tree 20c9c21a2cdfc520c11b972dbfda8df8f30204e8
parent 90e6274d2ecf3bcb44e3727a395e56b7ef467218
author Samuel Ortiz <sameo@linux.intel.com> 1345240074 +0200
committer Samuel Ortiz <sameo@linux.intel.com> 1348525043 +0200

NFC: Queue pn533 commands

Instead of returning EBUSY when getting a command while another one is
running, we queue them. Upon completion of the pending command, the next
one is processed.
Besides the fact that it simplifies the pn533 locking scheme, it also
comes with the nice side effect of fixing the following warning:

[   82.274297] =====================================
[   82.274297] [ BUG: bad unlock balance detected! ]
[   82.274298] 3.5.0-rc1+ #1 Not tainted
[   82.274299] -------------------------------------
[   82.274300] kworker/u:1/16 is trying to release lock (&dev->cmd_lock) at:
[   82.274305] [<ffffffff8144f246>] mutex_unlock+0x9/0xb
[   82.274305] but there are no more locks to release!
[   82.274306]
[   82.274306] other info that might help us debug this:
[   82.274306] 2 locks held by kworker/u:1/16:
[   82.274311]  #0:  (pn533){.+.+..}, at: [<ffffffff8103a67d>]
+process_one_work+0x145/0x2e2
[   82.274314]  #1:  ((&dev->cmd_work)){+.+...}, at: [<ffffffff8103a67d>]
+process_one_work+0x145/0x2e2
[   82.274314]
[   82.274314] stack backtrace:
[   82.274315] Pid: 16, comm: kworker/u:1 Not tainted 3.5.0-rc1+ #1
[   82.274315] Call Trace:
[   82.274317]  [<ffffffff8144f246>] ? mutex_unlock+0x9/0xb
[   82.274321]  [<ffffffff81059841>] print_unlock_inbalance_bug+0xda/0xe4
[   82.274323]  [<ffffffff8105c74c>] lock_release_non_nested+0xb2/0x232
[   82.274325]  [<ffffffff8105a61e>] ? mark_held_locks+0x6d/0x95
[   82.274326]  [<ffffffff8144f246>] ? mutex_unlock+0x9/0xb
[   82.274328]  [<ffffffff81451105>] ? _raw_spin_unlock_irqrestore+0x40/0x5c
[   82.274329]  [<ffffffff8144f246>] ? mutex_unlock+0x9/0xb
[   82.274330]  [<ffffffff8105ca42>] lock_release+0x176/0x1ac
[   82.274333]  [<ffffffff8123de14>] ? pn533_send_complete+0xa8/0xa8
[   82.274334]  [<ffffffff8144f1d6>] __mutex_unlock_slowpath+0xb0/0x117
[   82.274336]  [<ffffffff8144f246>] mutex_unlock+0x9/0xb
[   82.274337]  [<ffffffff8123de65>] pn533_wq_cmd_complete+0x51/0x55
[   82.274338]  [<ffffffff8103a6db>] process_one_work+0x1a3/0x2e2
[   82.274340]  [<ffffffff8103a67d>] ? process_one_work+0x145/0x2e2
[   82.274341]  [<ffffffff8103b119>] worker_thread+0xcf/0x153
[   82.274343]  [<ffffffff8103b04a>] ? manage_workers.isra.22+0x16b/0x16b
[   82.274344]  [<ffffffff8103b04a>] ? manage_workers.isra.22+0x16b/0x16b
[   82.274346]  [<ffffffff8103eb11>] kthread+0x95/0x9d
[   82.274348]  [<ffffffff81452ef4>] kernel_thread_helper+0x4/0x10
[   82.274351]  [<ffffffff81046561>] ? finish_task_switch+0x45/0xc3
[   82.274352]  [<ffffffff814514f0>] ? retint_restore_args+0x13/0x13
[   82.274353]  [<ffffffff8103ea7c>] ? __init_kthread_worker+0x55/0x55
[   82.274354]  [<ffffffff81452ef0>] ? gs_change+0x13/0x13

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>