batman-adv/patches/0008-batman-adv-Fix-debugfs-path-for-renamed-hardif.patch

   1 From: Sven Eckelmann <sven@narfation.org>
   2 Date: Fri, 1 Jun 2018 19:24:23 +0200
   3 Subject: [PATCH] batman-adv: Fix debugfs path for renamed hardif
   4
   5 batman-adv is creating special debugfs directories in the init
   6 net_namespace for each valid hard-interface (net_device). But it is
   7 possible to rename a net_device to a completely different name then the
   8 original one.
   9
  10 It can therefore happen that a user registers a new net_device which gets
  11 the name "wlan0" assigned by default. batman-adv is also adding a new
  12 directory under $debugfs/batman-adv/ with the name "wlan0".
  13
  14 The user then decides to rename this device to "wl_pri" and registers a
  15 different device. The kernel may now decide to use the name "wlan0" again
  16 for this new device. batman-adv will detect it as a valid net_device and
  17 tries to create a directory with the name "wlan0" under
  18 $debugfs/batman-adv/. But there already exists one with this name under
  19 this path and thus this fails. batman-adv will detect a problem and
  20 rollback the registering of this device.
  21
  22 batman-adv must therefore take care of renaming the debugfs directories
  23 for hard-interfaces whenever it detects such a net_device rename.
  24
  25 Fixes: 3c926a01c8e8 ("batman-adv: add debugfs structure for information per interface")
  26 Reported-by: John Soros <sorosj@gmail.com>
  27 Signed-off-by: Sven Eckelmann <sven@narfation.org>
  28
  29 Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/127086f503f6495518b95455efebee33d328f335
  30 ---
  31  net/batman-adv/debugfs.c        | 20 ++++++++++++++++++++
  32  net/batman-adv/debugfs.h        |  6 ++++++
  33  net/batman-adv/hard-interface.c |  3 +++
  34  3 files changed, 29 insertions(+)
  35
  36 diff --git a/net/batman-adv/debugfs.c b/net/batman-adv/debugfs.c
  37 index 4229b01ac7b54008e023df0ed6546a6d541498ba..7e5de7b9f6d53b846cebfa95bf694a20c640b2d6 100644
  38 --- a/net/batman-adv/debugfs.c
  39 +++ b/net/batman-adv/debugfs.c
  40 @@ -19,6 +19,7 @@
  41  #include "debugfs.h"
  42  #include "main.h"
  43
  44 +#include <linux/dcache.h>
  45  #include <linux/debugfs.h>
  46  #include <linux/err.h>
  47  #include <linux/errno.h>
  48 @@ -343,6 +344,25 @@ int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface)
  49         return -ENOMEM;
  50  }
  51
  52 +/**
  53 + * batadv_debugfs_rename_hardif() - Fix debugfs path for renamed hardif
  54 + * @hard_iface: hard interface which was renamed
  55 + */
  56 +void batadv_debugfs_rename_hardif(struct batadv_hard_iface *hard_iface)
  57 +{
  58 +       const char *name = hard_iface->net_dev->name;
  59 +       struct dentry *dir;
  60 +       struct dentry *d;
  61 +
  62 +       dir = hard_iface->debug_dir;
  63 +       if (!dir)
  64 +               return;
  65 +
  66 +       d = debugfs_rename(dir->d_parent, dir, dir->d_parent, name);
  67 +       if (!d)
  68 +               pr_err("Can't rename debugfs dir to %s\n", name);
  69 +}
  70 +
  71  /**
  72   * batadv_debugfs_del_hardif() - delete the base directory for a hard interface
  73   *  in debugfs.
  74 diff --git a/net/batman-adv/debugfs.h b/net/batman-adv/debugfs.h
  75 index 37b069698b04b369e68e4e8a31c3ac01575b0178..8538a7a75e937f50f8efdbf2fe879b4ac8dafadb 100644
  76 --- a/net/batman-adv/debugfs.h
  77 +++ b/net/batman-adv/debugfs.h
  78 @@ -32,6 +32,7 @@ void batadv_debugfs_destroy(void);
  79  int batadv_debugfs_add_meshif(struct net_device *dev);
  80  void batadv_debugfs_del_meshif(struct net_device *dev);
  81  int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface);
  82 +void batadv_debugfs_rename_hardif(struct batadv_hard_iface *hard_iface);
  83  void batadv_debugfs_del_hardif(struct batadv_hard_iface *hard_iface);
  84
  85  #else
  86 @@ -59,6 +60,11 @@ int batadv_debugfs_add_hardif(struct batadv_hard_iface *hard_iface)
  87         return 0;
  88  }
  89
  90 +static inline
  91 +void batadv_debugfs_rename_hardif(struct batadv_hard_iface *hard_iface)
  92 +{
  93 +}
  94 +
  95  static inline
  96  void batadv_debugfs_del_hardif(struct batadv_hard_iface *hard_iface)
  97  {
  98 diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
  99 index c405d15befd60bdabf9f50813c3bee446238d539..dc2763b1110727cc5dee62d555dd7c7b50f3b463 100644
 100 --- a/net/batman-adv/hard-interface.c
 101 +++ b/net/batman-adv/hard-interface.c
 102 @@ -1051,6 +1051,9 @@ static int batadv_hard_if_event(struct notifier_block *this,
 103                 if (batadv_is_wifi_hardif(hard_iface))
 104                         hard_iface->num_bcasts = BATADV_NUM_BCASTS_WIRELESS;
 105                 break;
 106 +       case NETDEV_CHANGENAME:
 107 +               batadv_debugfs_rename_hardif(hard_iface);
 108 +               break;
 109         default:
 110                 break;
 111         }