releases/3.10.16/hid-uhid-allocate-static-minor.patch

   1 From 19872d20c890073c5207d9e02bb8f14d451a11eb Mon Sep 17 00:00:00 2001
   2 From: David Herrmann <dh.herrmann@gmail.com>
   3 Date: Mon, 9 Sep 2013 18:33:54 +0200
   4 Subject: HID: uhid: allocate static minor
   5
   6 From: David Herrmann <dh.herrmann@gmail.com>
   7
   8 commit 19872d20c890073c5207d9e02bb8f14d451a11eb upstream.
   9
  10 udev has this nice feature of creating "dead" /dev/<node> device-nodes if
  11 it finds a devnode:<node> modalias. Once the node is accessed, the kernel
  12 automatically loads the module that provides the node. However, this
  13 requires udev to know the major:minor code to use for the node. This
  14 feature was introduced by:
  15
  16   commit 578454ff7eab61d13a26b568f99a89a2c9edc881
  17   Author: Kay Sievers <kay.sievers@vrfy.org>
  18   Date:   Thu May 20 18:07:20 2010 +0200
  19
  20       driver core: add devname module aliases to allow module on-demand auto-loading
  21
  22 However, uhid uses dynamic minor numbers so this doesn't actually work. We
  23 need to load uhid to know which minor it's going to use.
  24
  25 Hence, allocate a static minor (just like uinput does) and we're good
  26 to go.
  27
  28 Reported-by: Tom Gundersen <teg@jklm.no>
  29 Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
  30 Signed-off-by: Jiri Kosina <jkosina@suse.cz>
  31 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  32
  33 ---
  34  drivers/hid/uhid.c         |    3 ++-
  35  include/linux/miscdevice.h |    1 +
  36  2 files changed, 3 insertions(+), 1 deletion(-)
  37
  38 --- a/drivers/hid/uhid.c
  39 +++ b/drivers/hid/uhid.c
  40 @@ -640,7 +640,7 @@ static const struct file_operations uhid
  41
  42  static struct miscdevice uhid_misc = {
  43         .fops           = &uhid_fops,
  44 -       .minor          = MISC_DYNAMIC_MINOR,
  45 +       .minor          = UHID_MINOR,
  46         .name           = UHID_NAME,
  47  };
  48
  49 @@ -659,4 +659,5 @@ module_exit(uhid_exit);
  50  MODULE_LICENSE("GPL");
  51  MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
  52  MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
  53 +MODULE_ALIAS_MISCDEV(UHID_MINOR);
  54  MODULE_ALIAS("devname:" UHID_NAME);
  55 --- a/include/linux/miscdevice.h
  56 +++ b/include/linux/miscdevice.h
  57 @@ -45,6 +45,7 @@
  58  #define MAPPER_CTRL_MINOR      236
  59  #define LOOP_CTRL_MINOR                237
  60  #define VHOST_NET_MINOR                238
  61 +#define UHID_MINOR             239
  62  #define MISC_DYNAMIC_MINOR     255
  63
  64  struct device;