_php_stream_copy_to_stream_ex.patch

diff --git a/main/streams/streams.c b/main/streams/streams.c
index e1399927b2..a78b021870 100644
--- a/main/streams/streams.c
+++ b/main/streams/streams.c
@@ -1645,16 +1645,21 @@ PHPAPI zend_result _php_stream_copy_to_stream_ex(php_stream *src, php_stream *de
 	if (php_stream_mmap_possible(src)) {
 		char *p;
 
+		size_t mmap_max = PHP_STREAM_MMAP_MAX;
+		if (php_stream_is(dest, PHP_STREAM_IS_USERSPACE)) {
+			mmap_max = dest->chunk_size;
+		}
+
 		do {
 			/* We must not modify maxlen here, because otherwise the file copy fallback below can fail */
 			size_t chunk_size, must_read, mapped;
 			if (maxlen == 0) {
 				/* Unlimited read */
-				must_read = chunk_size = PHP_STREAM_MMAP_MAX;
+				must_read = chunk_size = mmap_max;
 			} else {
 				must_read = maxlen - haveread;
-				if (must_read >= PHP_STREAM_MMAP_MAX) {
-					chunk_size = PHP_STREAM_MMAP_MAX;
+				if (must_read >= mmap_max) {
+					chunk_size = mmap_max;
 				} else {
 					/* In case the length we still have to read from the file could be smaller than the file size,
 					 * chunk_size must not get bigger the size we're trying to read. */