linux.git/net/tipc/ref.c, branch v2.6.36

tipc: fix lockdep warning on address assignment

2010-03-16T21:15:45+00:00

So in the forward porting of various tipc packages, I was constantly
getting this lockdep warning everytime I used tipc-config to set a network
address for the protocol:

[ INFO: possible circular locking dependency detected ]
2.6.33 #1
tipc-config/1326 is trying to acquire lock:
(ref_table_lock){+.-...}, at: [] tipc_ref_discard+0x53/0xd4 [tipc]

but task is already holding lock:
(&(&entry->lock)->rlock#2){+.-...}, at: [] tipc_ref_lock+0x43/0x63 [tipc]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&(&entry->lock)->rlock#2){+.-...}:
[] __lock_acquire+0xb67/0xd0f
[] lock_acquire+0xdc/0x102
[] _raw_spin_lock_bh+0x3b/0x6e
[] tipc_ref_acquire+0xe8/0x11b [tipc]
[] tipc_createport_raw+0x78/0x1b9 [tipc]
[] tipc_createport+0x8b/0x125 [tipc]
[] tipc_subscr_start+0xce/0x126 [tipc]
[] process_signal_queue+0x47/0x7d [tipc]
[] tasklet_action+0x8c/0xf4
[] __do_softirq+0xf8/0x1cd
[] call_softirq+0x1c/0x30
[] _local_bh_enable_ip+0xb8/0xd7
[] local_bh_enable_ip+0xe/0x10
[] _raw_spin_unlock_bh+0x34/0x39
[] spin_unlock_bh.clone.0+0x15/0x17 [tipc]
[] tipc_k_signal+0x8d/0xb1 [tipc]
[] tipc_core_start+0x8a/0xad [tipc]
[] 0xffffffffa01b1087
[] do_one_initcall+0x72/0x18a
[] sys_init_module+0xd8/0x23a
[] system_call_fastpath+0x16/0x1b

-> #0 (ref_table_lock){+.-...}:
[] __lock_acquire+0xa11/0xd0f
[] lock_acquire+0xdc/0x102
[] _raw_write_lock_bh+0x3b/0x6e
[] tipc_ref_discard+0x53/0xd4 [tipc]
[] tipc_deleteport+0x40/0x119 [tipc]
[] release+0xeb/0x137 [tipc]
[] sock_release+0x1f/0x6f
[] sock_close+0x27/0x2b
[] __fput+0x12a/0x1df
[] fput+0x1a/0x1c
[] filp_close+0x68/0x72
[] sys_close+0xad/0xe7
[] system_call_fastpath+0x16/0x1b

Finally decided I should fix this.  Its a straightforward inversion,
tipc_ref_acquire takes two locks in this order:
ref_table_lock
entry->lock

while tipc_deleteport takes them in this order:
entry->lock (via tipc_port_lock())
ref_table_lock (via tipc_ref_discard())

when the same entry is referenced, we get the above warning.  The fix is equally
straightforward.  Theres no real relation between the entry->lock and the
ref_table_lock (they just are needed at the same time), so move the entry->lock
aquisition in tipc_ref_acquire down, after we unlock ref_table_lock (this is
safe since the ref_table_lock guards changes to the reference table, and we've
already claimed a slot there.  I've tested the below fix and confirmed that it
clears up the lockdep issue

Signed-off-by: Neil Horman 
CC: Allan Stephens 
Signed-off-by: David S. Miller

tipc: Eliminate improper use of TIPC_OK error code

2008-07-15T05:44:01+00:00

This patch corrects many places where TIPC routines indicated
successful completion by returning TIPC_OK instead of 0.
(The TIPC_OK symbol has the value 0, but it should only be used
in contexts that deal with the error code field of a TIPC
message header.)

Signed-off-by: Allan Stephens 
Signed-off-by: David S. Miller

tipc: Fix race condition when creating socket or native port

2008-05-12T22:42:28+00:00

This patch eliminates the (very remote) chance of a crash resulting
from a partially initialized socket or native port unexpectedly
receiving a message.  Now, during the creation of a socket or native
port, the underlying generic port's lock is not released until all
initialization required to handle incoming messages has been done.

Signed-off-by: Allan Stephens 
Signed-off-by: David S. Miller

[TIPC]: Cleanup of TIPC reference table code

2008-04-17T01:22:20+00:00

This patch is a largely cosmetic cleanup of the TIPC reference
table code.
- The object reference field in each table entry is now single
  32-bit integer instead of a union of two 32-bit integers.
- Variable naming has been made more consistent.
- Error message output has been made more consistent.
- Useless #includes have been eliminated.

Signed-off-by: Allan Stephens 
Signed-off-by: David S. Miller

[TIPC]: Optimized initialization of TIPC reference table

2008-04-17T01:21:47+00:00

This patch modifies TIPC's reference table code to delay initializing
table entries until they are actually needed by applications.

Signed-off-by: Allan Stephens 
Signed-off-by: David S. Miller

[TIPC]: Remove inlining of reference table locking routines

2008-04-17T01:21:16+00:00

This patch converts the TIPC reference table locking routines
into non-inlined routines, since they are mainly called from
non-performance critical areas of TIPC and the added code
footprint incurred through inlining can no longer be justified.

Signed-off-by: Allan Stephens 
Signed-off-by: David S. Miller

tipc: fix integer as NULL pointer sparse warnings in tipc

2008-02-25T02:38:31+00:00

net/tipc/cluster.c:145:2: warning: Using plain integer as NULL pointer
net/tipc/link.c:3254:36: warning: Using plain integer as NULL pointer
net/tipc/ref.c:151:15: warning: Using plain integer as NULL pointer
net/tipc/zone.c:85:2: warning: Using plain integer as NULL pointer

Signed-off-by: Harvey Harrison 
Signed-off-by: David S. Miller

[NET] TIPC: Fix whitespace errors.

2007-02-11T07:20:15+00:00

Signed-off-by: YOSHIFUJI Hideaki 
Signed-off-by: David S. Miller

[TIPC]: Removing useless casts

2006-07-21T22:52:20+00:00

Removing useless casts

Signed-off-by: Panagiotis Issaris 
Signed-off-by: David S. Miller

[PATCH] spin/rwlock init cleanups

2006-06-28T00:32:39+00:00

locking init cleanups:

 - convert " = SPIN_LOCK_UNLOCKED" to spin_lock_init() or DEFINE_SPINLOCK()
 - convert rwlocks in a similar manner

this patch was generated automatically.

Motivation:

 - cleanliness
 - lockdep needs control of lock initialization, which the open-coded
   variants do not give
 - it's also useful for -rt and for lock debugging in general

Signed-off-by: Ingo Molnar 
Signed-off-by: Arjan van de Ven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds