x86: rearrange bus_type parse

[sfrench/cifs-2.6.git] / Documentation / spinlocks.txt

diff --git a/Documentation/spinlocks.txt b/Documentation/spinlocks.txt
index a661d684768e99c2cb9737b1e5f85925554f9235..619699dde5938b64c6d63e1059cf0ed702c128af 100644 (file)
--- a/Documentation/spinlocks.txt
+++ b/Documentation/spinlocks.txt
@@ -1,7 +1,34 @@
-UPDATE March 21 2005 Amit Gud <gud@eth.net>
+SPIN_LOCK_UNLOCKED and RW_LOCK_UNLOCKED defeat lockdep state tracking and
+are hence deprecated.
 
-Macros SPIN_LOCK_UNLOCKED and RW_LOCK_UNLOCKED are deprecated and will be
-removed soon. So for any new code dynamic initialization should be used:
+Please use DEFINE_SPINLOCK()/DEFINE_RWLOCK() or
+__SPIN_LOCK_UNLOCKED()/__RW_LOCK_UNLOCKED() as appropriate for static
+initialization.
+
+Most of the time, you can simply turn:
+
+       static spinlock_t xxx_lock = SPIN_LOCK_UNLOCKED;
+
+into:
+
+       static DEFINE_SPINLOCK(xxx_lock);
+
+Static structure member variables go from:
+
+       struct foo bar {
+               .lock   =       SPIN_LOCK_UNLOCKED;
+       };
+
+to:
+
+       struct foo bar {
+               .lock   =       __SPIN_LOCK_UNLOCKED(bar.lock);
+       };
+
+Declaration of static rw_locks undergo a similar transformation.
+
+Dynamic initialization, when necessary, may be performed as
+demonstrated below.
 
    spinlock_t xxx_lock;
    rwlock_t xxx_rw_lock;
@@ -15,12 +42,9 @@ removed soon. So for any new code dynamic initialization should be used:
 
    module_init(xxx_init);
 
-Reasons for deprecation
-  - it hurts automatic lock validators
-  - it becomes intrusive for the realtime preemption patches
-
-Following discussion is still valid, however, with the dynamic initialization
-of spinlocks instead of static.
+The following discussion is still valid, however, with the dynamic
+initialization of spinlocks or with DEFINE_SPINLOCK, etc., used
+instead of SPIN_LOCK_UNLOCKED.
 
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