[Bluetooth] Restrict well known PSM to privileged users

[pandora-kernel.git] / kernel / rtmutex.c

diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index d2ef13b..4ab17da 100644 (file)
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -7,6 +7,8 @@
  *  Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
  *  Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt
  *  Copyright (C) 2006 Esben Nielsen
+ *
+ *  See Documentation/rt-mutex-design.txt for details.
  */
 #include <linux/spinlock.h>
 #include <linux/module.h>
@@ -249,6 +251,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
 
        /* Grab the next task */
        task = rt_mutex_owner(lock);
+       get_task_struct(task);
        spin_lock_irqsave(&task->pi_lock, flags);
 
        if (waiter == rt_mutex_top_waiter(lock)) {
@@ -267,7 +270,6 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
                __rt_mutex_adjust_prio(task);
        }
 
-       get_task_struct(task);
        spin_unlock_irqrestore(&task->pi_lock, flags);
 
        top_waiter = rt_mutex_top_waiter(lock);
@@ -407,7 +409,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
        struct task_struct *owner = rt_mutex_owner(lock);
        struct rt_mutex_waiter *top_waiter = waiter;
        unsigned long flags;
-       int boost = 0, res;
+       int chain_walk = 0, res;
 
        spin_lock_irqsave(&current->pi_lock, flags);
        __rt_mutex_adjust_prio(current);
@@ -431,25 +433,23 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
                plist_add(&waiter->pi_list_entry, &owner->pi_waiters);
 
                __rt_mutex_adjust_prio(owner);
-               if (owner->pi_blocked_on) {
-                       boost = 1;
-                       /* gets dropped in rt_mutex_adjust_prio_chain()! */
-                       get_task_struct(owner);
-               }
-               spin_unlock_irqrestore(&owner->pi_lock, flags);
-       }
-       else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock)) {
-               spin_lock_irqsave(&owner->pi_lock, flags);
-               if (owner->pi_blocked_on) {
-                       boost = 1;
-                       /* gets dropped in rt_mutex_adjust_prio_chain()! */
-                       get_task_struct(owner);
-               }
+               if (owner->pi_blocked_on)
+                       chain_walk = 1;
                spin_unlock_irqrestore(&owner->pi_lock, flags);
        }
-       if (!boost)
+       else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock))
+               chain_walk = 1;
+
+       if (!chain_walk)
                return 0;
 
+       /*
+        * The owner can't disappear while holding a lock,
+        * so the owner struct is protected by wait_lock.
+        * Gets dropped in rt_mutex_adjust_prio_chain()!
+        */
+       get_task_struct(owner);
+
        spin_unlock(&lock->wait_lock);
 
        res = rt_mutex_adjust_prio_chain(owner, detect_deadlock, lock, waiter,
@@ -530,7 +530,7 @@ static void remove_waiter(struct rt_mutex *lock,
        int first = (waiter == rt_mutex_top_waiter(lock));
        struct task_struct *owner = rt_mutex_owner(lock);
        unsigned long flags;
-       int boost = 0;
+       int chain_walk = 0;
 
        spin_lock_irqsave(&current->pi_lock, flags);
        plist_del(&waiter->list_entry, &lock->wait_list);
@@ -552,19 +552,20 @@ static void remove_waiter(struct rt_mutex *lock,
                }
                __rt_mutex_adjust_prio(owner);
 
-               if (owner->pi_blocked_on) {
-                       boost = 1;
-                       /* gets dropped in rt_mutex_adjust_prio_chain()! */
-                       get_task_struct(owner);
-               }
+               if (owner->pi_blocked_on)
+                       chain_walk = 1;
+
                spin_unlock_irqrestore(&owner->pi_lock, flags);
        }
 
        WARN_ON(!plist_node_empty(&waiter->pi_list_entry));
 
-       if (!boost)
+       if (!chain_walk)
                return;
 
+       /* gets dropped in rt_mutex_adjust_prio_chain()! */
+       get_task_struct(owner);
+
        spin_unlock(&lock->wait_lock);
 
        rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current);
@@ -590,10 +591,10 @@ void rt_mutex_adjust_pi(struct task_struct *task)
                return;
        }
 
-       /* gets dropped in rt_mutex_adjust_prio_chain()! */
-       get_task_struct(task);
        spin_unlock_irqrestore(&task->pi_lock, flags);
 
+       /* gets dropped in rt_mutex_adjust_prio_chain()! */
+       get_task_struct(task);
        rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
 }