diff --git a/include/common/buffer.h b/include/common/buffer.h
index 18ced917b..2d657d1f9 100644
--- a/include/common/buffer.h
+++ b/include/common/buffer.h
@@ -228,29 +228,6 @@ static inline int buffer_contig_space(const struct buffer *buf)
 	return right - left;
 }
 
-/* Return the amount of bytes that can be written into the buffer at once,
- * excluding the amount of reserved space passed in <res>, which is
- * preserved.
- */
-static inline int buffer_contig_space_with_res(const struct buffer *buf, int res)
-{
-	/* Proceed differently if the buffer is full, partially used or empty.
-	 * The hard situation is when it's partially used and either data or
-	 * reserved space wraps at the end.
-	 */
-	int spare = buf->size - res;
-
-	if (buffer_len(buf) >= spare)
-		spare = 0;
-	else if (buffer_len(buf)) {
-		spare = buffer_contig_space(buf) - res;
-		if (spare < 0)
-			spare = 0;
-	}
-	return spare;
-}
-
-
 /* Normalizes a pointer which is supposed to be relative to the beginning of a
  * buffer, so that wrapping is correctly handled. The intent is to use this
  * when increasing a pointer. Note that the wrapping test is only performed
diff --git a/include/proto/channel.h b/include/proto/channel.h
index 36633c643..e323d340d 100644
--- a/include/proto/channel.h
+++ b/include/proto/channel.h
@@ -280,14 +280,6 @@ static inline int buffer_max_len(const struct channel *chn)
 	return chn->buf->size - buffer_reserved(chn);
 }
 
-/* Return the amount of bytes that can be written into the buffer at once,
- * excluding reserved space, which is preserved.
- */
-static inline int buffer_contig_space_res(const struct channel *chn)
-{
-	return buffer_contig_space_with_res(chn->buf, buffer_reserved(chn));
-}
-
 /* Returns the amount of space available at the input of the buffer, taking the
  * reserved space into account if ->to_forward indicates that an end of transfer
  * is close to happen. The test is optimized to avoid as many operations as