_result ll_union_merge(const struct ll_merge_driver *drv_unused,
-			  mmbuffer_t *result,
+			  mmfile_t *result,
 			  const char *path,
 			  mmfile_t *orig, const char *orig_name,
 			  mmfile_t *src1, const char *name1,
@@ -189,7 +189,7 @@ static void create_temp(mmfile_t *src, char *path, size_t len)
  * User defined low-level merge driver support.
  */
 static enum ll_merge_result ll_ext_merge(const struct ll_merge_driver *fn,
-			mmbuffer_t *result,
+			mmfile_t *result,
 			const char *path,
 			mmfile_t *orig, const char *orig_name,
 			mmfile_t *src1, const char *name1,
@@ -403,7 +403,7 @@ static void normalize_file(mmfile_t *mm, const char *path, struct index_state *i
 	}
 }
 
-enum ll_merge_result ll_merge(mmbuffer_t *result_buf,
+enum ll_merge_result ll_merge(mmfile_t *result_buf,
 	     const char *path,
 	     mmfile_t *ancestor, const char *ancestor_label,
 	     mmfile_t *ours, const char *our_label,
diff --git a/merge-ll.h b/merge-ll.h
index f26aef238d..f95332c682 100644
--- a/merge-ll.h
+++ b/merge-ll.h
@@ -16,7 +16,7 @@
  *   If you have no special requests, skip this and pass `NULL`
  *   as the `opts` parameter to use the default options.
  *
- * - Allocate an mmbuffer_t variable for the result.
+ * - Allocate an mmfile_t variable for the result.
  *
  * - Allocate and fill variables with the file's original content
  *   and two modified versions (using `read_mmfile`, for example).
@@ -100,7 +100,7 @@ enum ll_merge_result {
  * `.gitattributes` or `.git/info/attributes` into account.
  * Returns 0 for a clean merge.
  */
-enum ll_merge_result ll_merge(mmbuffer_t *result_buf,
+enum ll_merge_result ll_merge(mmfile_t *result_buf,
 	     const char *path,
 	     mmfile_t *ancestor, const char *ancestor_label,
 	     mmfile_t *ours, const char *our_label,
diff --git a/merge-ort.c b/merge-ort.c
index c410a5d353..1d3d193d35 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -2111,7 +2111,7 @@ static int merge_3way(struct merge_options *opt,
 		      const struct object_id *b,
 		      const char *pathnames[3],
 		      const int extra_marker_size,
-		      mmbuffer_t *result_buf)
+		      mmfile_t *result_buf)
 {
 	mmfile_t orig, src1, src2;
 	struct ll_merge_options ll_opts = LL_MERGE_OPTIONS_INIT;
@@ -2247,7 +2247,7 @@ static int handle_content_merge(struct merge_options *opt,
 
 	/* Remaining rules depend on file vs. submodule vs. symlink. */
 	else if (S_ISREG(a->mode)) {
-		mmbuffer_t result_buf;
+		mmfile_t result_buf;
 		int ret = 0, merge_status;
 		int two_way;
 
diff --git a/notes-merge.c b/notes-merge.c
index 118cad2518..d361e70a48 100644
--- a/notes-merge.c
+++ b/notes-merge.c
@@ -355,7 +355,7 @@ static void write_note_to_worktree(const struct object_id *obj,
 static int ll_merge_in_worktree(struct notes_merge_options *o,
 				struct notes_merge_pair *p)
 {
-	mmbuffer_t result_buf;
+	mmfile_t result_buf;
 	mmfile_t base, local, remote;
 	enum ll_merge_result status;
 
diff --git a/rerere.c b/rerere.c
index 856347c9ae..8696f8e7b7 100644
--- a/rerere.c
+++ b/rerere.c
@@ -597,7 +597,7 @@ int rerere_remaining(struct repository *r, struct string_list *merge_rr)
  */
 static int try_merge(struct index_state *istate,
 		     const struct rerere_id *id, const char *path,
-		     mmfile_t *cur, mmbuffer_t *result)
+		     mmfile_t *cur, mmfile_t *result)
 {
 	enum ll_merge_result ret;
 	mmfile_t base = {NULL, 0}, other = {NULL, 0};
@@ -638,7 +638,7 @@ static int merge(struct index_state *istate, const struct rerere_id *id, const c
 	int ret;
 	struct strbuf buf = STRBUF_INIT;
 	mmfile_t cur = {NULL, 0};
-	mmbuffer_t result = {NULL, 0};
+	mmfile_t result = {NULL, 0};
 
