batman-adv/patches/0038-batman-adv-Introduce-own-OGM2-buffer-mutex.patch

   1 From: Sven Eckelmann <sven@narfation.org>
   2 Date: Sun, 13 Oct 2019 21:03:06 +0200
   3 Subject: batman-adv: Introduce own OGM2 buffer mutex
   4
   5 Only a single function is currently automatically locked by the rtnl_lock
   6 because (unlike B.A.T.M.A.N. IV) the OGM2 buffer is independent of the hard
   7 interfaces on which it will be transmitted. A private mutex can be used
   8 instead to avoid unnecessary delays which would have been introduced by the
   9 global lock.
  10
  11 Signed-off-by: Sven Eckelmann <sven@narfation.org>
  12
  13 Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/8069c581f9097f1f9398f2d49047a1dab8093821
  14
  15 diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c
  16 index a9f949501ff3c354d38e3ad333901310391f27d8..bf9ea404abe7cbe1dd2113881856cd35b718b7d1 100644
  17 --- a/net/batman-adv/bat_v_ogm.c
  18 +++ b/net/batman-adv/bat_v_ogm.c
  19 @@ -29,11 +29,12 @@
  20  #include <linux/kernel.h>
  21  #include <linux/kref.h>
  22  #include <linux/list.h>
  23 +#include <linux/lockdep.h>
  24 +#include <linux/mutex.h>
  25  #include <linux/netdevice.h>
  26  #include <linux/random.h>
  27  #include <linux/rculist.h>
  28  #include <linux/rcupdate.h>
  29 -#include <linux/rtnetlink.h>
  30  #include <linux/skbuff.h>
  31  #include <linux/slab.h>
  32  #include <linux/stddef.h>
  33 @@ -142,7 +143,7 @@ static void batadv_v_ogm_send_softif(struct batadv_priv *bat_priv)
  34         u16 tvlv_len = 0;
  35         int ret;
  36
  37 -       ASSERT_RTNL();
  38 +       lockdep_assert_held(&bat_priv->bat_v.ogm_buff_mutex);
  39
  40         if (atomic_read(&bat_priv->mesh_state) == BATADV_MESH_DEACTIVATING)
  41                 goto out;
  42 @@ -242,11 +243,12 @@ static void batadv_v_ogm_send(struct work_struct *work)
  43         struct batadv_priv_bat_v *bat_v;
  44         struct batadv_priv *bat_priv;
  45
  46 -       rtnl_lock();
  47         bat_v = container_of(work, struct batadv_priv_bat_v, ogm_wq.work);
  48         bat_priv = container_of(bat_v, struct batadv_priv, bat_v);
  49 +
  50 +       mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
  51         batadv_v_ogm_send_softif(bat_priv);
  52 -       rtnl_unlock();
  53 +       mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
  54  }
  55
  56  /**
  57 @@ -275,13 +277,15 @@ void batadv_v_ogm_primary_iface_set(struct batadv_hard_iface *primary_iface)
  58         struct batadv_priv *bat_priv = netdev_priv(primary_iface->soft_iface);
  59         struct batadv_ogm2_packet *ogm_packet;
  60
  61 -       ASSERT_RTNL();
  62 -
  63 +       mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
  64         if (!bat_priv->bat_v.ogm_buff)
  65 -               return;
  66 +               goto unlock;
  67
  68         ogm_packet = (struct batadv_ogm2_packet *)bat_priv->bat_v.ogm_buff;
  69         ether_addr_copy(ogm_packet->orig, primary_iface->net_dev->dev_addr);
  70 +
  71 +unlock:
  72 +       mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
  73  }
  74
  75  /**
  76 @@ -885,8 +889,6 @@ int batadv_v_ogm_init(struct batadv_priv *bat_priv)
  77         unsigned char *ogm_buff;
  78         u32 random_seqno;
  79
  80 -       ASSERT_RTNL();
  81 -
  82         bat_priv->bat_v.ogm_buff_len = BATADV_OGM2_HLEN;
  83         ogm_buff = kzalloc(bat_priv->bat_v.ogm_buff_len, GFP_ATOMIC);
  84         if (!ogm_buff)
  85 @@ -905,6 +907,8 @@ int batadv_v_ogm_init(struct batadv_priv *bat_priv)
  86         atomic_set(&bat_priv->bat_v.ogm_seqno, random_seqno);
  87         INIT_DELAYED_WORK(&bat_priv->bat_v.ogm_wq, batadv_v_ogm_send);
  88
  89 +       mutex_init(&bat_priv->bat_v.ogm_buff_mutex);
  90 +
  91         return 0;
  92  }
  93
  94 @@ -916,7 +920,11 @@ void batadv_v_ogm_free(struct batadv_priv *bat_priv)
  95  {
  96         cancel_delayed_work_sync(&bat_priv->bat_v.ogm_wq);
  97
  98 +       mutex_lock(&bat_priv->bat_v.ogm_buff_mutex);
  99 +
 100         kfree(bat_priv->bat_v.ogm_buff);
 101         bat_priv->bat_v.ogm_buff = NULL;
 102         bat_priv->bat_v.ogm_buff_len = 0;
 103 +
 104 +       mutex_unlock(&bat_priv->bat_v.ogm_buff_mutex);
 105  }
 106 diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
 107 index 49e4e6cb506f192e85e96e8b3e68be3fdc2dca57..44c423447fe163eb3b9df5ec5cf229bed6b8d65b 100644
 108 --- a/net/batman-adv/types.h
 109 +++ b/net/batman-adv/types.h
 110 @@ -28,6 +28,7 @@
 111  #include <linux/compiler.h>
 112  #include <linux/if_ether.h>
 113  #include <linux/kref.h>
 114 +#include <linux/mutex.h>
 115  #include <linux/netdevice.h>
 116  #include <linux/netlink.h>
 117  #include <linux/sched.h> /* for linux/wait.h */
 118 @@ -1479,15 +1480,18 @@ struct batadv_softif_vlan {
 119   * struct batadv_priv_bat_v - B.A.T.M.A.N. V per soft-interface private data
 120   */
 121  struct batadv_priv_bat_v {
 122 -       /** @ogm_buff: buffer holding the OGM packet. rtnl protected */
 123 +       /** @ogm_buff: buffer holding the OGM packet */
 124         unsigned char *ogm_buff;
 125
 126 -       /** @ogm_buff_len: length of the OGM packet buffer. rtnl protected */
 127 +       /** @ogm_buff_len: length of the OGM packet buffer */
 128         int ogm_buff_len;
 129
 130         /** @ogm_seqno: OGM sequence number - used to identify each OGM */
 131         atomic_t ogm_seqno;
 132
 133 +       /** @ogm_buff_mutex: lock protecting ogm_buff and ogm_buff_len */
 134 +       struct mutex ogm_buff_mutex;
 135 +
 136         /** @ogm_wq: workqueue used to schedule OGM transmissions */
 137         struct delayed_work ogm_wq;
 138  };