diff --git a/ChangeLog b/ChangeLog
index 097ef0de1..75fb85a3c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2013-01-07  Colin Watson  <cjwatson@ubuntu.com>
+
+	* grub-core/io/bufio.c (grub_bufio_open): Use grub_zalloc instead of
+	explicitly zeroing elements.
+	* grub-core/io/gzio.c (grub_gzio_open): Likewise.
+	* grub-core/io/lzopio.c (grub_lzopio_open): Remove explicit zeroing
+	of elements in a structure already allocated using grub_zalloc.
+	* grub-core/io/xzio.c (grub_xzio_open): Likewise.
+
 2013-01-07  Colin Watson  <cjwatson@ubuntu.com>
 
 	* docs/grub.texi (grub_cpu): New subsection.
diff --git a/grub-core/io/bufio.c b/grub-core/io/bufio.c
index 2a315e2d8..22438277d 100644
--- a/grub-core/io/bufio.c
+++ b/grub-core/io/bufio.c
@@ -48,7 +48,7 @@ grub_bufio_open (grub_file_t io, int size)
   grub_file_t file;
   grub_bufio_t bufio = 0;
 
-  file = (grub_file_t) grub_malloc (sizeof (*file));
+  file = (grub_file_t) grub_zalloc (sizeof (*file));
   if (! file)
     return 0;
 
@@ -61,7 +61,7 @@ grub_bufio_open (grub_file_t io, int size)
     size = ((io->size > GRUB_BUFIO_MAX_SIZE) ? GRUB_BUFIO_MAX_SIZE :
             io->size);
 
-  bufio = grub_malloc (sizeof (struct grub_bufio) + size);
+  bufio = grub_zalloc (sizeof (struct grub_bufio) + size);
   if (! bufio)
     {
       grub_free (file);
@@ -70,14 +70,10 @@ grub_bufio_open (grub_file_t io, int size)
 
   bufio->file = io;
   bufio->block_size = size;
-  bufio->buffer_len = 0;
-  bufio->buffer_at = 0;
 
   file->device = io->device;
-  file->offset = 0;
   file->size = io->size;
   file->data = bufio;
-  file->read_hook = 0;
   file->fs = &grub_bufio_fs;
   file->not_easily_seekable = io->not_easily_seekable;
 
diff --git a/grub-core/io/gzio.c b/grub-core/io/gzio.c
index 83c0b64cb..59f2206a1 100644
--- a/grub-core/io/gzio.c
+++ b/grub-core/io/gzio.c
@@ -1130,7 +1130,7 @@ grub_gzio_open (grub_file_t io)
   grub_file_t file;
   grub_gzio_t gzio = 0;
 
-  file = (grub_file_t) grub_malloc (sizeof (*file));
+  file = (grub_file_t) grub_zalloc (sizeof (*file));
   if (! file)
     return 0;
 
@@ -1144,9 +1144,7 @@ grub_gzio_open (grub_file_t io)
   gzio->file = io;
 
   file->device = io->device;
-  file->offset = 0;
   file->data = gzio;
-  file->read_hook = 0;
   file->fs = &grub_gzio_fs;
   file->not_easily_seekable = 1;
 
diff --git a/grub-core/io/lzopio.c b/grub-core/io/lzopio.c
index 77291d001..7fdb6d442 100644
--- a/grub-core/io/lzopio.c
+++ b/grub-core/io/lzopio.c
@@ -428,9 +428,7 @@ grub_lzopio_open (grub_file_t io)
   lzopio->file = io;
 
   file->device = io->device;
-  file->offset = 0;
   file->data = lzopio;
-  file->read_hook = 0;
   file->fs = &grub_lzopio_fs;
   file->size = GRUB_FILE_SIZE_UNKNOWN;
   file->not_easily_seekable = 1;
diff --git a/grub-core/io/xzio.c b/grub-core/io/xzio.c
index ae30e6f80..27657d83e 100644
--- a/grub-core/io/xzio.c
+++ b/grub-core/io/xzio.c
@@ -186,12 +186,9 @@ grub_xzio_open (grub_file_t io)
     }
 
   xzio->file = io;
-  xzio->saved_offset = 0;
 
   file->device = io->device;
-  file->offset = 0;
   file->data = xzio;
-  file->read_hook = 0;
   file->fs = &grub_xzio_fs;
   file->size = GRUB_FILE_SIZE_UNKNOWN;
   file->not_easily_seekable = 1;
@@ -210,10 +207,7 @@ grub_xzio_open (grub_file_t io)
     }
 
   xzio->buf.in = xzio->inbuf;
-  xzio->buf.in_pos = 0;
-  xzio->buf.in_size = 0;
   xzio->buf.out = xzio->outbuf;
-  xzio->buf.out_pos = 0;
   xzio->buf.out_size = XZBUFSIZ;
 
   /* FIXME: don't test footer on not easily seekable files.  */