 	/*
 	 * Normalize the conflicts in path and write it out to
@@ -947,7 +947,7 @@ static int handle_cache(struct index_state *istate,
 			const char *path, unsigned char *hash, const char *output)
 {
 	mmfile_t mmfile[3] = {{NULL}};
-	mmbuffer_t result = {NULL, 0};
+	mmfile_t result = {NULL, 0};
 	const struct cache_entry *ce;
 	int pos, len, i, has_conflicts;
 	struct rerere_io_mem io;
@@ -1040,7 +1040,7 @@ static int rerere_forget_one_path(struct index_state *istate,
 	     id->variant < id->collection->status_nr;
 	     id->variant++) {
 		mmfile_t cur;
-		mmbuffer_t result = {NULL, 0};
+		mmfile_t result = {NULL, 0};
 		int cleanly_resolved;
 
 		if (!has_rerere_resolution(id))
diff --git a/xdiff-interface.c b/xdiff-interface.c
index e3dd2184ae..bc340d5a8a 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -53,7 +53,7 @@ static int consume_one(void *priv_, char *s, unsigned long size)
 	return 0;
 }
 
-static int xdiff_outf(void *priv_, mmbuffer_t *mb, int nbuf)
+static int xdiff_outf(void *priv_, mmfile_t *mb, int nbuf)
 {
 	struct xdiff_emit_state *priv = priv_;
 	int i;
diff --git a/xdiff/xdiff.h b/xdiff/xdiff.h
index dc370712e9..334eb436f6 100644
--- a/xdiff/xdiff.h
+++ b/xdiff/xdiff.h
@@ -73,11 +73,6 @@ typedef struct s_mmfile {
 	long size;
 } mmfile_t;
 
-typedef struct s_mmbuffer {
-	char *ptr;
-	long size;
-} mmbuffer_t;
-
 typedef struct s_xpparam {
 	unsigned long flags;
 
@@ -96,7 +91,7 @@ typedef struct s_xdemitcb {
 			long old_begin, long old_nr,
 			long new_begin, long new_nr,
 			const char *func, long funclen);
-	int (*out_line)(void *, mmbuffer_t *, int);
+	int (*out_line)(void *, mmfile_t *, int);
 } xdemitcb_t;
 
 typedef long (*find_func_t)(const char *line, long line_len, char *buffer, long buffer_size, void *priv);
@@ -144,7 +139,7 @@ typedef struct s_xmparam {
 #define DEFAULT_CONFLICT_MARKER_SIZE 7
 
 int xdl_merge(mmfile_t *orig, mmfile_t *mf1, mmfile_t *mf2,
-		xmparam_t const *xmp, mmbuffer_t *result);
+		xmparam_t const *xmp, mmfile_t *result);
 
 #ifdef __cplusplus
 }
diff --git a/xdiff/xmerge.c b/xdiff/xmerge.c
index 659ad4ec97..7b37968d25 100644
--- a/xdiff/xmerge.c
+++ b/xdiff/xmerge.c
@@ -504,7 +504,7 @@ static int xdl_simplify_non_conflicts(xdfenv_t *xe1, xdmerge_t *m,
  */
 static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1,
 		xdfenv_t *xe2, xdchange_t *xscr2,
-		xmparam_t const *xmp, mmbuffer_t *result)
+		xmparam_t const *xmp, mmfile_t *result)
 {
 	xdmerge_t *changes, *c;
 	xpparam_t const *xpp = &xmp->xpp;
@@ -682,7 +682,7 @@ static int xdl_do_merge(xdfenv_t *xe1, xdchange_t *xscr1,
 }
 
 int xdl_merge(mmfile_t *orig, mmfile_t *mf1, mmfile_t *mf2,
-		xmparam_t const *xmp, mmbuffer_t *result)
+		xmparam_t const *xmp, mmfile_t *result)
 {
 	xdchange_t *xscr1 = NULL, *xscr2 = NULL;
 	xdfenv_t xe1, xe2;
diff --git a/xdiff/xutils.c b/xdiff/xutils.c
index 9a999acdc0..4215f646c5 100644
--- a/xdiff/xutils.c
+++ b/xdiff/xutils.c
@@ -39,7 +39,7 @@ uint64_t xdl_bogosqrt(uint64_t n) {
 int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
 		     xdemitcb_t *ecb) {
 	int i = 2;
-	mmbuffer_t mb[3];
+	mmfile_t mb[3];
 
 	mb[0].ptr = (char *) pre;
 	mb[0].size = psize;
@@ -392,7 +392,7 @@ static int xdl_format_hunk_hdr(long s1, long c1, long s2, long c2,
 			       const char *func, long funclen,
 			       xdemitcb_t *ecb) {
 	int nb = 0;
-	mmbuffer_t mb;
+	mmfile_t mb;
 	char buf[128];
 
 	memcpy(buf, "@@ -", 4);