linux-toradex.git/net/tipc/eth_media.c, branch v3.10.32

tipc: set skb->protocol in eth_media packet transmission

2013-04-17T18:18:33+00:00

The skb->protocol field is used by packet classifiers and for AF_PACKET
cooked format, TIPC needs to set it properly.

Fixes packet classification and ethertype of 0x0000 in cooked captures:

Out 20:c9:d0:43:12:d9 ethertype Unknown (0x0000), length 56:
	0x0000:  5b50 0028 0000 30d4 0100 1000 0100 1001  [P.(..0.........
	0x0010:  0000 03e8 0000 0001 20c9 d043 12d9 0000  ...........C....
	0x0020:  0000 0000 0000 0000                      ........

Signed-off-by: Patrick McHardy 
Signed-off-by: David S. Miller

tipc: move bcast_addr from struct tipc_media to struct tipc_bearer

2013-04-17T18:18:33+00:00

Some network protocols, like InfiniBand, don't have a fixed broadcast
address but one that depends on the configuration. Move the bcast_addr
to struct tipc_bearer and initialize it with the broadcast address of
the network device when the bearer is enabled.

Signed-off-by: Patrick McHardy 
Signed-off-by: David S. Miller

tipc: remove unused str2addr media callback

2013-04-17T18:18:33+00:00

Signed-off-by: Patrick McHardy 
Signed-off-by: David S. Miller

tipc: fix lockdep warning during bearer initialization

2012-08-20T09:26:30+00:00

When the lockdep validator is enabled, it will report the below
warning when we enable a TIPC bearer:

[ INFO: possible irq lock inversion dependency detected ]
---------------------------------------------------------
Possible interrupt unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(ptype_lock);
                                local_irq_disable();
                                lock(tipc_net_lock);
                                lock(ptype_lock);
   
   lock(tipc_net_lock);

  *** DEADLOCK ***

the shortest dependencies between 2nd lock and 1st lock:
  -> (ptype_lock){+.+...} ops: 10 {
[...]
SOFTIRQ-ON-W at:
                      [] __lock_acquire+0x528/0x13e0
                      [] lock_acquire+0x90/0x100
                      [] _raw_spin_lock+0x38/0x50
                      [] dev_add_pack+0x3a/0x60
                      [] arp_init+0x1a/0x48
                      [] inet_init+0x181/0x27e
                      [] do_one_initcall+0x34/0x170
                      [] kernel_init+0x110/0x1b2
                      [] kernel_thread_helper+0x6/0x10
[...]
   ... key      at: [] ptype_lock+0x10/0x20
   ... acquired at:
    [] lock_acquire+0x90/0x100
    [] _raw_spin_lock+0x38/0x50
    [] dev_add_pack+0x3a/0x60
    [] enable_bearer+0xf2/0x140 [tipc]
    [] tipc_enable_bearer+0x1ba/0x450 [tipc]
    [] tipc_cfg_do_cmd+0x5c4/0x830 [tipc]
    [] handle_cmd+0x42/0xd0 [tipc]
    [] genl_rcv_msg+0x232/0x280
    [] netlink_rcv_skb+0x86/0xb0
    [] genl_rcv+0x1c/0x30
    [] netlink_unicast+0x174/0x1f0
    [] netlink_sendmsg+0x1eb/0x2d0
    [] sock_aio_write+0x161/0x170
    [] do_sync_write+0xac/0xf0
    [] vfs_write+0x156/0x170
    [] sys_write+0x42/0x70
    [] sysenter_do_call+0x12/0x38
[...]
}
  -> (tipc_net_lock){+..-..} ops: 4 {
[...]
    IN-SOFTIRQ-R at:
                     [] __lock_acquire+0x64a/0x13e0
                     [] lock_acquire+0x90/0x100
                     [] _raw_read_lock_bh+0x3d/0x50
                     [] tipc_recv_msg+0x1d/0x830 [tipc]
                     [] recv_msg+0x3f/0x50 [tipc]
                     [] __netif_receive_skb+0x22a/0x590
                     [] netif_receive_skb+0x2b/0xf0
                     [] pcnet32_poll+0x292/0x780
                     [] net_rx_action+0xfa/0x1e0
                     [] __do_softirq+0xae/0x1e0
[...]
}

>From the log, we can see three different call chains between
CPU0 and CPU1:

Time 0 on CPU0:

  kernel_init()->inet_init()->dev_add_pack()

At time 0, the ptype_lock is held by CPU0 in dev_add_pack();

Time 1 on CPU1:

  tipc_enable_bearer()->enable_bearer()->dev_add_pack()

At time 1, tipc_enable_bearer() first holds tipc_net_lock, and then
wants to take ptype_lock to register TIPC protocol handler into the
networking stack.  But the ptype_lock has been taken by dev_add_pack()
on CPU0, so at this time the dev_add_pack() running on CPU1 has to be
busy looping.

