Enforce USB read limits (Issue #5583)

CHANGES.md

@@ -1,21 +1,21 @@
-CHANGES - 2.3rc1 - 2019-05-15
+CHANGES - 2.3rc1 - 2019-05-17
 =============================
 
 
 Changes in CUPS v2.3rc1
 -----------------------
 
-- The `cups-config` script no longer puts non-CUPS libraries when they are not
-  needed (Issue #5261)
+- The `cups-config` script no longer adds extra libraries when linking against
+  shared libraries (Issue #5261)
 - The supplied example print documents have been optimized for size
   (Issue #5529)
 - The `cupsctl` command now prevents setting "cups-files.conf" directives
   (Issue #5530)
 - The "forbidden" message in the web interface is now explained (Issue #5547)
 - The footer in the web interface covered some content on small displays
   (Issue #5574)
-- The `cups-config` script no longer adds extra libraries when linking against
-  shared libraries (Issue #5261)
+- The libusb-based USB backend now enforces read limits, improving print speed
+  in many cases (Issue #5583)
 - The `ippeveprinter` command now looks for print commands in the "command"
   subdirectory.
 - The `ipptool` command now supports `$date-current` and `$date-start` variables

backend/usb-libusb.c

@@ -1,9 +1,10 @@
 /*
  * LIBUSB interface code for CUPS.
  *
- * Copyright 2007-2015 by Apple Inc.
+ * Copyright 2007-2019 by Apple Inc.
  *
- * Licensed under Apache License v2.0.  See the file "LICENSE" for more information.
+ * Licensed under Apache License v2.0.  See the file "LICENSE" for more
+ * information.
  */
 
 /*
@@ -1742,8 +1743,7 @@ static void *read_thread(void *reference)
     * Make sure this loop executes no more than once every 250 miliseconds...
     */
 
-    if ((readstatus != LIBUSB_SUCCESS || rbytes == 0) &&
-        (g.wait_eof || !g.read_thread_stop))
+    if ((g.wait_eof || !g.read_thread_stop))
     {
       gettimeofday(&now, NULL);
       if (timercmp(&now, &end, <))