Merge 10.3 into 10.4

4 files changed, 24 insertions, 4 deletions

diff --git a/mysys/CMakeLists.txt b/mysys/CMakeLists.txt
index 93fca192b3a..97890cc9de7 100644
--- a/mysys/CMakeLists.txt
+++ b/mysys/CMakeLists.txt
@@ -1,4 +1,5 @@
 # Copyright (c) 2006, 2014, Oracle and/or its affiliates
+# Copyright (c) 2009, 2018, MariaDB Corporation
 # 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
diff --git a/mysys/mf_iocache.c b/mysys/mf_iocache.c
index 88678949e94..0f93b2303b3 100644
--- a/mysys/mf_iocache.c
+++ b/mysys/mf_iocache.c
@@ -354,6 +354,15 @@ int init_slave_io_cache(IO_CACHE *master, IO_CACHE *slave)
 
 void end_slave_io_cache(IO_CACHE *cache)
 {
+  /* Remove the cache from the next_file_user circular linked list. */
+  if (cache->next_file_user != cache)
+  {
+    IO_CACHE *p= cache->next_file_user;
+    while (p->next_file_user != cache)
+      p= p->next_file_user;
+    p->next_file_user= cache->next_file_user;
+
+  }
   my_free(cache->buffer);
 }
 
@@ -635,7 +644,7 @@ int _my_b_write(IO_CACHE *info, const uchar *Buffer, size_t Count)
 
 int _my_b_cache_read(IO_CACHE *info, uchar *Buffer, size_t Count)
 {
-  size_t length, diff_length, left_length= 0, max_length;
+  size_t length= 0, diff_length, left_length= 0, max_length;
   my_off_t pos_in_file;
   DBUG_ENTER("_my_b_cache_read");
 
@@ -751,7 +760,10 @@ int _my_b_cache_read(IO_CACHE *info, uchar *Buffer, size_t Count)
     else
     {
       info->error= 0;
-      DBUG_RETURN(0);                           /* EOF */
+      if (length == 0)                            /* nothing was read */
+        DBUG_RETURN(0);                           /* EOF */
+
+      length= 0;                       /* non-zero size read was done */
     }
   }
   else 
diff --git a/mysys/mf_iocache2.c b/mysys/mf_iocache2.c
index ef163ee24d3..2bb36129c91 100644
--- a/mysys/mf_iocache2.c
+++ b/mysys/mf_iocache2.c
@@ -1,4 +1,5 @@
-/* Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
+/* Copyright (c) 2000, 2018, Oracle and/or its affiliates.
+   Copyright (c) 2009, 2018, MariaDB Corporation
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -486,4 +487,3 @@ process_flags:
 err:
   return (size_t) -1;
 }
-
diff --git a/mysys/ptr_cmp.c b/mysys/ptr_cmp.c
index 1880e60a811..99c7df69b1d 100644
--- a/mysys/ptr_cmp.c
+++ b/mysys/ptr_cmp.c
@@ -61,9 +61,16 @@ static int ptr_compare_0(size_t *compare_length, uchar **a, uchar **b);
 static int ptr_compare_1(size_t *compare_length, uchar **a, uchar **b);
 static int ptr_compare_2(size_t *compare_length, uchar **a, uchar **b);
 static int ptr_compare_3(size_t *compare_length, uchar **a, uchar **b);
+static int degenerate_compare_func(size_t *compare_length, uchar **a, uchar **b)
+{
+  DBUG_ASSERT(*compare_length == 0);
+  return 0;
+}
 
 qsort2_cmp get_ptr_compare (size_t size)
 {
+  if (size == 0)
+    return (qsort2_cmp) degenerate_compare_func;
   if (size < 4)
     return (qsort2_cmp) ptr_compare;
   switch (size & 3) {