src/patches/suse-2.6.27.39/patches.drivers/cxgb3-get_drvinfo-deadlock.patch

   1 From: Steve Wise <swise@opengridcomputing.com>
   2 Subject: RDMA/cxgb3: deadlock in iw_cxgb3 can cause hang when configuring interface.
   3 References: bnc#430998
   4
   5 When the iw_cxgb3 module's cxgb3_client "add" func gets called by the
   6 cxgb3 module, the iwarp driver ends up calling the ethtool ops get_drvinfo
   7 function in cxgb3 to get the fw version and other info.  Currently the
   8 iwarp driver grabs the rtnl lock around this down call to serialize.
   9 As of 2.6.27 or so, things changed such that the rtnl lock is held around
  10 the call to the netdev driver open function.  Also the cxgb3_client "add"
  11 function doesn't get called if the device is down.
  12
  13 So, if you load cxgb3, then load iw_cxgb3, then ifconfig up the device,
  14 the iw_cxgb3 add func gets called with the rtnl_lock held.   If you
  15 load cxgb3, ifconfig up the device, then load iw_cxgb3, the add func
  16 gets called without the rtnl_lock held.  The former causes the deadlock,
  17 the latter does not.
  18
  19 In addition, there are iw_cxgb3 sysfs handlers that also can call
  20 down into cxgb3 to gather the fw and hw versions.  These can be called
  21 concurrently on different processors and at any time.  Thus we need to
  22 push this serialization down in the cxgb3 driver get_drvinfo func.
  23
  24 The fix is to remove rtnl lock usage, and use a per-device lock in cxgb3.
  25
  26 Signed-off-by: Steve Wise <swise@opengridcomputing.com>
  27 Acked-by: Divy Le Ray <divy@chelsio.com>
  28 Acked-by: John Jolly <jjolly@suse.de>
  29
  30 ---
  31  drivers/infiniband/hw/cxgb3/iwch_provider.c |    6 ------
  32  drivers/net/cxgb3/cxgb3_main.c              |    2 ++
  33  2 files changed, 2 insertions(+), 6 deletions(-)
  34
  35 --- a/drivers/infiniband/hw/cxgb3/iwch_provider.c
  36 +++ b/drivers/infiniband/hw/cxgb3/iwch_provider.c
  37 @@ -1102,9 +1102,7 @@ static u64 fw_vers_string_to_u64(struct
  38         char *cp, *next;
  39         unsigned fw_maj, fw_min, fw_mic;
  40
  41 -       rtnl_lock();
  42         lldev->ethtool_ops->get_drvinfo(lldev, &info);
  43 -       rtnl_unlock();
  44
  45         next = info.fw_version + 1;
  46         cp = strsep(&next, ".");
  47 @@ -1195,9 +1193,7 @@ static ssize_t show_fw_ver(struct device
  48         struct net_device *lldev = iwch_dev->rdev.t3cdev_p->lldev;
  49
  50         PDBG("%s dev 0x%p\n", __func__, dev);
  51 -       rtnl_lock();
  52         lldev->ethtool_ops->get_drvinfo(lldev, &info);
  53 -       rtnl_unlock();
  54         return sprintf(buf, "%s\n", info.fw_version);
  55  }
  56
  57 @@ -1210,9 +1206,7 @@ static ssize_t show_hca(struct device *d
  58         struct net_device *lldev = iwch_dev->rdev.t3cdev_p->lldev;
  59
  60         PDBG("%s dev 0x%p\n", __func__, dev);
  61 -       rtnl_lock();
  62         lldev->ethtool_ops->get_drvinfo(lldev, &info);
  63 -       rtnl_unlock();
  64         return sprintf(buf, "%s\n", info.driver);
  65  }
  66
  67 --- a/drivers/net/cxgb3/cxgb3_main.c
  68 +++ b/drivers/net/cxgb3/cxgb3_main.c
  69 @@ -1298,8 +1298,10 @@ static void get_drvinfo(struct net_devic
  70         u32 fw_vers = 0;
  71         u32 tp_vers = 0;
  72
  73 +       spin_lock(&adapter->stats_lock);
  74         t3_get_fw_version(adapter, &fw_vers);
  75         t3_get_tp_version(adapter, &tp_vers);
  76 +       spin_unlock(&adapter->stats_lock);
  77
  78         strcpy(info->driver, DRV_NAME);
  79         strcpy(info->version, DRV_VERSION);