llcp_sock_getname can be called without a device attached to the nfc_llcp_sock.

This would lead to the following BUG:

[  362.341807] BUG: unable to handle kernel NULL pointer dereference at           (null)
[  362.341815] IP: [<ffffffff836258e5>] llcp_sock_getname+0x75/0xc0
[  362.341818] PGD 31b35067 PUD 30631067 PMD 0
[  362.341821] Oops: 0000 [#627] PREEMPT SMP DEBUG_PAGEALLOC
[  362.341826] CPU 3
[  362.341827] Pid: 7816, comm: trinity-child55 Tainted: G      D W    3.5.0-rc4-next-20120628-sasha-00005-g9f23eb7 #479
[  362.341831] RIP: 0010:[<ffffffff836258e5>]  [<ffffffff836258e5>] llcp_sock_getname+0x75/0xc0
[  362.341832] RSP: 0018:ffff8800304fde88  EFLAGS: 00010286
[  362.341834] RAX: 0000000000000000 RBX: ffff880033cb8000 RCX: 0000000000000001
[  362.341835] RDX: ffff8800304fdec4 RSI: ffff8800304fdec8 RDI: ffff8800304fdeda
[  362.341836] RBP: ffff8800304fdea8 R08: 7ebcebcb772b7ffb R09: 5fbfcb9c35bdfd53
[  362.341838] R10: 4220020c54326244 R11: 0000000000000246 R12: ffff8800304fdec8
[  362.341839] R13: ffff8800304fdec4 R14: ffff8800304fdec8 R15: 0000000000000044
[  362.341841] FS:  00007effa376e700(0000) GS:ffff880035a00000(0000) knlGS:0000000000000000
[  362.341843] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  362.341844] CR2: 0000000000000000 CR3: 0000000030438000 CR4: 00000000000406e0
[  362.341851] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  362.341856] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  362.341858] Process trinity-child55 (pid: 7816, threadinfo ffff8800304fc000, task ffff880031270000)
[  362.341858] Stack:
[  362.341862]  ffff8800304fdea8 ffff880035156780 0000000000000000 0000000000001000
[  362.341865]  ffff8800304fdf78 ffffffff83183b40 00000000304fdec8 0000006000000000
[  362.341868]  ffff8800304f0027 ffffffff83729649 ffff8800304fdee8 ffff8800304fdf48
[  362.341869] Call Trace:
[  362.341874]  [<ffffffff83183b40>] sys_getpeername+0xa0/0x110
[  362.341877]  [<ffffffff83729649>] ? _raw_spin_unlock_irq+0x59/0x80
[  362.341882]  [<ffffffff810f342b>] ? do_setitimer+0x23b/0x290
[  362.341886]  [<ffffffff81985ede>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[  362.341889]  [<ffffffff8372a539>] system_call_fastpath+0x16/0x1b
[  362.341921] Code: 84 00 00 00 00 00 b8 b3 ff ff ff 48 85 db 74 54 66 41 c7 04 24 27 00 49 8d 7c 24 12 41 c7 45 00 60 00 00 00 48 8b 83 28 05 00 00 <8b> 00 41 89 44 24 04 0f b6 83 41 05 00 00 41 88 44 24 10 0f b6
[  362.341924] RIP  [<ffffffff836258e5>] llcp_sock_getname+0x75/0xc0
[  362.341925]  RSP <ffff8800304fde88>
[  362.341926] CR2: 0000000000000000
[  362.341928] ---[ end trace 6d450e935ee18bf3 ]---
Signed-off-by: NSasha Levin <levinsasha928@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

llcp_sock_getname() might get called before the LLCP socket was created.
This condition isn't checked, and llcp_sock_getname will simply deref a
NULL ptr in that case.

This exists starting with d646960f ("NFC: Initial LLCP support").
Signed-off-by: NSasha Levin <levinsasha928@gmail.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Fix the poll mask depending on the socket state. POLLOUT was missing
for example.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Blocking sockets should sleep on a CC (Connection Complete) reception
from the connect() call.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The socket local pointer needs to be set to NULL when the adapter is
removed or the MAC goes down.
If the socket release code is called after such an event, the socket
reference count still needs to be decreased in order for the socket to
eventually be freed.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The parent socket (the bound one) could be freed before its children, so
we should unlink the children without trying to reach it through the parent.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

This patch is an initial implementation for the NFC Logical Link Control
protocol. It's also known as NFC peer to peer mode.
This is a basic implementation as it lacks SDP (services Discovery
Protocol), frames aggregation support, and frame rejecion parsing.
Follow up patches will implement those missing features.
This code has been tested against a Nexus S phone implementing LLCP 1.0.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>