Time 2 on CPU0:

  netif_receive_skb()->recv_msg()->tipc_recv_msg()

At time 2, an incoming TIPC packet arrives at CPU0, hence
tipc_recv_msg() will be invoked. In tipc_recv_msg(), it first wants
to hold tipc_net_lock.  At the moment, below scenario happens:

On CPU0, below is our sequence of taking locks:

  lock(ptype_lock)->lock(tipc_net_lock)

On CPU1, our sequence of taking locks looks like:

  lock(tipc_net_lock)->lock(ptype_lock)

Obviously deadlock may happen in this case.

But please note the deadlock possibly doesn't occur at all when the
first TIPC bearer is enabled.  Before enable_bearer() -- running on
CPU1 does not hold ptype_lock, so the TIPC receive handler (i.e.
recv_msg()) is not registered successfully via dev_add_pack(), so
the tipc_recv_msg() cannot be called by recv_msg() even if a TIPC
message comes to CPU0. But when the second TIPC bearer is
registered, the deadlock can perhaps really happen.

To fix it, we will push the work of registering TIPC protocol
handler into workqueue context. After the change, both paths taking
ptype_lock are always in process contexts, thus, the deadlock should
never occur.

Signed-off-by: Ying Xue 
Signed-off-by: Jon Maloy 
Signed-off-by: Paul Gortmaker 
Signed-off-by: David S. Miller

tipc: optimize the initialization of network device notifier

2012-08-20T09:26:30+00:00

Ethernet media initialization is only done when TIPC is started or
switched to network mode. So the initialization of the network device
notifier structure can be moved out of this function and done
statically instead.

Signed-off-by: Ying Xue 
Signed-off-by: Jon Maloy 
Signed-off-by: Paul Gortmaker 
Signed-off-by: David S. Miller

tipc: compress out gratuitous extra carriage returns

2012-04-30T19:53:56+00:00

Some of the comment blocks are floating in limbo between two
functions, or between blocks of code.  Delete the extra line
feeds between any comment and its associated following block
of code, to be consistent with the majority of the rest of
the kernel.  Also delete trailing newlines at EOF and fix
a couple trivial typos in existing comments.

This is a 100% cosmetic change with no runtime impact.  We get
rid of over 500 lines of non-code, and being blank line deletes,
they won't even show up as noise in git blame.

Signed-off-by: Paul Gortmaker

tipc: rename struct media to struct tipc_media

2011-12-30T02:53:29+00:00

Give it a meaningful prefix, as suggested by DaveM, so that it
is consistent with things like struct tipc_bearer, and so it isn't
confused with anything else.  This has no impact on the actual
runtime code behaviour.

Signed-off-by: Paul Gortmaker

tipc: Eliminate useless memset operations in Ethernet media support

2011-12-27T16:33:44+00:00

Gets rid of two pointless operations that zero out the array used to
record information about TIPC's Ethernet bearers. There is no need to
initialize the array on start up since it is a global variable that is
already zero'd out, and there is no need to zero it out on exit because
the array is never referenced again.

Signed-off-by: Allan Stephens 
Signed-off-by: Paul Gortmaker

tipc: Do timely cleanup of disabled Ethernet bearer resources

2011-12-27T16:33:42+00:00

Modifies Ethernet bearer disable logic to break the association between
the bearer and its device driver at the time the bearer is disabled,
rather than when the TIPC module is unloaded. This allows the array
entry used by the disabled bearer to be re-used if the same bearer (or
a different one) is subsequently enabled.

Signed-off-by: Allan Stephens 
Signed-off-by: Paul Gortmaker

tipc: Minor optimization to deactivation of Ethernet media suppot

2011-12-27T16:33:41+00:00

Change TIPC's shutdown code to deactivate generic networking support
before terminating Ethernet media support. The deactivation of generic
networking support causes all existing bearers to be destroyed, meaning
the Ethernet media termination routine no longer has to bother marking
them as unavailable.

Signed-off-by: Allan Stephens 
Signed-off-by: Paul Gortmaker